Global Warming Threatens Tropics

Everyone knows that the artic and polar regions have been affected the most by global warming, but now, scientists in Costa Rica are saying that animals and plants in the tropics may face an even bigger threat. "Many lowland tropical species could be in trouble," warns Robert K. Colwell of the University of Connecticut and his team of researchers. "The tropics, in the popular view, are already hot, so how could global warming harm tropical species? We hope to put this concern on the conservation agenda," Colwell said.

"That's because some tropical species, insects are an example, are living near their maximum temperatures already and warmer conditions could cause them to decline," Colwell explained. "We chose the word 'attrition' to emphasize slow deterioration," he said. "How soon that will be evident enough for a consensus is difficult to say." The researchers predict that in a century, the temperature average will rise 5.8 degrees. This would make 53% of the species they studied subject to attrition. However, this doesn't mean that today's jungles will one day be dried up and lifeless. "Tis an ill wind that blows nobody any good. Some species will thrive," Colwell said. "But they are likely to be those already adapted to stressful conditions," like weeds.

There are some nearby locations of animals and plants that are currently experiencing rising temperatures, and fleeing from them. Particularly in the tropics, the answer may be not be to move out but to move up. The reason for this is that species in the tropics have to go north or south for thousands of kilometers to maintain their climate conditions that they are used to. "Instead," Colwell said, "the most likely escape route in the tropics is to follow temperature zone shifts upward in elevation on tropical mountainsides." The researchers say that when you move uphill, the temperature decreases between 9.4 and 11.7 for every 1,000 meters. To get a similar result of temperature change by traveling north or south, the traveling species would have to travel over 620 miles. But unfortuneatly, moving uphill can't work for everyone, species living on mountain tops have no where to go then.

Animals in other climate types are also affected by global warming. The warming climate has some risk factors for the small mammals in Yosemite National Park. Ranges for some high elevation animals like the alpine chipmunk have decreased. Ranges for low elevation animals like the harvest mouse have increased. A recent study has shown that many animals' ranges are changing from the current location to higher and cooler places.

Article posted on CNN.com

http://www.cnn.com/2008/TECH/science/10/10/tropics.threatened.ap/index.html