Extinctions During Human Era 1000 Times Worse
Amid a world with advancing technologies, increasing land development and human-driven climate change, the world's species are becoming extinct 1,000 times faster than they used to, according to new research.
Extinctions are about 1,000 times more frequent now than in the 60 million years before people came along - that's 10 times worse than scientists previously thought.
"This reinforces the urgency to conserve what is left and to try to reduce our impacts," lead author Jurriaan de Vos, a Brown University postdoctoral researcher, said in a statement. "It was very, very different before humans entered the scene."
Human population growth is mainly to blame for the dying off of species, which find themselves confined to smaller and smaller areas around the globe until eventually their habitat dwindles completely.
According to the researchers, the "normal" rate of extinction is about 0.1 extinctions per million species per year. Now, the new work finds that it's more along the lines of 100 extinctions per million species per year.
Normally, these types of estimates are based on fossil records alone, but that can be an inaccurate technique considering they often only allow identification of the animal or plant's genus, but not its exact species. This time around researchers also looked at the evolution of family trees, or phylogenies, of numerous plant and animal species.
Phylogenies, constructed by studying DNA, trace how groups of species have changed over time, adding new genetic lineages and losing unsuccessful ones.
"We've known for 20 years that current rates of species extinctions are exceptionally high," said senior author Stuart Pimm, a Duke University professor. "This new study comes up with a better estimate of the normal background rate - how fast species would go extinct were it not for human actions. It's lower than we thought, meaning that the current extinction crisis is much worse by comparison."
The findings were published in the journal Conservation Biology.