The Mercury touched 47°C in some parts of the Capital last week and the India Meteorological Department issued an Orange alert. The rising temperatures is a cause of worry because climatologists tell SHAlINI SAKSENA that things are only going to get hotter from here on
For the last few years, North India has been witnessing an unprecedented heatwave with temperatures touching 47°C upwards. Experts say that there can’t be just one reason for this kind of weather across North India. Of course, global warming is a major contributor but there are other factors as well, though not directly related.
Air pollution can be linked to extended summer months. “Usually pollutants lead to an increase in the minimum temperature. This is because the particles get scattered leading to the rise in temperature. On the other hand, the maximum temperature gets reduced. But this is not the case now. Though one needs more study and analyses to be absolutely sure that there is a direct link, it can’t be denied either that it is a distinct possibility,” Dr Arvind Kumar Srivastava, director National Climate Centre, Indian Meteorological Department, Pune, says.
He also tells you that since the effect of air pollution on temperature is a subject of a recent study.
“One has to understand that with 2014 being the hottest globally, there is no way that India can escape the effects to global warming. The onset can be delayed but to say that we will not be affected is far-fetched,” Srivastava says.
Up to 1960, the effect of global warming was restricted to a rise in maximum temperature. After 1960, there was an increase in the minimum temperature as well. In India, we saw this effect starting from the 1990s. This means that qualitatively, we should be prepared for increased temperatures in the coming years.
Having said that, climatologists say that there is a difference in the levels of increase in temperatures globally and at the national level. According to an ongoing temperature analysis by scientists at NASA’s Goddard Institute for Space Studies, the average global temperature on Earth has increased by about 0.8°C (1.4° Fahrenheit) since 1880. Two-thirds of the warming has occurred since 1975, at a rate of roughly 0.15-0.20°C per decade. Because oceans tend to warm and cool more slowly than land areas, continents have warmed the most.
In the Northern Hemisphere, where most of Earth’s land mass is located, the three decades from 1983 to 2012 were the warmest 30-year period of the last 1,400 years, according to the Inter-governmental Panel on Climate Change. In India, there has been an increasing trend of the order of 0.35°C was observed over the last 100 years.
Climatologist Prof Murari lal says: “In India, the coming decades are going to bring in enhanced intra-seasonal and inter-annual variability due to climate change (most models used for IPCC 2013-14 suggest this). Therefore the weather and climate during seasons and months over India would be highly variable,” Prof lal says.
Then there is fact that there was deficit rainfall in country — the country ended up with 14 per cent shortfall implies that there is less moisture in the air. This is also leading to an increase in temperature. But Srivastava tells you that there is no direct linkage that a weak monsoon will contribute to a rise in temperatures.
“There is no conclusive evidence that poor monsoon leads to a rise in temperatures. In my opinion there are three main reasons for rise in temperatures that we are witnessing. First, increase in greenhouse gases emission is a contributor. This is because global warming is not a cause but an effect. Second, the melting of the Polar ice means that there is less reflection. Ice helps cool the Polar by reflecting incoming solar radiation back into space. Third, in the last 20-30 years, the Pacific Ocean has seen frequent El Ninos,” Srivastava opines.
A fact that is corroborated by lal. “There was a time when El Nino had a pattern. It would occur every 10 years, then it would come every seven, down to three-and-a-half-years to now every year and this affects the monsoon. But one thing one has to understand that urbanisation — rampant construction, cutting down of trees, rise in the number of vehicles on the road also contribute to the overall heating of a place even though these are local factors. There is so much carbon dioxide and carbon monoxide that is being released into the atmosphere. Then the Government goes and introduces odd-even which leads to increase in the sale of second hand cars which in turn more carbon monoxide,” lal says.
Also, 90 per cent of the heat is being absorbed by the oceans and seas. This means that the waters are getting warmer. “This not only affects the marine life, it affects the ocean currents which in turn affect the climate,” lal explains.
He also tells you that lack of moisture, excessive abuse of water as a resource are other contributors to rising temperatures. “There was a time when Punjab was given free electricity so that farmers could water their fields; the result was that tubewells would be left running for hours at end, it was such a waste of ground level water. Then you are constructing high rise buildings. One needs water for during the construction and then for the people who are living in them, depleting the ground level water. Due to shortage of water, people have now started using ACs. With the high-rise buildings, there is no escape for this hot air and gets trapped heating a particular area. Why else is there is a difference in temperatures between Palam and SafdarjungIJ” lal asks.
