Sunday, April 12, 2009

Global Warming: The Heat is On...

The world cannot remain a fossil fool anymore, oblivious of the environmental destruction wrought as it guzzles fuels like coal and oil and causes global warming. Global Warming is the phenomenon of the increase in the average temperature of the earth’s surface due to the increased concentration of Greenhouse Gases (GHGs) like Carbon dioxide (CO2), Methane (CH4), Sulphur dioxide (SO2), Nitrogen Oxide (N2O), Chlorofluorocarbons due to the burning of fossil fuels.

The Inter-governmental Panel on Climate Change (IPCC) has been established by the World Meteorological Organisation (WMO) and the United Nations Environment Programme (UNEP) to assess scientific, technical and socio-economic information relevant for the understanding of climate change, its potential impacts and options or adaptations and mitigation.

The IPCC’s report has left no room for scepticism on Global Warming. “The warming of the climate system is unequivocal, as is now evident from increases in global average air and ocean temperatures, widespread melting of snow and ice and rising global mean sea level”, the report stated. The following are the main findings of the report :
* Global temperature will increase between 2 and 11.5 degrees Fahrenheit (1.1 and 6.4 degrees Celsius), by the end of this century over pre-industrial levels.
* A best-guess temperature rise is between 3.2 and 7.1 degrees Fahrenheit (1.8 and 4 degrees Celsius), though the high end remains possible.
* Sea levels are projected to rise between 7 and 23 inches (18 and 59 centimeters) by the end of the century.
* If recent melting in Greenland and Antarctica continues, sea levels could rise an additional 4 to 8 inches (10 to 20 centimeters).
* Temperatures and sea levels will continue to rise for centuries even if greenhouse gas emissions are stabilised today.
* Eleven of the last 12 years rank among the 12 warmest years in the instrumental record, which stretches back to 1850.
* Observational evidence suggests an increase in hurricane strength in the North Atlantic since 1970 that correlates with an increase in sea surface temperatures.
* In some projections, Arctic sea will disappear in the late summer by the later part of this century.
* It is very likely that hot extremes, heat waves, and heavy rains will continue to become more frequent.
* The Gulf Stream, which brings warm waters to the North Atlantic, may slow but is unlikely to shut down as depicted in the Hollywood disaster movie The Day After Tomorrow.

The report built on past IPCC assessment and incorporating new findings since 2001 provides the strongest statement so far on the extent and causes of climate change. It stated that the world has just eight years to act and bring down the concentration of heat-trapping gases in the atmosphere at 445 ppm if the rising global temperatures are to be contained between 2 to 2.4 degrees Celsius above the pre-industrial era.

The report warned that emissions of heat-trapping gases had increased alarmingly by 70 per cent between 1970 and 2004, with levels of carbon dioxide increasing by 80 per cent over the same period. In an ominous prediction, it noted that if the world continues to burn fossil fuels along current lines, then the dangerous emissions would rise by 90 per cent by 2030.

The recommendations mark repudiation of arguments of both developing and developed countries. Countering the argument of the developing countries, like India and China, that reducing emissions would hit their economies, the report says that at worst, the global Gross Domestic Product (GDP) would be blunted by about three per cent by 2030 if it undertakes these emission cuts. It, however, admits that some countries will bear the brunt more than others.

On the other hand, developed countries have also been bluntly told that they would have to change their lifestyles and alter consumption patterns. These countries, with a mere 20 of the world’s population, account for 50 per cent of greenhouse gas emissions. The message for them is that mere adoption of technologies would not do.

The report stated that the impact of human activities now extends to other aspects of climate, including ocean warming and sea level rise, continental average temperatures, temperature extremes and wind patterns. An important new finding is that sea level rise accelerated in the 20th century. The report also described other important changes that have become pronounced in recent years, such as more intense precipitation, an increase in precipitation in higher altitudes, the increased frequency of droughts across the world and probably tropical cyclones too, more warm nights and fewer cold nights, the increased retreat of glaciers since the 1990s and its contribution to sea level rise, and greater warming of the Arctic than the rest of the world.

India Too Feel’s the Heat
There was a jolt for India when the report, given the possible economic losses due to its long coastline, dependence on monsoon and large number of people dependent on agriculture, considered India to be one of the most vulnerable to climate change.

Rainfall: One of the direct effects of Global Warming is the altering of the heat budget and its regional variations in the atmosphere, the primary driver of weather systems around the world. The potential impact of warming on the monsoon in India is of serious concern, particularly with respect to agriculture, much of which is rain fed. Indeed, nearly 80 per cent of India’s water resources go to meet agricultural needs.

