'16% of species' may become extinct
One in six of the animals and plants on the planet could face extinction if nothing is done to reduce the rate of climate change, a study has found.
The new research suggests that biodiversity loss is accelerating with each Celsius degree rise in temperature.
If global warming continues unabated, raising the Earth's temperature by 4.3C compared with its pre-industrial level, 16% of species could be at risk, it is claimed.
Certain regions of the Earth are likely to be hardest hit, according to the forecast, with 23% of species affected in South America and 14% in Australia and New Zealand.
North America and Europe had the smallest proportion of species facing extinction, 5% and 6% respectively. All taxonomic groups - extended families of animals and plants - were equally at risk.
The research is based on an analysis of 131 different biodiversity studies taking into account a range of factors including modelling technique, taxonomic group, location, global temperature and species distribution.
Results published in the journal Science show that species loss is closely linked to climate change - not only increasing but accelerating as temperatures rise.
Author Dr Mark Urban, from the University of Connecticut in the US, wrote: "The factor that best explained variation in extinction risk was the level of future climate change ...
"Global extinction risks increase from 2.8% at present to 5.2% at the international policy target of a 2C post-industrial rise, which most experts believe is no longer achievable.
"If the Earth warms to 3C the extinction risk rises to 8.5%. If we follow our current, business-as-usual trajectory ... climate change threatens one in six species (16%)."
He added that regions around the world differed "significantly" in extinction risk.
South America, Australia and New Zealand all harboured vulnerable diverse groups of endemic species with small ranges.
Extinction risk in Australia and New Zealand was exacerbated by small habitats that limited the ability of species to move to new homes.
Dr Urban pointed out that in 1981 scientists predicted the signal of global climate change would soon emerge from the background "noise" of weather.
He said: "Thirty years later we are reaching a similar threshold for the effects of climate change on biodiversity.
"Extinction risks from climate change are expected not only to increase but to accelerate for every degree rise in global temperatures. The signal of climate change-induced extinctions will become increasingly apparent if we do not act now to limit future climate change."