The Amazonian rainforest is likely to suffer catastrophic damage, even with the lowest temperature rises forecast under climate change, researchers have decided.
The damage will be so severe that it will cause irreversible changes to the world's weather patterns, which is expected to bring more storms, floods and heat waves to Britain.
Up to 40 percent of the rainforest will be lost if temperature rises are restricted to 4 degrees Fahrenheit, which most climatologists regard as the least that can be expected by 2050.
Climate-change researchers issued the assessment of the forest's fragility after discovering a time-lag in the effects of temperature rises on the forest.
It had previously been thought that the trees and other vegetation, and the vast range of animals living among them, would be safe if temperatures rose no more than 4 degrees.
Researchers have now found that even that amount will destroy large tracts of the forest but that the die-back is slow, and will take up to a century to have its full effect.