Recent evidence of the unpredictability of the monsoon, the unusual distribution of rainfall in space and time, the shifting patterns of precipitation, the sustained deficit rainfall and drought-like conditions in some regions and excessive rainfall in others are being considered as permanent or quasi-permanent changes in monsoon behaviour as a result of Global Warming. It is said that rainfall extremes such as the Mumbai deluge of 2005 could become more frequent in India under the impact of climate change. Both 2005 and 2006 had spells of excessive rainfall that normally would have occurred once in 100 years or so.

A study by scientists of the Indian Institute of Tropical Meteorology (IITM), Pune has found a general increase in precipitation and Surface Air Temperature (SAT) for the country as a whole for the period 2071-2100. The annual mean increase in SAT ranges from 2 to 5°C and is more pronounced over northern India. As far as rainfall patterns are concerned, spatial rainfall patterns show a maximum increase over west central India and the northeastern region. Extreme precipitation is found to increase substantially over the western coast and west central India. Overall, the summer monsoon rainfall shows a 20 per cent increase over the present and the increase is seen in all the States except Punjab, Rajasthan and Tamil Nadu, which show a slight decrease. Similarly winter rainfall may experience a five to 25 per cent decline even as monsoon rainfall shows a 10-15 per cent increase.

These changes in rainfall pattern will have significant impact on water resource situation in the subcontinent. A fall in winter precipitation implies greater water stress during a lean summer monsoon season. Second, intense rain occurring during the summer monsoon months will mean that much of the monsoon rain would be lost as direct run-off, leading to lower groundwater recharging potential. Groundwater is the chief source of water to meet the domestic needs of over 80 per cent of the rural and 50 per cent of the urban populations and also meets the needs of about 50 per cent of irrigated agriculture.

Receding Himalayan Glaciers: Important rivers of northern India such as the Ganga and the Brahmaputra are fed by the meltwater from the Himalayan glaciers. There is enough evidence to prove melting of glaciers because of Global Warming in the 20th century, and the Himalayan glaciers, too, have been found to be retreating rapidly. Gangotri, one of the largest glaciers in the Himalayas, has been reducing at an alarming rate in recent years, influencing the stream run-off of Himalayan rivers. The reduced sizes of many permanent snow and ice fields have already led to water scarcity in villages in Himachal Pradesh.

Cyclones and Storm Surges: An important effect of Global Warming on meteorological conditions in an increase in sea surface temperature in the oceans, resulting in an increase in the intensity or wind speed of cyclones that form in them, particularly over the Bay of Bengal where over 80 per cent of the cyclones originate. Higher wind speeds will also result in bigger storm surges. The recent IPCC report has projected a global mean sea-level rise of 0.59 m by the end of the 21st century. Combining these projections with over surveys, scientists have concluded that storm surge heights will be far greater under warm conditions. The increased surge heights are over and above the mean sea level, which itself rises under the impact of warming. The risk of cyclone-related disasters is thus far greater in a warmer subcontinent. The vulnerability of the large number of Indians living on the 7000 km Indian coastline is huge due to the fact that a quarter of India’s population lives within 50 km of the coastline. The mean sea level rise itself, in the absence of protection, can inundate a large chunk of predominantly agricultural land on the coast, and the surviving coastline faces the threat of extreme storm surges.

Food Security: The impact of climate change on crop productivity and food security will also be severe. An increase in the atmospheric concentration of Carbon dioxide (CO2) and higher temperatures could have potentially serious consequences for both plant and animal species that depend on periodically available resources in the ecosystems. Another major impact could be a shift towards wetter forest types in the northeastern region and drier forest types in the northwestern region, thus impacting the biodiversity of the country.

Health: Global Warming and climatic changes will have a significant impact on health through vector borne diseases. This will be because of changes in the survival and reproduction rates of the carriers, the intensity and temporal pattern of vector activity, and the lifecycle of pathogens within the vectors. It is being anticipated that due to greater frequency and security of heat waves and other extreme weather conditions, there will be an increase in the number of deaths.

How to Beat the Heat?
As India prepares to launch on its 11th Five-Year Plan (2007-12) and target 10 per cent growth, it must ask whether it is doing enough to combat Global Warming. The imperative of escaping from poverty cannot justify ostentations consumption on a higher count of billionaires.
Developing countries such as India are more vulnerable to climate change than industrialised countries and hence have a greater stake in the success of global climate negotiations and strategies for greenhouse gas stabilisation. Any delay in action to address climate change will make further actions more expensive and even more difficult to agree upon and implement.

No comments: