[Marxism] Ancient air bubbles shed light on greenhouse gases
cbrown at michiganlegal.org
Fri Nov 25 13:42:38 MST 2005
Friday, November 25, 2005
Ancient air bubbles shed light on greenhouse gases
In a new study, European researchers analyze how people influence buildup of
carbon dioxide in the air.
Lauran Neergaard / Associated Press
WASHINGTON -- There is more carbon dioxide in the atmosphere today than at
any point during the past 650,000 years, according to a major study that let
scientists peer back in time at "greenhouse gases" that can help fuel global
By analyzing tiny air bubbles preserved in Antarctic ice for millennia, a
team of European researchers highlights how people are dramatically
influencing the buildup of these gases.
The remarkable research promises to spur "dramatically improved
understanding" of climate change, said geosciences specialist Edward Brook
of Oregon State University.
The study, by the European Project for Ice Coring in Antarctica, was to be
published today in the journal Science.
Today, scientists directly measure levels of carbon dioxide and other
greenhouse gases, which accumulate in the atmosphere as a result of
fuel-burning and other processes. Those gases help trap solar heat, like the
greenhouses for which they are named, resulting in a gradual warming of the
Those measurements are disturbing: Levels of carbon dioxide have climbed
from 280 parts per million two centuries ago to 380 ppm today. The Earth's
average temperature, meanwhile, increased about 1 degree Fahrenheit in
recent decades, a relatively rapid rise. Many climate specialists warn that
continued warming could have severe effects, such as rising sea levels and
changing rainfall patterns.
Skeptics sometimes dismiss the rise in greenhouse gases as part of a
naturally fluctuating cycle. The study provides more definitive evidence
countering that view, however.
Deep Antarctic ice encases tiny air bubbles formed when snowflakes fell over
hundreds of thousands of years. Extracting the air allows a direct
measurement of the atmosphere at past points in time, to determine the
naturally fluctuating range.
A previous ice core sample had traced greenhouse gases back about 440,000
years. This new sample, from East Antarctica, goes 210,000 years further
back in time.
Today's still rising level of carbon dioxide is 27 percent higher than its
peak during all those millenia, said lead researcher Thomas Stocker of the
University of Bern, Switzerland.
"We are out of that natural range today," he said.
Moreover, that rise is occurring at a speed that "is over a factor of a
hundred faster than anything we are seeing in the natural cycles," Stocker
added. "It puts the present changes in context."
The team, which included scientists from France and Germany, found similar
results for methane, another greenhouse gas.
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