Dangerous Feedback: Study Finds Global Warming Underestimated

Source: UPI
[May 22, 2006]

WAGENINGEN, Netherlands, May 22 (UPI) -- European scientists say climate change estimates for the next century may substantially underestimate the potential magnitude of global warming.

The team of researchers report actual warming due to human fossil fuel emissions may be 15 percent to 78 percent higher than warming estimates that do not take into account the feedback mechanism involving carbon dioxide and Earth's temperature.

Marten Scheffer of Wageningen University in the Netherlands -- along with colleagues at the Potsdam Institute for Climate Impact Research in Germany and the Center for Ecology and Hydrology in the United Kingdom -- used 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.

That higher concentration leads to still higher temperatures, in what scientists call a positive feedback loop.

"In view of our findings, estimates of future warming that ignore these effects may have to be raised by about 50 percent," said Scheffer.

The study is to appear in the May 26 issue of Geophysical Research Letters.