Published Thursday, August 26, 2004, in the New York Times

U.S. Report Turns Focus to Greenhouse Gases

By Andrew C. Revkin

In a striking shift in the way the Bush administration has portrayed
the science of climate change, a new report to Congress focuses on
federal research indicating that emissions of carbon dioxide and
other heat-trapping gases are the only likely explanation for global
warming over the last three decades.

In delivering the report to Congress yesterday, an administration
official, Dr. James R Mahoney, said it reflected "the best possible
scientific information" on climate change. Previously, President
Bush and other officials had emphasized uncertainties in
understanding the causes and consequences of warming as a reason
for rejecting binding restrictions on heat-trapping gases.

The report is among those submitted regularly to Congress as a
summary of recent and planned federal research on shifting global
conditions of all sorts. It also says the accumulating emissions
pose newly identified risks to farmers, citing studies showing that
carbon dioxide promotes the growth of invasive weeds far more than
it stimulates crops and that it reduces the nutritional value of
some rangeland grasses.

American and international panels of experts concluded as early as
2001 that smokestack and tailpipe discharges of heat-trapping gases
were the most likely cause of recent global warming. But the White
House had disputed those conclusions.

The last time the administration issued a document suggesting that
global warming had a human cause and posed big risks was in June
2002, in a submission to the United Nations under a climate treaty.
President Bush distanced himself from it, saying it was
something "put out by the bureaucracy."

That may be harder to do this time. The new report, online at
www.climatescience.gov, is accompanied by a letter signed by Mr.
Bush's secretaries of energy and commerce and his science adviser.

The White House declined yesterday to explain the change in
emphasis, referring reporters to Dr. Mahoney, assistant secretary of
commerce for oceans and atmosphere and the director of government
climate research.

In an interview, he said the report was mainly an update on the
overall climate research program and was not intended to be a
conclusive "state of the science'' summary of the administration's
thinking. A series of 21 reports are promised on particular issues
in coming years, he said, and the studies on climate models,
agriculture and other subjects mentioned in the new report
are "significant but not definitive.''

Still, the report was disputed by some groups, aligned with
industry, that oppose restrictions on carbon dioxide emissions and
have attacked science pointing to dangerous human-caused warming as
flawed.

Myron Ebell of the libertarian Competitive Enterprise Institute said
the report was "another indication that the administration continues
to be incoherent in its global warming policies."

At the same time, the report did not please environmental groups,
which have repeatedly criticized Mr. Bush for opposing efforts to
require restrictions on the gases linked to global warming, though
he has gradually come around to the position that warming is at
least partly caused by emissions.

"The Bush administration on the one hand isn't doing anything about
the problem, but on the other hand can't deny the growing science
behind global warming," said Jeremy Symons of the National Wildlife
Federation.

The studies in the report that point to a human cause for recent
warming all involved supercomputer simulations of climate, which
have increased in power over the last several years.

The latest analysis, done at the National Center for Atmospheric
Research in Boulder, Colo., found that natural shifts in the output
of the sun and other factors were responsible for the warming from
1900 to 1950, but could not explain the sharp and continuing rise
since 1970.

The report's section on agriculture focused on several studies in
which fields and grasslands were exposed to doubled concentrations
of carbon dioxide, with growth patterns in plants shifting in ways
that could harm yields.

In such conditions, it said, plots of shortgrass prairie in
northeastern Colorado contained less of the nutrient nitrogen, and
their grasses were less digestible than those that grew with no
extra carbon dioxide.

"In another experiment, increased CO2 stimulated the growth of five
of the most important species of invasive weeds, more than any other
plant species yet studied," the report said. "This suggests that
some weeds could become bigger problems as CO2 increases."


[BATN: See also:

New report warns of global warming effects on Europe
http://groups.yahoo.com/group/BATN/message/19991

Global warming clouds California's future
http://groups.yahoo.com/group/BATN/message/19952

Global warming threatens California, study says
http://groups.yahoo.com/group/BATN/message/19925

Heat waves to worsen as global warming heats Earth
http://groups.yahoo.com/group/BATN/message/19865

Global dimming linked to atmospheric soot, pollution
http://groups.yahoo.com/group/BATN/message/18087

Rate of atmospheric CO2 increase increasing
http://groups.yahoo.com/group/BATN/message/16972

Bush "misrepresents" global warming research
http://groups.yahoo.com/group/BATN/message/16431

Global warming may cause 25% extinction by 2050
http://groups.yahoo.com/group/BATN/message/15782

Widespread extinction by global warming predicted
http://groups.yahoo.com/group/BATN/message/15781

Particulates cited as major global warming factor
http://groups.yahoo.com/group/BATN/message/15598

Bush fiddles with fuel economy while world burns
http://groups.yahoo.com/group/BATN/message/15587

State air pollution may be big contributor to drought
http://groups.yahoo.com/group/BATN/message/15572

Bush's "states take lead" on global warming a sham
http://groups.yahoo.com/group/BATN/message/15393

Global warming threatens world's ski resorts
http://groups.yahoo.com/group/BATN/message/15248

Report proves humans primary global warming cause
http://groups.yahoo.com/group/BATN/message/15247

New study again links global warming to humans
http://groups.yahoo.com/group/BATN/message/15037

Global warming to affect California within 20 years
http://groups.yahoo.com/group/BATN/message/14741

As earth warms, the hottest issue is energy
http://groups.yahoo.com/group/BATN/message/14646

US Senate rejects measure to curb global warming
http://groups.yahoo.com/group/BATN/message/14592

States take the lead on global warming legislation
http://groups.yahoo.com/group/BATN/message/14561

Global warming: the 18 quadrillion-dollar question
http://groups.yahoo.com/group/BATN/message/14560

Global warming evidence appears to mount
http://groups.yahoo.com/group/BATN/message/14559

Shrinking polar ice caps linked to global warming
http://groups.yahoo.com/group/BATN/message/14557

UC Santa Cruz study backs global warming theories
http://groups.yahoo.com/group/BATN/message/14555

US strategy on greenhouse consistent: more delay
http://groups.yahoo.com/group/BATN/message/14508

... etc ... ]