CLIMATE CHANGE

Climate change refers to a statistically significant variation in either the mean state of the climate or in its variability, which is attributed directly or indirectly to anthropogenic activities that alter the composition of global atmosphere and which are in addition to natural climatic variability observed over comparable time periods.

While the world's climate has always varied naturally, the vast majority of scientists now believe that rising concentrations of "greenhouse gases" in the earth's atmosphere, resulting from economic and demographic growth over the last two centuries since the industrial revolution, are overriding this natural variability and leading to irreversible climate change. The implications of "global warming" are far reaching, and include rises in sea levels, changes in rainfall patterns (increasing the threat of drought or floods in many regions) and a greater threat of extreme weather events, such as intense storms and heat waves. Climate change could, therefore, have potentially dramatic negative socio-economic and environmental impacts.

PHENOMENON INVOLVED: GREENHOUSE GAS EFFECT

The atmosphere carries out the critical function of maintaining life-sustaining conditions on Earth, in the following way: each day, energy from the sun (largely in the visible part of the spectrum, but also some in the ultraviolet and infra red portions) is absorbed by the land, seas, mountains, etc. If all this energy were to be absorbed completely, the earth would gradually become hotter and hotter. But actually, the earth both absorbs and, simultaneously releases it in the form of infra red waves (which are invisible but can be felt as heat). All this rising heat is not lost to space, but is partly absorbed by some gases present in very small (or trace) quantities in the atmosphere, called greenhouse gases (GHGs).

The main greenhouse gases are water vapour, carbon dioxide, methane, nitrous oxide, and the chlorofluorocarbons (CFCs). Levels of all key greenhouse gases (with the possible exception of water vapour) are rising as a direct result of anthropogenic activities. Concentration of carbon dioxide (mainly from burning coal, oil, and natural gas), methane and nitrous oxide (due to agriculture and changes in land use), and CFCs (produced by industries) are changing at an unprecedented speed. The result is known as the "enhanced greenhouse effect". This could lead to greater warming, which in turn, could have an impact on world's climate leading to the phenomenon known as "climate change".

The climate system must adjust to rising greenhouse gas levels to keep the global "energy budget" in balance. In long term, the earth must get rid of energy at the same rate at which it receives energy from the sun. Since a thicker blanket of greenhouse gases helps to reduce energy loss to space, the climate must change somehow to restore the balance between incoming and outgoing energy. This adjustment will include a "global warming" of the earth's surface and lower atmosphere. But this is only part of the story. Warming up is the simplest way for the climate to get rid of the extra energy. But even small rise in temperature will be accompanied by many other changes: in cloud cover and wind patterns, for example. Some of these changes may act to enhance the warming, others to counteract it.

India scenario @ 1990 shows, total CO₂-equivalent emissions were 1001352 Gg and this figure was approximately 3% of global emissions. Energy sector contributes the main CO₂ source with 55% of national emissions, which includes the emissions from transport sector, coal mining, and fugitive emissions from oil and natural gas. Second largest source for GHGs in India was from the agriculture sector with 34% of national GHGs; leads from methane emissions from enteric fermentation in domestic animals, manure management, rice cultivation, and burning of agricultural residues. Emissions from land use change and forestry (LULUCF) sector, results in negligible emissions (ADB-GEF-UNDP 1998).

IMPACTS OF CLIMATE CHANGE

GLOBAL

Global climate is changing drastically w.r.t the anthropogenic activities. Extensive research and computer models have been developed in recent years to get a coherent relationship between the climatic change & various other factors. Industrialized countries contributes to the major part of the responsibility for growing concentration of green house gases and the major burden is on the developing countries that will receive the imminent negative impacts due to their vulnerable socioeconomic, political, and environmental conditions.

The effects of global warming are difficult to quantify because of the complicated relationships between air temperature, precipitation quantity and pattern, vegetative cover and soil moisture. However, it is likely to harm humanity in following ways:

• The most dramatic change has been in the temperature, with measurement records suggesting that warming by 0.3-0.6 °C has already taken place since the 1860s. Over the next hundred years, the earth's surface temperature is projected to increase by 1.4 to 5.8 °C.

• As a result of increased temperature, the large quantities of water locked in the polar ice caps and glaciers will be released as a consequence of warming. This, together with an increase in the thermal expansion of the oceans, will make the global mean sea level rise by 9 cm to 88 cm.

• A rise in sea level could inundate and erode coastal areas, increase flooding and salt-water intrusion; this will affect coastal agriculture, fisheries and aquaculture, freshwater resources, human settlements and tourism.

