The major drivers of the sixth mass extinction
are mainly triggered by human touch: land farming, logging and
settlement, introduction of invasive species, increased carbon emissions
and man-made toxins.
Paul Ehrlich, the Bing Professor of Population Studies in biology and a senior fellow at the Stanford Woods Institute for the Environment, worked with his colleagues in examining the fossil records and calculating the number of extinct species in between each mass extinction. They did a conservative computation by getting the median between current extinction rate and the all-time extinction rate. Even their lowest estimates turned out higher than the previous mass extinction events.
"We emphasize that our calculations very likely underestimate the severity of the extinction crisis, because our aim was to place a realistic lower bound on humanity's impact on biodiversity," the researchers wrote on the paper published in the June 19 issue of Science Advances.
"[The study] shows without any significant doubt that we are now entering the sixth great mass extinction event," Ehrlich said in a university news release.
To date, 41 percent of amphibian species and 26 percent of mammals are on the list of threatened and endangered species. Even if you combine the number of species lost from earlier mass extinctions, which includes up to 280 species, the current period is still way above that number. Earth lost 396 species between 1900 and 2010, according to the International Union of Conservation of Nature.
The analysis revealed that the major drivers of the sixth mass extinction are mainly triggered by humans and include land farming, logging and settlement, introduction of invasive species, increased carbon emissions, and man-made toxins.
"If it is allowed to continue, life would take many millions of years to recover, and our species itself would likely disappear early on," said Gerardo Ceballos, study lead author from the Universidad Autónoma de México.
The researchers hope that their study results would alert not only the public, but also the policymakers to intensify conservation efforts for the ecosystem.
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