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
QUOTE:
"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."
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.
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.
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