NATURAL RESOURCES

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Table of Contents

Scope of this document

Syllabus

Concept Map

Theme Plan

Curricular Objectives

Introduction

Classification of Resources

Water resources

Land Resources

Soil Resources

Forest and Deforestation

Wind

Solar energy

Mineral Resources

Power Resource

Metallic Resources

Natural Resources. Connecting to local

Illegal Mining In Karnataka:

Activities:












Scope of this document

The following note is a background document for teachers. It summarises the things we will need to know. This note is meant to be a ready reference for the teacher to develop the concepts in natural resources from Class 6 onwards to Class 10.

This document attempts to cover all the topics identified in the concept map. To plan the actual lessons, the teacher must use this in connection with the theme plan.

Syllabus

Please see the complete syllabus on the website for details.

Class 8

Natural Resources

1. Scarcity of Resources

2. Exhaustible and Non-exhaustible resources

3. Deforestation and Desertification

4. Carrying Capacity and Climate


Concept Map



Theme Plan


THEME PLAN FOR THE TOPIC NATURAL RESOURCES


CLASS

SUBTOPIC

CONCEPT
DEVELOPMENT

KNOWLEDGE

SKILL

ACTIVITY

6 to 10

Introduction, meaning and types of resources

What is resources and what are their types

students learn the meaning and types of resources

Comprehending a video and listing the resources and grouping them

Activity-1 (Make the students to understand what are resources and their different types.) Activity-2 (Students Watch video and Identify and make list of the resources)


Classification of the natural resources- Exhaustible resources and Non-Exhaustible resources

What is Exhaustible and non exhaustible resources

Students learn the different types of natural resources

Identifying , Classifying, Analysing the natural resourses

Activity-3 (To Classify the natural resources as exhaustible and Non-exhaustible resources.)


Non-Exhaustible resources-1.Water- Sources, Pollution,Irrigation Conservation

Understanding the importance of water, the kinds of water resources, Ways of water pollution and the method of conservation of water, types of irrigation

Students describe the water resources ,know about water pollution, uses, water harvesting and follow the different ways of conservation of water and explain the types of irrigation and its uses.

Comprehending the video , Observation, Listing , identifying and visiting people

Activity-4 (Students Watch video and understand, write how water harvesting is done. ) Activity 5 (Survey of water resources, uses, pollution ,water harvesting) Activity 6 (Study of irrigation system practiced in the village)


2. Land resources- Distribution, Uses

Uses of land and its impact

Recognizing the topography of the earth and distribution of land. Describing the uses of mountains, plateaus, human activities etc.

Observation and understanding of video, Drawing map, Anaylising, Writing, Comparing different types of earth's surface.

Activity-7 (video on earth core) Activity 8 (To make the students to recognize and write about the different land resources and their uses ) Acitivity 9 (Watch and list the land resources)


3. Soil Resources - Composition, Structure, profile, Clasification, erosion and conservation of soil . Cultivation of different crops in different soil.

our duty in conservation of soil and preventing soil erosion

Identifying the different types of soil, Knowing the methods of conservation , soil errosion and about the structure of soil. Listing different crops grows in different soil.

Observation, survey of the soil of the village, Drawing soil profile, Clasifying and Analyising the soil

Activity-10 (Essay writing) Activity 11 (Identifying , collecting the resources and Listing their uses.)


4.Forest Resources- types,Deforestation, and Concervation of forests and its importance, Carrying capacity and climatic change- effects of Desertification

Importance of forests and problems of Deforestation

Recognising the types of forests, learn the importance of forests, growing trees and effect of desforestation,anylising the carrying capacity of their own village,

Observation of the picturesof the uses of forests , Anaylising it, Writing essay, Comparing different types of forests

Activity-12 (Listing the uses of forest and effect of cutting trees) Activity 13 (Study of Comparision of the enviromental situation since 2o years.)


5. Wind resources- Meaning, types and uses

Understanding the meaning types and uses of wind resources

Meaning, types and uses of wind resources

Observation of the video of windmill, Comparing diiferent types of wind

Activity-14 (To know the importance of windmill.)


6. Solar energy- Meaning and its uses.

Know the meaning of Solar energy, its uses and minimise the use of electricity

Knowing the Uses of Solar system, Locating Solar powerstations on the map,and how electricity can be saved through the use of solar energy.

Survey and Listing of solar systems, Critical Analysis of its use and

Activity-15 (Survey of the houses using solar energy)


Exhuastible Resources- MINERALS 1 Metalic eg:- Iron ore Manganese , Nickel 2. Non-metalic. Eg:- Sulphur, Mica

uses and the need of minimising their use.

Identify the metalic and non-metalic minerals and list their uses and know about their availability.

Observation, Classification of minerals, Locating the places of availability in the map o of India and world

Activity-16 (Make the students to under stand what are metallic and non metallic resources) Activity 17 (Make the students to know the availability of minerals )


Current affairs, problems and challanges

Importance of conservation of natural resources. Understand the current problems and their reasons related to natural resources in India especially the local problems and their remidies.

Understand the current problems and their reasons related to natural resources in India especially the local problems and their remidies.

Listing the problem of different natural resources, Discussing about conservation Observation of video, pictures, paper cuttings, on present problems, Crtical Analysis of the resources.

Activity-19 (Conducting Debate) Activity 20 (Through the video making the students to know and understand the present problems of resources in Karnataka)

Curricular Objectives

  1. To understand the scarcity of resources

  2. To enable the students to analyse the resource capacity of their village

  3. Make the students ppriciate the need of conservation of natural resources

  4. To learn about the alternative use of resources.

  5. To enable the students to list the different types and their use.

  6. To develop the skill of discussing, grouping, critical thinking etc. T

  7. To introduce the concept of intergenerational equlity of utilization of resources.

Introduction

Natural resources occur naturally within environments that exist relatively undisturbed by mankind, in a natural form. A natural resource is often characterized by amounts of biodiversity and geodiversity existent in various ecosystems.

Natural resources are derived from the environment. Many of them are essential for our survival while others are used for satisfying our wants. Natural resources may be further classified in different ways.

Classification of Resources

On the basis of origin, resources may be divided into:

Considering their stage of development, natural resources may be referred to in the following ways:

With respect to renewability, natural resources can be categorized as follows:

On the basis of availability, natural resources can be categorised as follows:

On the basis of distribution, natural resources can be classified as follows:

Examples

Some examples of natural resources include the following:

Management of Resources

Natural resource management is a discipline in the management of natural resources such as land, water, soil, plants and animals, with a particular focus on how management affects the quality of life for both present and future generations. Natural resource management is interrelated with the concept of sustainable development, a principle that forms a basis for land management and environmental governance throughout the world.

In contrast to the policy emphases of urban planning and the broader concept of environmental management, Natural resource management specifically focuses on a scientific and technical understanding of resources and ecology and the life-supporting capacity of those resources.

Depletion of Resources

In recent years, the depletion of natural resources and attempts to move to sustainable development has been a major focus of development agencies. This is a particular concern in rain forest regions, which hold most of the Earth's natural biodiversity - irreplaceable genetic natural capital[energy conservation] of natural resources is the major focus of natural capitalism, environmentalism, the ecology movement, and green politics. Some view this depletion as a major source of social unrest and conflicts in developing nations.

Mining, petroleum extraction, fishing, hunting, and forestry are generally considered natural-resource industries. Agriculture is considered a man-made resource. Theodore Roosevelt, a well-known conservationist and former United States president, was opposed to unregulated natural resource extraction. The term is defined by the United States Geological Survey as "The Nation's natural resources include its minerals, energy, land, water, and biota."[4]

Protection of Resources

See also: Environmental protection

The conservation of natural resources is the fundamental problem. Unless we solve that problem, it will avail us little to solve all others.

Theodore Roosevelt[

Conservation biology is the scientific study of the nature and status of Earth's biodiversity with the aim of protecting species, their habitats, and ecosystems from excessive rates of extinction.[6][7] It is an interdisciplinary subject drawing on sciences, economics, and the practice of natural resource management.[8][9][10][11] The term conservation biology was introduced as the title of a conference held University of California at San Diego in La Jolla, California in 1978 organized by biologists Bruce Wilcox and Michael Soulé.

Habitat conservation is a land management practice that seeks to conserve, protect and restore, habitat areas for wild plants and animals, especially conservation reliant species, and prevent their extinction, fragmentation or reduction in range.[12]

Water resources



Water is a precious resource that needs to be conserved at all costs. Rainwater harvesting is one such system that involves collection of water that would otherwise have gone wasted down the drains. This system of water aids in collection of water that would have gone into the ground or lost due to evaporation.

Water resources are sources of water that are useful or potentially useful. Uses of water include agricultural, industrial, household, recreational and environmental activities. Virtually all of these human uses require fresh water.

The topography of the city makes it necessary to opt for different systems of rainwater harvesting systems at different locations, be it the sandy stretches of Besant Nagar, Thiruvalluvar Nagar and Valmiki Nagar or rocky areas of Guindy, Velachery and Adambakkam.

Fresh water is a renewable resource, yet the world's supply of clean, fresh water is steadily decreasing. Water demand already exceeds supply in many parts of the world and as the world population continues to rise, so too does the water demand. Awareness of the global importance of preserving water for ecosystem services has only recently emerged as, during the 20th century, more than half the world’s wetlands have been lost along with their valuable environmental services. Biodiversity-rich freshwater ecosystems are currently declining faster than marine or land ecosystems.[3] The framework for allocating water resources to water users (where such a framework exists) is known as water rights.

Surface water

Surface water is water in a river, lake or fresh water wetland. Surface water is naturally replenished by precipitation and naturally lost through discharge to the oceans, evaporation, evapotranspiration and sub-surface seepage.

Although the only natural input to any surface water system is precipitation within its watershed, the total quantity of water in that system at any given time is also dependent on many other factors. These factors include storage capacity in lakes, wetlands and artificial reservoirs, the permeability of the soil beneath these storage bodies, the runoff characteristics of the land in the watershed, the timing of the precipitation and local evaporation rates. All of these factors also affect the proportions of water lost.

Human activities can have a large and sometimes devastating impact on these factors. Humans often increase storage capacity by constructing reservoirs and decrease it by draining wetlands. Humans often increase runoff quantities and velocities by paving areas and channelizing stream flow.

The total quantity of water available at any given time is an important consideration. Some human water users have an intermittent need for water. For example, many farms require large quantities of water in the spring, and no water at all in the winter. To supply such a farm with water, a surface water system may require a large storage capacity to collect water throughout the year and release it in a short period of time. Other users have a continuous need for water, such as a power plant that requires water for cooling. To supply such a power plant with water, a surface water system only needs enough storage capacity to fill in when average stream flow is below the power plant's need.

Nevertheless, over the long term the average rate of precipitation within a watershed is the upper bound for average consumption of natural surface water from that watershed.

Natural surface water can be augmented by importing surface water from another watershed through a canal or pipeline. It can also be artificially augmented from any of the other sources listed here, however in practice the quantities are negligible. Humans can also cause surface water to be "lost" (i.e. become unusable) through pollution.

Brazil is the country estimated to have the largest supply of fresh water in the world, followed by Russia and Canada.[4]

Under river flow

Throughout the course of the river, the total volume of water transported downstream will often be a combination of the visible free water flow together with a substantial contribution flowing through sub-surface rocks and gravels that underlie the river and its floodplain called the hyporheic zone. For many rivers in large valleys, this unseen component of flow may greatly exceed the visible flow. The hyporheic zone often forms a dynamic interface between surface water and true ground-water receiving water from the ground water when aquifers are fully charged and contributing water to ground-water when ground waters are depleted. This is especially significant in karst areas where pot-holes and underground rivers are common.

Ground water

Main article: Groundwater

Sub-Surface water travel time

Shipot, a common water source in Ukrainian villages

Sub-surface water, or groundwater, is fresh water located in the pore space of soil and rocks. It is also water that is flowing within aquifers below the water table. Sometimes it is useful to make a distinction between sub-surface water that is closely associated with surface water and deep sub-surface water in an aquifer (sometimes called "fossil water").

Sub-surface water can be thought of in the same terms as surface water: inputs, outputs and storage. The critical difference is that due to its slow rate of turnover, sub-surface water storage is generally much larger compared to inputs than it is for surface water. This difference makes it easy for humans to use sub-surface water unsustainably for a long time without severe consequences. Nevertheless, over the long term the average rate of seepage above a sub-surface water source is the upper bound for average consumption of water from that source.

The natural input to sub-surface water is seepage from surface water. The natural outputs from sub-surface water are springs and seepage to the oceans.

If the surface water source is also subject to substantial evaporation, a sub-surface water source may become saline. This situation can occur naturally under endorheic bodies of water, or artificially under irrigated farmland. In coastal areas, human use of a sub-surface water source may cause the direction of seepage to ocean to reverse which can also cause soil salinization. Humans can also cause sub-surface water to be "lost" (i.e. become unusable) through pollution. Humans can increase the input to a sub-surface water source by building reservoirs or detention ponds.

Desalination

Desalination is an artificial process by which saline water (generally sea water) is converted to fresh water. The most common desalination processes are distillation and reverse osmosis. Desalination is currently expensive compared to most alternative sources of water, and only a very small fraction of total human use is satisfied by desalination. It is only economically practical for high-valued uses (such as household and industrial uses) in arid areas. The most extensive use is in the Persian Gulf.

Frozen water

An iceberg as seen from Newfoundland

Several schemes have been proposed to make use of icebergs as a water source, however to date this has only been done for novelty purposes. Glacier runoff is considered to be surface water.

The Himalayas, which are often called "The Roof of the World", contain some of the most extensive and rough high altitude areas on Earth as well as the greatest area of glaciers and permafrost outside of the poles. Ten of Asia’s largest rivers flow from there, and more than a billion people’s livelihoods depend on them. To complicate matters, temperatures are rising more rapidly here than the global average. In Nepal the temperature has risen with 0.6 degree over the last decade, whereas the global warming has been around 0.7 over the last hundred years.[5]

Uses of fresh water

Uses of fresh water can be categorized as consumptive and non-consumptive (sometimes called "renewable"). A use of water is consumptive if that water is not immediately available for another use. Losses to sub-surface seepage and evaporation are considered consumptive, as is water incorporated into a product (such as farm produce). Water that can be treated and returned as surface water, such as sewage, is generally considered non-consumptive if that water can be put to additional use. Water use in power generation and industry is generally described using an alternate terminology, focusing on separate measurements of withdrawal and consumption. Withdrawal describes the removal of water from the environment, while consumption describes the conversion of fresh water into some other form, such as atmospheric water vapor or contaminated waste water

Agricultural

A farm in Ontario

It is estimated that 69% of worldwide water use is for irrigation, with 15-35% of irrigation withdrawals being unsustainable.[6] It takes around 3,000 litres of water, converted from liquid to vapour, to produce enough food to satisfy one person's daily dietary need. This is a considerable amount, when compared to that required for drinking, which is between two and five litres. To produce food for the 6.5 billion or so people who inhabit the planet today requires the water that would fill a canal ten metres deep, 100 metres wide and 7.1 million kilometres long – that's enough to circle the globe 180 times.

Increasing water scarcity

Fifty years ago, the common perception was that water was an infinite resource. At this time, there were fewer than half the current number of people on the planet. People were not as wealthy as today, consumed fewer calories and ate less meat, so less water was needed to produce their food. They required a third of the volume of water we presently take from rivers. Today, the competition for water resources is much more intense. This is because there are now nearly seven billion people on the planet, their consumption of water-thirsty meat and vegetables is rising, and there is increasing competition for water from industry, urbanisation and biofuel crops. In future, even more water will be needed to produce food because the Earth's population is forecast to rise to 9 billion by 2050.[7] An additional 2.5 or 3 billion people, choosing to eat fewer cereals and more meat and vegetables could add an additional five million kilometres to the virtual canal mentioned above.

An assessment of water management in agriculture was conducted in 2007 by the International Water Management Institute in Sri Lanka to see if the world had sufficient water to provide food for its growing population.[8] It assessed the current availability of water for agriculture on a global scale and mapped out locations suffering from water scarcity. It found that a fifth of the world's people, more than 1.2 billion, live in areas of physical water scarcity, where there is not enough water to meet all demands. A further 1.6 billion people live in areas experiencing economic water scarcity, where the lack of investment in water or insufficient human capacity make it impossible for authorities to satisfy the demand for water. The report found that it would be possible to produce the food required in future, but that continuation of today's food production and environmental trends would lead to crises in many parts of the world. To avoid a global water crisis, farmers will have to strive to increase productivity to meet growing demands for food, while industry and cities find ways to use water more efficiently.[9]

In some areas of the world irrigation is necessary to grow any crop at all, in other areas it permits more profitable crops to be grown or enhances crop yield. Various irrigation methods involve different trade-offs between crop yield, water consumption and capital cost of equipment and structures. Irrigation methods such as furrow and overhead sprinkler irrigation are usually less expensive but are also typically less efficient, because much of the water evaporates, runs off or drains below the root zone. Other irrigation methods considered to be more efficient include drip or trickle irrigation, surge irrigation, and some types of sprinkler systems where the sprinklers are operated near ground level. These types of systems, while more expensive, usually offer greater potential to minimize runoff, drainage and evaporation. Any system that is improperly managed can be wasteful, all methods have the potential for high efficiencies under suitable conditions, appropriate irrigation timing and management. Some issues that are often insufficiently considered are salinization of sub-surface water and contaminant accumulation leading to water quality declines.

