Coping with Global Climate Change

By: R Ramesh and M Sudhakar
There appears to be a consensus now among climate scientists that man has significantly altered his environment by indiscriminate burning of fossil fuels; and this anthropogenic effect on climate has exceeded solar heating of the earth in the past two decades. Advanced models of climate have clearly shown that the unprecedented high temperatures recorded in the late nineties could not be explained if man made changes in the atmospheric chemistry are not taken into account. Therefore, it is time that we think about possible ways of coping with a warmer world in the near future.
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The conceivable effects of global warming might include melting of glaciers, increased runoff from continents, ocean stratification leading to less marine productivity and fish catch, sea level rise, loss of coastal land, increase in the frequency of storms, cyclones and extreme weather events accompanied by floods, loss of agricultural top soil, spreading of diseases such as malaria to the newly warmed regions, shifting of montane vegetation to higher altitude, etc. Some of these effects are already being felt and have even been documented. In addition to these, continued growth in population may lead to further use of fossil fuels and increase in the atmospheric and marine pollution; excessive use of nitrogenous fertilizers may exacerbate ground water pollution and increase the eutrophication of coastal seas (this causes large scale fish mortality by creating oxygen depleted conditions) and excessive irrigation may deplete ground water levels. It is indeed a tall order for a developing country like India to cope with environmental problems of such enormous magnitude, but cope we must.

First and foremost, we must educate the general public about the carbon footprint of the country and the climatic consequences of carbon consumption. It is important that clear evidence, such as that from the satellite pictures of the Himalayan and Arctic regions of the past three decades, is shared with them so as to remove the confusion created by the climate sceptics lobby. People have to be convinced about the ensuing dangers of industrialisation, only then will they be willing to cooperate with coping measures.

Of the various geoengineering projects planned to reduce the anticipated global warming, one important one is the attempt to increase the effective albedo (reflectivity) of the earth. This could be achieved by reflecting away more sun light than at present by using giant mirrors in outer space, creating more low level white clouds, increasing the reflecting aerosols in the atmosphere, etc. A simpler way to achieve this would be to paint the roof of every building white. Making special paints with high reflectivity and low cost would be the challenge for chemists.

We may have to map the coastal topography to identify the areas where land could be shortly lost to the sea by increasing sea levels, and relocate people living in such areas on a priority basis. We must also take measures for conserving our fresh water and ground water resources. We may build new tanks for storage of water and repair older ones by desilting them. We may start a public campaign for recharging ground water. Pollution of ground water needs to be monitored and the data made available to the public. Scientists may develop new varieties of plants that could be efficient under a warmer climate with higher carbon dioxide concentrations. Likewise, in the oceans, we may do mesocosm experiments to identify species of planktons that can remove atmospheric carbon dioxide more efficiently through photosynthesis.

The oceans can become acidic by absorbing larger quantities of carbon dioxide from the atmosphere. Ocean acidification is a serious threat to corals, foraminifera, pteropods, coccoliths and other molluscs, which secrete calcium carbonate shells. Many oceanographic experiments need to be done to quantify such effects before we can evolve strategies to tackle them. It is known that supply of micronutrients such as iron can help marine planktons remove the atmospheric carbon dioxide more efficiently. A number of experiments have been done by oceanographers in the Southern Ocean to quantify the effect of adding iron to the oceans. However, there are adverse environmental consequences of such large scale experiments and we need to exercise caution. Many of these experiments have not been conclusive and we are still in the process of understanding them.

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