Scientists exposed plants to a yearlong drought. The result is worrying for climate change

Europe and many other parts of the world are currently grappling with extreme drought—and that could be bad news for efforts to curb climate change, concludes a new global study of how shrubs and grasses respond to parched conditions. Grasslands and shrublands cover more than 40% of Earth’s terra firma, and they remove hefty amounts of carbon dioxide from the air. But by deliberately blocking precipitation from falling at 100 research sites around the world, researchers found that a single year of drought can reduce the growth of vegetation by more than 80%, greatly diminishing its ability to absorb carbon dioxide. Overall, plant growth in the artificially drought-stricken grassy patches fell by 36%, far more than earlier estimates. But the study, presented last week at the annual meeting of the Ecological Society of America in Montreal, also found great variability: Vegetation at 20% of the sites continued to thrive despite the lack of water. “I was surprised at how much drought impacts varied,” says Drew Peltier, a physiological ecologist at Northern Arizona University who was not involved in the study. “This suggests there is some resilience in these systems; the question is how much and for how long.” A decade ago, with droughts forecast to become more frequent and severe in a warming world, three ecologists—Melinda Smith of Colorado State University; Osvaldo Sala of Arizona State University, Tempe; and Richard Phillips from the University ...
Source: ScienceNOW - Category: Science Source Type: news