Are humans causing a mass extinction on the magnitude of the one that killed the dinosaurs?
The answer is yes, according to a new analysis - but we still have some time to stop it.
Mass extinctions include events in which 75 percent of the species on Earth disappear within a geologically short time period, usually on the order of a few hundred thousand to a couple million years. It's happened only five times before in the past 540 million years of multicellular life on Earth. (The last great extinction occurred 65 million years ago, when the dinosaurs were wiped out.) At current rates of extinction, the study found, Earth will enter its sixth mass extinction within the next 300 to 2,000 years.
"It's bittersweet, because we're showing that we have this crisis," study co-author Elizabeth Ferrer, a graduate student in biology at the University of California, Berkeley, told LiveScience. "But we still have time to fix this."
Others aren't so optimistic that humans will actually do anything to stop the looming disaster, saying that politics is successfully working against saving species and the planet.
Species go extinct all the time, said Anthony Barnosky, the curator of the Museum of Paleontology at UC Berkeley and another co-author of the paper, which appears in today’s (March 2) issue of the journal Nature. But new species also evolve constantly, meaning that biodiversity usually stays constant. Mass extinctions happen when that balance goes out of whack. Suddenly, extinctions far outpace the genesis of new species, and the old rules for species survival go out the window...
The culprits for the biodiversity loss include climate change, habitat loss, pollution and overfishing, the researchers wrote.
"Most of the mechanisms that are occurring today, most of them are caused by us," Ferrer said.
So can we fix it? Yes, there's time to cut dependence on fossil fuels, alleviate climate change and commit to conservation of habitat, the study scientists say. The more pressing question is, will we?
Barnosky and Ferrer both say they're optimistic that people will pull together to solve the problem once they understand the magnitude of the looming disaster. Jablonski puts himself into the "guardedly optimistic category."
"I think a lot of the problems probably have a lot more to do with politics than with science," Jablonski said.
That's where Paul Ehrlich, the president of the Center for Conservation Biology at Stanford University and author of "The Population Bomb" (Sierra Club-Ballantine, 1968), sees little hope.
"Everything we're doing in Washington [D.C.] today is working in the wrong direction," Ehrlich, who was not involved in the research, told LiveScience. "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 researchers take an upbeat view...
Humans on Verge of Causing 6th Great Mass Extinction
02 March 2011