Is Earth's Capacity To Absorb CO2 Much Greater Than Expected?

The research, by Bristol University, suggests that despite rising emissions, the world is is still able to store a significant amount of greenhouse gases in oceans and forests.

According to the study, the Earth has continued to absorb more than half of the carbon dioxide pumped out by humans over the last 160 years.

This is despite emissions of CO2 increasing from two billion tonnes per year in 1850 to current levels of 35 billion tonnes per year.

Previously it was thought that the Earth's capability to absorb CO2 would decrease as production booms, leading to an accumulation of greenhouse gases in the atmosphere.

But Wolfgang Knorr, author of the new study, found that the amount of CO2 in the atmosphere has remained just over 50 per cent, with only tiny fluctuations being recorded despite the massive hike in output.

He pointed out that his study relied entirely on empirical data, including historical records extracted from ice samples in the Antarctic, rather than speculative climate change models.

"Previous studies suggested that in the next ten years the amount of CO2 in the atmosphere will accelerate because there is a lot less uptake by the Earth, there is no indication of this," he said.

However scientists cautioned that the ability of the oceans and rainforests to absorb carbon dioxide in the future may collapse, leading to a massive increase in temperatures.

Another study released this week found the amount of CO2 released as a result of cutting down the rainforests could have been overestimated. The research by VU University in Amsterdam found emissions from deforestation could be as low as 12 per cent, rather than 20 per cent.

Also, research has found that marine plants in the Antarctic are fighting climate change by absorbing carbon from the atmosphere as the ice melts. The British Antarctic Survey (BAS) found that blooms of phytoplankton are thriving in swathes of water left open by the melting of ice shelves and glaciers.

But Dr Wolfgang Knorr cautioned that the world should still be trying to reduce carbon dioxide emissions as part of any climate change deal decided in Copenhagen next month.

He pointed out that the amount of greenhouse gases in the atmosphere is still increasing, even though half is absorbed by the Earth. Also there are fears that the oceans and soil become saturated and are unable to absorb any more CO2 in the future.

"Like all studies of this kind, there are uncertainties in the data, so rather than relying on Nature to provide a free service, soaking up our waste carbon, we need to ascertain why the proportion being absorbed has not changed," he said.

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Issued by:  Telegraph.co.uk

Author: Louise Gray

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Issue date: November 11, 2009

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