Guest essay by Eric Worrall
h/t JoNova – According to renowned Smithsonian Paleontologist Doug Erwin, people who claim we are in the midst of an anthropogenic mass extinction don’t have a clue what a mass extinction actually is.
Earth Is Not in the Midst of a Sixth Mass Extinction
“As scientists we have a responsibility to be accurate about such comparisons.”
At the annual meeting of the Geological Society of America, Smithsonian paleontologist Doug Erwin took the podium to address a ballroom full of geologists on the dynamics of mass extinctions and power grid failures—which, he claimed, unfold in the same way.
Erwin is one of the world’s experts on the End-Permian mass extinction, an unthinkable volcanic nightmare that nearly ended life on earth 252 million years ago. He proposed that earth’s great mass extinctions might unfold like these power grid failures: most of the losses may come, not from the initial shock—software glitches in the case of power grid failures, and asteroids and volcanoes in the case of ancient mass extinctions—but from the secondary cascade of failures that follow. These are devastating chain reactions that no one understands. Erwin thinks that most mass extinctions in earth’s history—global die-offs that killed the majority of animal life on earth—ultimately resulted, not from external shocks, but from the internal dynamics of food webs that faltered and failed catastrophically in unexpected ways, just as the darkening eastern seaboard did in 2003.
I had written to Erwin to get his take on the contemporary idea that there is currently a sixth mass extinction under way on our planet on par with the so-called Big Five mass extinctions in the history of animal life. Many popular science articles take this as a given, and indeed, there’s something emotionally satisfying about the idea that humans’ hubris and shortsightedness are so profound that we’re bringing down the whole planet with us.
Erwin says no. He thinks it’s junk science.
“Many of those making facile comparisons between the current situation and past mass extinctions don’t have a clue about the difference in the nature of the data, much less how truly awful the mass extinctions recorded in the marine fossil record actually were,” he wrote me in an email. “It is absolutely critical to recognize that I am NOT claiming that humans haven’t done great damage to marine and terrestrial [ecosystems], nor that many extinctions have not occurred and more will certainly occur in the near future. But I do think that as scientists we have a responsibility to be accurate about such comparisons.”
“People who claim we’re in the sixth mass extinction don’t understand enough about mass extinctions to understand the logical flaw in their argument,” he said. “To a certain extent they’re claiming it as a way of frightening people into action, when in fact, if it’s actually true we’re in a sixth mass extinction, then there’s no point in conservation biology.”
This is because by the time a mass extinction starts, the world would already be over.
“So if we really are in the middle of a mass extinction,” I started, “it wouldn’t be a matter of saving tigers and elephants—”
“Right, you probably have to worry about saving coyotes and rats.
“So you can ask, ‘Okay, well, how many geographically widespread, abundant, durably skeletonized marine taxa have gone extinct thus far?’ And the answer is, pretty close to zero,” Erwin pointed out. In fact, of the best-assessed groups of modern animals—like stony corals, amphibians, birds and mammals—somewhere between 0 and 1 percent of species have gone extinct in recent human history. By comparison, the hellscape of End-Permian mass extinction claimed upwards of 90 percent of all species on earth.
Read more: https://www.theatlantic.com/science/archive/2017/06/the-ends-of-the-world/529545/
Erwin does not rule out the possibility we might somehow trigger a mass extinction in the future. But killing off a few photogenic species simply doesn’t qualify.
Nothing we have done to the climate or the world in general comes anywhere close to the unimaginable circumstances of previous mass extinctions.
Picture previous mass extinctions; the sky darkened for months, maybe years by gigantic impacts or vast volcanic eruptions which lasted for thousands, of years; Poisonous fumes spreading across the entire world, choking the life out of entire continents; A handful of animals and plants somehow scrounging warmth and food from an almost lifeless wasteland.
Compare this nightmarish hellscape to the slight wobble we may have helped introduce to global temperatures, a wobble so small it cannot be reliably differentiated from previous natural wobbles which occurred in the last few centuries.
Add the measurable greening of the world which has occurred the last few decades.
This isn’t a mass extinction, this is a blossoming of life such as likely has not occurred for millions of years – all thanks to the fertilisation effect of Anthropogenic CO2.