Global Growth of Plants Is Offset by Drought, New Study Shows

The steady growth of global plant productivity in the 1980s and 1990s, spurred by warmer temperatures and longer growing seasons, has now been reversed because of the growing impacts of drought, particularly in the southern hemisphere, according to a new study. Examining data from NASA’s Terra satellite, researchers at the University of Montana determined that plant growth in the past decade began to decline slightly, after two decades of expansion. In the 1980s and 1990s, plant productivity increased by 6 percent, but in the 2000s it decreased by 1 percent, according to the study, published in the journal Science. Some scientists believed that a warmer world would stimulate plant productivity because of lengthened growing seasons and greater concentrations of carbon dioxide in the air. But Steve Running, co-author of the Science paper, said his study might indicate that these benefits are being offset by worsening regional droughts as temperatures rise and precipitation patterns change. The study showed that while plant productivity in high-latitude northern hemisphere ecosystems expanded in the 2000s, the Southern Hemisphere was plagued by regional droughts. “This is a pretty serious warning that warmer temperatures are not going to endlessly improve plant growth,” said Running.