One isn't inclined to pay much attention to a bedraggled street person waving a sign saying "The End Is Near," but when the National Science Foundation is saying it could be lights out for the earth it's a little harder to shrug off.
Anthony Barnosky, a biologist at the University of California at Berkeley, has just published the results of an NSF-funded study suggesting that the earth is sinking into a mass die-off that could see three-quarters or more of its animals go extinct. That level of annihilation has only occurred five times before in the past 540 million years, although this would be the first death event that humans could be around for.
H. Richard Lane, program director for the NSF's Division of Earth Sciences, doesn't see that as a coincidence.
"A modern global mass extinction is a largely unaddressed hazard of climate change and human activities," he said. "Its continued progression, as this paper shows, could result in unforeseen--and irreversible--consequences to the environment and to humanity."
Among the indicators of doom that Barnosky and his team studied were critically endangered mammals struggling to cope with habitat loss, disease and global warming.
Using fossil records, they calculated that mammals go extinct at an average rate of less than two species every million years. But at least 80 kinds of mammals have met the end of the line in just the past 500 years, a speedy series of extinctions that Barnosky's team says preceded the great kill-offs of eons past. (Here are a few animals that have recently called it quits.)
The researchers estimate that if threatened species start being eliminated at a steady rate that draws on through future years, a sixth mass extinction could be upon us in three to 22 centuries. But there's hope, said Barnosky:
"Our findings highlight how essential it is to save critically endangered, endangered and vulnerable species. With them, Earth's biodiversity remains in pretty good shape compared to the long-term biodiversity baseline. If most of them die, even if their disappearance is stretched out over the next 1,000 years, the sixth mass extinction will have arrived."
You can read more about the study at the NSF's website.