PARIS – 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, a climate study said Sunday.
Output of man-made greenhouse gases is putting Earth on track for 4 degrees Celsius of warming by 2100 compared with the preindustrial 18th century, it said.
The unprecedented speed of warming will be a shock for many species, as it will badly affect the climatic range in which they can live, it warned.
Other experts say that the deaths of crops and animals are likely to prompt mass migrations of people over the rest of the century, and conflicts with those already in the lands they enter.
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 percent of plants and 35 percent of animals could see their living space halved by 2080 at current emission growth for carbon dioxide, 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, as well as plants and reptiles.
The regions that will lose the most are sub-Saharan Africa, Central America, Amazonia and Australia, the paper said.
Lead researcher Rachel Warren said the estimates “are probably conservative,” as they were based only on the impact of rising global temperatures.
Other symptoms of climate change — storms, droughts, floods and pests, for instance — will amplify the problem.
“Animals in particular may decline more, as our predictions will be compounded by a loss of food from plants,” Warren said in a press release.
“There will also be a knockon effect for humans because these species are important for things like water and air purification, flood control, nutrient cycling and ecotourism.”
The study, published in Nature Climate Change, said there was a ray of light.
If carbon emissions peak in 2016 and decline by 3 to 4 percent annually thereafter, this would limit 2100 warming to 2 degrees, avoiding 60 percent of the projected impact from business-as-usual emissions.
But if the peak is delayed until 2021, emissions will have to fall yearly by 6 percent to achieve 2 degrees of warming, which would require a costlier effort to rein in energy use.
Alternatively, if emissions peak by 2030 and then are reduced at 5 percent annually to limit warming to around 2.8 degrees, the loss of climatic range will be reduced by 40 percent compared with business as usual.
U.N. members have adopted the 2-degree target in world climate talks, which aim to conclude a new treaty on carbon emissions by 2015 and have it ratified by 2020.
But the negotiations have been making poor progress, and the yearly rise in emissions, driven especially by the burning of coal in big developing countries, has led many scientists to conclude that warming of 3 or 4 degrees is probable by century’s end.
The new study says that loss of climate range will be bound to boost the risk of species extinction.
The Nobel-winning Intergovernmental Panel on Climate Change (IPCC) has estimated that 20 to 30 percent of species will be at increasingly high risk of extinction if warming exceeds 2 or 3 degrees above preindustrial levels.