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Climate change could drive to extinction as many as one in six animal and plant species, according to a new analysis.
In a study published in the journal Science, Mark Urban, an ecologist at the University of Connecticut, also found that as the planet warms in the future, species will disappear at an accelerating rate.
"We have the choice," he said. "The world can decide where on that curve they want the future Earth to be."
As dire as Urban's conclusions are, other experts said the real toll may turn out to be even worse. The number of extinctions "may well be two to three times higher," said John J Wiens, an evolutionary biologist at the University of Arizona. Global warming has raised the planet's average surface temperature about 1.5 degrees Fahrenheit since the Industrial Revolution.
In 2003, Camille Parmesan of the University of Texas and Gary Yohe of Wesleyan University analysed studies of more than 1,700 plant and animal species. They found that, on average, their ranges shifted 3.8 miles per decade toward the planet's poles.
If emissions of carbon dioxide and other greenhouse gases continue to grow, climate researchers project the world could warm by as much as 8 degrees Fahrenheit. As the change continues, scientists fear some species won't be able to find suitable habitats.
For example, the American pika, a hamster-like mammal that lives on mountains in the West, has been retreating to higher elevations in recent decades. Since the 1990s, some pika populations along the species' southernmost ranges have vanished.
Hundreds of studies published over the past two decades have yielded a wide range of predictions regarding the number of extinctions. Some have predicted few extinctions, while others have predicted that 50 per cent of species face oblivion.
There are many reasons for the wide variation. Some scientists looked only at plants in the Amazon, while others focused on butterflies in Canada. Because scientists rarely were able to say just how quickly a given species might shift ranges, they sometimes produced a range of estimates.
To get a clearer picture, Urban decided to revisit every climate extinction model ever published. He threw out all the studies that examined just a single species and ended up with 131 studies examining plants, amphibians, fish, mammals, reptiles and invertebrates spread out across the planet.
©2015 The New York Times News Service
