Tens of thousands of animals and plants could become extinct within the coming decades as a direct result of global warming.
This is the main conclusion of a study into how climate change will affect the diversity of species in the most precious wildlife havens of the world.
Scientists believe that if atmospheric levels of carbon dioxide double from pre-industrial times - which is expected by the end of the century - then biodiversity will be devastated.
"It isn't just polar bears and penguins that we must worry about anymore," said Lee Hannah of Conservation International, which is based in Washington.
"The hotspots studied in this research paper are essentially refugee camps for many of our planet's most unique plant and animals species," Dr Hannah said.
"If those areas are no longer habitable due to global warming then we will ... be destroying the last sanctuaries many of these species have left," he said.
The scientists, led by Lee Malcolm of the University of Toronto, investigated how rising temperatures could affect the species richness of 25 "biodiversity hotspots" - areas of the world that are rich in species found nowhere else. The 25 hotspots included in the study cover just 1 per cent of the global landmass yet they account for some 44 per cent of the plants and 35 per cent of the world's vertebrate animals.
"Climate change is one of the most serious threats to the planet's biodiversity. We now have strong scientific evidence that global warming will result in catastrophic species loss across the planet," Dr Malcolm said.
As temperatures rise due to increasing concentrations of carbon dioxide in the atmosphere, many species will be forced into extinction, the study found.
Mountain animals and plants that need cool temperatures will for instance not be able to migrate to higher altitudes and moisture-loving species will be unable to evolve the drought resistance in the relatively short time needed to survive climate change.
The study, published yesterday in the journal Conservation Biology, predicts that many unique habitats will be lost as climate change brings about rapid changes to the environment.
"We project the eventual loss of thousands, perhaps tens of thousands, of hotspot endemic plant and vertebrate species under a climate associated with a doubling of carbon dioxide concentrations," the study says.
The wildlife havens that could be worst affected include the Cape floristic region of South Africa, the natural landscape of southwest Australia, the tropical Andes and the Atlantic forests of Brazil, Paraguay and Argentina.
"Although some hotspots appear to be unusually vulnerable to global warming ... high rates of habitat loss were also observed in areas that are not hotspots, indicating the global nature of the threat posed to biodiversity by climate change," the scientists say.
The computer modelling used by the scientists found that in some instances the mass extinctions caused by climate change were greater than those caused by deforestation, which many environmentalists had assumed was the single most destructive human activity. In the worst-case assessment, a doubling of carbon dioxide concentrations led to the extinction of 40 per cent of species in some of the hotspots - a potential loss of some 56,000 endemic plants and 3,700 endemic vertebrate species.
Hotspots under threat
* Tropical Andes of South America: Home to the threatened Andean flamingo, yellow-eared parrot and spectacled bear, this is one of the richest and most diverse regions in the world with 450 endemic amphibians at risk of extinction.
* Cape floristic region of South Africa: The only hotspot with an entire floral kingdom. It holds five of South Africa's 12 endemic plant families. Sited at the southern-most tip of the African continent, the region is unique in terms of Mediterranean-type vegetation and its plants would find it difficult to escape rising temperatures.
* South-western Australia: This region is rich in its own unique collection of plants and animals, especially reptiles, such as the western swamp turtle. Endemic vertebrates include the numbat, a small marsupial, honey possum and red-capped parrot.
© 2006 Independent News and Media Limited