Friday, May 6, 2011

Global climate change affects tropical as well as polar regions

David Gable in Environment News Network: The most often heard victims of climate change are the polar bears in the far north losing their hunting grounds to the melting polar ice. Maps show the greatest area of warming temperatures are at the north and south poles. However, equally important are the effects of climate change in the tropical regions of the world. As temperatures rise here, poorly adaptable species may be lost forever. It may also encourage the spread of diseases and unprecedented heat waves which may lead to forest fires.

Studies of climate changes effects in the tropics have been conducted by William Laurance, Distinguished Research Professor at James Cook University in Queensland, Australia. His research has covered the entire world, from the Amazon to Africa, to tropical Australia. He notes prior research conducted by biologist, Justin Welbergen, who made observations on an Australian day where temperatures reached 42.9 degrees C (109 F). The extreme heat caused the deaths of 1,453 flying foxes along the northeastern Australian coastline. Since then, tens of thousands more have died. Prior to 1994, few mass die-offs were ever recorded.

Tropical species are perfectly suited for their climate. There are no seasons like in the northern latitudes, so these species have never experienced any serious deviations in temperature. In the tropics the only way to experience different temperatures is to change elevation. Generally, the temperature drops 6 degrees C (11 F) for every thousand meters up. Therefore, tropical species are also perfectly suited for their elevation.

This means trouble for mountaintop species because they are effectively on an island and have nowhere else to go. As temperatures rise, these high elevation species will be the first in danger. Laurance's colleague, Steve Williams, has created a model which suggests that extinctions will increase if temperatures rise more than three degrees. If they rise by 5-6 degrees, most endemic life in north Queensland will be exterminated….

A male Red-winged Parrot at the Mareeba Wetlands, Queensland, Australia. Shot by David Cook Wildlife Photography, Wikimedia Commons via Flickr, under the Creative Commons Attribution 2.0 Generic license

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