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India and the challenge of global warming

N. Gopal Raj

A sharp rise in sea level could have a considerable impact as about a quarter of the population lives within 50 km of the coastline. Balancing greenhouse gas emissions and economic growth is another worry.

"WARMING OF the climate system is unequivocal," said the Intergovernmental Panel on Climate Change (IPCC) in its latest assessment report, pointing to increased global air and ocean temperatures, widespread melting of snow and ice, and rising sea levels. The international panel of scientists that has the task of evaluating evidence of climate change found that the burning of fossil fuels, some agricultural practices, and changes in land use have been generating gases like carbon dioxide, methane, and nitrous oxide that trapped heat and produced runaway global warming.

If the production of these greenhouse gases continued to soar, global temperatures could rise by up to 6.4 degrees Celsius by the end of this century with far-reaching consequences for the climate, warned the IPCC.

The widespread melting of mountain glaciers and polar ice caps had already contributed to rising sea levels, according to the IPCC's fourth assessment report, a summary of which was released on Friday (February 2, 2007). According to the report, there has been an acceleration in sea level rise since 1993. Between 1961 and 2003, the sea level had increased an average rate of 1.8 mm a year. But between 1993 and 2003, the rate of rise had nearly doubled to 3.1 mm a year.

The fourth assessment report predicted sea levels increasing by up to 0.59 metres by the end of the 21st century. But the report also points out that 125,000 years ago, which was the last time the polar regions were significantly warmer than at present for an extended period, sea levels rose by four to six metres as the ice melted.

However, the IPCC took the view that an increase in sea level on a similar scale as the Greenland ice sheet disappeared under the influence of global warming might take thousands of years.

Some experts fear the IPCC prediction is too conservative. Recently, Stefan Rahmstorf of the Potsdam Institute of Climate Impact Research in Germany published a paper in the journal Science arguing that "a rise [in sea level] of over 1 metre by 2100 for strong warming scenarios cannot be ruled out."

A sharp rise in sea level could have a considerable impact on India. The United Nations Environment Programme included India among the 27 countries that are most vulnerable to a sea level rise. About a quarter of India's population lives within 50 km of the coastline. The mega cities of Mumbai and Chennai with large and growing populations and huge investments in infrastructure are located on the coast.

Besides, much of the coastal region has fertile agricultural land. Low-level areas, such as those in Orissa and West Bengal, could be vulnerable to inundation. An increase in sea level could also lead to salt water entering the groundwater aquifers on which people depend for drinking water and to irrigate their fields, points out Suruchi Bhadwal of The Energy and Resources Institute in Delhi.

Simulations with a regional climate model indicated that by the middle of this century powerful cyclones could arise more frequently in the Bay of Bengal during the post-monsoon period as a result of climate change, according to a paper by A.S. Unnikrishnan of the National Institute of Oceanography in Goa and other scientists that was published last year. Some empirical studies of cyclones that had occurred in the Bay were already discerning such a trend, they added.

The monsoon has hitherto been a largely stable phenomenon, remarked J. Srinivasan, an atmospheric scientist at the Indian Institute of Science in Bangalore. But there was growing evidence that global warming had put the climate in a different mode and therefore the future could be different from the past, he told this correspondent

Simulations with climate models as well as observational data indicated that droughts and spells of excessive rain like the deluge that struck Mumbai in 2005 were likely to become more frequent in India as the world warmed. It was worrying that both during the 2005 and 2006 monsoons there were spells of exceptionally heavy rain that ordinarily would have occurred once in a hundred years, noted Dr. Srinivasan

"Any major changes in rainfall patterns will have far-reaching consequences for agriculture and water availability," he pointed out.

Melting glaciers

Glaciers in the Himalayas feed important rivers such as the Ganga, the Indus, and the Brahmaputra that provide water for millions of people as well as for irrigation and industry. The accelerated melting these glaciers are experiencing as a result of the earth's warming will have a profound effect on future water availability.

The Gangotri glacier, one of the largest in the Himalayas, has been retreating rapidly in recent decades. Anil Kulkarni of the Space Applications Centre in Ahmedabad along with other scientists examined the data for 466 glaciers in the Himalayas and found that their surface area has shrunk by about 21 per cent since 1962. As the glaciers retreated, they became more fragmented. The smaller glaciers were more sensitive to global warming, said the scientists in a paper published recently.

Changes in temperature and rainfall associated with global warming could result in about 80 per cent of the existing forests in the country undergoing a change in the type of vegetation, according to R. Sukumar, an environmental scientist at the Indian Institute of Science. Such changes were bound to have a very significant impact on the forests and the wildlife they supported. As the Indian forests were already highly fragmented, many species of plants and animals might not be able to cope with climate change and could, therefore, face extinction.

Hitherto, it has been the developed countries that have been the worst emitters of greenhouse gases. The U.N. Framework Convention on Climate Change, which came into force in 1994 and seeks to stop the emissions from rising to dangerous levels, recognised as much, noting that "the largest share of historical and current global emissions of greenhouse gases has originated in developed countries, that per capita emissions in developing countries are still relatively low and that the share of global emissions originating in developing countries will grow to meet their social and development needs."

Consequently, when the Kyoto Protocol was negotiated, developed countries were required to reduce their greenhouse gas emissions while no such obligation was placed on developing countries. But as evidence of global warming becomes incontrovertible and the consequences of climate change grow clearer and more alarming, there is likely to be increasing pressure on the United States, which spews out more greenhouse gases than any other nation but refuses to accept the Kyoto Protocol, as well as on China and India to reduce their emissions.

"Compared with Europe, Japan and the United States, China and India have contributed far less to the heightened carbon dioxide concentrations now in the atmosphere," point out Christopher Flavin and Gary Gardner of the Worldwatch Institute based in Washington, D.C. "But [China's and India's] emissions have increased by 67 per cent and 88 per cent respectively since 1990, and their shares are projected to grow steadily in the decades to come, making it clear that no serious solution to the world's climate problem is possible without their active participation."

India's carbon dioxide equivalent emissions of greenhouse gases could increase to 3,000 million tonnes by 2020, which would be about twice the emission level in 2000, according to information given in a paper by Subodh Sharma of the Ministry of Environment and Forests and others that was published in the journal Current Science last year. Even so, India's emissions would account for less than five per cent of global emissions in 2020 and its per capita emissions would be low when compared to most developed countries.

Since greenhouse gas emissions were directly linked to economic growth, India's economic activities would necessarily involve increased emissions, pointed out the authors of the Current Science paper. Any constraint on emissions would hamper economic development, they stated.

There are measures that India could easily take to limit its emissions, believes N.H. Ravindranath of the Centre for Sustainable Technologies at the Indian Institute of Science. The burning of coal for power generation was a major source of emissions and clean coal technologies could help reduce the pollution. Electricity consumption could be reduced by about 25 per cent with greater energy efficiencies in manufacturing processes, houses, and offices, and by using better irrigation pumps.

There had to be greater use of renewable sources of energy, he argues. Mass transportation systems needed to be supported and the country should invest heavily in the railways so that goods could be transported with the least consumption of fossil fuels.

The poor in India, from fishermen along the coast to tribals and dryland farmers, would be very vulnerable to changes brought about by global warming, pointed out Dr. Ravindranath. "India should play a positive role in promoting global action to reduce greenhouse gas emissions," he told this correspondent.

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