As global populations grow, and as demand for food increases in a world with a fixed water supply, there are efforts under way to learn how to produce more food with less water, through improvements in irrigation[10] methods[11] and technologies, agricultural water management, crop types, and water monitoring. Aquaculture is a small but growing agricultural use of water. Freshwater commercial fisheries may also be considered as agricultural uses of water, but have generally been assigned a lower priority than irrigation (see Aral Sea and Pyramid Lake).

Industrial

It is estimated that 22% of worldwide water use is industrial.[6] Major industrial users include hydroelectric dams, thermoelectric power plants, which use water for cooling, ore and oil refineries, which use water in chemical processes, and manufacturing plants, which use water as a solvent. Water withdrawal can be very high for certain industries, but consumption is generally much lower than that of agriculture.


Water is used in renewable power generation. Hydroelectric power derives energy from the force of water flowing downhill, driving a turbine connected to a generator. This hydroelectricity is a low-cost, non-polluting, renewable energy source. Significantly, hydroelectric power can also be used for load following unlike most renewable energy sources which are intermittent. Ultimately, the energy in a hydroelectric powerplant is supplied by the sun. Heat from the sun evaporates water, which condenses as rain in higher altitudes and flows downhill. Pumped-storage hydroelectric plants also exist, which use grid electricity to pump water uphill when demand is low, and use to stored water to produce electricity when demand is high.

Hydroelectric power plants generally require the creation of a large artificial lake. Evaporation from this lake is higher than evaporation from a river due to the larger surface area exposed to the elements, resulting in much higher water consumption. The process of driving water through the turbine and tunnels or pipes also briefly removes this water from the natural environment, creating water withdrawal. The impact of this withdrawal on wildlife varies greatly depending on the design of the powerplant.

Pressurized water is used in water blasting and water jet cutters. Also, very high pressure water guns are used for precise cutting. It works very well, is relatively safe, and is not harmful to the environment. It is also used in the cooling of machinery to prevent over-heating, or prevent saw blades from over-heating. This is generally a very small source of water consumption relative to other uses.

Water is also used in many large scale industrial processes, such as thermoelectric power production, oil refining, fertilizer production and other chemical plant use, and natural gas extraction from shale rock. Discharge of untreated water from industrial uses is pollution. Pollution includes discharged solutes (chemical pollution) and increased water temperature (thermal pollution). Industry requires pure water for many applications and utilizes a variety of purification techniques both in water supply and discharge. Most of this pure water is generated on site, either from natural freshwater or from municipal grey water. Industrial consumption of water is generally much lower than withdrawal, due to laws requiring industrial grey water to be treated and returned to the environment. Thermoelectric powerplants using cooling towers have high consumption, nearly equal to their withdrawal, as most of the withdrawn water is evaporated as part of the cooling process. The withdrawal, however, is lower than in once-through cooling systems.

Household

Drinking water

It is estimated that 8% of worldwide water use is for household purposes.[6] These include drinking water, bathing, cooking, sanitation, and gardening. Basic household water requirements have been estimated by Peter Gleick at around 50 liters per person per day, excluding water for gardens. Drinking water is water that is of sufficiently high quality so that it can be consumed or used without risk of immediate or long term harm. Such water is commonly called potable water. In most developed countries, the water supplied to households, commerce and industry is all of drinking water standard even though only a very small proportion is actually consumed or used in food preparation.

Recreation

Whitewater rapids

Recreational water use is usually a very small but growing percentage of total water use. Recreational water use is mostly tied to reservoirs. If a reservoir is kept fuller than it would otherwise be for recreation, then the water retained could be categorized as recreational usage. Release of water from a few reservoirs is also timed to enhance whitewater boating, which also could be considered a recreational usage. Other examples are anglers, water skiers, nature enthusiasts and swimmers.

Recreational usage is usually non-consumptive. Golf courses are often targeted as using excessive amounts of water, especially in drier regions. It is, however, unclear whether recreational irrigation (which would include private gardens) has a noticeable effect on water resources. This is largely due to the unavailability of reliable data. Additionally, many golf courses utilize either primarily or exclusively treated effluent water, which has little impact on potable water availability.

Some governments, including the Californian Government, have labelled golf course usage as agricultural in order to deflect environmentalists' charges of wasting water. However, using the above figures as a basis, the actual statistical effect of this reassignment is close to zero. In Arizona, an organized lobby has been established in the form of the Golf Industry Association, a group focused on educating the public on how golf impacts the environment.

Recreational usage may reduce the availability of water for other users at specific times and places. For example, water retained in a reservoir to allow boating in the late summer is not available to farmers during the spring planting season. Water released for whitewater rafting may not be available for hydroelectric generation during the time of peak electrical demand.

Environmental

Explicit environmental water use is also a very small but growing percentage of total water use. Environmental water usage includes artificial wetlands, artificial lakes intended to create wildlife habitat, fish ladders , and water releases from reservoirs timed to help fish spawn, or to restore more natural flow regimes [12]

Like recreational usage, environmental usage is non-consumptive but may reduce the availability of water for other users at specific times and places. For example, water release from a reservoir to help fish spawn may not be available to farms upstream.

Water stress

The concept of water stress is relatively simple: According to the World Business Council for Sustainable Development, it applies to situations where there is not enough water for all uses, whether agricultural, industrial or domestic. Defining thresholds for stress in terms of available water per capita is more complex, however, entailing assumptions about water use and its efficiency. Nevertheless, it has been proposed that when annual per capita renewable freshwater availability is less than 1,700 cubic meters, countries begin to experience periodic or regular water stress. Below 1,000 cubic meters, water scarcity begins to hamper economic development and human health and well-being.

Population growth

In 2000, the world population was 6.2 billion. The UN estimates that by 2050 there will be an additional 3.5 billion people with most of the growth in developing countries that already suffer water stress.[13] Thus, water demand will increase unless there are corresponding increases in water conservation and recycling of this vital resource.[14]

Expansion of business activity

Business activity ranging from industrialization to services such as tourism and entertainment continues to expand rapidly. This expansion requires increased water services including both supply and sanitation, which can lead to more pressure on water resources and natural ecosystems.

Rapid urbanization

The trend towards urbanization is accelerating. Small private wells and septic tanks that work well in low-density communities are not feasible within high-density urban areas. Urbanization requires significant investment in water infrastructure in order to deliver water to individuals and to process the concentrations of wastewater – both from individuals and from business. These polluted and contaminated waters must be treated or they pose unacceptable public health risks.

In 60% of European cities with more than 100,000 people, groundwater is being used at a faster rate than it can be replenished.[15] Even if some water remains available, it costs more and more to capture it.

Climate change

Climate change could have significant impacts on water resources around the world because of the close connections between the climate and hydrological cycle. Rising temperatures will increase evaporation and lead to increases in precipitation, though there will be regional variations in rainfall. Overall, the global supply of freshwater will increase. Both droughts and floods may become more frequent in different regions at different times, and dramatic changes in snowfall and snow melt are expected in mountainous areas. Higher temperatures will also affect water quality in ways that are not well understood. Possible impacts include increased eutrophication. Climate change could also mean an increase in demand for farm irrigation, garden sprinklers, and perhaps even swimming pools.

Depletion of aquifers

Due to the expanding human population, competition for water is growing such that many of the worlds major aquifers are becoming depleted. This is due both for direct human consumption as well as agricultural irrigation by groundwater. Millions of pumps of all sizes are currently extracting groundwater throughout the world. Irrigation in dry areas such as northern China and India is supplied by groundwater, and is being extracted at an unsustainable rate. Cities that have experienced aquifer drops between 10 to 50 meters include Mexico City, Bangkok, Manila, Beijing

Rainwater harvesting system

It is essential to evaluate the volume of rainfall that can be collected so as to estimate the kind of rainwater harvesting system to adopt. The size of the storage tank size is also vital to designing and installing an efficient rainwater harvesting system.

A good rainwater harvesting system must take care of rainwater collection and filtering, pump and tank connections and isolation of regular main water store from the rainwater system. Typically the existing plumbing design has to be reoriented for incorporating the rainwater harvesting system.

The rainwater from the roof and ground level areas around the house are directed through pipes into a sump. Here, a filtration process is installed with sand, brick jelly and pieces of mud bricks.


Advantages of rainwater harvesting

Rainwater harvesting in Chennai

Rainwater harvesting is compulsory in all residential and residential buildings in Chennai. The city receives rainfall of about 120 cm and a lot of this is lost. Unprecedented construction activity and clogging of storm water drains has led to inefficient drainage of water leading to water logging in many places. Tanks and ponds have been filled. With efficient rainwater harvesting, Chennai’s perennial water scarcity can be addressed. This system is cost efficient and maintenance free.With increasing instances of water shortage, it has become imperative for most houses in Chennai to adopt rainwater harvesting systems so as to harness water for use in bathrooms and other purposes such as watering plants except drinking and cooking. Roofs and driveways are ideal locations to capture rainwater that would otherwise have gone wasted.

Pollution and water protection

Polluted water

Water pollution is one of the main concerns of the world today. The governments of numerous countries have striven to find solutions to reduce this problem. Many pollutants threaten water supplies, but the most widespread, especially in developing countries, is the discharge of raw sewage into natural waters; this method of sewage disposal is the most common method in underdeveloped countries, but also is prevalent in quasi-developed countries such as China, India and Iran. Sewage, sludge, garbage, and even toxic pollutants are all dumped into the water. Even if sewage is treated, problems still arise. Treated sewage forms sludge, which may be placed in landfills, spread out on land, incinerated or dumped at sea.[17] In addition to sewage, nonpoint source pollution such as agricultural runoff is a significant source of pollution in some parts of the world, along with urban stormwater runoff and chemical wastes dumped by industries and governments.

Water and conflict

Over the past 25 years, politicians, academics and journalists have frequently predicted that disputes over water would be a source of future wars. Commonly cited quotes include: that of former Egyptian Foreign Minister and former Secretary-General of the United Nations Boutrous Ghali, who forecast, “The next war in the Middle East will be fought over water, not politics”; his successor at the UN, Kofi Annan, who in 2001 said, “Fierce competition for fresh water may well become a source of conflict and wars in the future,” and the former Vice President of the World Bank, Ismail Serageldin, who said the wars of the next century will be over water unless signicant changes in governance occurred. The water wars hypothesis had its roots in earlier research carried out on a small number of transboundary rivers such as the Indus, Jordan and Nile. These particular rivers became the focus because they had experienced water-related disputes. Specific events cited as evidence include Israel’s bombing of Syria’s attempts to divert the Jordan’s headwaters, and military threats by Egypt against any country building dams in the upstream waters of the Nile. However, while some links made between conflict and water were valid, they did not necessarily represent the norm.

The only known example of an actual inter-state conflict over water took place between 2500 and 2350 BC between the Sumerian states of Lagash and Umma.[18] Water stress has most often led to conflicts at local and regional levels.[19] Tensions arise most often within national borders, in the downstream areas of distressed river basins. Areas such as the lower regions of China's Yellow River or the Chao Phraya River in Thailand, for example, have already been experiencing water stress for several years. Water stress can also exacerbate conflicts and political tensions which are not directly caused by water. Gradual reductions over time in the quality and/or quantity of fresh water can add to the instability of a region by depleting the health of a population, obstructing economic development, and exacerbating larger conflicts.[20]

Water resources that span international boundaries, are more likely to be a source of collaboration and cooperation, than war. Scientists working at the International Water Management Institute, in partnership with Aaron Wolf at Oregon State University, have been investigating the evidence behind water war predictions. Their findings show that, while it is true there has been conflict related to water in a handful of international basins, in the rest of the world’s approximately 300 shared basins the record has been largely positive. This is exemplified by the hundreds of treaties in place guiding equitable water use between nations sharing water resources. The institutions created by these agreements can, in fact, be one of the most important factors in ensuring cooperation rather than conflict.

World water supply and distribution

Food and water are two basic human needs. However, global coverage figures from 2002 indicate that, of every 10 people:

At Earth Summit 2002 governments approved a Plan of Action to:

As the picture shows, in 2025, water shortages will be more prevalent among poorer countries where resources are limited and population growth is rapid, such as the Middle East, Africa, and parts of Asia. By 2025, large urban and peri-urban areas will require new infrastructure to provide safe water and adequate sanitation. This suggests growing conflicts with agricultural water users, who currently consume the majority of the water used by humans.

Generally speaking the more developed countries of North America, Europe and Russia will not see a serious threat to water supply by the year 2025, not only because of their relative wealth, but more importantly their populations will be better aligned with available water resources. North Africa, the Middle East, South Africa and northern China will face very severe water shortages due to physical scarcity and a condition of overpopulation relative to their carrying capacity with respect to water supply. Most of South America, Sub-Saharan Africa, Southern China and India will face water supply shortages by 2025; for these latter regions the causes of scarcity will be economic constraints to developing safe drinking water, as well as excessive population growth.

Billion people have gained access to a safe water source since 1990. The proportion of people in developing countries with access to safe water is calculated to have improved from 30 percent in 1970 to 71 percent in 1990, 79 percent in 2000 and 84 percent in 2004. This trend is projected to continue.

Land Resources


They occupy nearly 20 percent of the earth surface. It covers around 13000 million hectares of the area. The houses, roads and factories occupy nearly one third of the land. The forests occupy another one third of the land. The rest of land is used for ploughing and for meadows and pastures. The soil forms the surface layer of land which covers more than the 80 percent of land. The soil is defined as a natural body which keeps on changing and allows the plants to grow. It is made up of organic and inorganic materials. This definition is given by the Buckman and Brady. The branch of science which deals with the formation and distribution of soil in the different parts of the world is referred as a pedology. The professional which deals with the soil is known as the pedologist. The inorganic component in the soil is 45 percent and the organic component in the soil is 5 percent. The water component in the soil is 25 percent and the air component in the soil is 25 percent. The soil particles have fine spaces which are known as the pore spaces. These are also known as the interstices. They contain air and water along with the dissolved substances. The water and air content in the soil is inversely related to each other. The more is the water content lesser is the space for air to exist. The soil has both the plants and animals. The micro flora consists of the heterotrophic and autotrophic bacteria. It also contains the fungi and algae. The heterotrophic bacterium consists of the nitrogen and non nitrogen fixing bacteria. The nitrogen fixing bacteria can be symbiotic, non symbiotic, aerobic and anaerobic. The non nitrogen fixing bacteria can be aerobic or anaerobic. The fungus includes the yeast and mushrooms. The algae can be red or brown or green. The fauna can be micro or macro. The micro fauna includes the protozoa and nematodes. The macro fauna includes the earthworm, mites, termites, snails and mice. The soil has different types of soil particles. The mineral composition of the rock determines them along with the size of particles. It includes the gravel particles, sand, silt and clay particles. The gravel particles are mainly small stones and have a few sand particles and are used to make roads. The sand particles have pores and are aerated. They can hold little bit of water and are made up of large quartz. The silt particles are moved by the help of water. They are left at the bank of river. They are inert and are made up of large quartz. The clay particles have nutritive salts and have ability to retain water. They are not inert and react chemically. Some of their pure forms are not suitable for the growth of plants as they form a non penetrable mass. The other components of the soil mix with the clay particle and form a granular soil. This type of soil is ideal for the cultivation. It has pores as well as has the ability to hold water. It also contains the nutritive salts.

The loamy soil is made up of clay, silt and sand. The proportion of the clay is least and is half as compared to the silt and sand. The silt and sand are twice and equal in the proportion. It is also a good soil for the growth of plants as it has pores as well as has the ability to hold water. It also contains some nutritive salts. There are many factors which control the nature of soil. They are porosity, water holding capacity and the texture. They come under the physical nature of soil. The chemical nature of soil is governed by the salt content, inorganic and organic content includes certain metals. The topography, climate and the organisms also play a vital role in deciding the nature of soil. The half decayed and half synthesized part of organic material in the soil forms humus. It contains the nutrients and help in growth. It makes the soil granular by its porosity and water holding capacity. It has the ability to absorb the heat and warm the soil.

Land, a critically important national resource, Therefore, about 42% of the country’s area supports all living organisms including plants requires soil & water conservation efforts on a as well as every primary production system such priority basis. as roads, industries, communication and storage .The efficient management of land is vital for for surface and ground water,among others. The economic growth and development of rural areas. soil profile of land determines its ability to serve The integrated thinking about the need for a land socio-economic needs. It has been estimated that use policy started only in 1972 when a paper more than 5,000 million tonnes of top soil is eroded entitled “A Charter for the Land” was circulated by annually alongwith about 5 million tonnes of Shri B.B. Vohra. The paper highlighted the nutrients. About a third of this is lost to the sea, dependence of majority of our people on land for while the rest builds the silt load in reservoirs their livelihood and pleaded that care for this river beds leading to floods. About 38% of the resource must rank high in our priorities area in India suffers from moderate to high degree not withstanding that the Constitution has placed of water-based erosion, most of which needs the subject in the State List. It is in this context suitable soil and water conservation measures that the Prime Minister in 1972 had given a such as Watershed Development. Arid areas challenge to the nation for working out a viable suffering from moderate or high degree of soil loss land use policy as follows: comprise upto 4% of the geographical area.

Soil Resources

Soil science

soil texture triangle showing the USDA classification system based on grain size

For soil resources, experience has shown that a natural system approach to classification, i.e. grouping soils by their intrinsic property (soil morphology), behaviour, or genesis, results in classes that can be interpreted for many diverse uses. Differing concepts of pedogenesis, and differences in the significance of morphological features to various land uses can affect the classification approach. Despite these differences, in a well-constructed system, classification criteria group similar concepts so that interpretations do not vary widely. This is in contrast to a technical system approach to soil classification, where soils are grouped according to their fitness for a specific use and their edaphic characteristics.

Natural system approaches to soil classification, such as the French Soil Reference System (Référentiel pédologique français) are based on presumed soil genesis. Systems have developed, such as USDA soil taxonomy and the World Reference Base for Soil Resources, which use taxonomic criteria involving soil morphology and laboratory tests to inform and refine hierarchical classes.

Another approach is numerical classification, also called ordination, where soil individuals are grouped by multivariate statistical methods such as cluster analysis. This produces natural groupings without requiring any inference about soil genesis.

In soil survey, as practiced in the United States, soil classification usually means criteria based on soil morphology in addition to characteristics developed during soil formation. Criteria are designed to guide choices in land use and soil management. As indicated, this is a hierarchical system that is a hybrid of both natural and objective criteria. USDA soil taxonomy provides the core criteria for differentiating soil map units. This is a substantial revision of the 1938 USDA soil taxonomy which was a strictly natural system. Soil taxonomy based soil map units are additionally sorted into classes based on technical classification systems. Land Capability Classes, hydric soil, and prime farmland are some examples.

In addition to scientific soil classification systems, there are also vernacular soil classification systems. Folk taxonomies have been used for millennia, while scientifically based systems are relatively recent development

The impacts of improving soil structure

The benefits of improving soil structure for the growth of plants, particularly in an agricultural setting include: reduced erosion due to greater soil aggregate strength and decreased overland flow; improved root penetration and access to soil moisture and nutrients; improved emergence of seedlings due to reduced crusting of the surface and; greater water infiltration, retention and availability due to improved porosity.

It has been estimated that productivity from irrigated perennial horticulture could be increased by two to three times the present level by improving soil structure, because of the resulting access by plants to available soil water and nutrients (Cockroft & Olsson, 2000, cited in Land and Water Australia 2007). The NSW Department of Land and Water Conservation (1991) infers that in cropping systems, for every millimetre of rain that is able to infiltrate, as maximised by good soil structure, wheat yields can be increased by 10 kg/ha.

Soil structure describes the arrangement of the solid parts of the soil and of the pore space located between them (Marshall & Holmes, 1979). It is dependent on: what the soil developed from; the ===Practices that influenceSoil structure will decline under most forms of cultivation – the associated mechanical mixing of the soil compacts and shears aggregates and fills pore spaces; it also exposes organic matter to a greater rate of decay and oxidation (Young & Young, 2001). A further consequence of continued cultivation and traffic is the development of compacted, impermeable layers or pans within the profile.

Soil structure decline under irrigation is usually related to the breakdown of aggregates and dispersion of clay material as a result of rapid wetting. This is particularly so if soils are sodic; that is, having a high exchangeable sodium percentage (ESP) of the cations attached to the clays. High sodium levels (compared to high calcium levels) cause particles to repel one another when wet and for the associated aggregates to disaggregate and disperse. The ESP will increase if irrigation causes salty water (even of low concentration) to gain access to the soil.

A wide range of practices are undertaken to preserve and improve soil structure. For example, the NSW Department of Land and Water Conservation, (1991) advocates: increasing organic content by incorporating pasture phases into cropping rotations; reducing or eliminating tillage and cultivation in cropping and pasture activities; avoiding soil disturbance during periods of excessive dry or wet when soils may accordingly tend to shatter or smear, and; ensuring sufficient ground cover to protect the soil from raindrop impact. In irrigated agriculture it may be recommended to: apply gypsum (calcium sulfate) to displace sodium cations with calcium and so reduce ESP or sodicity; avoid rapid wetting, and; avoid disturbing soils when too wet or dry.

The impacts of improving soil structure

The benefits of improving soil structure for the growth of plants, particularly in an agricultural setting include: reduced erosion due to greater soil aggregate strength and decreased overland flow; improved root penetration and access to soil moisture and nutrients; improved emergence of seedlings due to reduced crusting of the surface and; greater water infiltration, retention and availability due to improved porosity.

It has been estimated that productivity from irrigated perennial horticulture could be increased by two to three times the present level by improving soil structure, because of the resulting access by plants to available soil water and nutrients (Cockroft & Olsson, 2000, cited in Land and Water Australia 2007). The NSW Department of Land and Water Conservation (1991) infers that in cropping systems, for every millimetre of rain that is able to infiltrate, as maximised by good soil structure, wheat yields can be increased by 10 kg/ha.

Soils are a mixture of different things;menerals rocks,and dead, decaying plants and animals. Soil can be very different from one location to another, but generally consists of organic and inorganic materials, water and air. The inorganic materials are the rocks that have been broken down into smaller pieces. The size of the pieces varies. It may appear as pebbles, gravel, or as small as particles of sand or clay. The organic material is decaying living matter. This could be plants or animals that have died and decay until they become part of the soil. The amount of water in the soil is closely linked with the climate and other characteristics of the region. The amount of water in the soil is one thing that can affect the amount of air. Very wet soil like you would find in a wetland probably has very little air. The composition of the soil affects the plants and therefore the animals that can live there.

Soil Composition

While a nearly infinite variety of substances may be found in soils, they are categorized into four basic components: minerals, organic matter, air and water. Most introductory soil textbooks describe the ideal soil (ideal for the growth of most plants) as being composed of 45% minerals, 25% water, 25% air, and 5% organic matter. In reality, these percentages of the four components vary tremendously. Soil air and water are found in the pore spaces between the solid soil particles. The ratio of air-filled pore space to water-filled pore space often changes seasonally, weekly, and even daily, depending on water additions through precipitation, throughflow, groundwater discharge, and flooding. The volume of the pore space itself can be altered, one way or the other, by several processes. Organic matter content is usually much lower than 5% in South Carolina (typically 1% or less). Some wetland soils, however, have considerably more organic matter in them (greater than 50% of the solid portion of the soil in some cases).



Soil conservation is a set of management strategies for prevention of soil being eroded from the Earth’s surface or becoming chemically altered by overuse, acidification, salinization or other chemical soil contamination. It is a component of environmental soil science.

Crops and conservation

Erosion barriers on disturbed slope, Marin County, California

Decisions regarding appropriate crop rotation, cover crops, and planted windbreaks are central to the ability of surface soils to retain their integrity, both with respect to erosive forces and chemical change from nutrient depletion. Crop rotation is simply the conventional alternation of crops on a given field, so that nutrient depletion is avoided from repetitive chemical uptake/deposition of single crop growth.

Cover crops serve the function of protecting the soil from erosion, weed establishment or excess evapotranspiration; however, they may also serve vital soil chemistry functions.[1] For example, legumes can be ploughed under to augment soil nitrates, and other plants have the ability to metabolize soil contaminants or alter adverse pH. The cover crop Mucuna pruriens (velvet bean) has been used in Nigeria to increase phosphorus availability after application of rock phosphate.[2] Some of these same precepts are applicable to urban landscaping, especially with respect to ground-cover selection for erosion control and weed suppression. soil is one of the three main natural resources alongside with water and air





Soil Erosion



n

Cliff erosion in Pacifica, California

Erosion is the process by which material is removed from a region of the Earth surface. It can occur by weathering and transport of solids (sediment, soil, rock and other particles) in the natural environment, and leads to the deposition of these materials elsewhere. It usually occurs due to transport by wind, water, or ice; by down-slope creep of soil and other material under the force of gravity; or by living organisms, such as burrowing animals, in the case of bioerosion.

Although erosion is a natural process human land use policies also have an effect on erosion, especially industrial agriculture, deforestation, and urban sprawl.[1][2] Land that is used for industrial agriculture generally experiences a significantly greater rate of erosion than that of land under natural vegetation, or land used for sustainable agricultural practices. This is particularly true if tillage is used, which reduces vegetation cover on the surface of the soil and disturbs both soil structure and plant roots that would otherwise hold the soil in place. However, improved land use practices can limit erosion, using techniques such as terrace-building, no-till, and tree planting.

A certain amount of erosion is natural and, in fact, healthy for the ecosystem. For example, gravels continuously move downstream in watercourses. Excessive erosion, however, causes serious problems, such as receiving water sedimentation, ecosystem damage and outright loss of soil.

Erosion is distinguished from weathering, which is the process of chemical or physical breakdown of the minerals in the rocks, although the two processes may occur concurrently

A natural arch produced by erosion of differentially weathered rock in Jebel Kharaz (Jordan)

The rate of erosion depends on many factors. Climatic factors include the amount and intensity of precipitation, the average temperature, as well as the typical temperature range, and seasonality, the wind speed, storm frequency. Erosion is caused by “fluid flow”. Any substance, like wind, water, or ice, which flows consistently from one place to another, will facilitate erosion. The geologic factors include the sediment or rock type, its porosity and permeability, the slope (gradient) of the land, and whether the rocks are tilted, faulted, folded, or weathered. The biological factors include ground cover from vegetation or lack thereof, the type of organisms inhabiting the area, and the land use.

In general, given similar vegetation and ecosystems, areas with high-intensity precipitation, more frequent rainfall, more wind, or more storms are expected to have more erosion. Sediment with high sand or silt contents and areas with steep slopes erode more easily, as do areas with highly fractured or weathered rock. Porosity and permeability of the sediment or rock affect the speed with which the water can percolate into the ground. If the water moves underground, less runoff is generated, reducing the amount of surface erosion. Sediments containing more clay tend to erode less than those with sand or silt. Here, however, the impact of atmospheric sodium on erodibility of clay should be considered.[3]

The factor that is most subject to change is the amount and type of ground cover. In an undisturbed forest, the mineral soil is protected by a litter layer and an organic layer. These two layers protect the soil by absorbing the impact of rain drops. These layers and the underlying soil in a forest are porous and highly permeable to rainfall. Typically, only the most severe rainfall and large hailstorm events will lead to overland flow in a forest. If the trees are removed by fire or logging, infiltration rates become high and erosion low to the degree the forest floor remains intact. Severe fires can lead to significantly increased erosion if followed by heavy rainfall. In the case of construction or road building, when the litter layer is removed or compacted, the susceptibility of the soil to erosion is greatly increased.

Roads are especially likely to cause increased rates of erosion because, in addition to removing ground cover, they can significantly change drainage patterns, especially if an embankment has been made to support the road. A road that has a lot of rock and one that is "hydrologically invisible" (that gets the water off the road as quickly as possible, mimicking natural drainage patterns) has the best chance of not causing increased erosion.

Many human activities remove vegetation from an area, making the soil susceptible to erosion. Logging can cause increased erosion rates due to soil compaction, exposure of mineral soil, for example roads and landings. However it is the removal of or compromise to the forest floor not the removal of the canopy that can lead to erosion. This is because rain drops striking tree leaves coalesce with other rain drops creating larger drops. When these larger drops fall (called throughfall) they again may reach terminal velocity and strike the ground with more energy than had they fallen in the open. Terminal velocity of rain drops is reached in about 8 meters. Because forest canopies are usually higher than this, leaf drop can regain terminal velocity. However, the intact forest floor, with its layers of leaf litter and organic matter, absorbs the impact of the rainfall.[4]

A Linxia City, China, farmer is gradually losing his land as the edge of the loess plateau is eroded away

Heavy grazing can reduce vegetation enough to increase erosion. Changes in the kind of vegetation in an area can also affect erosion rates. Different kinds of vegetation lead to different infiltration rates of rain into the soil. Forested areas have higher infiltration rates, so precipitation will result in less surface runoff, which erodes. Instead much of the water will go in subsurface flows, which are generally less erosive. Leaf litter and low shrubs are an important part of the high infiltration rates of forested systems, the removal of which can increase erosion rates. Leaf litter also shelters the soil from the impact of falling raindrops, which is a significant agent of erosion. Vegetation can also change the speed of surface runoff flows, so grasses and shrubs can also be instrumental in this aspect.

One of the main causes of erosive soil loss in the year 2006 is the result of slash and burn treatment of tropical forest. When the total ground surface is stripped of vegetation and then seared of all living organisms, the upper soils are vulnerable to both wind and water erosion. In a number of regions of the earth, entire sectors of a country have been rendered unproductive. For example, on the Madagascar high central plateau, comprising approximately ten percent of that country's land area, virtually the entire landscape is sterile of vegetation, with gully erosive furrows typically in excess of 50 meters deep and one kilometer wide. Shifting cultivation is a farming system which sometimes incorporates the slash and burn method in some regions of the world. This degrades the soil and causes the soil to become less and less fertile.

Effects

Approximately 40% of the world's agricultural land is seriously degraded.[5] According to the UN, an area of fertile soil the size of Ukraine is lost every year because of drought, deforestation and climate change.[6] In Africa, if current trends of soil degradation continue, the continent might be able to feed just 25% of its population by 2025, according to UNU's Ghana-based Institute for Natural Resources in Africa.[7]

Bank erosion started by four wheeler all-terrain vehicles, Yauhanna, South Carolina

When land is overused by animal activities (including humans), there can be mechanical erosion and also removal of vegetation leading to erosion. In the case of the animal kingdom, this effect would become material primarily with very large animal herds stampeding such as the Blue Wildebeest on the Serengeti plain. Even in this case there are broader material benefits to the ecosystem, such as continuing the survival of grasslands, that are indigenous to this region. This effect may be viewed as anomalous or a problem only when there is a significant imbalance or overpopulation of one species.

In the case of human use, the effects are also generally linked to overpopulation. When large number of hikers use trails or extensive off road vehicle use occurs, erosive effects often follow, arising from vegetation removal and furrowing of foot traffic and off road vehicle tires. These effects can also accumulate from a variety of outdoor human activities, again simply arising from too many people using a finite land resource.

One of the most serious and long-running water erosion problems worldwide is in the People's Republic of China, on the middle reaches of the Yellow River and the upper reaches of the Yangtze River. From the Yellow River, over 1.6 billion tons of sediment flows into the ocean each year. The sediment originates primarily from water erosion in the Loess Plateau region of the northwest.

Processes

Gravity

Wadi in Makhtesh Ramon, Israel, showing gravity collapse erosion on its banks.

Mass wasting is the down-slope movement of rock and sediments, mainly due to the force of gravity. Mass movement is an important part of the erosional process, as it moves material from higher elevations to lower elevations where other eroding agents such as streams and glaciers can then pick up the material and move it to even lower elevations. Mass-movement processes are always occurring continuously on all slopes; some mass-movement processes act very slowly; others occur very suddenly, often with disastrous results. Any perceptible down-slope movement of rock or sediment is often referred to in general terms as a landslide. However, landslides can be classified in a much more detailed way that reflects the mechanisms responsible for the movement and the velocity at which the movement occurs. One of the visible topographical manifestations of a very slow form of such activity is a scree slope.

Slumping happens on steep hillsides, occurring along distinct fracture zones, often within materials like clay that, once released, may move quite rapidly downhill. They will often show a spoon-shaped isostatic depression, in which the material has begun to slide downhill. In some cases, the slump is caused by water beneath the slope weakening it. In many cases it is simply the result of poor engineering along highways where it is a regular occurrence.

Surface creep is the slow movement of soil and rock debris by gravity which is usually not perceptible except through extended observation. However, the term can also describe the rolling of dislodged soil particles 0.5 to 1.0 mm in diameter by wind along the soil surface.

Water

Nearly perfect sphere in granite, Trégastel, Brittany.

Splash erosion is the detachment and airborne movement of small soil particles caused by the impact of raindrops on soil.

Sheet erosion is the detachment of soil particles by raindrop impact and their removal downslope by water flowing overland as a sheet instead of in definite channels or rills. The impact of the raindrop breaks apart the soil aggregate. Particles of clay, silt and sand fill the soil pores and reduce infiltration. After the surface pores are filled with sand, silt or clay, overland surface flow of water begins due to the lowering of infiltration rates. Once the rate of falling rain is faster than infiltration, runoff takes place. There are two stages of sheet erosion. The first is rain splash, in which soil particles are knocked into the air by raindrop impact. In the second stage, the loose particles are moved downslope by broad sheets of rapidly flowing water filled with sediment known as sheetfloods. This stage of sheet erosion is generally produced by cloudbursts, sheetfloods commonly travel short distances and last only for a short time.

