November 6, 2009 – Original Source: The Times
Alarming predictions that climate change will lead to the extinction of hundreds of species may be exaggerated, according to Oxford scientists.
They say that many biodiversity forecasts have not taken into account the complexities of the landscape and frequently underestimate the ability of plants and animals to adapt to changes in their environment.
“The evidence of climate change-driven extinctions have really been overplayed,” said Professor Kathy Willis, a long-term ecologist at the University of Oxford and lead author of the article.
Professor Willis warned that alarmist reports were leading to ill-founded biodiversity policies in government and some major conservation groups. She said that climate change has become a “buzz word” that is taking priority while, in practice, changes in human use of land have a greater impact on the survival of species. “I’m certainly not a climate change denier, far from it, but we have to have sound policies for managing our ecosystems,” she said.
The International Union for the Conservation of Nature backed the article, saying that climate change is “far from the number-one threat” to the survival of most species. “There are so many other immediate threats that, by the time climate change really kicks in, many species will not exist any more,” said Jean Christophe Vie, deputy head of the IUCN species program, which is responsible for compiling the international Redlist of endangered species.
He listed hunting, overfishing, and destruction of habitat by humans as more critical for the majority of species.
However, the Royal Society for the Protection of Birds disagreed, saying that climate change was the single biggest threat to biodiversity on the planet. “There’s an absolutely undeniable affect that’s happening now,” said John Clare, an RSPB spokesman. “There have been huge declines in British sea birds.”
The article, published today in the journal Science, reviews recent research on climate change and biodiversity, arguing that many simulations are not sufficiently detailed to give accurate predictions.
In particular, the landscape is often described at very low resolution, not taking into account finer variations in vegetation and altitude that are vital predictors for biodiversity.
In one analysis of the likelihood of survival of alpine plant species in the Swiss Alps, the landscape was depicted with a 16km by 16km (10 miles by 10 miles) grid scale. This model predicted that all suitable habitats for alpine plants would have disappeared by the end of the century. When the simulation was repeated with a 25m by 25m (82ft by 82ft) scale, the model predicted that areas of suitable habitat would remain for all plant species.
The article suggests that migration to new regions and changes in living patterns of species would take place but that actual extinction would be rare.
Other studies comparing predictions of extinction rates with actual extinction rates have come to similar conclusions. According to a high-profile paper published in the journal Nature in 2004, up to 35 per cent of bird species would be extinct by 2050 due to changes in climate. To be on track to meet this figure, Professor Keith Bennett, head of geography at Queen’s University Belfast, calculated that about 36 species would have to have become extinct each year between 2004 and 2008. In reality, three species of bird became extinct.
He said that many species are far more versatile than some prediction models give them credit for. “If it gets a couple of degrees warmer than they’re comfortable with, they don’t just die, they move,” he said.