Tuesday, May 6, 2008

Global warming - Worst impact in the tropics?

When thinking about negative effects of global warming we usually think about rapid melting of Arctic's ice sheet and the struggling polar bears fighting for their survival as the temperatures increase. But the results of the latest study carried out by team led by University of Washington scientists showed that although temperature changes will be much more extreme at high latitudes, tropical species have a far greater risk of extinction with warming of just a degree or two. Although temperature change of just a degree or two doesn't seem significant, it is of greater significance to tropical species since they are used to a living environment within a very small temperature range, and once temperatures get beyond that range many species might not be able to cope and will face extinction.

Joshua Tewksbury, a UW assistant professor of biology said: "In the tropics many species appear to be living at or near their thermal optimum, a temperature that lets them thrive. But once temperature gets above the thermal optimum, fitness levels most likely decline quickly and there may not be much they can do about it." Tropical species can only tolerate a narrow range of temperatures as they used to a constant climate throughout all year without any significant oscillations in temperature. On the other hand Arctic species live well below their thermal limit, and most will continue to do so even with climate change.

This negative impact could be even worse for biodiversity since tropical climates holds variety of different species, and the richest biodiversity on our planet. Majority of species on our planet live in tropics and these are areas with unique complexity of different lives that create specific ecosystems. In these ecosystems insects play key role by pollinating our crops and breaking down organic matter back into its nutrients so other organisms can use them. Insects are in fact link that connects all other links in ecosystem, and are therefore vital for proper functioning of these ecosystems. According to this study global warming will have tremendous negative effect on insects in tropics, and they will lose their ability to reproduce. This will of course affect all tropical ecosystems and rich biodiversity in tropics will seize to exist without its most important link.

Chances for tropical species to adapt to global warming are not encouraging since current climate is nearly ideal and any temperature increases will spell trouble for them as these species have so far only encountered very small temperature changes. These species need time to adapt and global warming is simply coming too soon, not giving them enough precious time to cope with the higher temperatures. Sadly, extinction of many tropic species looks to be certainty in years to come.

Global warming - Worst impact in the tropics?

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