The extinction risk of climate change -- that is, the expected number of species expected to become extinct due to the effects of global warming -- has been estimated in a 2004 Nature study to be between 15 and 37 percent of known species by 2050. More properly, changes in habitat by 2050 will put them outside the survival range for the inhabitants, thus committing the species to extinction. In biology, a species is one of the basic units of biodiversity. ... In biology and ecology, extinction is the ceasing of existence of a species or group of species. ... Conceptual assessment of the risks and impacts of global warming according to the Intergovernmental Panel on Climate Change and how those risks increase relative to increasing global temperatures. ... Galunggung in 1982, showing a combination of natural events. ...

From the abstract:

Climate change over the past 30 years has produced numerous shifts in the distributions and abundances of species and has been implicated in one species-level extinction. Using projections of species' distributions for future climate scenarios, we assess extinction risks for sample regions that cover some 20% of the Earth's terrestrial surface. Exploring three approaches in which the estimated probability of extinction shows a power-law relationship with geographical range size, we predict, on the basis of mid-range climate-warming scenarios for 2050, that 15−37% of species in our sample of regions and taxa will be 'committed to extinction'. When the average of the three methods and two dispersal scenarios is taken, minimal climate-warming scenarios produce lower projections of species committed to extinction (18%) than mid-range (24%) and maximum-change (35%) scenarios. These estimates show the importance of rapid implementation of technologies to decrease greenhouse gas emissions and strategies for carbon sequestration.

References

• Chris D. Thomas, Alison Cameron, Rhys E. Green, Michel Bakkenes, Linda J. Beaumont, Yvonne C. Collingham, Barend F. N. Erasmus, Marinez Ferreira de Siqueira, Alan Grainger, Lee Hannah, Lesley Hughes, Brian Huntley, Albert S. van Jaarsveld, Guy F. Midgley, Lera Miles, Miguel A. Ortega-Huerta, A. Townsend Peterson, Oliver L. Phillips and Stephen E. Williams. Extinction risk from climate change. Nature 427, 145-148 (8 January 2004) | doi: 10.1038/nature02121