New Data Shows Global Plant Productivity Weakening Due to Regional Drought-

According to a new study of NASA satellite data, global plant productivity that had once been flourishing with warming temperatures and an extended growing season is now declining due to regional drought. Plant productivity is a measure of the photosynthesis process that green plants use to convert solar energy, carbon dioxide and water into sugar, oxygen and ultimately plant tissue. During the 1980s and 90s, there was an observed 6 percent increase in plant productivity – and through careful monitoring, researchers have found that it has only dropped 1 percent over the last decade. However, even this small decline could potentially affect food security, biofuels and the global carbon cycle. Researchers Steven Running and Maosheng Zhao of the University of Montana in Missoula have detected the global shift from thorough analysis of NASA satellite data. The researchers examined statistics from the Moderate Resolution Imaging Spectroradiometer on NASA’s Terra satellite, and compared them with growing season climate data that included figures on temperature, solar radiation and water. “We see this as a bit of a surprise, and potentially significant on a policy level because previous interpretations suggested global warming might actually help plant growth around the world,” Running said. In 2003, a similar study led by scientist Ramakrishna Nemani, now a researcher at NASA’s Ames Research Center in Moffett Field, Calif., determined plant productivity was on the rise due to rising global temperatures and other related statistics. Intending on simply updating prior-collected data, Running and Zhao expected to see a comparable increase. However, the researchers instead found a decline between 2000 and 2009 that they linked to regional drought which, in fact, negated the positive influence of a longer growing season. “This is a pretty serious warning that warmer temperatures are not going to endlessly improve plant growth,” Running said. The team published its findings August 19 in Science.