Satellites see a greener EarthSeptember 4, 2001
WASHINGTON, Sept. 4 — Earth’s northern hemisphere is a greener place than it was 20 years ago, with denser vegetation and a longer growing season in some places, scientists reported Tuesday.
IN THE AREA above 40 degrees north latitude — which includes New York City, Madrid, Ankara and Beijing — satellite data show plants have been growing more vigorously since 1981.
One suspected cause is rising temperatures, possibly linked to the buildup of greenhouse gases in the atmosphere, according to a statement released by the NASA, the American Geophysical Union and Boston University.
Eurasia seemed to be greening more than North America, with more lush vegetation for longer periods of time, the statement said.
The growing season is now nearly 18 days longer in Eurasia than it was two decades ago, with spring arriving a week early and autumn delayed by 10 days. In North America, the growing season appears to be as much as 12 days longer.
The Eurasian greening was especially persistent over a broad swath from central Europe through Siberia to Russia’s Far East, where most of the vegetation is forests and woodlands. North America shows a fragmented pattern of change notable only in the forests of the east and grasslands of the upper Midwest.
These results will appear in the Sept. 16 issue of the Journal of Geophysical Research — Atmospheres.