When are we letting Nature recharge itselfIJ Everywhere there is concrete jungle. Roads are being paved with concrete and so are the footpaths. The trees are boxed into small spaces; they don’t have place to grow or for that matter breathe. There was a time when it would rain for days on end making it possible for the ground to soak up water. Today, there are heavy showers for an hour. The water runs down the drains with little time for the Earth to soak up the water. Uttarakhand forest fire is a perfect example of what will happen if we continue to abuse our natural resources. “Nature will try to balance things. But a fire that has yet to be doused comes with its consequences — it contributes to the rise heat in the region,” lal says.
Erratic rainfall is part and parcel of climate in India. As are cyclones, typhoons, floods and drought. These are trends that one has witnessed in the recent past. But to conclusively say that these can be attributed to climate change, climatologists say, requires more in-depth study. The examination and analyses of climate change in South Asia has to be understood against the physical, economical and societal environments of many nations located in this region. The socio-economic environment of several countries in this region is characterised by high population density and relatively low rates of economic growth. Many countries here are quite vulnerable to extreme climate events like cyclones and floods under current climate.
Climatologists say that short winters, scorching summers and erratic rainfall are getting common in India. But it is not just the Capital that is facing this extreme climate. The entire world is facing a major climate change. According to the UN’s World Meteorological Organisation, which monitors global weather, the first six weeks of 2014 have seen an unusual number of extremes of heat, cold and rain in most parts of the globe.
Experts say that the present weather conditions in the Capital can be an effect of global warming together with other factors like variations in land use and industrialisation. But there is no single reason that be be pinpointed. It is an amalgamation of several factors that have mitigated the present situation even though global warming is a phenomenon one can’t ignore. It will continue and the oscillations in climate will become even more common.
“One has to understand that the land surface is getting hotter since the oceans are getting warmer. Earlier, sea breeze would cool down the areas near the coast but this is not happening now. Analysing daytime temperature extremes, we see a reduction in the number of cool days and an increased frequency of warm days. The changes in cool and warm days appear to be somewhat smaller compared to the cool and warm night frequency changes,” Srivastava says.
Climatologists do agree that to nail a pattern needs more research. The problem, experts feel, is that the impact of climate change is seen over a long period of time. For most people it is a matter of a rise of only 2°C — instead of the temperature hovering at 45°C it will now be 47°C. But scientists know the huge impact of this increase. There is peak in demand for electricity which means more coal is burnt to generate it which, in turn, means that we are adding to the carbon budget. In 2014, India’s carbon emissions shot up to 7.7 per cent.
While this figure may not be as high as in other countries, India can no longer ignore the fact that it is the third largest polluting country in the world, after China and the US.
One is told that since the climate is not static, any assumption made about the future based on the past
may be inappropriate. Assumptions about the probability, frequency and severity of extreme events should be re-evaluated. Climate change issue has presented decision-makers with a set of formidable complications: A considerable number of uncertainties have the potential for irreversible damage to our ecosystem.
Climate change, one is told, happens over a period of time. Therefore, a steady rise in temperature or for that matter winter setting in late or its intensity reducing may not register but India can no longer ignore that it is witnessing a change and it is time that some strong measures are taken urgently.
But even then, one is told that it may be already too late to undo the damage that has done to the environment. “Even if we were to stop all activities that contribute to greenhouse gas emissions, it will take centuries before Nature will be able to revive itself. In the short term, we will see more drought and floods and that is something that we should be worried about since these are extreme events. But to see an abrupt climate change is not something that is on the cards, it will take a long time say a century,” lal tells you and agrees that while 47°C is something that is common in June, there is cause to worry that temperatures are rising to this level in May. What is worse is that this is likely to continue till mid-July in North India.
“Even though there is prediction of 100 per cent to 106 per cent monsoon, it will bring with it drought in regions like Rajasthan and Gujarat (North-west) while North-east will witness many floods. The good part is that there will be five to six monsoon depressions in Bay of Bengal; this will bring good rain to the Gangetic plains (North India) with a break of three to five days and then rain again. It is the monsoon trough that causes rains in Delhi and North India,” lal tells you.
But, perhaps, what is more alarming is the rise in the U/V index. Dr Gufran Beig, chief project scientist, System of Air Quality and Weather Forecasting And Research at the Indian Institute of Tropical Meteorology, says that usually when there are high temperatures, strong winds start to blow and keep the air pollution under check.
“This is a pollution related issue but an extension to this is the U/V index which is very high causing health problems including skin problems leading to toxicity. In Delhi dust is a major contributor to PM 10 as opposed to PM 2.5. But even if there is dust, it has been found that this gets washed away with high winds. However, it has been found that if the winds are calm the particulate matter settles down, this is dangerous.
Usually, with high temperatures comes loo but it is not happening this time around and the pollution is suspended in the air leading to rise in temperatures. This kind of a situation occurs in end of May and June, to see it now, is unusual as is the high temperatures in many parts of the country,” Dr Beig says.