• The frequency and duration of heat waves will increase, which, combined with greater humidity and urban air pollution, will cause a greater number of heat related illness and deaths.

• A general reduction is expected in potential crop yields in most tropical and sub-tropical regions. Mid-continental areas -- such as the United States' "grain belt" and vast areas of Asia -- are likely to dry. Where dry land agriculture relies solely on rain, as in sub-Saharan Africa, yields would decrease dramatically even with minimal increases in temperature. Such changes could cause disruptions in food supply.

• By the 2080's, substantial dieback of tropical forests and grasslands is predicted to occur, particularly in parts of South America and Africa.

• The availability of water in the rivers of Australia, India, southern Africa, South America, Europe and the Middle East is expected to decrease. Salt-water intrusion from rising sea levels will further reduce the quality and quantity of freshwater supplies.

• Most of the world's endangered species -- around 25 per cent of mammals and 12 per cent of birds -- may become extinct over the next few decades as warmer conditions alter the forests, wetlands, and rangelands they depend on.

• Higher temperatures are expected to expand the range of some dangerous "vector-borne" diseases, such as malaria, which already kills 1 million people annually, most of them children.

• Environmental damage -- such as overgrazed rangeland, deforested mountainsides, and denuded agricultural soils -- means that nature will be more vulnerable than previously to changes in climate.

• World's vast human population, much of it poor, is vulnerable to climate stress as millions live in dangerous places -- on floodplains or in shantytowns on exposed hillsides around the enormous cities of the developing world.

• Higher summer temperatures will increase the demand for energy for space cooling.

• Some regions at mid-latitudes will have increased crop yields for increases in temperature of a few degrees Celsius.

• An increase in global timber supply from appropriately managed forests.

• More water in some water-scarce regions-for example, in parts of Southeast Asia.

• Reduced winter mortality in mid-and high latitudes.

• Higher winter temperatures will reduce energy demand for space heating.

• In India, climate change could represent additional pressure on ecological and socio-economic systems that are already under stress due to rapid urbanization, industrialization, and economic development. With its huge and growing population, a 7500-km long densely-populated and low-lying coastline, and an economy that is closely tied to its natural resource base, India is considerably vulnerable to the impacts of climate change.

• Most countries in temperate and tropical Asia have already felt the impact of extreme climate events such as droughts and floods. The intensity of extreme rainfall events is projected to be higher in a warmer atmosphere, suggesting a decrease in return period for extreme precipitation events and the possibility of more frequent flash floods in parts of India, Nepal, and Bangladesh.

• Increases in temperature and seasonal variability in precipitation are expected to result in more rapid recession of Himalayan glaciers. In fact, the Gangotri glacier is already retreating at a rate of 18-20 meters a year.

• An increase in rainfall is simulated over the eastern region of India but the northwestern deserts may see a small decrease in the absolute amount of rainfall.

• Warmer and wetter conditions would increase the potential for a higher incidence of heat-related and infectious diseases. The incidence and extent of vector-borne diseases, which are significant causes of mortality and morbidity in tropical Asia, are likely to spread into new regions on the margins of present endemic areas as a result of climate change.

COMBATING CLIMATE CHANGE

To slow or reverse greenhouse gas emissions all governments need to develop and implement policies to combat climate change. In the early years these policies tended to be rather fragmented; now they are becoming more coherent and linked to sustainable development. The overall aims are to achieve production that is less carbon-intensive and to increase the use of alternative sources of energy, while boosting energy efficiency - in industries, in buildings, in transportation and appliances. Fiscal measures were among the most widely used in developed countries, often combined with financial incentives such as grants and preferential loan rates and tariffs.

• India signed UNFCCC on 10 June 1992 and ratified it on 1 November 1993.

• India acceded to the Kyoto Protocol on 26 August 2002.

• Ministry of Environment and Forests (Govt. of India), the nodal ministry to deal the climate change issues has a separate cell for climate change and another group known as 'Working group on the UNFCCC and Kyoto Protocol' to deliberate the actions that has to be made with regard to the climatic change issues.

• In accordance with the Annex decision 17/CP.7; the Govt. of India has constituted the National CDM Authority (NCDMA) on 16th April, 2004. The Indian NCDMA is operational since December 2003.

• Ministry of Non-conventional Energy Sources has separate Climatic Change Advisory Committee working to create appropriate methodologies for implementing RETs in the country and thus increasing the CDM potential.

• In addition to the above groups established by MoEF & MNES a separate group is working under the Planning Commission on the PMO advice.