The climate of the earth, if it was a book, would have made the most fascinating and interesting reading! Having pulsated between an Ice Ball Earth to a Hot House or Green House earth, the climate today is proving to be a boon and bane both for our earth. Till a few years ago, our Earth was like a self-driven vehicle, correcting its course in the dark abbeys of the Universe. But now with the levers of the earth’s driving system in the hands of modern, intelligent, over-zealous man, our Earth is like a zombie, trying to avert collisions with the nature, at places crashing in to the natural systems.
This ear of the earth has been termed as the Anthropocene by Paul Crutzen, winner of the Nobel Prize in 1995 for unraveling the mechanisms that damage the protective ozone layer in the atmosphere. Amongst the agencies that damage the ozone layer, includes climate as well. Climate is such an agent that controls many actions of the nature. Erosion, for example, is one factor, which decides how much muck a river will carry this year. This depends upon the rainfall. More rains mean more erosion and more waste material to reach the rivers. The quantity of sediments carried by the rivers, in turn decides the living conditions of the organisms and plants in the oceans. Remember, it was blue-green algae which produced enough oxygen to make our air worth breathing and our planet inhabitable by other higher evolved creatures.
As long as our planet was being ruled by dumb giants like dinosaurs the nature was correcting its own course and controlling the excesses. But since the day the higher evolved creature, the man took the reins things started going haywire. As long as the man was the hunter and gatherer, things were normal. But from the day around eight thousand years ago, our ancestor started settling down and began farming; the climate began to be affected. But how could those simpletons affect the climate? One might ask. These ancestors of ours had started cultivating and burning grass and agricultural waste.
Our environment is supposedly made of four spheres, viz. Lithosphere, Hydrosphere, Atmosphere and Biosphere. These spheres are intimately connected with each other in such a manner that if one is disturbed the other gets disturbed. Burning of grass etc. (part of biosphere) upset the atmosphere and so forth. The agri-products that were burned were stores of carbon and they were converted to carbon dioxide-a greenhouse gas. Through the ages, as the man ‘developed’ further the practice of burning carbon in some or other form continued and more and more carbon dioxide was and is being added to the atmosphere. Suppose our ancestors had not burned the carbon then? Actually the nature was preparing for another advancement of Ice Age at that time and it was postponed, albeit temporarily. From 14th to 18th century we did have a min Ice Age even in India.
A climate scientist, Bill Ruddiman of Virginia University, USA has been working on the carbon additions by our ancestors and to prove his contentions he has taken the help of the Ice cores from Antarctica. He says that the Carbon dioxide levels gradually rose from 260 to 280 parts per million volume (ppmv) and methane levels from 600 to 750 ppmv. The temperature during the last chapter of the earth’s history, the Holocene has seen rise due to human released greenhouse gases by about 0.8 degrees C says Ruddiman. Of course this is just a hypothesis and there are contenders against it. The addition of greenhouse gases by the past volcanoes is tremendous, compared to the puny humans, many think!
The debate will be discussed in further articles in this column, however, it is clear that we humans for all our comforts burn carbon and produce carbon dioxide. We have been doing that since ages. But how long we will be able to carry on like this is anybody’s guess.