The temperatures recorded in the first week of April were the highest ever recorded in Calcutta

The verdict is out and it’s loud and clear: it’s pay back time, folks, for all the injuries we have inflicted on Mother Nature. Nature has her own way of avenging itself, says the latest Intergovernmental Panel on Climate Change (IPCC) report, released earlier this month. Based on 75 individual studies that looked into as many as 29,000 data sets, this unprecedented scientific effort has found that all continents have, in some way or another, been affected by climate change. Human activity over the past few decades has left a discernible mark on most of the planet’s systems.

At a meeting in Brussels on April 6, IPCC scientists released a brief summary of their findings on how human activities are impacting global weather. The report warns that with global warming gathering momentum, the frequency and severity of floods and droughts will increase, depending on the location. There also looms the peril of a rise in temperatures by 1-2°C in tropical areas which, apart from creating heat waves, is likely to result in lower crop yields. The sea surface temperature is also predicted to rise by 1-3°C, which would severely affect most corals. There is also an increased risk of extinction among 20-30 per cent of plant and animal species if global temperatures go up.

While scientists find it difficult to establish a one-to-one connection between an individual, freaky weather event and climate change, everyone admits such abnormal occurrences have become far too frequent. For instance, the UK’s Met Office forecasts that the year 2007 is set to be the warmest on record. An extended warming period, resulting from an El Niñ event, is likely to increase global average surface temperatures this year by 0.54°C above the long-term (1961-1990) average of 14°C, beating the current record of 0.52°C, which was set in 1998, according to the World Meteorological Organization (WMO), Geneva.

El Niñ is a disruption of the ocean-atmosphere system in the tropical Pacific that has important consequences for weather and climate around the globe. It often results in the escalation of the sea surface temperature. The potential for a record summer arises partly from a moderate-strength El Niñ already established in the Pacific Ocean and this is expected to persist through the first few months of the year. The lag between El Niñ and the full global surface temperature response means that the warming effect of El Niñ is extended and, therefore, has a greater influence on global temperatures during the year. “This new information represents another warning that climate change is happening around the world,” says Katie Hopkins of the Met Office Consulting, UK.

So what does all this mean for the Indian sub-continent? The consequences of the global rise in temperatures are yet to be determined in our case, say experts. “It’s true the UK Met office has predicted that 2007 will be the warmest year on record. The prediction is based on many factors, including the El Niñ conditions that prevailed during the end of last year. However, the El Niñ conditions have now faded away and as per the predictions La Niña (cooling over central Pacific) conditions are to be established. Therefore, the expected warming may not take place,” Dr Madhavan Rajeevan, director, India Meteorological Department, Pune, told KnowHow. Nonetheless, there are chances that this summer will be a little warmer than usual, he adds.

For the first time in India, Rajeevan’s team at IMD’s National Climate Centre in Pune will soon begin to forecast summer mean temperatures in India, in an attempt to inform people about developing heat wave conditions well in advance.

For a vast country as India with varied geographical and climatic conditions it is difficult to make precise regional predictions as the conditions and magnitude of such effects vary from place to place, says Prof. B.N. Goswami, director, Indian Institute of Tropical Meteorology, Pune. “The prediction in question is a global one, so it doesn’t mean that all regions across the globe will be affected in the same manner,” he adds. However, he too conceded that India as a whole has been experiencing a steady rise in temperatures over the past few years. And what’s more, Calcutta may experience a slightly more severe summer than ever before. The temperatures recorded in the first week of April — the highest ever recorded in the city — could be an indication of this.

However, while some cities have witnessed a steep rise in temperatures, others have witnessed a drop in the them. And we cannot claim that the rise in temperatures is going to be a permanent trend, Goswami says.

Dr G.C. Debnath, director, IMD, Calcutta, is also of the same opinion. The IPCC report is a generalised one and one can’t say much about how this region is going to be affected as the temperature variation varies from region to region as well as the season, he says.

But going by the IPCC report, although no particular region can be zeroed in on to determine the climatic effects, people living at or near sea level, often crowded into cities along the coast, will be more vulnerable. Many millions of people will become vulnerable to flooding owing to a rise in sea levels by the 2080s, say the scientists. Drought, disease and extreme weather events will also become more frequent around the world, threatening the lives and livelihoods of countless more, warns another report in Nature.

The list of ominous signs seems to be endless. An article on Climate Change Index (an aggregate of several factors, it is a measure for the strength of future climate change relative to today’s natural variability), published in a recent volume of Geophysical Research Letters, also says that the strongest climate changes by the end of the 21st century will occur in the tropics and in high altitudes in the northern hemisphere. This also indicates the probability that the climate in less developed — and thus more sensitive and less adaptable — countries is expected to change more strongly than in more developed countries.