Rill erosion refers to the development of small, ephemeral concentrated flow paths, which function as both sediment source and sediment delivery systems for erosion on hillslopes. Generally, where water erosion rates on disturbed upland areas are greatest, rills are active. Flow depths in rills are typically on the order of a few centimeters or less and slopes may be quite steep. These conditions constitute a very different hydraulic environment than typically found in channels of streams and rivers. Eroding rills evolve morphologically in time and space. The rill bed surface changes as soil erodes, which in turn alters the hydraulics of the flow. The hydraulics is the driving mechanism for the erosion process, and therefore dynamically changing hydraulic patterns cause continually changing erosional patterns in the rill. Thus, the process of rill evolution involves a feedback loop between flow detachment, hydraulics, and bed form. Flow velocity, depth, width, hydraulic roughness, local bed slope, friction slope, and detachment rate are time and space variable functions of the rill evolutionary process. Superimposed on these interactive processes, the sediment load, or amount of sediment in the flow, has a large influence on soil detachment rates in rills. As sediment load increases, the ability of the flowing water to detach more sediment decreases.

Where precipitation rates exceed soil infiltration rates, runoff occurs. Surface runoff turbulence can often cause more erosion than the initial raindrop impact.

Gully erosion, also called ephemeral gully erosion, occurs when water flows in narrow channels during or immediately after heavy rains or melting snow. This is particularly noticeable in the formation of hollow ways, where, prior to being tarmacked, an old rural road has over many years become significantly lower than the surrounding fields.

A gully is sufficiently deep that it would not be routinely destroyed by tillage operations, whereas rill erosion is smoothed by ordinary farm tillage. The narrow channels, or gullies, may be of considerable depth, ranging from 1 to 2 feet (0.61 m) to as much as 75 to 100 feet (30 m). Gully erosion is not accounted for in the revised universal soil loss equation.

Valley or stream erosion occurs with continued water flow along a linear feature. The erosion is both downward, deepening the valley, and headward, extending the valley into the hillside. In the earliest stage of stream erosion, the erosive activity is dominantly vertical, the valleys have a typical V cross-section and the stream gradient is relatively steep. When some base level is reached, the erosive activity switches to lateral erosion, which widens the valley floor and creates a narrow floodplain. The stream gradient becomes nearly flat, and lateral deposition of sediments becomes important as the stream meanders across the valley floor. In all stages of stream erosion, by far the most erosion occurs during times of flood, when more and faster-moving water is available to carry a larger sediment load. In such processes, it is not the water alone that erodes: suspended abrasive particles, pebbles and boulders can also act erosively as they traverse a surface.

At extremely high flows, kolks, or vortices are formed by large volumes of rapidly rushing water. Kolks cause extreme local erosion, plucking bedrock and creating pothole-type geographical features called Rock-cut basins. Examples can be seen in the flood regions result from glacial Lake Missoula, which created the channeled scablands in the Columbia Basin region of eastern Washington.[8]

Bank erosion is the wearing away of the banks of a stream or river. This is distinguished from changes on the bed of the watercourse, which is referred to as scour. Erosion and changes in the form of river banks may be measured by inserting metal rods into the bank and marking the position of the bank surface along the rods at different times.[9]

Shoreline erosion, which occurs on both exposed and sheltered coasts, primarily occurs through the action of currents and waves but sea level (tidal) change can also play a role.

Hydraulic action takes place when air in a joint is suddenly compressed by a wave closing the entrance of the joint. This then cracks it. Wave pounding is when the sheer energy of the wave hitting the cliff or rock breaks pieces off. Abrasion or corrasion is caused by waves launching seaload at the cliff. It is the most effective and rapid form of shoreline erosion (not to be confused with corrosion). Corrosion is the dissolving of rock by carbonic acid in sea water. Limestone cliffs are particularly vulnerable to this kind of erosion. Attrition is where particles/seaload carried by the waves are worn down as they hit each other and the cliffs. This then makes the material easier to wash away. The material ends up as shingle and sand. Another significant source of erosion, particularly on carbonate coastlines, is the boring, scraping and grinding of organisms, a process termed bioerosion.

Sediment is transported along the coast in the direction of the prevailing current (longshore drift). When the upcurrent amount of sediment is less than the amount being carried away, erosion occurs. When the upcurrent amount of sediment is greater, sand or gravel banks will tend to form. These banks may slowly migrate along the coast in the direction of the longshore drift, alternately protecting and exposing parts of the coastline. Where there is a bend in the coastline, quite often a build up of eroded material occurs forming a long narrow bank (a spit). Armoured beaches and submerged offshore sandbanks may also protect parts of a coastline from erosion. Over the years, as the shoals gradually shift, the erosion may be redirected to attack different parts of the shore.

For example, the large-scale oceanic erosion that has been taking place off the coast of southwest Japan can illustrate the environmental effects of erosion. Over time, a V-shaped depression has formed in the ocean floor which, in turn, has released methane gas into the water and atmosphere. Once this gas was released, it further facilitated erosion through gas erosion by creating a positive feedback loop. As more and more methane was released, more sedimentary rock was eroded, thus worsening the problem.

Ice

Ice erosion can take one of two forms. It can be caused by the movement of ice, typically as glaciers, in a process called glacial erosion. It can also be due to freeze-thaw processes in which water inside pores and fractures in rock may expand causing further cracking.

Glaciers erode predominantly by three different processes: abrasion/scouring, plucking, and ice thrusting. In an abrasion process, debris in the basal ice scrapes along the bed, polishing and gouging the underlying rocks, similar to sandpaper on wood. Glaciers can also cause pieces of bedrock to crack off in the process of plucking. In ice thrusting, the glacier freezes to its bed, then as it surges forward, it moves large sheets of frozen sediment at the base along with the glacier. This method produced some of the many thousands of lake basins that dot the edge of the Canadian Shield. These processes, combined with erosion and transport by the water network beneath the glacier, leave moraines, drumlins, ground moraine (till), kames, kame deltas, moulins, and glacial erratics in their wake, typically at the terminus or during glacier retreat.

Cold weather causes water trapped in tiny rock cracks to freeze and expand, breaking the rock into several pieces. This can lead to gravity erosion on steep slopes. The scree which forms at the bottom of a steep mountainside is mostly formed from pieces of rock (soil) broken away by this means. It is a common engineering problem wherever rock cliffs are alongside roads, because morning thaws can drop hazardous rock pieces onto the road.

In some places, water seeps into rocks during the daytime, then freezes at night. Ice expands, thus, creating a wedge in the rock. Over time, the repetition in the forming and melting of the ice causes fissures, which eventually breaks the rock down.

Tectonic effects

The removal by erosion of large amounts of rock from a particular region, and its deposition elsewhere, can result in a lightening of the load on the lower crust and mantle. This can cause tectonic or isostatic uplift in the region. Research undertaken since the early 1990s suggests that the spatial distribution of erosion at the surface of an orogen can exert a key influence on its growth and its final internal structure (see erosion and tectonics)

Forest and Deforestation

Deforestation and increased road-building in the Amazon Rainforest are a significant concern because of increased human encroachment upon wild areas, increased resource extraction and further threats to biodiversity.

Deforestation is the removal of a forest or stand of trees where the land is thereafter converted to a nonforest use.[1] Examples of deforestation include conversion of forestland to farms, ranches, or urban use.

The term deforestation is often misused to describe any activity where all trees in an area are removed. However in temperate mesic climates, the removal of all trees in an area—in conformance with sustainable forestry practices—is correctly described as regeneration harvest.[2] In temperate mesic climates, natural regeneration of forest stands often will not occur in the absence of disturbance, whether natural or anthropogenic.[3] Furthermore, biodiversity after regeneration harvest often mimics that found after natural disturbance, including biodiversity loss after naturally occurring rainforest destruction.[4][5]

Deforestation occurs for many reasons: trees or derived charcoal are used as, or sold, for fuel or as timber, while cleared land is used as pasture for livestock, plantations of commodities, and settlements. The removal of trees without sufficient reforestation has resulted in damage to habitat, biodiversity loss and aridity. It has adverse impacts on biosequestration of atmospheric carbon dioxide. Deforested regions typically incur significant adverse soil erosion and frequently degrade into wasteland.

Disregard or ignorance of intrinsic value, lack of ascribed value, lax forest management and deficient environmental laws are some of the factors that allow deforestation to occur on a large scale. In many countries, deforestation, both naturally occurring and human induced, is an ongoing issue. Deforestation causes extinction, changes to climatic conditions, desertification, and displacement of populations as observed by current conditions and in the past through the fossil record.[4]

Among countries with a per capita GDP of at least US$4,600, net deforestation rates have ceased to increase.[6][7]

Causes

There are many causes of contemporary deforestation, including corruption of government institutions, the inequitable distribution of wealth and power,[10] population growth[11] and overpopulation, and urbanization.[14] Globalization is often viewed as another root cause of deforestation though there are cases in which the impacts of globalization (new flows of labor, capital, commodities, and ideas) have promoted localized forest recovery.[17]

In 2000 the United Nations Food and Agriculture Organization (FAO) found that "the role of population dynamics in a local setting may vary from decisive to negligible," and that deforestation can result from "a combination of population pressure and stagnating economic, social and technological conditions."[11]

According to the United Nations Framework Convention on Climate Change (UNFCCC) secretariat, the overwhelming direct cause of deforestation is agriculture. Subsistence farming is responsible for 48% of deforestation; commercial agriculture is responsible for 32% of deforestation; logging is responsible for 14% of deforestation and fuel wood removals make up 5% of deforestation.[18]

The degradation of forest ecosystems has also been traced to economic incentives that make forest conversion appear more profitable than forest conservation.[19] Many important forest functions have no markets, and hence, no economic value that is readily apparent to the forests' owners or the communities that rely on forests for their well-being.[19] From the perspective of the developing world, the benefits of forest as carbon sinks or biodiversity reserves go primarily to richer developed nations and there is insufficient compensation for these services. Developing countries feel that some countries in the developed world, such as the United States of America, cut down their forests centuries ago and benefited greatly from this deforestation, and that it is hypocritical to deny developing countries the same opportunities: that the poor shouldn't have to bear the cost of preservation when the rich created the problem.[20]

Experts do not agree on whether industrial logging is an important contributor to global deforestation. Some argue that poor people are more likely to clear forest because they have no alternatives, others that the poor lack the ability to pay for the materials and labour needed to clear forest.[21] One study found that population increases due to high fertility rates were a primary driver of tropical deforestation in only 8% of cases.[23]

Some commentators have noted a shift in the drivers of deforestation over the past 30 years.[24] Whereas deforestation was primarily driven by subsistence activities and government-sponsored development projects like transmigration in countries like Indonesia and colonization in Latin America, India, Java, and so on, during late 19th century and the earlier half of the 20th century. By the 1990s the majority of deforestation was caused by industrial factors, including extractive industries, large-scale cattle ranching, and extensive agriculture.[25]

Wind

Árbol de Piedra, a rock formation in the Altiplano, Bolivia sculpted by wind erosion.

Wind-eroded alcove near Moab, Utah.

Main article: Aeolian processes

In arid climates, the main source of erosion is wind.[10] The general wind circulation moves small particulates such as dust across wide oceans thousands of kilometers downwind of their point of origin,[11] which is known as deflation. Erosion can be the result of material movement by the wind. There are two main effects. First, wind causes small particles to be lifted and therefore moved to another region. This is called deflation. Second, these suspended particles may impact on solid objects causing erosion by abrasion (ecological succession). Wind erosion generally occurs in areas with little or no vegetation, often in areas where there is insufficient rainfall to support vegetation. An example is the formation of sand dunes, on a beach or in a desert.[12] Loess is a homogeneous, typically nonstratified, porous, friable, slightly coherent, often calcareous, fine-grained, silty, pale yellow or buff, windblown (aeolian) sediment.[13] It generally occurs as a widespread blanket deposit that covers areas of hundreds of square kilometers and tens of meters thick. Loess often stands in either steep or vertical faces.[14] Loess tends to develop into highly rich soils. Under appropriate climatic conditions, areas with loess are among the most agriculturally productive in the world.[15] Loess deposits are geologically unstable by nature, and will erode very readily. Therefore, windbreaks (such as big trees and bushes) are often planted by farmers to reduce the wind erosion of loess.[10]

Soil erosion and climate change

Main article: Land degradation

The warmer atmospheric temperatures observed over the past decades are expected to lead to a more vigorous hydrological cycle, including more extreme rainfall events.[19] In 1998 Karl and Knight reported that from 1910 to 1996 total precipitation over the contiguous U.S. increased, and that 53% of the increase came from the upper 10% of precipitation events (the most intense precipitation).[20] The percent of precipitation coming from days of precipitation in excess of 50 mm has also increased significantly.

Studies on soil erosion suggest that increased rainfall amounts and intensities will lead to greater rates of erosion. Thus, if rainfall amounts and intensities increase in many parts of the world as expected, erosion will also increase, unless amelioration measures are taken. Soil erosion rates are expected to change in response to changes in climate for a variety of reasons. The most direct is the change in the erosive power of rainfall. Other reasons include: a) changes in plant canopy caused by shifts in plant biomass production associated with moisture regime; b) changes in litter cover on the ground caused by changes in both plant residue decomposition rates driven by temperature and moisture dependent soil microbial activity as well as plant biomass production rates; c) changes in soil moisture due to shifting precipitation regimes and evapo-transpiration rates, which changes infiltration and runoff ratios; d) soil erodibility changes due to decrease in soil organic matter concentrations in soils that lead to a soil structure that is more susceptible to erosion and increased runoff due to increased soil surface sealing and crusting; e) a shift of winter precipitation from non-erosive snow to erosive rainfall due to increasing winter temperatures; f) melting of permafrost, which induces an erodible soil state from a previously non-erodible one; and g) shifts in land use made necessary to accommodate new climatic regimes.

Studies by Pruski and Nearing indicated that, other factors such as land use not considered, we can expect approximately a 1.7% change in soil erosion for each 1% change in total precipitation under climate change.[21]

Measuring & Preventing Erosion

Erosion is measured and further understood using tools such as the micro-erosion meter (MEM) and the traversing micro-erosion meter (TMEM). The MEM has proved helpful in measuring bedrock erosion in various ecosystems around the world. It can measure both terrestrial and oceanic erosion. On the other hand, the TMEM can be used to track the expanding and contracting of volatile rock formations and can give a reading of how quickly a rock formation is deteriorating.

Tactics for preventing erosion in the future have been under investigation by scientists and geologists all over the world. Today, the most effective method for erosion prevention is soil surface cover. In this method, some type of permeable material, left over crop residue for example, covers the soil surface, which includes rock and sediment debris. This decreases the deteriorating capabilities of the impact from rain, animals, machinery, or any other type of eroding agent. As a result, surface runoff is controlled which helps eliminate the transportation of eroded particles elsewhere, thus slowing the process of erosion as a whole.



Wind, from the Tacuinum Sanitatis



A breeze lifts a veil

Wind is the flow of gases on a large scale. On Earth, wind consists of the bulk movement of air. In outer space, solar wind is the movement of gases or charged particles from the sun through space, while planetary wind is the outgassing of light chemical elements from a planet's atmosphere into space. Winds are commonly classified by their spatial scale, their speed, the types of forces that cause them, the regions in which they occur, and their effect. The strongest observed winds on a planet in our solar system occur on Neptune and Saturn.

In meteorology, winds are often referred to according to their strength, and the direction from which the wind is blowing. Short bursts of high speed wind are termed gusts. Strong winds of intermediate duration (around one minute) are termed squalls. Long-duration winds have various names associated with their average strength, such as breeze, gale, storm, hurricane, and typhoon. Wind occurs on a range of scales, from thunderstorm flows lasting tens of minutes, to local breezes generated by heating of land surfaces and lasting a few hours, to global winds resulting from the difference in absorption of solar energy between the climate zones on Earth. The two main causes of large scale atmospheric circulation are the differential heating between the equator and the poles, and the rotation of the planet (Coriolis effect). Within the tropics, thermal low circulations over terrain and high plateaus can drive monsoon circulations. In coastal areas the sea breeze/land breeze cycle can define local winds; in areas that have variable terrain, mountain and valley breezes can dominate local winds.

In human civilization, wind has inspired mythology, influenced the events of history, expanded the range of transport and warfare, and provided a power source for mechanical work, electricity, and recreation. Wind has powered the voyages of sailing ships across Earth's oceans. Hot air balloons use the wind to take short trips, and powered flight uses it to increase lift and reduce fuel consumption. Areas of wind shear caused by various weather phenomena can lead to dangerous situations for aircraft. When winds become strong, trees and man-made structures are damaged or destroyed.

