• Environment is defined as total planetary inheritance and totality of all resources. It includes all biotic and abiotic factors that influence each other.
• All living elements—the birds, animals & plants, forests, fisheries, etc.—are biotic elements, abiotic elements include air, water, land, etc. Rocks and sunlight are examples of abiotic elements of environment.
• A study of environment calls for a study of inter-relationship between these biotic and abiotic components of environment.
• Environment crises occurs when carrying capacity of environment is challenged through excessive exploitation of natural resources or when generation of wastes exceeds absorptive capacity of environment.
Functions of Environment
• The environment performs four vital functions: (i) it supplies resources: resources here include both renewable and non-renewable resources, (ii) it assimilates waste (iii) it sustains life by providing genetic and biodiversity and (iv) it provides aesthetic services like scenery, etc.
• Renewable resources are those which can be used without possibility of resource becoming depleted or exhausted. That is, a continuous supply of resource remains available. Examples of renewable resources are trees in forests and fishes in ocean.
• Non-renewable resources, on other hand, are those which get exhausted with extraction and use; for example, fossil fuels.
• The environment can perform these functions without any interruption as long as demand for these functions is within its carrying capacity.
• This implies that resource extraction is not above rate of regeneration of resource and that wastes generated are within assimilating capacity of environment.
• When this is not so, environment fails to perform its third and vital function of life sustenance and this results in an environmental crisis. This is situation today all over world.
• Absorptive capacity means ability of environment to absorb degradation.
• Global environmental issues such as global warming and ozone depletion contribute to increased financial commitments for government. Thus, it is clear that opportunity costs of negative environmental impacts are high.
• Global warming is a gradual increase in average temperature of earth’s lower atmosphere as a result of increase in greenhouse gases since Industrial Revolution. It is caused by man-made increases in carbon dioxide and other greenhouse gases through burning of fossil fuels and deforestation.
• Adding carbon dioxide, methane & other gases (that have potential to absorb heat) to atmosphere with no other changes will make our planet’s surface warmer.
• Some of longer-term results of global warming are melting of polar ice with a resulting rise in sea level and coastal flooding; disruption of drinking water supplies dependent on snow melts; extinction of species as ecological niches disappear; more frequent tropical storms; and an increased incidence of tropical diseases.
• Ozone depletion refers to phenomenon of reductions in amount of ozone in stratosphere.
• The problem of ozone depletion is caused by high levels of chlorine and bromine compounds in stratosphere.
• The origins of these compounds are chlorofluorocarbons (CFCs), used as cooling substances in air conditioners and refrigerators, or as aerosol propellants, and bromo fluorocarbons (halons), used in fire extinguishers.
• As a result of depletion of ozone layer, more ultraviolet (UV) radiation comes to Earth and causes damage to living organisms.
• UV radiation seems responsible for skin cancer in humans; it lowers production of phytoplankton and thus affects other aquatic organisms. It can influence growth of terrestrial plants.
State of India’s Environment
• The threat to India’s environment poses a dichotomy—the threat of poverty-induced environmental degradation and, at same time, threat of pollution from affluence and a rapidly growing industrial sector.
• Air pollution, water contamination, soil erosion, deforestation and wildlife extinction are some of most pressing environmental concerns of India.
• In 1974, Government of India set up Central Pollution Control Board to address two major environmental concerns of India, air pollution and water pollution.
• The priority issues identified are: (i) land degradation (ii) biodiversity loss (iii) air pollution with special reference to vehicular pollution in urban cities (iv) management of fresh water and (v) solid waste management.
• Land in India suffers from varying degrees and types of degradation stemming mainly from unstable use and inappropriate management practices.
• Some of factors responsible for land degradation are: (i) loss of vegetation occurring due to deforestation (ii) unsustainable fuel wood and fodder extraction (iii) shifting cultivation (iv) encroachment into forest lands (v) forest fires and overgrazing (vi) non-adoption of adequate soil conservation measures (vii) improper crop rotation (viii) indiscriminate use of agro-chemicals such as fertilisers and pesticides (ix) improper planning and management of irrigation systems (x) extraction of groundwater in competing uses of land for forestry, agriculture, pastures, human settlements and industries exert enormous pressure on country’s finite land resources. (xi) open-access resources and (xii) poverty of agriculture-dependent people.
