If it wasn't official before, it is now: humans have joined the ranks of asteroids and ice ages in terms of their biodiversity-obliterating power.
Life on Earth has so far managed to overcome five mass extinctions, which are characterized by the extinction of the majority of species on the planet in a relatively short period of time. Causes of previous mass extinctions include ice ages and asteroids, and scientists have repeatedly concluded that humans are currently causing a sixth.
Yet, some critics insist that scientists must be overestimating the rate of species extinction, so scientists recently fired back with a best-case scenario report. Even when they used the most conservative plausible estimates of the current extinction rate and doubled the standard estimate for the background — that is, not human-related-rate of extinction, they found that extinctions have been occurring at an extremely rapid rate over the past several centuries.
"We can confidently conclude that modern extinction rates are exceptionally high, that they are increasing, and that they suggest a mass extinction under way— the sixth of its kind in Earth's 4.5 billion years of history," the researchers report in a paper published in the journal Science Advances.
The generously high background extinction rate that the researchers used was two mammal species extinctions for every 10,000 species over the course of 100 years. At this "natural" rate of extinction, it would have taken between 800 and 10,000 years to reach the number of extinctions that have occurred in the past century.
This should concern you even if you aren't a nature lover. Because regardless of how much intrinsic value you see in biodiversity, its disappearance would rob us of valuable ecosystem services such as water purification and crop pollination.
"If the currently elevated extinction pace is allowed to continue, humans will soon (in as little as three human lifetimes) be deprived of many biodiversity benefits," the researchers warn.
Turning this mass extinction around will require immense and immediate effort, and as the researchers remind us, "the window of opportunity is rapidly closing."
Photo: Sascha Kohlmann | Flickr