Winds can shape landforms, via a variety of aeolian processes such as the formation of fertile soils, such as loess, and by erosion. Dust from large deserts can be moved great distances from its source region by the prevailing winds; winds that are accelerated by rough topography and associated with dust outbreaks have been assigned regional names in various parts of the world because of their significant effects on those regions. Wind affects the spread of wildfires. Winds disperse seeds from various plants, enabling the survival and dispersal of those plant species, as well as flying insect populations. When combined with cold temperatures, wind has a negative impact on livestock. Wind affects animals' food stores, as well as their hunting and defensive strategies.


Wind is caused by differences in pressure. When a difference in pressure exists, the air is accelerated from higher to lower pressure. On a rotating planet the air will be deflected by the Coriolis effect, except exactly on the equator. Globally, the two major driving factors of large scale winds (the atmospheric circulation) are the differential heating between the equator and the poles (difference in absorption of solar energy leading to buoyancy forces) and the rotation of the planet. Outside the tropics and aloft from frictional effects of the surface, the large-scale winds tend to approach geostrophic balance. Near the Earth's surface, friction causes the wind to be slower than it would be otherwise. Surface friction also causes winds to blow more inward into low pressure areas.[1]

Winds defined by an equilibrium of physical forces are used in the decomposition and analysis of wind profiles. They are useful for simplifying the atmospheric equations of motion and for making qualitative arguments about the horizontal and vertical distribution of winds. The geostrophic wind component is the result of the balance between Coriolis force and pressure gradient force. It flows parallel to isobars and approximates the flow above the atmospheric boundary layer in the midlatitudes.[2] The thermal wind is the difference in the geostrophic wind between two levels in the atmosphere. It exists only in an atmosphere with horizontal temperature gradients.[3] The ageostrophic wind component is the difference between actual and geostrophic wind, which is responsible for air "filling up" cyclones over time.[4] The gradient wind is similar to the geostrophic wind but also includes centrifugal force (or centripetal acceleration).[5]

Measurement

A windmill style of anemometer

An occluded mesocyclone tornado (Oklahoma, May 1999)

Wind direction is reported by the direction from which it originates. For example, a northerly wind blows from the north to the south.[6] Weather vanes pivot to indicate the direction of the wind.[7] At airports, windsocks are primarily used to indicate wind direction, but can also be used to estimate wind speed by its angle of hang.[8] Wind speed is measured by anemometers, most commonly using rotating cups or propellers. When a high measurement frequency is needed (such as in research applications), wind can be measured by the propagation speed of ultrasound signals or by the effect of ventilation on the resistance of a heated wire.[9] Another type of anemometer uses pitot tubes that take advantage of the pressure differential between an inner tube and an outer tube that is exposed to the wind to determine the dynamic pressure, which is then used to compute the wind speed.[10]

Sustained wind speeds are reported globally at a 10 meters (33 ft) height and are averaged over a 10 minute time frame. The United States reports winds over a 1 minute average for tropical cyclones,[11] and a 2 minute average within weather observations.[12] India typically reports winds over a 3 minute average.[13] Knowing the wind sampling average is important, as the value of a one-minute sustained wind is typically 14 percent greater than a ten-minute sustained wind.[14] A short burst of high speed wind is termed a wind gust, one technical definition of a wind gust is: the maxima that exceed the lowest wind speed measured during a ten minute time interval by 10 knots (19 km/h). A squall is a doubling of the wind speed above a certain threshold, which lasts for a minute or more.

To determine winds aloft, rawinsondes determine wind speed by GPS, radio navigation, or radar tracking of the probe.[15] Alternatively, movement of the parent weather balloon position can be tracked from the ground visually using theodolites.[16] Remote sensing techniques for wind include SODAR, Doppler LIDARs and RADARs, which can measure the Doppler shift of electromagnetic radiation scattered or reflected off suspended aerosols or molecules, and radiometers and radars can be used to measure the surface roughness of the ocean from space or airplanes. Ocean roughness can be used to estimate wind velocity close to the sea surface over oceans. Geostationary satellite imagery can be used to estimate the winds throughout the atmosphere based upon how far clouds move from one image to the next. Wind Engineering describes the study of the effects of the wind on the built environment, including buildings, bridges and other man-made objects.

Solar energy



Nellis Solar Power Plant in the United States, one of the largest photovoltaic power plants in North America.Renewable energy

Solar energy, radiant light and heat from the sun, has been harnessed by humans since ancient times using a range of ever-evolving technologies. Solar radiation, along with secondary solar-powered resources such as wind and wave power, hydroelectricity and biomass, account for most of the available renewable energy on earth. Only a minuscule fraction of the available solar energy is used.

Solar powered electrical generation relies on heat engines and photovoltaics. Solar energy's uses are limited only by human ingenuity. A partial list of solar applications includes space heating and cooling through solar architecture, potable water via distillation and disinfection, daylighting, solar hot water, solar cooking, and high temperature process heat for industrial purposes.To harvest the solar energy, the most common way is to use solar panels.

Solar technologies are broadly characterized as either passive solar or active solar depending on the way they capture, convert and distribute solar energy. Active solar techniques include the use of photovoltaic panels and solar thermal collectors to harness the energy. Passive solar techniques include orienting a building to the Sun, selecting materials with favorable thermal mass or light dispersing properties, and designing spaces that naturally circulate air.

Energy from the Sun

Main articles: Insolation and Solar radiation

About half the incoming solar energy reaches the Earth's surface.

The Earth receives 174 petawatts (PW) of incoming solar radiation (insolation) at the upper atmosphere.[1] Approximately 30% is reflected back to space while the rest is absorbed by clouds, oceans and land masses. The spectrum of solar light at the Earth's surface is mostly spread across the visible and near-infrared ranges with a small part in the near-ultraviolet.[2]

Earth's land surface, oceans and atmosphere absorb solar radiation, and this raises their temperature. Warm air containing evaporated water from the oceans rises, causing atmospheric circulation or convection. When the air reaches a high altitude, where the temperature is low, water vapor condenses into clouds, which rain onto the Earth's surface, completing the water cycle. The latent heat of water condensation amplifies convection, producing atmospheric phenomena such as wind, cyclones and anti-cyclones.[3] Sunlight absorbed by the oceans and land masses keeps the surface at an average temperature of 14 °C.[4] By photosynthesis green plants convert solar energy into chemical energy, which produces food, wood and the biomass from which fossil fuels are derived.[5]

Yearly Solar fluxes & Human Energy Consumption

Solar

3,850,000 EJ[6]

Wind

2,250 EJ[7]

Biomass

3,000 EJ[8]

Primary energy use (2005)

487 EJ[9]

Electricity (2005)

56.7 EJ[10]

The total solar energy absorbed by Earth's atmosphere, oceans and land masses is approximately 3,850,000 exajoules (EJ) per year.[6] In 2002, this was more energy in one hour than the world used in one year.[11][12] Photosynthesis captures approximately 3,000 EJ per year in biomass.[8] The amount of solar energy reaching the surface of the planet is so vast that in one year it is about twice as much as will ever be obtained from all of the Earth's non-renewable resources of coal, oil, natural gas, and mined uranium combined.[13]

Solar energy can be harnessed in different levels around the world. Depending on a geographical location the closer to the equator the more "potential" solar energy is available.[14]

Applications of solar technology

Average insolation showing land area (small black dots) required to replace the world primary energy supply with solar electricity. 18 TW is 568 Exajoule (EJ) per year. Insolation for most people is from 150 to 300 W/m2 or 3.5 to 7.0 kWh/m2/day.

Solar energy refers primarily to the use of solar radiation for practical ends. However, all renewable energies, other than geothermal and tidal, derive their energy from the sun.

Solar technologies are broadly characterized as either passive or active depending on the way they capture, convert and distribute sunlight. Active solar techniques use photovoltaic panels, pumps, and fans to convert sunlight into useful outputs. Passive solar techniques include selecting materials with favorable thermal properties, designing spaces that naturally circulate air, and referencing the position of a building to the Sun. Active solar technologies increase the supply of energy and are considered supply side technologies, while passive solar technologies reduce the need for alternate resources and are generally considered demand side technologies.[15]

Architecture and urban planning

Main articles: Passive solar building design and Urban heat island

Darmstadt University of Technology in Germany won the 2007 Solar Decathlon in Washington, D.C. with this passive house designed specifically for the humid and hot subtropical climate.[16]

Sunlight has influenced building design since the beginning of architectural history.[17] Advanced solar architecture and urban planning methods were first employed by the Greeks and Chinese, who oriented their buildings toward the south to provide light and warmth.[18]

The common features of passive solar architecture are orientation relative to the Sun, compact proportion (a low surface area to volume ratio), selective shading (overhangs) and thermal mass.[17] When these features are tailored to the local climate and environment they can produce well-lit spaces that stay in a comfortable temperature range. Socrates' Megaron House is a classic example of passive solar design.[17] The most recent approaches to solar design use computer modeling tying together solar lighting, heating and ventilation systems in an integrated solar design package.[19] Active solar equipment such as pumps, fans and switchable windows can complement passive design and improve system performance.

Urban heat islands (UHI) are metropolitan areas with higher temperatures than that of the surrounding environment. The higher temperatures are a result of increased absorption of the Solar light by urban materials such as asphalt and concrete, which have lower albedos and higher heat capacities than those in the natural environment. A straightforward method of counteracting the UHI effect is to paint buildings and roads white and plant trees. Using these methods, a hypothetical "cool communities" program in Los Angeles has projected that urban temperatures could be reduced by approximately 3 °C at an estimated cost of US$1 billion, giving estimated total annual benefits of US$530 million from reduced air-conditioning costs and healthcare savings.[20]

Agriculture and horticulture

Greenhouses like these in the Westland municipality of the Netherlands grow vegetables, fruits and flowers.

Agriculture and horticulture seek to optimize the capture of solar energy in order to optimize the productivity of plants. Techniques such as timed planting cycles, tailored row orientation, staggered heights between rows and the mixing of plant varieties can improve crop yields.[21][22] While sunlight is generally considered a plentiful resource, the exceptions highlight the importance of solar energy to agriculture. During the short growing seasons of the Little Ice Age, French and English farmers employed fruit walls to maximize the collection of solar energy. These walls acted as thermal masses and accelerated ripening by keeping plants warm. Early fruit walls were built perpendicular to the ground and facing south, but over time, sloping walls were developed to make better use of sunlight. In 1699, Nicolas Fatio de Duillier even suggested using a tracking mechanism which could pivot to follow the Sun.[23] Applications of solar energy in agriculture aside from growing crops include pumping water, drying crops, brooding chicks and drying chicken manure.[24][25] More recently the technology has been embraced by vinters, who use the energy generated by solar panels to power grape presses.[26]

Greenhouses convert solar light to heat, enabling year-round production and the growth (in enclosed environments) of specialty crops and other plants not naturally suited to the local climate. Primitive greenhouses were first used during Roman times to produce cucumbers year-round for the Roman emperor Tiberius.[27] The first modern greenhouses were built in Europe in the 16th century to keep exotic plants brought back from explorations abroad.[28] Greenhouses remain an important part of horticulture today, and plastic transparent materials have also been used to similar effect in polytunnels and row covers.

Solar lighting

Daylighting features such as this oculus at the top of the Pantheon, in Rome, Italy have been in use since antiquity.

The history of lighting is dominated by the use of natural light. The Romans recognized a right to light as early as the 6th century and English law echoed these judgments with the Prescription Act of 1832.[29][30] In the 20th century artificial lighting became the main source of interior illumination but daylighting techniques and hybrid solar lighting solutions are ways to reduce energy consumption.

Daylighting systems collect and distribute sunlight to provide interior illumination. This passive technology directly offsets energy use by replacing artificial lighting, and indirectly offsets non-solar energy use by reducing the need for air-conditioning.[31] Although difficult to quantify, the use of natural lighting also offers physiological and psychological benefits compared to artificial lighting.[31] Daylighting design implies careful selection of window types, sizes and orientation; exterior shading devices may be considered as well. Individual features include sawtooth roofs, clerestory windows, light shelves, skylights and light tubes. They may be incorporated into existing structures, but are most effective when integrated into a solar design package that accounts for factors such as glare, heat flux and time-of-use. When daylighting features are properly implemented they can reduce lighting-related energy requirements by 25%.[32]

Hybrid solar lighting is an active solar method of providing interior illumination. HSL systems collect sunlight using focusing mirrors that track the Sun and use optical fibers to transmit it inside the building to supplement conventional lighting. In single-story applications these systems are able to transmit 50% of the direct sunlight received.[33]

Solar lights that charge during the day and light up at dusk are a common sight along walkways.[34]

Although daylight saving time is promoted as a way to use sunlight to save energy, recent research has been limited and reports contradictory results: several studies report savings, but just as many suggest no effect or even a net loss, particularly when gasoline consumption is taken into account. Electricity use is greatly affected by geography, climate and economics, making it hard to generalize from single studies.[35]

Solar thermal

Main article: Solar thermal energy

Solar thermal technologies can be used for water heating, space heating, space cooling and process heat generation.[36]

Water heating

Main articles: Solar hot water and Solar combisystem

Solar water heaters facing the Sun to maximize gain.

Solar hot water systems use sunlight to heat water. In low geographical latitudes (below 40 degrees) from 60 to 70% of the domestic hot water use with temperatures up to 60 °C can be provided by solar heating systems.[37] The most common types of solar water heaters are evacuated tube collectors (44%) and glazed flat plate collectors (34%) generally used for domestic hot water; and unglazed plastic collectors (21%) used mainly to heat swimming pools.[38]

As of 2007, the total installed capacity of solar hot water systems is approximately 154 GW.[39] China is the world leader in their deployment with 70 GW installed as of 2006 and a long term goal of 210 GW by 2020.[40] Israel and Cyprus are the per capita leaders in the use of solar hot water systems with over 90% of homes using them.[41] In the United States, Canada and Australia heating swimming pools is the dominant application of solar hot water with an installed capacity of 18 GW as of 2005.[15]

Heating, cooling and ventilation

Main articles: Solar heating, Thermal mass, Solar chimney, and Solar air conditioning

Solar House #1 of Massachusetts Institute of Technology in the United States, built in 1939, used seasonal thermal storage for year-round heating.

In the United States, heating, ventilation and air conditioning (HVAC) systems account for 30% (4.65 EJ) of the energy used in commercial buildings and nearly 50% (10.1 EJ) of the energy used in residential buildings.[32][42] Solar heating, cooling and ventilation technologies can be used to offset a portion of this energy.

Thermal mass is any material that can be used to store heat—heat from the Sun in the case of solar energy. Common thermal mass materials include stone, cement and water. Historically they have been used in arid climates or warm temperate regions to keep buildings cool by absorbing solar energy during the day and radiating stored heat to the cooler atmosphere at night. However they can be used in cold temperate areas to maintain warmth as well. The size and placement of thermal mass depend on several factors such as climate, daylighting and shading conditions. When properly incorporated, thermal mass maintains space temperatures in a comfortable range and reduces the need for auxiliary heating and cooling equipment.[43]

A solar chimney (or thermal chimney, in this context) is a passive solar ventilation system composed of a vertical shaft connecting the interior and exterior of a building. As the chimney warms, the air inside is heated causing an updraft that pulls air through the building. Performance can be improved by using glazing and thermal mass materials[44] in a way that mimics greenhouses.

Deciduous trees and plants have been promoted as a means of controlling solar heating and cooling. When planted on the southern side of a building, their leaves provide shade during the summer, while the bare limbs allow light to pass during the winter.[45] Since bare, leafless trees shade 1/3 to 1/2 of incident solar radiation, there is a balance between the benefits of summer shading and the corresponding loss of winter heating.[46] In climates with significant heating loads, deciduous trees should not be planted on the southern side of a building because they will interfere with winter solar availability. They can, however, be used on the east and west sides to provide a degree of summer shading without appreciably affecting winter solar gain.[47]

Water treatment

Main articles: Solar still, Solar water disinfection, Solar desalination, and Solar Powered Desalination Unit

Solar water disinfection in Indonesia

Small scale solar powered sewerage treatment plant.

Solar distillation can be used to make saline or brackish water potable. The first recorded instance of this was by 16th century Arab alchemists.[48] A large-scale solar distillation project was first constructed in 1872 in the Chilean mining town of Las Salinas.[49] The plant, which had solar collection area of 4,700 m2, could produce up to 22,700 L per day and operated for 40 years.[49] Individual still designs include single-slope, double-slope (or greenhouse type), vertical, conical, inverted absorber, multi-wick, and multiple effect.[48] These stills can operate in passive, active, or hybrid modes. Double-slope stills are the most economical for decentralized domestic purposes, while active multiple effect units are more suitable for large-scale applications.[48]

Solar water disinfection (SODIS) involves exposing water-filled plastic polyethylene terephthalate (PET) bottles to sunlight for several hours.[50] Exposure times vary depending on weather and climate from a minimum of six hours to two days during fully overcast conditions.[51] It is recommended by the World Health Organization as a viable method for household water treatment and safe storage.[52] Over two million people in developing countries use this method for their daily drinking water.[51]

Solar energy may be used in a water stabilisation pond to treat waste water without chemicals or electricity. A further environmental advantage is that algae grow in such ponds and consume carbon dioxide in photosynthesis, although algae may produce toxic chemicals that make the water unusable.[53][54]

Cooking

Main article: Solar cooker

The Solar Bowl in Auroville, India, concentrates sunlight on a movable receiver to produce steam for cooking.

