Greatest Warming Is in the North, but Biggest Impact on Life Is in the Tropics

http://www.sciencedaily.com/releases/2010/10/101006141548.htm

ScienceDaily (Oct. 6, 2010) — In recent decades documented biological changes in the far Northern Hemisphere have been attributed to global warming, changes from species extinctions to shifting geographic ranges. Such changes were expected because warming has been fastest in the northern temperate zone and the Arctic.

But new research published in the Oct. 7 edition of Nature adds to growing evidence that, even though the temperature increase has been smaller in the tropics, the impact of warming on life could be much greater there than in colder climates.

The study focused on ectothermic, or cold-blooded, organisms (those whose body temperature approximates the temperature of their surroundings).

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In fact, previous research from the University of Washington has indicated that small temperature changes can push tropical organisms beyond their optimal body temperatures and cause substantial stress, while organisms in temperate and polar regions can tolerate much larger increases because they already are used to large seasonal temperature swings.

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