More Evidence of Negative Feedback if Global Temperatures Warm

ScienceDaily: Soils that experience seasonal freeze-thaw cycles currently cover c. 55 million km2. This equates to more than half of the total land area of the northern hemisphere. Forecasts such as the IPCC-Report 2007 anticipate that due to global warming the soil temperature there in the future will fluctuate more frequently around the freezing point. The change between freeze-thaw cycles is considered to be one of the major factors for the release of nitrogen into the soil and consequently for an increase in microbial activity.