People And Their Problems

New Delhi, 24 March 2007

Landmark IPCC Report

Global Warming Likely to Continue

By Dhurjati Mukherjee

The UN Inter-governmental Panel on Climate Change (IPCC), a 2500-member strong group of scientists, in its fourth report issued in Paris recently, has presented overwhelming scientific consensus on greenhouse gas emissions and put the onus on these human-induced gases since the Industrial Revolution. In the past, climate scientists had made strides in pinpointing useful information and generating powerful computer models. In the new report prepared by scientists from 113 countries, researchers have gone one step ahead in using nearly two dozen models to produce projections of temperature and sea-level rises, all anchored with multiple lines of scientific evidence.

“Warning of the climate system is unequivocal as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice and rising global mean sea level”, the report said. As expected, most of the increase in global averaged temperatures since the mid 20^th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations. That is an advance since the Third Assessment Report’s conclusion that “most of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations”.  Discernible human influences now extend top other aspects of climate, including ocean warming, continental-average temperatures, temperature extremes and wind patterns.

Continued greenhouse gas emissions at or above current rates would cause further warming and induce many changes in the global climate system during the 21^st century that would very likely be larger than those observed during the 20^th century. It is indeed significant to note that global temperatures are predicted to rise by 1.1 to 6.4⁰C with a rise of 4⁰C most likely by the year 2100, which would have disastrous consequences for the human race.

At Continental, regional and ocean basin scales, numerous long-term changes in climate have been observed. These include changes in Arctic temperatures and ice, widespread changes in precipitation amounts, ocean salinity, wind patterns and aspects of extreme weather, including droughts, heavy precipitation, heat waves and the intensity of tropical cyclones. Indian scientists, who were part of the IPCC exercise, said that most computer-based models predict an increase in monsoon rainfall when the rise in only atmospheric carbon dioxide is taken into account. 

The obvious effects may be summarized as follows: loss of food production with global levels expected to fall by 10 per cent while African crops slumping between 15 and 35 per cent; increased flooding with sea levels rising up to 59 cm. and Bangladesh and Vietnam to be the worst hit countries along with coastal cities such as London, New York, Tokyo, Hong Kong, Kolkata and Karachi; upward trend is very likely in hot extremes and heat waves will continue; melting ice of West Antarctica and Greenland; more diseases exposing 80 million additional people; 25 to 50 per cent land species threatened with extinction; and water shortages affecting southern Africa and the Mediterranean severely. 

In fact, the situation today has reached a critical stage. It has been clearly stated in the report that even if concentrations could be held at the current levels, the effects of global warming would continue for centuries because it takes very long to remove the gases from the atmosphere. There is need to seriously ponder what needs to be done at this juncture as it goes without saying that eliminating the threat of global warming would require radical action.

The report has pointed out that a concerted action could stave off the direct consequences of global warming such as widespread flooding, drought and extreme weather conditions. Stabilizing atmospheric levels of carbon dioxide, the primary contributor to global warming, would require reducing carbon dioxide emissions by 70 to 80 per cent. Such a reduction would bring equilibrium with the planner’s natural ability to absorb carbon dioxide. It may be worthwhile to recall here that the last time the planet was in balance was more than 150 years ago before the widespread use of coal and steam engines. 

Scrapping all fossil fuel powered electricity plants worldwide and replacing them with wind mills, solar panels and nuclear power plants would make a serious dent in the problem but the question remains whether this will become possible in the immediate future. Compounding the problem is the fast pace of industrial development that has been taking place in the Third World countries, especially in China and India.

The impact of climate change on food production has been an area of great concern. The effect of high temperatures may affect India’s rice production. Temperature is a major determinant of crop development and growth and studies reveal that rice yields would dip by 10 per cent for each degree increase in minimum temperature during the growing season. Climatologists expect that global mean air temperature may go up between 1.4 to 5.8 ⁰C by the end of the century, depending on changes in greenhouse gas concentrations.

With rapid population growth, rice production in the country has to be enhanced to about 122 million tonnes by the year 2020 to meet the increasing demand. But scientific studies presented at a recent conference of the International Rice Research Institute (in October 2006) have contended that the results of climate change impact may adversely affect rice yields not just in Northwest India but all over the country.

Even an impact assessment of climate change carried out on behalf of the Indian Council for Agricultural Research (ICAR) indicated that though in the short-term, rice production may not be affected significantly; in the long-term climate change would have serious impacts. In another study on Northwest India by the ICAR, researchers pegged the range of yield reduction from the technological determined level from 7 per cent in 2020 to 25 per cent in 2080.  

The Executive Director of the UN Environment Programme, Achim Steiner, stated and very rightly: “Anyone who would continue to risk inaction on the basis of the evidence presented will one day in the history books be considered irresponsible”. Another report by the Panel is expected later this year that would address the most effective measures for slowing global warming.

The Kyoto Protocol has so far been the main plan for capping greenhouse gases until 2012 but it has been severely weakened since the US pulled out in 2001. Though talks are under way for its post-2012 commitments, the participation on America and China is an urgent necessity. By some estimates, today’s emissions must be reduced by half globally by 2050 to peg the temperature rise by 2100 to 2⁰ C compared with post-industrial levels. However, at this juncture scientists the world over would eagerly await the measures, preferably country-specific and time bound, that are expected to be announced by the IPCC to control the pace of climate change and reduce global warming to the extent humanly possible.---INFA

 (Copyright, India News and Feature Alliance)