Exotic frogs and toads are dying out in the jungles of Latin America, apparent victims of global warming in what might be a harbinger of one of the worst waves of extinction since the dinosaurs.

Accelerating extinctions would derail a United Nations goal of "a significant reduction in the current rate of biodiversity loss" by 2010. That target will be reviewed at a UN meeting of environment ministers in Curitiba, Brazil, on March 20-31.

Many scientists say global warming widely blamed on burning fossil fuels in factories, power plants and vehicles is adding to other human threats including destruction of habitats from expanding cities, deforestation and pollution.

For now, amphibians such as frogs, toads, salamanders and newts are on the front-line they live both in water and on land and have a porous skin sensitive to changes in temperature and moisture. A skin fungus is also decimating amphibians.

In coming decades, threats could widen to creatures ranging from polar bears to tropical butterflies. A few species might benefit, such as forests expanding north to the Arctic.

The latest 2004 Red List gives "climate change" alongside "disease" as main factors for the extinction of the Golden Toad of Costa Rica, Ecuador's Jambato Toad and an Ecuadorean toad known as Atelopus Longirostis.

A study in the journal Nature in January said two-thirds of 110 species of Harlequin frog in central and South America had died out in the past 20 years. It implicated a warming climate in helping spread fungus.

In the worst case, some studies say the world could be facing one of the biggest waves of species loss since the dinosaurs were wiped out 65 million years ago.

Larigauderie said the UN goal of slowing biodiversity loss was impossible. "It's totally unrealistic. We don't know what there is out there and we don't know how it's changing," she said.

Overall, the Red List says 844 species have disappeared since 1500, ranging from the dodo to the Tasmanian tiger.

In one of the bleakest projections, a 2004 international study said a quarter of all species perhaps a million could be condemned to extinction by 2050, partly because of a warming climate.

Species limited to a single mountain-top like the Golden Toad were unable to escape if it got too hot. In other cases, cities, roads or farmland may block the path of animals and plants moving towards the poles, the study said.

Source: China Daily