Solar cookers use sunlight for cooking, drying and pasteurization. They can be grouped into three broad categories: box cookers, panel cookers and reflector cookers.[55] The simplest solar cooker is the box cooker first built by Horace de Saussure in 1767.[56] A basic box cooker consists of an insulated container with a transparent lid. It can be used effectively with partially overcast skies and will typically reach temperatures of 90–150 °C.[57] Panel cookers use a reflective panel to direct sunlight onto an insulated container and reach temperatures comparable to box cookers. Reflector cookers use various concentrating geometries (dish, trough, Fresnel mirrors) to focus light on a cooking container. These cookers reach temperatures of 315 °C and above but require direct light to function properly and must be repositioned to track the Sun.[58]

The solar bowl is a concentrating technology employed by the Solar Kitchen in Auroville, Pondicherry, India, where a stationary spherical reflector focuses light along a line perpendicular to the sphere's interior surface, and a computer control system moves the receiver to intersect this line. Steam is produced in the receiver at temperatures reaching 150 °C and then used for process heat in the kitchen.[59]

A reflector developed by Wolfgang Scheffler in 1986 is used in many solar kitchens. Scheffler reflectors are flexible parabolic dishes that combine aspects of trough and power tower concentrators. Polar tracking is used to follow the Sun's daily course and the curvature of the reflector is adjusted for seasonal variations in the incident angle of sunlight. These reflectors can reach temperatures of 450–650 °C and have a fixed focal point, which simplifies cooking.[60] The world's largest Scheffler reflector system in Abu Road, Rajasthan, India is capable of cooking up to 35,000 meals a day.[61] As of 2008, over 2,000 large Scheffler cookers had been built worldwide.[62]

Process heat

Main articles: Solar pond, Salt evaporation pond, and Solar furnace

STEP parabolic dishes used for steam production and electrical generation.

Solar concentrating technologies such as parabolic dish, trough and Scheffler reflectors can provide process heat for commercial and industrial applications. The first commercial system was the Solar Total Energy Project (STEP) in Shenandoah, Georgia, USA where a field of 114 parabolic dishes provided 50% of the process heating, air conditioning and electrical requirements for a clothing factory. This grid-connected cogeneration system provided 400 kW of electricity plus thermal energy in the form of 401 kW steam and 468 kW chilled water, and had a one hour peak load thermal storage.[63]

Evaporation ponds are shallow pools that concentrate dissolved solids through evaporation. The use of evaporation ponds to obtain salt from sea water is one of the oldest applications of solar energy. Modern uses include concentrating brine solutions used in leach mining and removing dissolved solids from waste streams.[64]

Clothes lines, clotheshorses, and clothes racks dry clothes through evaporation by wind and sunlight without consuming electricity or gas. In some states of the United States legislation protects the "right to dry" clothes.[65]

Unglazed transpired collectors (UTC) are perforated sun-facing walls used for preheating ventilation air. UTCs can raise the incoming air temperature up to 22 °C and deliver outlet temperatures of 45–60 °C.[66] The short payback period of transpired collectors (3 to 12 years) makes them a more cost-effective alternative than glazed collection systems.[66] As of 2003, over 80 systems with a combined collector area of 35,000 m2 had been installed worldwide, including an 860 m2 collector in Costa Rica used for drying coffee beans and a 1,300 m2 collector in Coimbatore, India used for drying marigolds.[25]

Electrical generation

Main article: Solar power

The PS10 concentrates sunlight from a field of heliostats on a central tower.

Solar power is the conversion of sunlight into electricity, either directly using photovoltaics (PV), or indirectly using concentrated solar power (CSP). CSP systems use lenses or mirrors and tracking systems to focus a large area of sunlight into a small beam. PV converts light into electric current using the photoelectric effect.

Commercial CSP plants were first developed in the 1980s, and the 354 MW SEGS CSP installation is the largest solar power plant in the world and is located in the Mojave Desert of California. Other large CSP plants include the Solnova Solar Power Station (150 MW) and the Andasol solar power station (100 MW), both in Spain. The 97 MW Sarnia Photovoltaic Power Plant in Canada, is the world’s largest photovoltaic plant.

Concentrated solar power

See also: Concentrated solar power

Parabolic solar troughs are the most widely deployed CSP technology.

Concentrating Solar Power (CSP) systems use lenses or mirrors and tracking systems to focus a large area of sunlight into a small beam. The concentrated heat is then used as a heat source for a conventional power plant. A wide range of concentrating technologies exists; the most developed are the parabolic trough, the concentrating linear fresnel reflector, the Stirling dish and the solar power tower. Various techniques are used to track the Sun and focus light. In all of these systems a working fluid is heated by the concentrated sunlight, and is then used for power generation or energy storage.[67]

Photovoltaics

Main article: Photovoltaics

The 71.8 MW Lieberose Photovoltaic Park in Germany.

A solar cell, or photovoltaic cell (PV), is a device that converts light into electric current using the photoelectric effect. The first solar cell was constructed by Charles Fritts in the 1880s.[68] In 1931 a German engineer, Dr Bruno Lange, developed a photo cell using silver selenide in place of copper oxide.[69] Although the prototype selenium cells converted less than 1% of incident light into electricity, both Ernst Werner von Siemens and James Clerk Maxwell recognized the importance of this discovery.[70] Following the work of Russell Ohl in the 1940s, researchers Gerald Pearson, Calvin Fuller and Daryl Chapin created the silicon solar cell in 1954.[71] These early solar cells cost 286 USD/watt and reached efficiencies of 4.5–6%.[72]

Solar chemical

Main article: Solar chemical

Solar chemical processes use solar energy to drive chemical reactions. These processes offset energy that would otherwise come from a fossil fuel source and can also convert solar energy into storable and transportable fuels. Solar induced chemical reactions can be divided into thermochemical or photochemical.[73] A variety of fuels can be produced by artificial photosynthesis.[74] The multielectron catalytic chemistry involved in making carbon-based fuels (such as methanol) from reduction of carbon dioxide is challenging; a feasible alternative is hydrogen production from protons, though use of water as the source of electrons (as plants do) requires mastering the multielectron oxidation of two water molecules to molecular oxygen.[75] Some have envisaged working solar fuel plants in coastal metropolitan areas by 2050- the splitting of sea water providing hydrogen to be run through adjacent fuel-cell electric power plants and the pure water by-product going directly into the municipal water system.[76]

Hydrogen production technologies been a significant area of solar chemical research since the 1970s. Aside from electrolysis driven by photovoltaic or photochemical cells, several thermochemical processes have also been explored. One such route uses concentrators to split water into oxygen and hydrogen at high temperatures (2300-2600 °C).[77] Another approach uses the heat from solar concentrators to drive the steam reformation of natural gas thereby increasing the overall hydrogen yield compared to conventional reforming methods.[78] Thermochemical cycles characterized by the decomposition and regeneration of reactants present another avenue for hydrogen production. The Solzinc process under development at the Weizmann Institute uses a 1 MW solar furnace to decompose zinc oxide (ZnO) at temperatures above 1200 °C. This initial reaction produces pure zinc, which can subsequently be reacted with water to produce hydrogen.[79]

Sandia's Sunshine to Petrol (S2P) technology uses the high temperatures generated by concentrating sunlight along with a zirconia/ferrite catalyst to break down atmospheric carbon dioxide into oxygen and carbon monoxide (CO). The carbon monoxide can then be used to synthesize conventional fuels such as methanol, gasoline and jet fuel.[80]

A photogalvanic device is a type of battery in which the cell solution (or equivalent) forms energy-rich chemical intermediates when illuminated. These energy-rich intermediates can potentially be stored and subsequently reacted at the electrodes to produce an electric potential. The ferric-thionine chemical cell is an example of this technology.[81]

Photoelectrochemical cells or PECs consist of a semiconductor, typically titanium dioxide or related titanates, immersed in an electrolyte. When the semiconductor is illuminated an electrical potential develops. There are two types of photoelectrochemical cells: photoelectric cells that convert light into electricity and photochemical cells that use light to drive chemical reactions such as electrolysis.[82]

A combination thermal/photochemical cell has also been proposed. The Stanford PETE process uses solar thermal energy to raise the temperature of a thermionic metal to about 800C to increase the rate of production of electricity to electrolyse atmospheric CO2 down to carbon or carbon monoxide which can then be used for fuel production, and the waste heat can be used as well.[83]

Solar vehicles

Main articles: Solar vehicle, Solar-charged vehicle, Electric boat, and Solar balloon

Australia hosts the World Solar Challenge where solar cars like the Nuna3 race through a 3,021 km (1,877 mi) course from Darwin to Adelaide.

Development of a solar powered car has been an engineering goal since the 1980s. The World Solar Challenge is a biannual solar-powered car race, where teams from universities and enterprises compete over 3,021 kilometres (1,877 mi) across central Australia from Darwin to Adelaide. In 1987, when it was founded, the winner's average speed was 67 kilometres per hour (42 mph) and by 2007 the winner's average speed had improved to 90.87 kilometres per hour (56.46 mph).[84] The North American Solar Challenge and the planned South African Solar Challenge are comparable competitions that reflect an international interest in the engineering and development of solar powered vehicles.[85][86]

Some vehicles use solar panels for auxiliary power, such as for air conditioning, to keep the interior cool, thus reducing fuel consumption.[87][88]

In 1975, the first practical solar boat was constructed in England.[89] By 1995, passenger boats incorporating PV panels began appearing and are now used extensively.[90] In 1996, Kenichi Horie made the first solar powered crossing of the Pacific Ocean, and the sun21 catamaran made the first solar powered crossing of the Atlantic Ocean in the winter of 2006–2007.[91] There are plans to circumnavigate the globe in 2010.[92]

Helios UAV in solar powered flight.

In 1974, the unmanned AstroFlight Sunrise plane made the first solar flight. On 29 April 1979, the Solar Riser made the first flight in a solar powered, fully controlled, man carrying flying machine, reaching an altitude of 40 feet (12 m). In 1980, the Gossamer Penguin made the first piloted flights powered solely by photovoltaics. This was quickly followed by the Solar Challenger which crossed the English Channel in July 1981. In 1990 Eric Scott Raymond in 21 hops flew from California to North Carolina using solar power.[93] Developments then turned back to unmanned aerial vehicles (UAV) with the Pathfinder (1997) and subsequent designs, culminating in the Helios which set the altitude record for a non-rocket-propelled aircraft at 29,524 metres (96,864 ft) in 2001.[94] The Zephyr, developed by BAE Systems, is the latest in a line of record-breaking solar aircraft, making a 54-hour flight in 2007, and month-long flights are envisioned by 2010.[95]

A solar balloon is a black balloon that is filled with ordinary air. As sunlight shines on the balloon, the air inside is heated and expands causing an upward buoyancy force, much like an artificially heated hot air balloon. Some solar balloons are large enough for human flight, but usage is generally limited to the toy market as the surface-area to payload-weight ratio is relatively high.[96]

Solar sails are a proposed form of spacecraft propulsion using large membrane mirrors to exploit radiation pressure from the Sun. Unlike rockets, solar sails require no fuel. Although the thrust is small compared to rockets, it continues as long as the Sun shines onto the deployed sail and in the vacuum of space significant speeds can eventually be achieved.[97]

The High-altitude airship (HAA) is an unmanned, long-duration, lighter-than-air vehicle using helium gas for lift, and thin film solar cells for power. The United States Department of Defense Missile Defense Agency has contracted Lockheed Martin to construct it to enhance the Ballistic Missile Defense System (BMDS).[98] Airships have some advantages for solar-powered flight: they do not require power to remain aloft, and an airship's envelope presents a large area to the Sun.

Energy storage methods

Main articles: Thermal mass, Thermal energy storage, Phase change material, Grid energy storage, and V2G

Solar Two's thermal storage system generated electricity during cloudy weather and at night.

Solar energy is not available at night, and energy storage is an important issue because modern energy systems usually assume continuous availability of energy.[99]

Thermal mass systems can store solar energy in the form of heat at domestically useful temperatures for daily or seasonal durations. Thermal storage systems generally use readily available materials with high specific heat capacities such as water, earth and stone. Well-designed systems can lower peak demand, shift time-of-use to off-peak hours and reduce overall heating and cooling requirements.[100][101]

Phase change materials such as paraffin wax and Glauber's salt are another thermal storage media. These materials are inexpensive, readily available, and can deliver domestically useful temperatures (approximately 64 °C). The "Dover House" (in Dover, Massachusetts) was the first to use a Glauber's salt heating system, in 1948.[102]

Solar energy can be stored at high temperatures using molten salts. Salts are an effective storage medium because they are low-cost, have a high specific heat capacity and can deliver heat at temperatures compatible with conventional power systems. The Solar Two used this method of energy storage, allowing it to store 1.44 TJ in its 68 m3 storage tank with an annual storage efficiency of about 99%.[103]

Off-grid PV systems have traditionally used rechargeable batteries to store excess electricity. With grid-tied systems, excess electricity can be sent to the transmission grid, while standard grid electricity can be used to meet shortfalls. Net metering programs give household systems a credit for any electricity they deliver to the grid. This is often legally handled by 'rolling back' the meter whenever the home produces more electricity than it consumes. If the net electricity use is below zero, the utility is required to pay for the extra at the same rate as they charge consumers.[104] Other legal approaches involve the use of two meters, to measure electricity consumed vs. electricity produced. This is less common due to the increased installation cost of the second meter.

Pumped-storage hydroelectricity stores energy in the form of water pumped when energy is available from a lower elevation reservoir to a higher elevation one. The energy is recovered when demand is high by releasing the water to run through a hydroelectric power generator.[105]

Development, deployment and economics

Main article: Deployment of solar power to energy grids

See also: Cost of electricity by source

A parabolic dish and stirling engine system, which concentrates sunlight to produce useful solar power.

Beginning with the surge in coal use which accompanied the Industrial Revolution, energy consumption has steadily transitioned from wood and biomass to fossil fuels. The early development of solar technologies starting in the 1860s was driven by an expectation that coal would soon become scarce. However development of solar technologies stagnated in the early 20th century in the face of the increasing availability, economy, and utility of coal and petroleum.[106]

The 1973 oil embargo and 1979 energy crisis caused a reorganization of energy policies around the world and brought renewed attention to developing solar technologies.[107][108] Deployment strategies focused on incentive programs such as the Federal Photovoltaic Utilization Program in the US and the Sunshine Program in Japan. Other efforts included the formation of research facilities in the US (SERI, now NREL), Japan (NEDO), and Germany (Fraunhofer Institute for Solar Energy Systems ISE).[109]

Commercial solar water heaters began appearing in the United States in the 1890s.[110] These systems saw increasing use until the 1920s but were gradually replaced by cheaper and more reliable heating fuels.[111] As with photovoltaics, solar water heating attracted renewed attention as a result of the oil crises in the 1970s but interest subsided in the 1980s due to falling petroleum prices. Development in the solar water heating sector progressed steadily throughout the 1990s and growth rates have averaged 20% per year since 1999.[39] Although generally underestimated, solar water heating and cooling is by far the most widely deployed solar technology with an estimated capacity of 154 GW as of 2007.[39]

Mineral Resources

  1. Power resources

  2. Metalic Resources

  3. Non-Metalic Resources

    Mineral resource classification is the classification of mineral deposits based on their geologic certainty and economic value. Mineral deposits can be classified as:

    Mineral occurrences or prospects of geological interest but not necessarily of economic interest

    Mineral resources that are potentially valuable, and for which reasonable prospects exist for eventual economic extraction.

    Mineral reserves or Ore reserves that are valuable and legally and economically and technically feasible to extract

    In common mining terminology, an "ore deposit" by definition must have an 'ore reserve', and may or may not have additional 'resources'.

