September 7, 2001
Semptember 15 Begins Hispanic Heritage Month

Earth's Becoming A Greener Greenhouse

NASA satellite data suggest that for more than two decades there's been a gradual greening of the northern latitudes of Earth.

Researchers confirm that plant life seen above 40 degrees north latitude, which represents a line stretching from New York to Madrid to Beijing, has been growing more vigorously since 1981. One suspected cause is rising temperatures possibly linked to the buildup of greenhouse gases in our atmosphere.

Over this same time period, parts of the Northern Hemisphere have become much greener and the growing season has increased by several days. Further, Eurasia appears to be greening more than North America, with more lush vegetation for longer periods of time.

The results of this NASA-funded research will appear in the September 16 issue of the Journal of Geophysical Research - Atmospheres.

"When we looked at temperature and satellite vegetation data, we saw that year-to-year changes in growth and duration of the growing season of northern vegetation are tightly linked to year-to-year changes in temperature," Liming Zhou of Boston University said. The area of vegetation has not extended, but the existing vegetation has increased in density.

The researchers used a temperature data set developed from the Global Historical Climate Network. Dr. James Hansen, of GISS, developed this data set and said, "The data were compiled from several thousand meteorological stations in the United States and around the world. The stations also include many rural sites where the data are collected by cooperative private observers."