Saturday, May 3, 2008

Humans get 10 more years to save Earth

2 May 2008, 0318 hrs IST,Nitin Sethi,TNN

NEW DELHI: While humans have been heedless in making global warming a reality, nature has given Earth a break.

Nations and leaders may get a rare chance to sink their differences and fix climate change as latest research shows that natural phenomena could keep Earth's temperatures in check for the next 10 years.

The 10-year window, beginning 2010, will not last for ever. And from 2020 onwards, temperatures will begin to rise again. But till then, phenomena like cooler North Atlantic waters could counter heating up of Earth due to greenhouse gas emissions as has been predicted by UN's Intergovernmental Panel on Climate Change (IPCC). This could mean temperatures would continue to be at existing levels.

The heartening news, which could mean that the world has moved a step or two away from the brink of climate change, has been published in the latest issue of Nature . The research published in the reputed journal says Earth could benefit from a phase where certain phenomena cancel out the effects of greenhouse gases.

IPCC in its fourth assessment report had warned that at current rates of greenhouse gas emissions from the rich and the developing worlds, the global climate could warm by 0.2 degree Celsius in a decade, raising the sea level and leading to dramatic consequences for coastal societies in particular.

It's known that though increasing greenhouse gas emissions push temperatures upwards, the warming curve is not smooth — there would be periods when processes aid the heating, while the opposite happens during other periods.

Now, research carried out by scientists from Leibniz Institute of Marine Sciences and Max Plank Institute of Meteorology, both based in Germany, has shown that the next decade is going to be one such period when natural occurrences negate the effect of increasing emissions and keep global climate cooler than what was forecast earlier.

All predictions of global temperature changes are based on complex mathematical models that create future scenarios according to parameters and data that scientists feed in.

Due to numerous physical phenomena involved, these predictions work better when the average temperature increase for a longer period — several decades — is calculated. The breakthrough has come with scientists being able to predict changes that could occur over 10-year intervals — what climatologists consider a much shorter time period.

The scientists studied temperatures measured on the surface of oceans — a crucial factor in determining variations of global average temperatures. They were able to predict workings of a critical phenomenon called meriodional overturning circulation (MOC). It brings warm water into the north Atlantic, releasing heat into the atmosphere. This then returns to cooler waters in the southern portions of the ocean. But MOC is known to change intensity over decades.

Researchers were able to predict that MOC would weaken over the next decade and as a result would cool north Atlantic waters, consequently keeping global temperatures under control.

MOC, in a sense, would work just the way El Nino and La Nina do to affect global temperatures in the Pacific Ocean. These are more familiar in India as they can impact monsoons. While the research might have brought down the immediate threat levels globally and can allow governments and decision-makers — especially in the US, Europe and North Africa — to plan for lower levels of crisis management, there could be other spin offs.

This kind of predictive studies could also help simulate, once models get better, precipitation in different regions at more accurate levels. Researchers across the world too are working on improving the ability of such simulations to predict more than just global temperatures.


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