Study Raises Specter of Mass Extinction
‘No sign of real attention being paid’
A new study of the effects of climate change on life all across the planet reaffirms that we are heading toward the mass extinction of species.
For several years, scientists have been describing the changes now underway as heralding a “Sixth Great Extinction.” This latest study outlines that the process is no longer something in the future but is already taking its course – and a lot quicker than the previous five.
Mass extinctions are classified as events in which 75 percent of species disappear within a geologically short period of time—a few hundred thousand to a couple of million years. These events have happened five times in the 540 million years of multicellular life on Earth.
The last, or fifth, great extinction occurred 65 million years ago, when, the dinosaurs were wiped out. Our best understanding of that one is that an asteroid slammed into what is now the Yucatan peninsula of Mexico, creating an initial firestorm and then an ash cloud that blocked out sunlight, causing a kind of “nuclear winter.”
That whole process took hundreds of thousands of years to unfold, but if there was a silver lining in the ash cloud, it was that the demise of the dinosaurs left an opening for the ascent of the mammals – including humans.
This time, we’re the asteroid!
Will most of life on earth go the way of the dodo?
At current rates of extinction, the new study finds, Earth will enter its sixth mass extinction within the next 300 to 2,000 years. But that doesn’t mean that we have time to spare. The terminology refers to the time when 75 percent of all living species are either already extinct or are irretrievably doomed. And the process that’s bringing that about is already in full motion, happening very fast, and, by many estimates, on the very edge of a tipping point.
One of the study’s co-authors, Elizabeth Ferrer, says the team took a conservative approach to analyzing the figures and comparing the rate of extinction today to what can be seen in the fossil record. They found that species are going extinct three to 12 times faster than would be expected if there were no crisis.
“It’s bittersweet, because we’re showing that we have this crisis,” she told LiveScience. “But we still have time to fix this.”
What’s bittersweet to scientists who are watching the unfolding of this catastrophe is that very little of any significance is actually being done to fix what’s happening.
“Everything we’re doing in Washington today is working in the wrong direction,” says Paul Ehrlich, president of the Center for Conservation Biology at Stanford University. “There isn’t a single powerful person in the world who is really talking about what the situation is. It’s hard to be cheery when you don’t see the slightest sign of any real attention being paid.”
Other paleontologists who have studied the fossil record to see how mass extinction events unfold, agree that once these tipping points are reached, the normal processes of life all start to go out of balance and become largely unpredictable.
“When we kick over into a mass extinction regime, results are extreme, they’re irreversible and they’re unpredictable,” said David Jablonski, a paleontologist at the University of Chicago, referring to what happens when we reach the tipping point. (Jablonski was not involved in the study.) The research, he said, “shows absolutely without a doubt that we do have this major problem.”