Sixth mass extinction to destroy 75 % of existing species

Almaty. March 4. Kazakhstan Today - The Earth may be at the beginning of the sixth mass extinction, which may make 75 % of the existing species extinct, Kazakhstan Today reports.

The Earth has undergone mass extinctions, during which more than 75% of existing species disappear, exactly five times in the past 540 million years. If things continue as they are we may be at the beginning of the sixth, a group of biologists and paleontologists suggest in a cautionary paper in Wednesday's edition of the journal Nature, USAToday reported.

One possible cause of the largest extinction event in the history of life on Earth was a meteor that crashed off the coast of Australia about 251 million years ago. Scientists in 2004 found evidence of an impact crater there, believed to be from a meteor strike.

But they also signal that the threat is at such an early stage, with so many questions yet to be answered, that there's hope for avoiding this outcome.

The projection comes from researchers at the University of California, Berkeley, the University of Sao Paulo in Brazil and the National Evolutionary Synthesis Center in Durham, N.C. They looked at the animals currently listed as "critically endangered," "endangered" and "threatened" by the International Union for Conservation of Nature.

The IUCN lists 18,351 species on its "Red List of Threatened Species," considered the global standard for the conservation status of animal and plant species. All are at risk based on current and projected habitat loss or destruction due to human encroachment and climate change. Of those, 1,940 are listed as critically endangered, meaning the species' numbers have decreased, or will decrease, by 80% within three generations.

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