Dangerous climate change level on terrestrial ecosystems was so complicated that there were inconsistent conclusions and disputations about the impacts on natural ecosystems under varied warmer levels.

Researchers of Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences have studied the problem by the atmospheric-vegetation interaction model (AVIM2) over China at four warmer levels of 1, 2, 3 and 4 ℃ over China during the 21st century. Future climate data were projected by regional climate model from the Hadley Centre under Special Report on Emissions Scenarios (SRES) B2 scenario. Results show that, terrestrial land surface temperature is projected to increase by about 1℃ in 2010, 2℃ in 2038, 3℃ in 2068 and 4℃ in 2098 relative to the baseline period (1961–1990). Average net primary productivity (NPP) is likely to decrease in China as a whole.

The Tibetan Plateau is the only ecoregion with increasing NPP as the climate becomes warmer. Main conclusions were: 1 ℃ warmer, favorable or adverse impact on ecosystem would be equivalent with regional variation; 2 ℃ warmer, slight adverse impacts would be significant; 3 ℃ warmer, moderate adverse impact would take priority and 4 ℃ warmer, moderate adverse impact regions would increase significantly. For China as a whole, irreversible impact would not occur.