Giant Study Pinpoints Changes From Climate Warming
US: May 15, 2008
WASHINGTON - Human-generated climate change made flowers bloom sooner and
autumn leaves fall later, turned some polar bears into cannibals and some
birds into early breeders, a vast global study reported on Wednesday.
Hundreds of previous studies have noted these specific changes and most
suggested a link to so-called anthropogenic global warming, but a new
analysis published in the journal Nature correlated these earlier studies
with changes in temperature, the study's lead author said.
There was a close relationship between temperature shifts between 1970 and
2004 and changes in plants, animals and the physical world, such as the
retreat of glaciers and the water level in desert lakes, the study found.
"When you look at all of the glaciers and all of the snowpack and all of the
birds laying eggs earlier and all of the plants having spring earlier across
a continent, then we see we can detect anthropogenic signals," said Cynthia
Rosenzweig of NASA's Goddard Institute for Space Studies.
They worked to rule out observed changes that could have been caused by
other factors besides anthropogenic climate change.
Building on research done to support findings reported in 2007 by the UN's
Intergovernmental Panel on Climate Change, Rosenzweig and her co-authors
brought together nearly 30,000 sets of data about biological and physical
changes around the world, and then matched that up with a detailed database
of global temperature change.
PENGUINS, POLAR BEARS AND POLLEN
"We overlay those two global datasets and then we do a spatial pattern
analysis globally about the co-location of significant temperature trends
and observed changes consistent with warming," Rosenzweig said in a
telephone interview. "We see that those are strongly co-located."
The link between human-caused global warming -- generated by industrial and
vehicle emissions of carbon dioxide to produce a temperature-boosting
greenhouse effect -- and observed biological and physical changes is very
strong, she said.
On a global scale, the correlation is more than 99 percent between the two
factors; on a continental scale, she said, the correlation if very likely
between 90 and 99 percent.
Going continent by continent, here are some observed changes in the natural
world attributable to climate change, according to the study:
NORTH AMERICA: Earlier plant flowering of 89 species from American holly to
sassafras; intraspecific predation, cannibalism and declining population of
polar bears; earlier breeding and arrival dates of birds including robins
and Canada geese.
EUROPE: Glacier melting in the Alps; changes in 19 countries of
leaf-unfolding and flowering of such plants as hazel, lilac, apple, linden
and birch; early pollen release in the Netherlands; long-term changes in
fish communities in Upper Rhone River.
ASIA: Greater growth of Siberian pines in Mongolia; earlier break-up and
thinning of river and lake ice in Mongolia; change in freeze depth of
permafrost in Russia; earlier flowering of gingko in Japan.
SOUTH AMERICA: Glacier wastage in Peru; melting Patagonia ice fields
contributing to sea-level rise.
AFRICA: Decreasing aquatic ecosystem productivity of Lake Tanganyika.
AUSTRALIA: Early arrival of migratory birds including flycatchers and
fantails; declining water levels in Western Victoria.
ANTARCTICA: 50 percent decline in population of emperor penguins on
Antarctic Peninsula; retreating glaciers.
(Editing by David Wiessler)
Story by Deborah Zabarenko
REUTERS NEWS SERVICE
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