Much of the carbon dioxide we have been generating the past hundred years has been removed from the atmosphere by the oceans. Turns out we can’t rely on that:
The Southern Ocean around Antarctica is so loaded with carbon dioxide that it can barely absorb any more, so more of the gas will stay in the atmosphere to warm up the planet, scientists reported Thursday.
Human activity is the main culprit, said researcher Corinne Le Quere, who called the finding very alarming.
The phenomenon wasn’t expected to be apparent for decades, Le Quere said in a telephone interview from the University of East Anglia in Britain.
“We thought we would be able to detect these only the second half of this century, say 2050 or so,” she said. But data from 1981 through 2004 show the sink is already full of carbon dioxide. “So I find this really quite alarming.”
The Southern Ocean is one of the world’s biggest reservoirs of carbon, known as a carbon sink. When carbon is in a sink — whether it’s an ocean or a forest, both of which can lock up carbon dioxide — it stays out of the atmosphere and does not contribute to global warming.
And the laws of physical chemistry tell us that as temperature rises in a liquid, its ability to hold on to gases diminishes; in other words, as the oceans warm, they will tend to release carbon dioxide.