More than half of common species of plants and a third of animal species are likely to see their living space halved by 2080 on current trends of carbon emissions, according to a new study.
Output of man-made greenhouse gases is putting Earth on track for four degrees Celsius of warming by 2100, it said.
The unprecedented speed of warming will be a shock for many species because it will affect the climatic range in which they can live, the report warned.
Investigators from Britain's University of East Anglia looked at 48,786 species and measured how their range would be affected according to models of carbon dioxide emissions.
Fifty-five per cent of plants and 35 per cent of animals could see their living space halved by 2080 at current emission growth, they found. The figures take into account the species' ability to migrate into habitat that may open up as a result of warming.
The species most at risk are amphibians, plants and reptiles, and regions that would lose most are sub-Saharan Africa, Central America, Amazonia and Australia, the paper said.
Lead researcher Rachel Warren said the estimates "are probably conservative".
Other symptoms of climate change - storms, droughts, floods and pests, for instance - would amplify the problem.
"Animals in particular may decline more as our predictions will be compounded by a loss of food from plants," Warren said.
"There will also be a knock-on effect for humans because these species are important for things like water and air purification, flood control, nutrient cycling and eco-tourism."
The study, published in Nature Climate Change, said there was a ray of light.
If carbon emissions peak in 2016 - and decline by 3-4 per cent annually thereafter - this would limit 2100 warming to four degrees Celsius.