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Experts Back Pentagon Warning on Climate |
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By Stephen Leahy*
Abrupt
climate change, which could trigger catastrophes such as a decline
of temperatures in Europe to Siberian levels, is indeed possible,
scientists told Tierramérica.
TORONTO - A controversial Pentagon report that
warns climate change may lead to global catastrophe in just a few
years is based on solid findings, say scientists interviewed by
Tierramérica.
The study by the Pentagon (U.S. Defense Department) has caused a
storm since its dissemination in the U.S. business magazine Fortune
in January. Its conclusion is that abrupt climate change poses a
much greater danger than terrorism.
Titled "An Abrupt Climate Change Scenario and Its Implications for
United States National Security", the report looks at a worse case
scenario in which the huge current called the "Atlantic conveyor
belt", which brings warm water from the south Atlantic to the north,
begins to slow down by 2010. With less warm water flowing north,
the climate of the eastern United States and northern Europe would
change dramatically.
If this were to occur, the report predicts, the climate of Britain
and northern Europe would be more like Siberia's and the average
annual rainfall would decline by nearly 30 percent.
"Given that the levels of carbon dioxide in the atmosphere are the
highest they've been for a very long time, abrupt climate change
may be more likely," Richard Alley, a U.S. geophysicist, told Tierramérica.
Alley, who is a professor at Pennsylvania State University, headed
a prestigious U.S. National Academy of Science research committee
on Abrupt Climate Change in 2001.
That committee rejected the notion that climate change only occurs
gradually, over periods of 50 to 100 years, and presented historic
evidence that the climate can see dramatic alterations within just
a few years.
That echoes recent statements by David King, the British government's
chief scientist, who in an interview with the journal Science last
month also chastised the U.S. government for failing to take up
the challenge of global warming.
The Pentagon report, written by consultants based on interviews
with scientists, predicts that violent storms could make large parts
of the Netherlands uninhabitable, and that by the 2020, Europe's
annual average temperature would decline 3.5 degrees Celsius.
Asia and North America would see average temperatures fall 2.8 degrees,
while South America, southern Africa and Australia would see temperatures
rise an average of 2.2 degrees, according to the report.
Massive droughts and rising sea levels would likely force 400 million
people to migrate, while Europe and the United States could become
"virtual fortresses" trying to keep them out.
Under such conditions widespread war is expected, the report concludes.
The authors, hired by the Pentagon, were Peter Schwartz, who has
served as CIA (U.S. Central Intelligence Agency) consultant and
former head of planning at Royal Dutch/Shell Group, and Doug Randall,
of Global Business Network, a California-based company that tracks
and predicts business trends.
Both were reportedly surprised by the enormous implications of abrupt
climate change.
"I think this study is very good because it's important for policymakers
to realize what could happen," given the evidence that the Atlantic
conveyor belt current is being affected by climate change Alley
told Tierramérica.
Tropical oceans are much saltier than they were 40 years ago, while
the seas at the poles are less so, Raymond Schmitt, a senior scientist
at the Woods Hole Oceanographic Institution in the U.S. state of
Massachusetts, told Tierramérica.
Huge amounts of fresh water are flowing into the North Atlantic,
reducing salinity, and that could be the first step to slowing the
conveyor belt. "We don't know what will happen but the stakes are
very high if it does," said Schmitt.
Over the past decade scientists have been assembling historical
climate records based on ice cores in the Antarctic, deep sea sediments
from the Cariaco Trench off the coast of Venezuela and elsewhere.
These paint a surprising picture of rapid shifts in regional climates.
An abrupt change called the Younger Dryas period pushed a warm temperate
Europe back into Ice Age conditions 1,300 years ago because the
Atlantic conveyor belt current slowed and likely reversed direction.
The name Dryas comes from a typical tundra plant that appeared in
parts of southern Europe when the temperatures fell.
But that Atlantic conveyor is not the only contributor to abrupt
alterations in regional climates.
Drought prone regions such as the Sahel (southern Sahara) and central
North America can get locked into a feedback loop of ever-drier
conditions, says Alley.
With climate change, precipitation patterns intensify -- drier gets
drier, wetter gets wetter. "We're already seeing that pattern,"
Schmitt said.
The melting of the West Antarctic Ice Sheet could also reach a threshold
point where it accelerates raising sea levels as much as five meters.
The El Niño-La Nina cycle could also get stuck at one end of the
cycle for many years, rather than shifting back and forth every
few years. In addition to the seasons, this cycle is the most powerful
forcing driving global weather.
* Stephen Leahy is an IPS contributor.
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