Human activities of pollution are modifying the natural process of green house effect. The advent of the Industrial Revolution in the 1700s boosted up the activities of burning of fossil fuels like coal, oil and natural gas which released lots of heat absorbing gases into the atmosphere.
Clearing of land for agriculture or for urban settlements wiped out the vegetation that acted as ecological sink for some of those gases like carbon dioxide. These heat absorbing gases accumulate in high concentrations in the upper atmosphere around the earth extending up to 100 km above its surface and act as glass panels of a green house. These accumulated gases allow much of the short wave solar radiation to reach to the earth surface but stop much of the long wave infrared rays against escaping out as heat. They absorb these infrared radiations and then re-radiate most of them back to the earth surface.
Thus, the temperature of the atmosphere rises gradually causing an unnatural heating effect which is called as the Global Warming. The Global Warming is the enhanced green house effect due to greater accumulation of GHGs in the upper atmosphere.
The warming of the earth’s atmosphere attributed to a buildup of green house gases in high concentration in the atmosphere is called as the Global Warming. It is a term which is used to refer to the observed increase in the average temperature of the earth’s atmosphere and oceans in recent decades.
Scientific discoveries reveal that the world experienced warmest atmosphere during last 50 years out of the period of 100 years. The global mean temperature increased by about 0.5 to 1 degree Celsius, within a period of last 100 years.
Global Warming and Climate Change
The regular pattern of weather conditions of a particular place is called as climate of that place. This regular pattern of weather conditions is considerably disturbed by fluctuations in temperature. The disturbance in the pattern of weather conditions at a particular place may rightly be called as Climate Change.
The Global Warming itself is not the Climate Change as the effects of global warming may not be uniformly negative. But, it is the abnormal rise in global temperature that is causing changes in the global climate. Let us see, how abnormal changes in temperature may lead to climate change.
Temperature has significant role in the regulation of water cycle in the environment. Hence, rise in global temperature can change the pattern of water cycle. On the other hand, increased temperature can cause most of the ice to melt down. The increased evaporation of water due to high temperature may alter the pattern of cloud formation and rains at different places. The physical features of the earth also play important roles in causing temperature variations that finally result into variations in air pressures. These variations cause disastrous conditions like storms, cyclones, tornadoes and hurricanes etc.
International agencies studying the climate change have projected the globally averaged temperature to increase by 1.4 to 5.8 degrees Celsius over the period 1990 to 2100. The Intergovernmental Panel on Climate Change (IPCC) does important climatic researches and surveys on periodic basis. It has hundreds of scientists from many different countries that study and analyse the meteorological changes and provide a collective pictures of global warming and other changes in the climate systems. The Third Assessment Report of IPCC was released in January 2001.
According to the reports of Asia-Least Cost Green House Gas Abatement Strategy (ALGAS) Project, the energy sector is the largest contributor of GHG (55%) in India. The ALGAS Project in India is funded by the Asian Development Bank, Global EnvironmentalFacility (GEF) and United Nations Environmental Programme (UNEP).
Impact of Global Warming
The Global Warming has various types of impacts on the whole earth and its systems. Some of the major impacts of Global Warming are mentioned below.
- Global Warming may cause frequent natural disasters like cyclones, storms and hurricanes, floods and droughts. It may also cause cloud bursts, avalanches, landslides, mud- flows and earthquakes.
- Global Warming is causing melting of ice and glaciers which is leading to a rise in sea- level. As a result, the creeping up of oceans swallow low lying islands and coastal areas.
The rising sea level is causing loss of land, loss of property and loss of lives. It may also cause large scale displacement of people which may further create a problem of rehabilitation.
- It is damaging forests, agriculture and water supplies.
- It is damaging various ecosystems like mangrove- swamps, coral reefs and coastal lagoons etc. due to various reasons like reduction in pH of oceanic water and increasing deposits of acids.
- Some populations of migratory birds have been declining because of unfavorable variations in climatic conditions. On the other hand the migration time of spring butterflies in Britain has become earlier than it was 30 years ago.
It has been observed that the behaviors of some bird species have changed due to climatic variations in the Indian state of Orissa. Some birds like Black Headed Oriole and Open Billed Stork have changed their times of migration where as some birds like Bronze Winged Jacana and Indian Small Skylark have changed their nesting behaviors
6. The change in climate due to rise in global temperature is causing migration of species of wild animals towards poles and high altitudes. Since those areas are already inhabited by animals of different species, the migrated species receive the status of Refugee Species.
Prevention and Control of Global Warming
The Global Warming can be prevented and controlled by following important measures-
- Reduction on the consumption of fossil fuels by depending on non- conventional renewable sources of energy like wind, sunlight, nuclear and bio- energy.
- Checking the GHGs at the source of their production and disposing them elsewhere.
- Collection or recovery of GHGs already present in the atmosphere and their disposal.
- Learning to adopt and accept the changes in the climate.
- International co-operation for reduction of GHGs emission with full majority.
Periodic Surveys, researches and assessments have proved that the global warming causing changes in the world climates is increasing day by day. It is currently recognized as an important global issue. Representatives from over 160 countries have met regularly to discuss ways to reduce GHG emission. In 1997 a conference was organized in Kyōto, Japan, in which world nations signed an agreement called as Kyōto Protocol.
According to the Protocol, the industrialized nations were required to cut their GHG emissions to an average of 5 percent below 1990 levels, by 2012. Russia’s cabinet approved the treaty in 2004 and paved the way to start it with effect from 2005. The protocol has been ratified by more than 126 countries. But Australia and U.S. did not support the protocol.
In early December 2005, representatives from 90 countries met in Montreal, Canada, to discuss ways on cutting down the use of fossil fuels so as to ensure less emission of carbon dioxide. According to the Montreal bulletins, the CO2 level in the atmosphere is now higher within past 650,000 years. Unfortunately the two biggest CO2 emitters of the world – Australia and United States refused to cut down their emissions.
Global warming, linked to greenhouse effect, Kyōto Protocol, Montreal bulletins