The ocean, which has absorbed some excess carbon dioxide from the atmosphere for centuries, may be losing that ability, a new report says.
The buildup of carbon dioxide in the air since the beginning of the industrial revolution has raised concerns that it would trap solar energy and cause a warming of the climate.
The oceans are believed to absorb about one-quarter of human-related carbon emissions.
Their four-year study concluded that an increase in winds over the Southern Ocean is preventing it from absorbing more carbon and is causing the sea to release some of the gas that it had stored.
"This is serious. All climate models predict that this kind of 'feedback' will continue and intensify during this century," lead author Corinne Le Quere of England's University of East Anglia said in a statement.
In addition to East Anglia, researchers participating in the study were from the British Antarctic Survey and the Max-Planck Institute for Biogeochemistry in Jena, Germany.