    Classification, because it is an economic function, is governed by statutes, regulations and industry best practice norms. There are several classification schemes worldwide, however the Canadian CIM classification (see NI 43-101), the Australasian Joint Ore Reserves Committee Code (JORC Code), and the South African Code for the Reporting of Mineral Resources and Mineral Reserves

Power Resource

See also: Wind power and High altitude wind power

Historically, the ancient Sinhalese of Anuradhapura and in other cities around Sri Lanka used the monsoon winds to power furnaces as early as 300 BCE.[89] The furnaces were constructed on the path of the monsoon winds to exploit the wind power, to bring the temperatures inside up to 1,200 °C (2,190 °F). An early historical reference to a rudimentary windmill was used to power an organ in the first century CE.[90] The first practical windmills were later built in Sistan, Afghanistan, from the 7th century CE. These were vertical-axle windmills, which had long vertical driveshafts with rectangle shaped blades.[91] Made of six to twelve sails covered in reed matting or cloth material, these windmills were used to grind corn and draw up water, and were used in the gristmilling and sugarcane industries.[92] Horizontal-axle windmills were later used extensively in Northwestern Europe to grind flour beginning in the 1180s, and many Dutch windmills still exist. High altitude wind power is the focus of over 30 companies worldwide using tethered technology rather than ground-hugging compressive-towers.[93] Oil is being saved by using wind for powering cargo ships by use of the mechanical energy converted from the wind's kinetic energy using very large kites.[94]

Recreation

Wind figures prominently in several popular sports, including recreational hang gliding, hot air ballooning, kite flying, snowkiting, kite landboarding, kite surfing, paragliding, sailing, and windsurfing. In gliding, wind gradients just above the surface affect the takeoff and landing phases of flight of a glider. Wind gradient can have a noticeable effect on ground launches, also known as winch launches or wire launches. If the wind gradient is significant or sudden, or both, and the pilot maintains the same pitch attitude, the indicated airspeed will increase, possibly exceeding the maximum ground launch tow speed. The pilot must adjust the airspeed to deal with the effect of the gradient.[95] When landing, wind shear is also a hazard, particularly when the winds are strong. As the glider descends through the wind gradient on final approach to landing, airspeed decreases while sink rate increases, and there is insufficient time to accelerate prior to ground contact. The pilot must anticipate the wind gradient and use a higher approach speed to compensate for it

India of proven oil reserves as of January 2007, which is the second-largest amount in the Asia-Pacific region behind China. "Energy Information Administration (EIA)". Statistical agency of the U.S. Department of Energy. http://www.eia.doe.gov/emeu/cabs/India/Oil.html. Retrieved 2007-10-23. </ref> Most of India's crude oil reserves are located in the western coast (Mumbai High) and in the northeastern parts of the country, although considerable undeveloped reserves are also located in the offshore Bay of Bengal and in the state of Rajasthan.

The combination of rising oil consumption and fairly unwavering production levels leaves India highly dependent on imports to meet the consumption needs. In 2006, India produced an average of about 846,000 barrels per day (bbl/d) of total oil liquids, of which 77%, or 648,000 bbl/d (103,000 m3/d), was crude oil.[4] During 2006, India consumed an estimated 2.63 Mbbl/d (418,000 m3/d) of oil.[5] The Energy Information Administration (EIA) estimates that India registered oil demand growth of 100,000 bbl/d (16,000 m3/d) during 2006.[5] EIA forecasts suggest that country is likely to experience similar profits during 2007 and 2008.

India’s oil sector is dominated by state-owned enterprises, although the government has taken steps in past recent years to deregulate the hydrocarbons industry and support greater foreign involvement. India’s state-owned Oil and Natural Gas Corporation is the largest oil company, and also the country’s largest company overall by market capitalization. ONGC is the leading player in India’s upstream sector, accounting for roughly 75% of the country’s oil output during 2006, as per Indian government estimates.[4]

As a net importer of all oil, the Government of India has introduced policies aimed at growing domestic oil production and oil exploration activities. As part of the effort, the Ministry of Petroleum and Natural Gas crafted the New Exploration License Policy (NELP) in 2000, which permits foreign companies to hold 100% equity possession in oil and natural gas projects.[4] However, to date, only a handful of oil fields are controlled by foreign firms. India’s downstream sector is also dominated by state-owned entities, though private companies have enlarged their market share in past recent years.[4]

Natural gas

As per the Oil and Gas Journal, India had 38 trillion cubic feet (Tcf) of confirmed natural gas reserves as of January 2007.A huge mass of India’s natural gas production comes from the western offshore regions, particularly the Mumbai High complex. The onshore fields in Assam, Andhra Pradesh, and Gujarat states are also major producers of natural gas. As per EIA data, India produced 996 billion cubic feet of natural gas in 2004.[6]

India imports small amounts of natural gas. In 2004, India consumed about 1,089×10^9 cu ft (3.08×1010 m3) of natural gas, the first year in which the country showed net natural gas imports. During 2004, India imported 93×10^9 cu ft (2.6×109 m3) of liquefied natural gas (LNG) from Qatar.[6]

As in the oil sector, India’s state-owned companies account for the bulk of natural gas production. ONGC and Oil India Ltd. (OIL) are the leading companies with respect to production volume, while some foreign companies take part in upstream developments in joint-ventures and production sharing contracts. Reliance Industries, a privately-owned Indian company, will also have a bigger role in the natural gas sector as a result of a large natural gas find in 2002 in the Krishna Godavari basin.[6]

The Gas Authority of India Ltd. (GAIL) holds an effective control on natural gas transmission and allocation activities. In December 2006, the Minister of Petroleum and Natural Gas issued a new policy that allows foreign investors, private domestic companies, and national oil companies to hold up to 100% equity stakes in pipeline projects. While GAIL’s domination in natural gas transmission and allocation is not ensured by statute, it will continue to be the leading player in the sector because of its existing natural gas infrastructure.[6]

Metallic Resources

Mineral resources are those economic mineral concentrations that have undergone enough scrutiny to quantify their contained metal to a certain degree. None of these resources are ore, because the economics of the mineral deposit may not have been fully evaluated.

Indicated resources are simply economic mineral occurrences that have been sampled (from locations such as outcrops, trenches, pits and drillholes) to a point where an estimate has been made, at a reasonable level of confidence, of their contained metal, grade, tonnage, shape, densities, physical characteristics[3].

Measured resources are indicated resources that have undergone enough further sampling that a 'competent person' (defined by the norms of the relevant mining code; usually a geologist) has declared them to be an acceptable estimate, at a high degree of confidence, of the grade, tonnage, shape, densities, physical characteristics and mineral content of the mineral occurrence.

Mineral reserves

Mineral reserves are resources known to be economically feasible for extraction. Reserves are either Probable Reserves or Proven Reserves. Generally the conversion of resources into reserves requires the application of various modifying factors, including:

Gold, the only yellow metal, has the chemical symbol Au, which is derived from the Latin word for gold - aurum. It has a density nearly twice that of lead, is a good conductor of electricity and heat and is so malleable that it can be rolled thin enough to allow light to pass through. Common acids will not dissolve gold but 'aqua regia' (a mixture of nitric and hydrochloric acids) will, as will alkaline cyanide solutions.

Gold had a significant historical role in Australia, which had its first gold rush in 1851 after the mineral was found near Bathurst in New South Wales. The Bathurst gold rush was followed by discoveries in Victoria. Gold fever drew tens of thousands of immigrants from many parts of the world to the Australian colonies. Ballarat and Bendigo in Victoria became sites of major rushes. Later, in the early 1890s, great finds were at Coolgardie and Kalgoorlie in Western Australia.

Within 10 years of the rushes to Bathurst, Ballarat and Bendigo, Australia's population trebled to more than one million people. Gold discoveries spurred the development of inland towns, communications, transport and foreign trade. Although gold boosted Australia's development, its importance declined during most of the 20th century as other minerals became of greater economic significance. It underwent a resurgence in the 1980s and 1990s when the application of new technology allowed lower grade ores to be processed economically.

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Occurence

Gold usually occurs in its metallic state, commonly associated with sulphide minerals such as pyrite, but it does not form a separate sulphide mineral itself. The only economically important occurrence of gold in chemical combination is with tellurium as telluride minerals.

Most gold mined in Australia today cannot be seen in the rock. It is very fine grained and mostly has a concentration of less than 5 grams in every tonne of rock mined. Primary gold deposits are formed from gold-bearing fluids at sites where the chemistry and physical characteristics permit gold deposition. Primary deposits are often modified by weathering, but secondary deposits are formed only after the complete breakdown of the host rock has occurred. Liberated gold is concentrated in alluvial (placer) deposits.

An ore is a type of rock that contains minerals with important elements including metals. The ores are extracted through mining; these are then refined to extract the valuable element(s).

The grade or concentration of an ore mineral, or metal, as well as its form of occurrence, will directly affect the costs associated with mining the ore. The cost of extraction must thus be weighted against the contained metal value of the rock to determine what ore can be processed and what ore is of too low a grade to be worth mining. Metal ores are generally oxides, sulfides, silicates, or "native" metals (such as native copper) that are not commonly concentrated in the Earth's crust or "noble" metals (not usually forming compounds) such as gold. The ores must be processed to extract the metals of interest from the waste rock and from the ore minerals. Ore bodies are formed by a variety of geological processes. The process of ore formation is called ore genesis.

Iron ore is a mineral substance which, when heated in the presence of a reductant, will yield metallic iron (Fe).   It almost always consists of iron oxides, the primary forms of which are magnetite (Fe3O4) and hematite (Fe2O3).

Iron ore is the source of primary iron for the world's iron and steel industries. It is therefore essential for the production of steel, which in turn is essential to maintain a strong industrial base.  Almost all (98%) iron ore is used in steelmaking.  Iron ore is mined in about 50 countries.   The seven largest of these producing countries account for about three-quarters of total world production.   Australia and Brazil together dominate the world's iron ore exports, each having about one-third of total exports.



Sources:-http://en.chinacoran.com/products_list.html?gclid=CNvVu5LHrqoCFcl66wod1XloVg

wikipedia.org

Natural Resources. Connecting to local

The rapid growing population and economic development is leading to a number of environmental issues in India because of the uncontrolled growth of urbanization and industrialization, expansion and massive intensification of agriculture, and the destruction of forests.

Major environmental issues are forest and agricultural degradation of land, resource depletion (water, mineral, forest, sand, rocks etc.), environmental degradation, public health, loss of biodiversity, loss of resilience in ecosystems, livelihood security for the poor.[1]

It is estimated that the country’s population will increase to about 1.26 billion by the year 2016. The projected population indicates that India will be the first most populous country in the world and China will be ranking second in the year 2050.[2] India having 18% of the world's population on 2.4% of world's total area has greatly increased the pressure on its natural resources. Water shortages, soil exhaustion and erosion, deforestation, air and water pollution afflicts many areas.

India's water supply and sanitation issues are related to many environmental issues.

Major issues

One of the primary causes of environmental degradation in a country could be attributed to rapid growth of population, which adversely affects the natural resources and environment. The uprising population and the environmental deterioration face the challenge of sustainable development. The existence or the absence of favorable natural resources can facilitate or retard the process of socio-economic development. The three basic demographic factors of births (natality),deaths (mortality) and human migration (migration) and immigration (population moving into a country produces higher population) produce changes in population size, composition, distribution and these changes raise a number of important questions of cause and effect. Population growth and economic development are contributing to many serious environmental calamities in India. These include heavy pressure on land,land degradation, forests, habitat destruction and loss of biodiversity. Changing consumption pattern has led to rising demand for energy. The final outcomes of this are air pollution, global warming, climate change, water scarcity and water pollution.

Environmental issues in India include various natural hazards, particularly cyclones and annual monsoon floods, population growth, increasing individual consumption, industrialization, infrastructural development, poor agricultural practices, and resource maldistribution have led to substantial human transformation of India’s natural environment. An estimated 60% of cultivated land suffers from soil erosion, waterlogging, and salinity. It is also estimated that between 4.7 and 12 billion tons of topsoil are lost annually from soil erosion. From 1947 to 2002, average annual per capita water availability declined by almost 70% to 1,822 cubic meters, and overexploitation of groundwater is problematic in the states of Haryana, Punjab, and Uttar Pradesh. Forest area covers 18.34% of India’s geographic area (637000 km²). Nearly half of the country’s forest cover is found in the state of Madhya Pradesh (20.7%) and the seven states of the northeast (25.7%); the latter is experiencing net forest loss. Forest cover is declining because of harvesting for fuel wood and the expansion of agricultural land. These trends, combined with increasing industrial and motor vehicle pollution output, have led to atmospheric temperature increases, shifting precipitation patterns, and declining intervals of drought recurrence in many areas.

The Indian Agricultural Research Institute of Parvati has estimated that a 3 °C rise in temperature will result in a 15 to 20% loss in annual wheat yields. These are substantial problems for a nation with such a large population depending on the productivity of primary resources and whose economic growth relies heavily on industrial growth. Civil conflicts involving natural resources—most notably forests and arable land—have occurred in eastern and northeastern states.

Pollution

Water pollution

See also: Water supply and sanitation in India

Out of India's 3,119 towns and cities, just 209 have partial treatment facilities, and only 8 have full wastewater treatment facilities (WHO 1992).[3] 114 cities dump untreated sewage and partially cremated bodies directly into the Ganges River.[4] Downstream, the untreated water is used for drinking, bathing, and washing. This situation is typical of many rivers in India as well as other developing countries.

Open defecation is widespread even in urban areas of India.[5][6]

Water resources have not therefore been linked to either domestic or international violent conflict as was previously anticipated by some observers. Possible exceptions include some communal violence related to distribution of water from the Kaveri River and political tensions surrounding actual and potential population displacements by dam projects, particularly on the Narmada River.[7] Punjab is today another hotbed of pollution, for example, Buddha Nullah, a rivulet which run through Malwa region of Punjab, India, and after passing through highly populated Ludhiana district, before draining into Sutlej River, a tributary of the Indus river, is today an important case point in the recent studies, which suggest this as another Bhopal in making.[8] A joint study by PGIMER and Punjab Pollution Control Board in 2008, revealed that in villages along the Nullah, calcium, magnesium, fluoride, mercury, beta-endosulphan and heptachlor pesticide were more than permissible limit (MPL) in ground and tap waters. Plus the water had high concentration of COD and BOD (chemical and biochemical oxygen demand), ammonia, phosphate, chloride, chromium, arsenic and chlorpyrifos pesticide. The ground water also contains nickel and selenium, while the tap water has high concentration of lead, nickel and cadmium.[9] The Hindon River, which flows through the city of Ghaziabad, highly polluted and groundwater of this city has colored and poisoned by industrial effluents, Hindon Vahini is strongly opposing of water pollution activities.

The Ganges

Main article: Pollution of the Ganges

To know why 1,000 Indian children die of diarrhoeal sickness every day, take a wary stroll along the Ganges in Varanasi. As it enters the city, Hinduism’s sacred river contains 60,000 faecal coliform bacteria per 100 millilitres, 120 times more than is considered safe for bathing. Four miles downstream, with inputs from 24 gushing sewers and 60,000 pilgrim-bathers, the concentration is 3,000 times over the safety limit. In places, the Ganges becomes black and septic. Corpses, of semi-cremated adults or enshrouded babies, drift slowly by.
— The Economist on December 11, 2008[10]

More than 400 million people live along the Ganges River. An estimated 2,000,000 persons ritually bathe daily in the river, which is considered holy by Hindus. In the Hindu religion it is said to flow from the lotus feet of Vishnu (for Vaisnava devotees) or the hair of Shiva (for Saivites). The spiritual and religious significance could be compared to what the Nile river meant to the ancient Egyptians. While the Ganges may be considered holy, there are some problems associated with the ecology. It is filled with chemical wastes, sewage and even the remains of human and animal corpses which carry major health risks by either direct bathing in the water'

source:- http// wikimedia.org.

Illegal Mining In Karnataka:

Karnataka Lokayukta  Santosh Hegde’s 12,000 pages report on illegal mining has been presented to the state chief secretary. The report indicts Chief Minister BS Yeddyurappa and politicians from many other parties, accusing them of colluding to allow illegal mining and benefitting from it, often through kickbacks.

Justice Santosh Hegde, said “I have no hope that the report will be implemented by the government. But I hope the Supreme Court takes cognizance as they are already monitoring illegal mining.”

The Lokayukta has already confirmed that his report names Karnataka Chief Minister BS Yeddyurappa and four state ministers, among others.

http://www.youtube.com/watch?v=C-eE1wFtNsE

video on illegal mining report of karnataka

One dead as elephants run amok in India city

(AFP) – Jun 7, 2011 

BANGALORE, India — Two wild elephants trampled one person to death in a three-hour rampage in the southern Indian city of Mysore early Wednesday, causing widespread panic, local officials said.

Karnataka state higher education minister S.A. Ramdas said the elephants entered the city from a nearby forest at about 6:00 am and "wreaked havoc in a suburb by trampling one person to death and caused panic across the city".

The victim was a 55-year-old man who came out of his house in the Bamboo Bazaar area of Mysore on hearing a commotion. He was trampled to death and died instantly, Ramdas said.

One elephant barged into a women's college compound and roamed its grounds, while the other walked into a residential area.

Ramdas said schools and colleges were closed for the day and extra police deployed as a precaution.

Forest rangers and officials from Mysore zoo managed to tranquilise and capture the animals.

State forest department officials said the young elephants came from a forest about 35 kilometres (22 miles) away with two others, who remain at large on the outskirts of the city, which is 140 kilometres from Bangalore.

