Global warming could fundamentally alter one third of all habitats

Global warming could fundamentally change one third of the world’s habitats by the end of this century, causing the extinction of certain species, according to a new study by WWF.

According to the report, Global Warming and Terrestrial Biodiversity Decline, the northern latitudes of Canada, Russia and Scandinavia, where they are predicting that warming will be most rapid, up to 70% of habitat could be changed. In other regions of Russia, Canada, Norway, Sweden, and Finland, as well as Kyrgystan, Latvia, Urguay, Bhutan and Mongola are likely to loose 45% or more of current habitat. Many coastal and island species will be at risk from the combined threat of warming oceans, sea-level rise and range shifts.

Using models that simulate global climate and vegetation change the authors of the report investigated three threats to global terrestrial biodiversity:

  • rates of global warming that may exceed the migration capabilities of species;
  • losses of existing habitat during progressive shifts of climatic conditions;
  • reductions in species diversity as a result of reductions in habitat patch size.

Though the ability of species to migrate is poorly understood, the researchers analysed how fast they might be required to move in order to keep up with the projected warming. The required migration rates for plant species due to global warming appear to be 10 times greater than those recorded from the last glacial retreat, says the report, with the likely result being extensive species extinction and local loss of both plant and animal species.

“As global warming accelerates, plants and animals will come under increasing pressure to migrate to find suitable habitat,” said Adam Markham, one of the report’s authors, and Executive Director of US NGO, Clean Air-Cool Planet. “Some will just not be able to move fast enough. In some places, plants would need to move ten times faster than they did during the last ice age merely to survive. It is likely that global warming will mean extinction for some plants and animals.”

The species that are most at risk are those living in isolated or fragmented habitats, including animal species such as the Gelada baboon in Ethiopia, the mountain pygmy possum of Australia, and the monarch butterfly at its Mexican wintering grounds. The Costa Rican golden toad has probably already become extinct, says WWF, though amphibian experts are attributing it to the recent spate of disease-related amphibian die-offs (see related story). Most of the northern spruce and fir forest of New England and New York State in the US could also ultimately be lost, says the report.

On a less fatalistic note, current adjustments in species’ behaviour which are being attributed to global warming include earlier nesting for bird species such as the great tit in Scotland, and the Mexican jay in Arizona. According to the report, butterflies are shifting their ranges northwards throughout Europe, and polar bears and walrus are beginning to feel the impacts of reduced sea ice.

“This is a wake-up call for world leaders – if they do not act to stop global warming, wildlife around the globe may suffer the consequences,” said Jennifer Morgan, Director of WWF’s Climate Change Campaign. “World leaders must give top priority to reducing levels of carbon pollution. They must not miss the chance of this November’s climate summit for stepping up action and preventing a catastrophe that could change the world as we know it.”

WWF have also recently launched a global warning campaign in conjunction with other leading environmental organisations, in preparation for November’s climate summit in the Hague (see related story).

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