A joint press release
by the American Geophysical Union, the Centre for Ecology and Hydrology Dorset and Wageningen University claims that climate change estimates for the next century may have substantially underestimated the potential magnitude of global warming. A paper to be published May 26th will quantify a two-way phenomenon by which greenhouse gases not only contribute to higher temperatures, but are themselves increased by higher temperatures. This higher concentration leads to still higher temperatures, in what scientists call a positive feedback loop. These new conclusions are based on existing data from polar ice cores and temperature reconstructions based on geological proxy date, but the data was interpreted in a new way.
[Source: Wageningen University]