Given its potential to damage areas far away from human habitation, the study finds that global warming represents one of the most pervasive threats to our planet's biodiversity – in some areas rivaling and even surpassing deforestation as the main threat to biodiversity.
The study expands on a much-debated 2004 paper published in the journal Nature that suggested a quarter of the world's species would be committed to extinction by 2050 as a result of global warming. This latest study picks up where the Nature paper left off, incorporating critiques and suggestions from other scientists while increasing the global scope of the research to include diverse hotspots around the world. The results reinforce the massive species extinction risks identified in the 2004 study.
"Climate change is rapidly becoming the most serious threats to the planet's biodiversity," said lead author Dr. Jay Malcolm, an assistant forestry professor at the University of Toronto. "This study provides even stronger scientific evidence that global warming will result in catastrophic species loss across the planet."
Using vegetation models, the research is one of the first attempts to assess the potential effects of climate change on terrestrial biodiversity on a global scale rather than just looking at individual species. Scientists looked specifically at the effect that climate change would have on 25 of the 34 globally outstanding "biodiversity hotspots" – areas containing a large number of species unique to these regions alone, yet facing enormous threats.
"It isn't just polar bears and penguins that we must worry about anymore," said Lee Hannah, co-author of the study and senior fellow for climate change at Conservation International. "The hotspots studied in this paper are essentially refugee camps for many of our planet's most unique plant and animal species. If those areas are no longer habitable due to global warming then we will quite literally be destroying the last sanctuaries many of these species have left."
Since these biodiversity hotspots make up about one percent of the Earth's surface, but contain 44 percent of all terrestrial vertebrate species and 35 percent of the world's plant species, they are good indicators of the magnitude of global species that might be affected by rising CO2 levels in the atmosphere.
"These species lose their last options if we allow climate change to continue unchecked," said Dr. Lara Hansen, Chief Climate Scientist at global conservation group World Wildlife Fund. "Keeping the natural wealth of this planet means we must avoid dangerous climate change – and that means we have got to reduce carbon dioxide emissions."
Areas particularly vulnerable to climate change include the tropical Andes, the Cape Floristic region of South Africa, Southwest Australia, and the Atlantic forests of Brazil, Paraguay and Argentina.
These areas are particularly vulnerable because the species in these regions have restricted migration options due to geographical limitations.
The report was funded by the Center for Applied Biodiversity Science at Conservation International, World Wildlife Fund, David Suzuki Foundation, and the Natural Sciences and Engineering Research Council of Canada.
The study's authors include scientists from the University of Toronto, University of New England, USDA Forest Service, WWF – World Wide Fund for Nature (In US and Canada known as World Wildlife Fund) and Conservation International.