NAmerica Soaking Up Carbon From Air

HULTGREN arne at snowcrest.net
Sun Oct 25 23:43:51 EST 1998


NAmerica Soaking Up Carbon From Air

By Randolph E. Schmid

Associated Press Writer

Friday, October 16, 1998; 1:52 a.m. EDT

WASHINGTON (AP) -- Somehow, North America seems to be

soaking up a lot of the carbon scientists had expected to find in the

atmosphere.

Carbon dioxide in the air has been increasing, but not as rapidly as

expected by researchers studying the threat of global warming. So they

have been trying to figure out where the excess was going.

A report in today's edition of the journal Science concludes that much of

this missing carbon is being absorbed in North America -- possibly by

regrowth over abandoned farms and previously logged forests.

The absorption could total between 1.2 billion and 2.2 billion tons

annually, a ``substantial portion'' of the carbon being added to the

atmosphere, according to the government and academic researchers.

Even before it was published, however, the paper was generating

controversy.

``I don't believe this result,'' said David Schimel, an ecologist at the

National Center for Atmospheric Research in Boulder, Colo. Other

studies indicate the amount of carbon taken up by North America can be

no more than 700 million tons, he said.

Environmentalists worry that groups opposed to the 1997 Kyoto climate

treaty will use the findings to argue that the United States does not need
to

reduce its emissions of so-called greenhouse gases.

``There is a huge concern that this result will be misinterpreted,'' Schimel

said in a telephone interview.

Pieter Tans, one of the scientists who worked on the paper, admitted that

the ``uncertainties are still large.''

``This is not ironclad. We say in the paper the evidence is still somewhat

tentative,'' said Tans, an atmospheric chemist at the National Oceanic and

Atmospheric Administration's Climate Monitoring and Diagnostics

Laboratory in Boulder.

But, he said, ``we do think that we have used good models. ... We think

we've used data in a proper way. ... We've tried to look at all the

uncertainties and this is what we get.''

Carbon dioxide released by burning fossil fuels such as coal and oil has

been increasing in the atmosphere. That has led to concerns that it might

cause global warning by trapping heat from the sun, somewhat like the

glass of a greenhouse.

The analysis measured carbon dioxide levels around the world and

concludes that whatever is absorbing it is located in the temperate region

of the Northern Hemisphere, roughly between 25 degrees and 51 degrees

north latitude.

Comparing carbon dioxide levels in America, Europe and Asia led the

scientists to believe that the major absorption is occurring in North

America. Regrowth on farmland and previously cut forests is a strong

possibility, because growing plants absorb carbon dioxide, using the

carbon for growth and releasing oxygen into the air.

The analysis looked at carbon dioxide levels between 1988 and 1992

measured at 63 atmospheric sampling stations.

``The current uptake of carbon by terrestrial ecosystems is helping to slow

down the rise of CO2 in the atmosphere, but we need to know why it is

happening. Only then may we be able to project for how long into the

future this process may continue,'' Tans said.

Other co-authors of the paper were Jerry Mahlman, Song-Miao Fan,

Emanuel Gloor, Stephen Pacala and Jorge Sarmiento of Princeton

University and Taro Takahaski of Columbia University's Lamont-Doherty

Earth Observatory.

© Copyright 1998 The Associated Press







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