Greenhouse gas/temperature feedback mechanism may raise warming beyond previous estimates

WASHINGTON - A team of European scientists reports that climate change estimates for the next century may have substantially underestimated the potential magnitude of global warming. They say that actual warming due to human fossil fuel emissions may be 15-to-78 percent higher than warming estimates that do not take into account the feedback mechanism involving carbon dioxide and Earth's temperature.

In a paper to be published on 26 May in Geophysical Research Letters, Marten Scheffer of Wageningen University in the Netherlands and colleagues at the Potsdam Institute for Climate Impact Research in Germany and the Centre for Ecology and Hydrology in the United Kingdom use newly acquired ancient climate data to quantify the two-way phenomenon by which greenhouse gases not only contribute to higher temperatures, but are themselves increased by the higher temperatures. This higher concentration leads to still higher temperatures, in what scientists call a positive feedback loop.