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  • Climate change 'worse threat than deforestation'


[NAIROBI] Climate change could become as big a threat to the planet's biodiversity as deforestation by the end of the century, warn researchers.

In a study published in Conservation Biology on Tuesday (11 April), they say a doubling in atmospheric carbon dioxide could strip biodiversity-rich 'hotspots' of thousands, or even tens of thousands, of species.

The most vulnerable species are likely to be those living in confined geographical areas, such as mountain ranges, because of the difficulty of dispersing from these areas.

"Species will be stranded with nowhere to go," says lead researcher Jay Malcolm of the University of Toronto, Canada.

"Although we usually think of the Arctic as being vulnerable, the study shows that other places where species have limited ranges — such as islands, mountains, and continent tips — are also vulnerable."

The researchers used computer simulations of future climate and vegetation to estimate the changes in habitat and associated species extinctions that would occur if carbon dioxide levels doubled over the next 100 years.

Malcolm told SciDev.Net that some regions could lose up to 75 per cent of their species.

The study predicts up to 9,400 extinctions from the tropical Andes, 5,750 from the Mediterranean Basin, 3,395 from the Caribbean, and 3,865 from South Africa's Cape region.

Bob Scholes, an ecologist at South Africa's Council for Scientific and Industrial Research, says the main cause of biodiversity loss is usually assumed to be habitat loss.

But, he explains, what has been missing is the understanding that climate change and habitat loss interact.

"It is much harder for species to adapt to climate change by migration if the landscape is fragmented," he says.

According to Malcolm. "This is a serious issue that we have to address as a global community. We need to reduce greenhouse gas emissions as soon as possible."

Link to abstract of paper in Conservation Biology

Reference: Conservation Biology 20, 538 (2006)

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