A new study published in a prominent scientific journal has provided the first concrete evidence that global warming is contributing to the extinction of dozens of plant and animal species worldwide.
For over 25 years, scientists have speculated that rising temperatures, worldwide, is hastening the spread of disease and wiping out entire species. And now a study in the journal "Nature", confirms it.
Using data from 70 researchers around the world, a team led by American biologist Alan Pounds has discovered that spikes in global temperatures from the last 20 years have coincided exactly with the extinction of several frog species in Central and South America.
"There's a very clear relationship between temperature and the timing of the die-offs," says Mr. Pounds.
Conservationists have been perplexed by the worldwide decline of amphibians, ever since the problem was first recognized in 1990. Since then, at least 70 species of frogs have disappeared.
Stanford University biologist Terry Root says nearly a third of the world's 6,000 species of frogs, toads, and salamanders are threatened. "I believe, as do a lot of biologists, that we are standing at the edge of a mass extinction."
Scientists say amphibians are in greater danger than any other group of animals because their permeable skins make them sensitive to environmental changes. But researchers say thousands of plant and animal species are also at risk. In rainforests, rare plants are blooming earlier, disrupting their natural reproductive cycles. And in the Arctic, polar bears are declining in numbers as rising temperatures threaten the ice floes they depend on for breeding.
Ecologist Dr. Karen Master says 18 to 35 percent of the world's plant and animal species could disappear in the next 45 years.
"Quite honestly the evidence is truly mounting that many fragile and wonderful and special eco-systems are at risk," she says.
And humans are not immune. The World Health Organization estimates that 150,000 more people will die and more than five million others will get sick this year because global warming is helping to spread insect and water-borne disease.
The Earth's average temperature rose one degree in the 20th century and a group of United Nations scientists warn it could rise another ten degrees by the year 2100.