There are two more important hazards which are posing challenges to future existence of our civilization are Green House Effect and Ozone Depletion.
Green House Effect:
This is a phenomenon characterized by warming of the Earth’s atmosphere resulting from absorption of infrared radiation from atmospheric constituents. Radiant energy arrives through sunlight, which is remitted by the surface at infrared wave lengths as heat. Carbon dioxide and water vapour in the atmosphere absorb this infrared radiation and act as a blanket, with net effect atmospheric temperature rise.
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In the Earth more deforestation and burning of fossil fuel enhances water vapour, carbon dioxide, ethane, so there is likely to be a gradual increase in the mean air temperature of several degrees, which may result in melting of polar ice and a rise in mean sea level.
The rise in sea level will have immediate impact on coastal life such as aquaculture, agriculture and forestry. This may also result substantive loss of life, submergence of areas, destruction of property. The global process of industrialization has brought such a change in the situation. This warming of Earth due to greenhouse effect is a challenge to human civilization.
Image Source: astrocampschool.org
Ozone Depletion:
Ozone is a form of oxygen having molecules 03. “It is formed by the action of ultraviolet radiation on ordinary oxygen and is a gas, boiling point—112° centigrade” (The Cambridge Paper Back Encyclopedia). The gas Ozone is concentrated on the stratosphere. It is produced by the action of ultraviolet light from the sun in the air.
The ozone layer shields the Earth from harmful effects of solar ultra violet radiation, but can be decomposed by complex chemical reactions, notably involving chlorofluorocarbons (CPAs). International concern over the appearance of a ‘hole’ in the Ozone layer over the Antarctic in the 1980s led to a movement for the CFC producing devices.
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In 1987, the Montreal Protocol was signed by around 40 countries to limit their use, with the intention that by 1999 worldwide consumption of CFCs should be 50 percent of 1986 levels. In 1989, the European Community Meeting agreed to cut CFCs consumption by 85% as soon as possible and altogether by the end of the century.
Reports that short-lived holes have been observed above the Arctic have led to renewed efforts in Europe to reach agreement on accelerated reduction in CFC consumption. The Antarctica hole was estimated to be 28 mn sq. km in 1998, a 5 percent rise as compared with 1996″. (The Cambridge paperback encyclopedia).
The protocol as was signed among the nations decided that Ozone Depleting Substances (ODS) would be phase out. In India under Environment (Protection) Act 1986, it was decided that industries using ODS would be discouraged, commercial banks have instructed not to issue finance for industries those who would use ODS technologies.
Environmental protection became a key issue at Stockholm conference, in 1972. The United Nations Framework Convention on climate change (UNFCCC) aimed at stabilisation of greenhouse gas concentrations in the atmosphere at levels that would prevent dangerous anthropogenic interference with the climate system.
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However, as per existing commitments, India is not required to adopt any restrictions and limitation of greenhouse gas emissions. But later protocol such as Kyoto conference called for joint efforts of developed and developing economies to cut greenhouse gas emissions.
Empirical data suggests that, Globally SPM has increased the level of death; hypertension in Mexico and Bangkok, Solid wastes from many cities remains uncollected, solid degradation and soil erosion have caused decline in GNP of many countries.
Deforestation in all the countries, (particularly tropical regions) increased ultraviolet ray radiation. Ultraviolet radiation produces petrochemical smog out of nitric oxides and unburnt hydrocarbons. Thus environmental degradation has been causing serious problems for developed as well as developing economy.