Africa / Asia / Biodiversity / Climate Change / Environment / Latin America

Greatest warming is in the North, but biggest impact on life is in the tropics

Dracaena guianensis (3)

Even though global warming is not increasing temperatures in the tropics as much as in the northern temperate zone and the Arctic, the metabolic effects on cold-blooded creatures that live there, such as this caiman lizard, will be greater than on creatures living farther north. (Credit: Tim Vickers/Wikimedia Commons)

Newswise and the University of Washington (USA) report on research published in Nature this week (7 October 2010 edition) on the differential biological impacts of global warming.

‘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 expectation was that physiological changes would also be greatest in the north temperate-Arctic region, but when we ran the numbers that expectation was flipped on its head,” said lead author Michael Dillon, an assistant professor of zoology and physiology at the University of Wyoming. . . .

‘”Metabolic rate tells you how fast the animal is living and thus its intensity of life,” Huey said. Using a well-documented, century-old understanding that metabolic rates for cold-blooded animals increase faster the warmer the temperature, the researchers determined that the effects on metabolism will be greatest in the tropics, even though that region has the smallest actual warming.

‘Metabolic impacts will be less in the Arctic, even though it has shown the most warming. . . .

‘Temperatures rose fastest in the Arctic, not quite as fast in the northern temperate zone and even more slowly in the tropics. “Just because the temperature change in the tropics is small doesn’t mean the biological impacts will be small,” Huey said. “All of the studies we’re doing suggest the opposite is true.”

‘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.

‘The scientists say the effects of warming temperatures in the tropics have largely been ignored because temperature increases have been much greater farther north and because so few researchers work in the tropics.

‘”I think this argues strongly that we need more studies of the impacts of warming on organisms in the tropics,” Dillon said. . . .’

Read the whole article at Newswise: Greatest warming is in the North, but biggest impact on life is in the topics, 6 October 2010.

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