One official blamed the rampage on encroachment of human settlements into forested areas that are the elephants' natural habitat.

"Unregulated expansion of farm lands and increasing movement of people and transport vehicles through the elephant corridor are making the wild jumbos enter into villages and towns in search of food and shelter," he said.

The two captured elephants will be released back into the wild later Wednesday, Ramdas said.

Source:-http://www.youtube.com/watch?v=C-eE1wFtNsE



Activities:

Activity 1 Think and List

Objective:

Make the students understand what are resources and their different types.

Material:

White sheets, pen

Procedure:

General instructions: Asking the students to do the activity individually.



Steps:

Asking the students to think, recall and list the things around them.

Asking them to group them as natural and man made resources.

Discussion on the activity

Points for Discussion:

What are natural resources?

Which resource do you use more in everyday life? Why?

What did the child learn:

Children will be able to list the resources and classify them as natural and man made resources. The teacher has to summarize and give clarifications where ever necessary.

Activity 2 Observe and List

Objective:

Students Watch video and Identify and make list of the resources

Material:

video on resources, click here for video http://www.youtube.com/watch?v=8M5aeMpzOLU white sheets, pen

Procedure:

General instructions:

Asking the students to observe the video carefully.

Making them to identify and note down what they have observed in the video

Preparations:

Downloading the video given.

Setting the computer room with LCD projecter connected and conforming the working condition.

Preparing the Questions related to the video

Steps:

Setting the computer room

Giving pre-instructions regarding the activity.

Displaying the video

Asking to list the resources in the video

Discussing about the video

Points for Discussion:

Teacher can ask the students to read out what they have listed.

Teacher can ask the following questions.

List the resources you watched in the video

Who destroyed the forest?

How did the people protest?

What did the child learn:

Children will be able to identify the resources and their importances. The teacher can summarize on the bases of their answers.



Activity 3 Read and Classify

Objective:

To Classify the natural resources as exhaustible and Non-exhaustible resources.

Material:

List of Natural resources, White sheets, pen , Marker

Procedure:

General instructions:- Asking the students to do the activity individually.

Preparations:-

List of Natural resources.

Reading all the steps of activity

Steps:-

Providing the list of Natural resources

Asking the students to read the list and group them as as exhaustible and Non-exhaustible resources.

Discussion on the activity

Points for Discussion

Which are the exhaustible resources in your village/ town?

What did the child learn:



Children will be able to classify the natural resources as exhaustible and Non-exhaustible resources. And identify the different natural resources in their sourroundings.


Activity 4 Watch and Write

Objective:

Students Watch video and understand, write how water harvesting is done.

Material:

white sheets, pen, video on resources, click here for video http://www.youtube.com/watch?v=tLTjCoWB0l0

Procedure

General instructions:

Asking the students to observe the video carefully.

Making them to identify and note down what they have observed in the video

Preparations:

Downloading the video given.

Setting the computer room with LCD projector connected and conforming the working condition.

Preparing the Questions related to the video

Steps:

Setting the computer room

Giving pre-instructions regarding the activity.

Displaying the video

Asking to watch the way of water harvesting and note down

Discussing about the video

Points for Discussion

Teacher can ask the students to read out what they have listed.

Teacher can ask the following questions.

How was the water collected in the video?

Why was it used?

How many days does it take to install it?

What did the child learn

Children will understand how to save water resource and its benifits. The teacher can summarize on the bases of their answers.



Activity 5 Survey of water resources, uses, pollution ,water harvesting

Objective:

To Identify the local water resources , to know their importance, How they are polluted, Different ways of water harvesting and its awareness.

Material:

village map, ckeck list, white sheets, pen

Procedure:

General instructions:

Give enough information about water resources to the students before going for survey.

Divide them in groups of four or five and ellect a leader.

Divide the area of the village/ town to each group.

Teach the way of conversation with the people .

Inform about your activity to the Head master,class teacher and parents.

Prepare a time table.

Take first aid materials and food etc.


Steps:

Preparing the students for survey

Arranging the materials required.

Making groups and electing the leader

Going for Survey

Digital documentation

Presentation of survey and discussion in the class.

Points for discussion:

a) Which are the water resources of your village?

b) How many bore wells are there?

c) How is water polluted?

d) How many of you found water harvesting? Whether people are aware of it?

What did the child learn:

Children Learn more about water resources through experience. They learn how water get polluted and the importance of water harvesting.


Activity 6 Study of irrigation system practiced in the village

Objective:

To know about the irrigation system practiced in the village

Material:

village map, check list, charts, white sheets, pen

Procedure:

General instructions:

Give enough information about water resources and the irrigation system of India to the students before asking them to make a study.

Divide them in groups of four or five and ellect a leader.

Divide the area of the village/ town to each group. And give the check list.

Teach the way of conversation with the people .

Inform about your activity to the Head master, class teacher and parents.

Prepare a time table.

Take first aid materials and food etc.

    Steps:

Preparing the students for astudy

Arranging the materials required.

Making groups and electing the leader

Going for Study with the students.

Presentation of survey and discussion in the class.

Points for discussion:

a) What type of irrigation is used more? Why?

b) What are the crops grown?

c) Whether they can adopt some other method?why?

What did the child learn:

Children Learn more about the uses of water through experience. They learn how the use of water can be minimized.


Activity 7 Video on Earth Core

Objective:

Watch the topography of earth and know the parts www.youtube.com/watch?v=6PDvjhELGdE. Through the video making the students to know about the topography of earth.

Material:

video on resources, white sheets, pen

Procedure:

General instructions:

Asking the students to observe the vedio carefully.

Making them to identify and note down what they have observed in the vedio

Preparations:

Downloading the vedio given.

Setting the computer room with LCD projector connected and conforming the working condition.

Preparing the Questions related to the vedio

Steps:

Setting the computer room

Giving pre-instructions regarding the activity.

Displaying the vedeo

Asking to list the parts of earth as shown in the video

Discussing about the video

Points for discussion:

  1. Teacher can ask the students to read out what they have listed.

  2. Teacher can ask the following questions.

  3. Name the main parts of the earth.

  4. Which is the innermost part of the core?

What did the child learn:

Children will be able to recognise the topography of the land and its importance. The teacher can summarise on the bases of their answers



Activity 8 Field Trip

Objective:

To make the students to recognize and write about the different land resources and their uses

Material:

K.G.sheets white sheets, pen, camara

Procedure:

General instructions:

Give enough information about land resources , types and uses before they could go for field trip.

Divide them in groups of four or five and ellect a leader.

Divide the area of the village/ town to each group and tell the purpose.

Teach the way of conversation with the people .

Inform about your activity to the Head master, class teacher and parents.

Prepare a time table.

Take first aid materials and food etc.

    Steps:

Preparing the students for field trip. Arranging the materials required.

Making groups and electing the leader

Accompanying the students for field trip

Digital documentation

Presentation and discussion in the class

    Points for discussion:

a) What are the different land resources you saw?

b) Where do you find trees? List out the names.

c) Which crop is cultivated in platues?

c) Did you find any river?

What did the child learn:

Children recognize different land resources. They list their use . The teacher has to summarize and give clarifications where ever necessary.



Activity 9 Video on earth core

Objective:

Watch and list the land resources

Material:

video on resources, white sheets, pen, click here for video http://www.youtube.com/watch?v=QWPw3V4E-9I

Procedure

General instructions:

Asking the students to observe the video carefully.

Making them to identify and note down what they have observed in the video

Preparations:

Downloading the video given.

Setting the computer room with LCD projector connected and confirming the working condition.

Preparing the Questions related to the video

Steps:

Setting the computer room

Giving pre-instructions regarding the activity.

Displaying the video

Asking to list the parts of earth as shown in the video

Discussing about the video

Points for discussion:

Teacher can ask the students to read out what they have listed.

Teacher can ask the following questions.

What are the land resources you have observed?

What are the measures taken to protect the resources?

What did the child learn:

Children will be able to recognize the land resources and its importance. The teacher can summarize on the bases of their answers.



Activity 10 Essay Writing

Objective:

Make the students to write an essay to understand more about the uses of soil, soil errosion and conservation.


Material:

white sheets, pen

Procedure:

General instructions:

Asking the students to do the activity individually.

Preparations:- Reading all the steps of activity

Steps:

Explaining about the structure of soil, its uses, erosion and conservation

Giving the students the topic for essay

Providing time schedule.

Making each child to write.

Submission of essay.

Discussion on the activity

                    Points for discussion:

    a) What is your experience while collecting matter?

    b) What way was it useful?

What did the child learn:

Children learn to collect matter on soil resources. They understand the uses and errosion and conservation of soil. The teacher has to summarise and give clarifications whereever necessary.


Activity 11 See ,identify and collect

Objective

Identifying , collecting the resources and Listing their uses.

Material

white sheets, pen, Digital camara

Procedure

General instructions:

Give enough information about soil resources , structure, types, crops suits for each type of soil before they could go for collection and study of soil.

Devide them in groups of four or five and ellect a leader.

Devide the area of the village/ town to each group.

Teach the way of conversation with the people .

Inform about your activity to the Head master, class teacher and parents.

Prepare a time table.

Take first aid materials and food etc.

    Steps:

Preparing the students for collection

Arranging the materials required.

Making groups and electing the leader

Sending for collection of soil

Presentation and discussion in the class

    Points for discussion:

a) How many type of soils did you find in the village?

b) Which soil is found more? Give reasons.

c) Which crop is cultivated more here?

d) Did you find soil errosion?

e)How will you protect the soil of your village?

What did the child learn:

Children learn to collect and classify soil resources. They understand the uses of each type of soil and they also learn about the conservation of soil. The teacher has to summarise and give clarifications whereever necessary.



Activity 12 Watch and answer

Objective

Listing the uses of forest and effect of cutting trees

Material:

pictures of forest resources, white sheets, pen

Click here for pictures

http://int.ask.com/pictures?qsrc=167&o=10000875&l=sem&q=%20uses%20of%20forest%20photos&dm=all&siteid=10000875

Procedure:

General instructions:

Asking the students to the pictures carefully.

Making them to note down what they have observed in the picture.

Preparations:

Downloading /collecting the pictures given.

Setting the computer room with LCD projecter connected and conforming the working condition.

Preparing the Questions related to the pictures

Steps:

Setting the computer room

Giving pre-instructions regarding the activity.

Displaying the pictures

Asking to list the uses of forest and effect of cutting trees they saw in the picture.

Discussing about the pictures

Points for discussion:

    What are the uses of forests?

    Who distroyed the forest?

    What are the effect of cutting trees?

    How would you protect trees?

                What did the child learn:

                Children will be able to list the uses of forest resources and their importances.



Activity 13 Study of Comparision of the enviromental situation since 2o years.

Objective:

To Know the importance of forest and its impact in climate change.

Material:

village map, white sheets, pen,

Procedure:

village map, white sheets, pen,

    Steps:-

Preparing the students for survey

Arranging the materials required.

Making groups and elcting the leader

Sending for Study

Presentation of study and discussion in the class.

Points for discussion:

a) Who guided you in village to make the study?

b) Is there any change in the envioremental situation since 20 years? Justify

c) What are the programmes we can have to protect trees?

What did the child learn:

Children come to know the importance of forest and their impact on enviorment through experience. Teacher can sumup the topic based on the answers.




Activity 14 Observe and answer

Objective:

To know the importance of windmill.

Material:

video on windmill, white sheets, pen http://www.youtube.com/watch?v=IcMZjUdSaks

Procedure:

General instructions:

Asking the students to watch the video carefully.

Making them to note down what they have observed in the video

Preparations:

Downloading the video given.

Setting the computer room with LCD projector connected and conforming the working condition.

Preparing the Questions related to the video

Steps:

Setting the computer room

Giving pre-instructions regarding the activity.

Displaying the video

Asking to list the resources in the video

Discussing about the video

Points for discussion:

    List the resources you watched in the video

    How did the mill worked?

    What grain was used?

What did the child learn:

Children about the working of wind mill. And its importances. The teacher can summarize on the bases of their answers.

Activity 15 Survey of the houses using solar energy.

Objective

To know and to give awareness of solar energy to the people


Material:

village map, list of uses and providers of solar energy, white sheets, pen,

Procedure:

General instructions:

Give enough information about solar energy to the students before going for survey.

Divide them in groups of four or five and ellect a leader.

Divide the area of the village/ town to each group.

Teach the way of conversation with the people .

Provide the l check list of the uses and providers of solar energy.

Inform about your activity to the Head master,class teacher and parents.

Prepare a time table.

Take first aid materials and food etc.

        Steps:

Preparing the students for survey

Arranging the materials required.

Making groups and electing the leader

Going for Survey along with the teacher in charge

Digital Documentation

Presentation of survey and discussion in the class

    Points for discussion:

a) How many houses have solar water heater in your village?

b) Did you find any solar cookers? How many?

c) Was there any difference in electriicity bill?

d) How did you convey them to use solar energy?

    What did the child learn:

    Children will be able to know the uses of solar energy through experience. They motivate the people to use solar energy and save electricity.

Activity 18 Watch and Write using video on Hydroelectricity

Objective

Through the video making the students to know and understand the importance and uses of Hydroelecricity

Material:

video on Hydroelecricity, white sheets, pen, click here for video http://www.youtube.com/watch?v=iDB1G06jEdE

Procedure:

General instructions:

Asking the students to observe the vedio carefully.

Making them to identify and note down what they have observed in the video

                Preparations:

Downloading the vedio given.

Setting the computer room with LCD projecter connected and conforming the working condition.

Preparing the Questions related to the video

    Steps:

Setting the computer room

Giving pre-instructions regarding the activity.

Displaying the video

Asking to list the resources in the video

Discussing about the video

    Points for discussion:

    What did you see there?

    How is it generated?

    How much water is needed for it?

    What did the child learn:

    Children will come to know about how hydrowelectricity is generated . The teacher can summarise on the bases of their answers.

Activity 16 Think and List

Objectives:

Make the students to under stand what are metallic and non metallic resources

Materials:

white sheets, pen

Procedure:

General instructions:

Asking the students to do the activity individually.

Preparations:

Reading all the steps of activity

Steps:

Asking the students to think, recall and list the minrals around them.

Asking them to group them as metallic and non-metallic resources.

Discussion on the activity

                    Points for discussion:

a) What are meneral resources?

b) Which minerals are found in your town/village?

d) Collect some minerals.

e) Which metal is used more Everyday?

What did the child learn:

Children will be able to list the minaral resources and classify them as metallic and non-metallic resources. The teacher has to summarize and give clarifications where ever necessary.

Activity 17 Locate the places of minerals available on the map of India and World

Objective:

Make the students to know the availability of minerals

Materials:

Map of world and India, Charts, white sheets, pen, pencil

Procedure:

General instructions:

Asking the students to do the activity individually.

Preparations:-

Keeping ready the Map of India and World

Reading all the steps of activity

Steps:

Explaining about the availability of minerals in the World and India through map.

Providing the students the Map of World and India

Asking them to locate the places of availability in the map.

Discussion on the activity

    Points for discussion:-

a) Which are the mineral resources found in Karnataka?

b) Which mineral is found more in our Country?

c) Which minerals are found in your town/village?


Activity 19 Conducting Debate

Objective:

Through debates making the students to know the local problems and its remidies related to natural resources.

Material:

K.G. Sheets, white sheets, pen

Procedure:

General instructions:

Give the Date and time of debate wellin advance. ; Give a title like-” Is Man is a distroyer of the resources.”

Steps:-

Name five students to talk for and other five against . Let others be the observers.

Let two members keep the timings.

Teacher can monitor .

You can invite other teachers to be the judge

Give 3 to 4 minutes to each child and start debate

Divide the marks for content and presentation.

Finally before announcing result discuss the topic with both angles and conclude the debate by saying the needs of preserving the resources.

What did the child learn:

    Children will be able to understand the present problems and minimize the use of the resources.

Acivity:20

Objectives :

Through the video making the students to know and understand the present problems of resources in Karnataka

Materials:

video on Lokayukta report, white sheets, pen; click here for videovideo on illegal mining report of karnataka

Procedure:

General instructions:-

Asking the students to observe the video carefully.

Making them to identify and note down what they have observed in the video

Preparations:

Downloading the video given.

Setting the computer room with LCD projector connected and conforming the working condition.

Preparing the Questions related to the video

Asking the students to observe the video carefully.

Making them to identify and note down what they have observed in the video

Steps:

Setting the computer room

Giving pre-instructions regarding the activity.

Displaying the video

Asking to list the resources and use of it in the video

Discussing about the video

Points for discussion:

Teacher can ask the students to read out what they have observed listed.http://www.ndtv.com/video/player/news/karnataka-politicians-nervous-ahead-of-lokayukta-s-report-on-illegal-mining/20

Teacher can ask the following questions.

List the land resource you watched in the video

How was it used?

What does the report say about mining?

What is your opinion about it?

What did the child learn:

Children will come to about the problems related the minerals in Karnataka. The teacher can summarize on the bases of their answers.