Plant leaves, flowers emerging earlier

NEW YORK, May 3 (UPI) -- Plants are leafing out and flowering earlier each spring than even controlled environmental warming experiments have predicted, U.S. scientists say.

Data from a major new archive of historical observations assembled with the help of a NASA researcher suggest the warming experiments are dramatically underestimating how plants actually respond to climate change, NASA reported Wednesday.

"This suggests we need to reassess how we design and use results from these experiments," said Elizabeth Wolkovich, who led the new research while a postdoctoral fellow at the University of California, San Diego.

Wolkovich worked with Benjamin Cook of NASA's Goddard Institute for Space Studies to create the massive new archive of long-term, natural phenology observations.

The archive includes data from 1,558 species of wild plants on four continents and shows leafing and flowering will advance, on average, five to six days per degree Celsius of warming.

Estimates based on data from warming experiments are under-predicting advances in flowering by eight and a half times and advances in leafing by four times, researchers said.

"These results are important because we rely heavily on warming experiments to predict what will happen to ecosystems in the future," Cook said.

"With these long-term observational records you may be able to pick up a shift in a plant community over a few years that you wouldn't be able to observe in an experiment."