Giant Study Pinpoints Changes From Climate Warming
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
Story Date: 15/5/2008
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