• The per capita forest land in country is only 0.06 hectares against requirement of 0.47 hectares to meet basic needs, resulting in an excess felling of about 15 million cubic metres of forests over permissible limit.
• Estimates of soil erosion show that soil is being eroded at a rate of 5.3 billion tonnes a year for entire excess of recharge capacity.
• According to Government of India, quantity of nutrients lost due to erosion each year ranges from 5.8 to 8.4 million tonnes.
• Vehicular emissions are of particular concern since these are ground-level sources and, thus, have maximum impact on general population.
• The various measures adopted by Ministry of Environment and central and state pollution control boards may not yield a reward unless we consciously adopt a path of sustainable development.
• Environment and economy are interdependent and need each other. Hence, a development that ignores its repercussions on environment will destroy environment that sustains life forms.
• The concept of sustainable development was emphasised by United Nations Conference on Environment and Development (UNCED), which defined it as: ‘Development that meets needs of present generation without compromising ability of future generation to meet their own needs’.
• The term Sustainable development has its origin in International Union for Conservation of Nature (IUCN) 1980 World Commission Strategy Report.
• Meeting needs of all requires redistributing resources and is hence a moral issue.
• Sustainable development aims at decreasing absolute poverty of poor by providing lasting and secure livelihoods that minimise resource depletion, environmental degradation, cultural disruption and social instability.
• The present generation can promote development that enhances natural and built environment in ways that are compatible with: (i) conservation of natural assets (ii) preservation of regenerative capacity of world’s natural ecological system (iii) avoiding imposition of added costs or risks on future generations.
• In 2015, UN formulated 17 Sustainable Development Goals (SDGs) intended to be achieved by year 2030.
Strategies for Sustainable Development Use of Non-conventional Sources of Energy
• India is hugely dependent on thermal and hydropower plants to meet its power needs. Both of these have adverse environmental impacts.
• Thermal power plants emit large quantities of carbon dioxide which is a greenhouse gas. It produces fly ash which, if not used properly, can cause pollution of water bodies, land & other components of environment.
• Wind power and solar rays are good examples of conventional energy sources. In recent years, some efforts have been made to tap these energy resources.
LPG, Gobar Gas in Rural Areas
• Households in rural areas usually use wood, dung cake or other biomass as fuel. This practice has several adverse implications like deforestation, reduction in green cover, wastage of cattle dung and air pollution.
• To rectify situation, subsidised LPG is being provided. In addition, gobar gas plants are being provided through easy loans and subsidies.
• Liquefied petroleum gas (LPG) is a clean fuel as it reduces household pollution to a large extent. Energy wastage is minimised.
• For gobar gas plant to function, cattle dung is fed to plant and gas is produced which is used as fuel while slurry which is left over is a very good organic fertiliser and soil conditioner.
CNG in Urban Areas
• In Delhi, use of Compressed Natural Gas (CNG) as fuel in public transport system has significantly lowered air pollution and air has become cleaner.
• In areas where speed of wind is generally high, windmills can provide electricity without any adverse impact on environment. Wind turbines move with wind and electricity is generated. The initial cost is high but benefits are such that high cost gets easily absorbed.
Solar Power through Photovoltaic Cells
• India is naturally endowed with a large quantity of solar energy in form of sunlight.
• With help of photovoltaic cells, solar energy can be converted into electricity. These cells use special kinds of materials to capture solar energy and then convert energy into electricity.
• This technology is extremely useful for remote areas and for places where supply of power through grid or power lines is either not possible or proves very costly. This technique is totally free from pollution.
• India is leading an international body known as International Solar Alliance (ISA).
• In mountainous regions, streams can be found almost everywhere. A large percentage of such streams are perennial.
• Mini-hydel plants use energy of such streams to move small turbines. The turbines generate electricity which can be used locally.
• Farmers, in large numbers all over country, have started using compost made from organic wastes of different types. In certain parts of country, cattle are maintained only because they produce dung which is an important fertiliser and soil conditioner.
• Earthworms can convert organic matter into compost faster than normal composting process.