Climate change threatens one in six species

American Pika, an animal whose habitats are threatened by climate change. Creative Commons: 2010

American Pika, an animal whose habitats are threatened by climate change. Creative Commons: 2010

Climate change could drive one in six species of animal and planet life to extinction.

That’s the finding of a new study, published in the journal Science, which found an average global rate of extinction of 7.9% – that’s one out of every 13 species.

If global carbon emissions continue to rise, the extinction rate would move to one out of every six species by the end of this century.

The study is noteworthy for the large scale of collected data used to compile its findings.

University of Connecticut ecologist Mark Urban analyzed data from 131 peer-reviewed studies, every climate extinction model ever published.

Over the last couple of decades, there have been a number of studies connecting climate change to extinctions.

Those studies often focused on one species or a group of related species such as butterflies. Other studies were based on different degrees of rising global temperatures.

These studies often produced different estimates for extinctions as a result.

To gain a clearer picture, Dr. Urban discarded any research connected with only a single species that might artificially inflate the data in his analysis.

He concentrated on 131 studies on plants, amphibians, fish, mammals, reptiles and invertebrates spread throughout the earth.

Urban found that by a surface temperature increase of 2C (3.6F) 5.2% of species would become extinct.

A rise of 4.3C (7.7F) would see the extinction rate rise to 16% of species.

The rate of extinctions would not increase steadily but would accelerate with rising temperatures.

The earth’s temperature has raised about 0.85C (1.5F)  since the advent of the Industrial Revolution.

Some scientists project a rise of 4.5C (8F) as global emissions grow.

Species respond to temperature changes by shifting their ranges.

Scientists have found that, on average, species ranges have been shifting 3.8 miles towards the planet’s poles per decade. Scientists fear that the continuing rise of global temperatures will make finding suitable habitats difficult for many species.

As these pressures increase, populations may begin to decline, slowly dwindling towards extinction.

The areas of greatest risk to biodiversity are tropical ones in South America, Australia and New Zealand, according to the research.

Tropical forests contain some of the highest concentrations of the world’s species. The Amazon rainforest alone contains one in 10 of all the world’s known species.

Durban believes that the climate models accuracy could be improved if man-made habitat loss in the form of cities, farms and other barriers were taken into account.

Habitat loss is major source of extinction for the world’s species, along with unsustainable hunting and fishing. But these other sources are compounded with the damage climate change presents to biodiversity.

Other scientific experts feel that the situation could be even more dire for the earth’s species. John J. Wiens, an evolutionary biologist at the University of Arizona, said the extinctions “may well be two to three times higher” than Urban’s estimates.

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