Southern Ocean saturated with carbon dioxide-study
Pastor Dale Morgan
*Southern Ocean saturated with carbon dioxide-study*
17 May 2007 18:00:14 GMT
Source: Reuters
By Deborah Zabarenko, Environment Correspondent
WASHINGTON, May 17 (Reuters) - 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 on 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.
The new research, published in the latest edition of the journal
Science, indicates that the Southern Ocean has been saturated with
carbon dioxide at least since the 1980s.
This is significant because the Southern Ocean accounts for 15 percent
of the global carbon sink, Le Quere said.
GLOBAL WARMING SPURS WINDS
Increased winds over the last half-century are to blame for the change,
Le Quere said. These winds blend the carbon dioxide throughout the
Southern Ocean, mixing the naturally occurring carbon that usually stays
deep down with the human-caused carbon.
When natural carbon is brought up to the surface by the winds, it is
harder for the Southern Ocean to accommodate more human-generated
carbon, which comes from factories, coal-fired power plants and
petroleum-powered motor vehicle exhaust.
The winds themselves are caused by two separate human factors.
First, the human-spawned ozone depletion in the upper atmosphere over
the Southern Ocean has created large changes in temperature throughout
the atmosphere, Le Quere said.
Second, the uneven nature of global warming has produced higher
temperatures in the northern parts of the world than in the south, which
has also made the winds accelerate in the Southern Ocean.
"Since the beginning of the industrial revolution the world's oceans
have absorbed about a quarter of the 500 gigatons (500 billion tons) of
carbon emitted into the atmosphere by humans," Chris Rapley of the
British Antarctic Survey said in a statement.
"The possibility that in a warmer world the Southern Ocean -- the
strongest ocean sink -- is weakening is a cause for concern," Rapley said.
Another sign of warming in the Antarctic was reported on Tuesday by
NASA, which found vast areas of snow melted on the southern continent in
2005 in a process that may accelerate invisible melting deep beneath the
surface.