December 19, 2003

Earth Warming at Faster Pace, Say Top Science Group's Leaders

San Francisco Chronicle: Leaders of one of the nation's top scientific
organizations issued a new warning this week that
human activities -- most notably the greenhouse gas
emissions from power plants and other industries --
are warming Earth's climate at a faster rate than
ever.

Save the Environment, Show Up for Democracy in 2004:
Defeat Bush (again!)


http://www.commondreams.org/headlines03/1218-01.htm

Published on Thursday, December 18, 2003 by the San
Francisco Chronicle
Earth Warming at Faster Pace, Say Top Science Group's Leaders
Statement by American Geophysical Union's council
warns temperature change is real and human-caused

by David Perlman

Leaders of one of the nation's top scientific
organizations issued a new warning this week that
human activities -- most notably the greenhouse gas
emissions from power plants and other industries --
are warming Earth's climate at a faster rate than
ever.

The statement came from the 28-member council of the
American Geophysical Union, whose 41,000 members
include more than 10,000 experts on the planet's
atmosphere and changing climate.

The unprecedented increases in greenhouse gas
concentrations, together with other human influences
on climate over the past century and those anticipated
for the future, constitute a real basis for concern.


Although the vast majority of climate researchers are
persuaded that the evidence, combined with computer
models, show that global warming is real and
dangerous, a few scientists still hold to the view
that most of the changes are due more to natural
cycles than human-induced causes.

Lead scientist of the organization that circulated the
statement is Robert Dickinson, professor of
atmospheric sciences at the Georgia Institute of
Technology. Another significant signer was John
Christy, director of the University of Alabama's Earth
Systems Science Center, a more cautious supporter of
the idea that humans are causing climate change.

In a phone interview, Christy said that while he
supports the AGU declaration, and is convinced that
human activities are the major cause of the global
warming that has been measured, he is "still a strong
critic of scientists who make catastrophic predictions
of huge increases in global temperatures and
tremendous rises in sea levels."

"It is scientifically inconceivable that after
changing forests into cities, turning millions of
acres into farmland, putting massive quantities of
soot and dust into the atmosphere and sending
quantities of greenhouse gases into the air, that the
natural course of climate change hasn't been increased
in the past century.''

The AGU has issued milder statements on global change
in the past, with more emphasis on theories about
natural changes than on evidence of human- caused
rapid warming. But this statement declared:
"Scientific evidence strongly indicates that natural
influences cannot explain the rapid increase in global
near-surface temperatures observed in the second half
of the 20th century."

Although they cannot yet predict the pace of change,
the scientists did declare that since 1900 more than
80 percent of the atmosphere's heat-trapping carbon
dioxide -- the major greenhouse gas -- has been caused
by fossil fuel burning and changes in land use. They
also said that levels of the gas "may be rising faster
than at any time in Earth's history, except possibly
following rare events like impacts from
extraterrestrial objects."

Without specifying numbers, the scientists did make
these predictions: "Mid-continent warming will be
greater than over the oceans, and there will be
greater warming at higher latitudes. Some polar and
glacial ice will melt, and the oceans will warm; both
effects will contribute to higher sea levels. There
will be considerable regional variations in the
resulting impacts.

"The unprecedented increases in greenhouse gas
concentrations, together with other human influences
on climate over the past century and those anticipated
for the future, constitute a real basis for concern."

In a related development, researchers at the Woods
Hole Oceanographic Institute in Massachusetts are
reporting that the tropical Atlantic Ocean is much
saltier than it was 50 years ago, according to the
Boston Globe.

Scientists have assumed that global warming would
speed evaporation in parts of the world's oceans but
had no direct way of measuring the change. In the
Woods Hole study, published in the journal Nature,
scientists estimated that tropical evaporation rates
increased 10 percent during the last 15 years.

As a purely scientific organization, the AGU took no
stand on the politics of the international Kyoto
Protocol limiting greenhouse gas emissions, which
President Bush has refused to sign.

But the AGU did suggest that continuing scientific
research "provides a basis for mitigating the harmful
effects of global climate change through decreased
human influences." Among the AGU's suggestions:
slowing greenhouse gas emissions, improving land
management practices and removing carbon from the
atmosphere.

2003 San Francisco Chronicle

###



Posted by richard at December 19, 2003 10:00 AM