Earth enters sixth extinction phase
Vertebrates vanishing 114 times faster than normal; humans under threat too
With animals disappearing about 100 times faster than they used to, the world has embarked on its sixth mass extinction and humans could be among the first victims, said scientists in a report published in the Science Advances journal. Authored by scientists at Stanford, Princeton and Berkeley universities, the researchers found that vertebrates were vanishing at a rate 114 times faster than normal. And humans are likely to be among the species lost. The study —which its authors described as “conservative” is based on documented extinctions of vertebrates, or animals with internal skeletons such as frogs, reptiles and tigers, from fossil records and other historical data.
The causes of species loss ranges from climate change to pollution to deforestation and more. “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 lead author Gerardo Ceballos of the Universidad Autonoma de Mexico. “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,” said the study.
The modern rate of species loss was compared to the “natural rates of species disappearance before human activity dominated.” It can be difficult to estimate this rate, also known as the background rate, since humans don’t know exactly what happened throughout the course of Earth’s 4.5 billion year history. The research however, found that that since 1900 more than 400 vertebrates have disappeared — an extinction rate 100 times higher than in other — non-extinction — periods. “There are examples of species all over the world that are essentially the walking dead. We are sawing off the limb that we are sitting on,” said Stanford University professor Paul Ehrlich. According to the International Union for Conservation of Nature, about 41 percent of all amphibian species and 26 percent of all mammals are threatened with extinction.
The last similar event was 65 million years ago, when dinosaurs disappeared, most probably as a result of an asteroid. This time around the research, which mainly highlights climate change, pollution and deforestation as causes for the rapid change, notes that a knock-on effect of the loss of entire ecosystems could be the primary cause.
As our ecosystems unravel, the Centre for Biological Diversity has noted that we could face a “snowball” effect whereby individual species extinction ultimately fuels more losses. The report, which builds on findings published by Duke University last year, does note that averting this loss is possible through intensified conservation effects to alleviate the pressure on populations of threatened species —notably habitat loss, over-exploitation for economic gain and climate change. But that “window of opportunity is rapid closing.”