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Hot Antidote for Cool Climes

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Recent research shows that the next ice age can be staved off if we act SO fast:-

Conventional wisdom says that the build up of carbon dioxide in the atmosphere is not good for the earth’s inhabitants. Carbon dioxide absorbs heat, passes it around, and raises the earth’s temperatures. The rising temperatures release more carbon dioxide, and the gas absorbs more heat, passes it around, and raises the temperatures further. We would want to avoid this chain reaction, unless we can control it like in a nuclear reactor. That is exactly what we might end up doing, according to new research published last month.

We do not like scorching temperatures, but mild heat may be preferable to intense cold. When the earth is in an ice age — a phenomenon frequent in its history — snow covers a substantial part of the globe, making agriculture impossible, except in some warm areas. Human beings just managed to scrape through the last ice age. We are in the middle of an interglacial period (period between two ice ages), and we do not know precisely when the next ice age will come.

As it now turns out now, higher carbon dioxide levels in the atmosphere are the best way to keep the ice age away. Says Gary Shaffer, scientist at Niels Bohr Institute in Copenhagen: “If we use the fossil fuel reserves wisely, we can modulate the carbon dioxide levels and keep the ice ages away for at least half a million years.”

Shaffer is not proposing a new idea but he has gathered enough data about it to crystal gaze with confidence. He has just finished a study on the earth’s climate for the next half a million years, using a new model he developed with his colleagues. The model points to one reassuring possibility. If we reduce fossil fuel use — compared to 1990s levels — globally by 20 per cent by 2020 and 60 per cent by 2050, we would have done enough to keep the temperature rise to one degree centigrade. And we would also have enough fossil fuel reserves to increase the atmospheric carbon dioxide levels at some time in the future when the temperatures begin to drop.

Shaffer’s study is a tangential piece of good news at a time when everything regarding climate change seems to be gloomy. While all studies point to disaster, Shaffer says that we would be in reasonable shape if we act fast enough.

There was more direct good news recently. The journal Nature reported that forests have been soaking up carbon dioxide at levels much higher than previously thought. Recent studies in the Amazon forests suggest that increasing levels of carbon dioxide spur plant growth, but scientists were not sure whether this happens all over the world. Now Simon Lewis and his colleagues at the University of Leeds say that it happens in Africa as well. In fact, forests have absorbed around 18 per cent of the increase in carbon dioxide emissions.

These two studies are unrelated, but they together point to one fact: the earth can recover from a potentially disastrous climate change if we act quickly, and that plants should be an important part of our strategy to fight climate change. Just three months ago, climate scientist James Hansen of Columbia University and 10 other leading scientists argued in a paper in the Open Atmospheric Science Journal that carbon dioxide levels should be brought back to pre-industrial levels of 350 parts per million (ppm), from the current 385 ppm, by the end of the century if we want to avoid total ice melt in the earth. “Ice sheets are the issue that matters,” Hansen had said some time ago, “especially to countries like China and India that have a large population near the coast.”

Hansen and others also calculated what it takes to do this. Technologies are being developed (one in Columbia University itself) to take carbon dioxide from the air and put it back to the earth. Hansen calculated that it would take at least $10 trillion to remove 50 ppm of carbon dioxide. But the good news is that the scientists have also calculated that improved agriculture and forestry methods can remove at least this much carbon dioxide in 100 years.

The Nature paper shows that the forests could make a more significant contribution as they grow faster when there is more carbon dioxide in the air. “We were very lucky,” says Lewis. “There is now more reason to preserve our forests.”

Palaeo-climate studies unambiguously show that the earth warmed up or cooled down depending on the carbon dioxide levels in the atmosphere. There was a time when the entire earth had frozen, and it was the release of carbon dioxide that slowly warmed it. There could be a day when snow conditions return, but the presence of more carbon dioxide in the air would ward off snow for longer periods. And when an ice age is still inevitable, as is bound to happen during certain periods owing to the eccentricity of the earth’s orbit, we could pump carbon dioxide into the atmosphere. “We should not use up our fossil fuel reserves completely,” says Shaffer. “We should save it for use when we need it.”

A scientific conference to be held in Copenhagen next week is likely to give us new guidelines on exactly how to go about it in this new light.

Sources: The Telegraph (Kolkata, India)

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