Many scientists say it’s abundantly clear that Earth is entering its sixth mass-extinction event, meaning three-quarters of all species could disappear in the coming centuries, reports CNN on July 11, 2017. That’s terrifying, especially since humans are contributing to this shift.
But that’s not even the full picture of the “biological annihilation” people are inflicting on the natural world, according to recent scientific study. Gerardo Ceballos, an ecology professor at the Universidad Nacional Autónoma de México, and his co-authors, including well-known Stanford University biologist Paul Ehrlich, cite striking new evidence that populations of species we thought were common are suffering in unseen ways.
“What is at stake is really the state of humanity,” Ceballos claims. Their key findings are shocking: Nearly one-third of the 27,600 land-based mammal, bird, amphibian and reptile species studied are shrinking in terms of their numbers and territorial range. The researchers called that an “extremely high degree of population decay.”
The scientists also looked at a well-studied group of 177 mammal species and found that all of them had lost at least 30% of their territory between 1900 and 2015; more than 40% of those species “experienced severe population declines,” meaning they lost at least 80% of their geographic range during that time.
Looking at the extinction crisis not only in terms of species that are on the brink but also those whose populations and ranges are shrinking helps show that “Earth’s sixth mass extinction is more severe” than previously thought, the authors write. They say a major extinction event is “ongoing.”
“It’s the most comprehensive study of this sort to date that I’m aware of,” said Anthony Barnosky, executive director of the Jasper Ridge Biological Preserve at Stanford University, who was not involved in the study. Its value, Barnosky said, is that it makes visible a phenomenon typically unseen by scientists and the public: that even populations of relatively common species are crashing.
“We’ve got this stuff going on that we can’t really see because we’re not constantly counting numbers of individuals,” he said. “But when you realize that we’ve wiped out 50% of the Earth’s wildlife in the last 40 years, it doesn’t take complicated math to figure out that, if we keep cutting by half every 40 years, pretty soon there’s going to be nothing left.”
Stuart Pimm, chair of conservation ecology at Duke University in North Carolina, summed up: “When I look out over the woods that constitute my view from my window here, I know we no longer have wolves or panthers or black bears wandering around. We have eliminated a lot of species from a lot of areas. So we no longer have a functional set of species across large parts of the planet.”
“What good mapping does is to tell you where you need to act,” Pimm said. “The value of the Ceballos’ paper is a sense of the problem. But given there’s a problem, what the bloody hell are we going to do about it?”
And the causes are well-known. People are burning fossil fuels, contributing to climate change. We are chopping down forests and other habitat for agriculture, to the point 37% of Earth’s land surface now is farmland or pasture. The global population of people continues to rise, along with our thirst for land and consumption.
“The good news is, we still have time,” he said. “These results show it is time to act. The window of opportunity is small, but we can still do something to save species and populations.” For this science and religion need to collaborate with each other. That is precisely the message of Laudato Si.