Giant study pinpoints changes from climate warming

By Deborah Zabarenko, Environment Correspondent

WASHINGTON (Reuters) - 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 U.N.'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."