The Sea Change in Global Warming

Fresh fears about global warming were raised yesterday by a study which found that the oceans seem to be losing their ability to absorb carbon dioxide.

Oceans normally act as a "sink" for the gas by absorbing it through natural processes.

But a report by British scientists has concluded CO2 levels in the North Atlantic have halved in ten years.

One of the authors, Professor Andrew Watson, of East Anglia university, said this could increase global warming by leaving more CO2 in the atmosphere.

He said: "We suspect that the 'sink' is much more sensitive to changes in climate than we had expected.

"If you have a series of relatively warm winters, the ocean surface doesn't cool so much, you don't get so much sub-surface water formed and so the CO2 is not being taken down into the deep water."

The scientists recorded the Atlantic's CO2 levels by taking readings from water collected by thousands of ships which crossed the ocean between 1995 and 2005.

One proposal to increase oceans' ability to absorb CO2 is to create a network of pipes to improve the circulation of water far below the surface.

But Prof Watson said he was sceptical about the long-term impact of such a scheme.