New Delhi, March 7 -- Researchers have found that 104 of the 5,203 amphibian species they studied are already exposed to overheating in shaded terrestrial conditions, concluding that the pot is boiling for these 2 per cent of the species.

They expressed concern that a 4 C rise in global temperatures could push 7.5 per cent or 391 of the species studied beyond their physiological limits.

The study, published in Nature, said amphibians are vertebrates most at risk due to climate change, with over 40 per cent of amphibian species listed as being under threat. Thermal extremes may drive amphibians to extinction, according to the researchers.

Amphibians are 'ectothermic', meaning they can regulate body heat by external sources. They are als...