Friday, November 20, 2009

Growing CO2 could cause 6 metre rise in sea level

A file picture of a Greenpeace message about reducing the CO2 emission level on Le Meridien Hotel, New Delhi.

Photo: AP

If the world fails to get the growing carbon emission under control, sea levels could rise by up to six metres, said a new study.

According to the study by the British Antarctic Survey (BAS), temperatures in the Antarctica were increased by six degrees Celsius during the past periods when the volume of high carbon dioxide (CO2) was high in the atmosphere.This could cause a sea level rise of up six metres, threatening coastal cities like London, New York and San Francisco, it said.Louise Sime, who led the BAS study, looked at ice cores to see how temperatures changed during periods of high carbon dioxide.

During the last period of high CO2, 125,000 years ago, she found temperatures were up to 6 degrees Celsius higher than present day levels.Such a hike in temperature could lead to a rise in sea levels of between 4 to 6 metres over hundreds of years as the ice sheets melt, The Telegraph reported.“We didn’t expect to see such warm temperatures, and we don’t yet know in detail what caused them. But they indicate that Antarctica’s climate may have undergone rapid shifts during past periods of high CO2.”

Dr Sime said the study suggests that current high levels of CO2 could also cause a rise in temperature. She said further research could predict the affect on sea level rise.“If we can pin down how much warmer temperatures were in Antarctica and Greenland at this time, then we can test predictions of how melting of the large ice sheets may contribute to sea level rise.”

It is the latest research to warn of the consequences of increased greenhouse gases on the Earth’s climate, The Telegraph Reported.All the recent studies are adding pressure on world leader to agree in international deal on climate change at a UN summit in Copenhagen this December.

A recent study appeared in Nature Geoscience found that carbon dioxide levels rose by almost a third in the last seven years. It warned that if the world continues to pump out pollution at such a rate it will cause temperatures to rise by six degrees Celsius, causing massive droughts, extinction of species and sea level rise.

Another study added to the urgency by claiming that the oceans are losing their ability to absorb CO2. Samar Khatiwala of Columbia University, found that the proportion of fossil fuel emissions absorbed by the oceans since 2000 may have decline by as much as 10 per cent.

“What our ocean study and other recent land studies suggest is that we cannot count on these sinks operating in the future as they have in the past, and keep on subsidising our ever-growing appetite for fossil fuels,” he said.But, Dr Wolfgang Knorr, of Bristol University, who has been studying the same subject said there is not yet enough evidence to prove that the Earth is losing its ability to absorb CO2.

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