Global Warming, Temperature Homogenization and Species Extinction

Abstract

The global mean surface air temperature has increased by about 0.5 °C over the past century, and is expected to increase by 1.5 to 4.0 °C in response to a doubling of atmospheric CO₂ (relative to the pre-industrial level) over the next century (IPCC 1996). Variations in the rise in temperature at regional to continental scales are expected to depend on both latitude and altitude. General circulation models (GCMs) project a maximum mean warming in high latitudes, in part a consequence of ice-albedo feedback associated with reduced sea ice cover (IPCC 1996). At high elevations, a similar feedback-induced temperature enhancement is likely to occur if warming reduces the duration of snowcover. Hence, the equator-to-pole and sea-level-to-mountaintop temperature gradients will likely shrink. This predicted climate change would homogenize the temperature of the earth; the ecological effect of this abiotic homogenization is the focus of this chapter.