Plants and soils could trigger warming

Plants and soils may release large amounts of carbon dioxide as global climate warms in a positive feedback that could worsen the warming, U.S. researchers say. Writing in the Journal of Climate, the researchers say this finding contrasts with the expectation that plants and soils will act as carbons "sinks," absorbing carbon dioxide "We have been counting on plants and soils to soak up and store much of the carbon we're releasing when we burn fossil fuels," study co-author Paul Higgins of the American Meteorological Society said. "However, our results suggest the opposite possibility. Plants and soils could react to warming by releasing additional carbon dioxide, increasing greenhouse gas concentrations and leading to even more climate warming." If that happens, the scientists said, a given level of human emissions could result in much larger climate changes than is currently anticipated. Greater reductions in greenhouse gas emissions could be required to ensure carbon dioxide concentrations remain at safe levels for the climate system, they said.