We’re not in the middle of a mass extinction

Hooray?

All is not great– obviously– but that doesn’t make for a mass extinction.  Really enjoyed this take from Peter Brannen in the Atlantic:

Given how severely humans have damaged the natural world over the millennia, it was an idea I found attractive, and it’s one even shared by many geologists and paleontologists. Our destruction is so familiar—so synonymous with civilization—in fact, that we tend to overlook how strange the world that we’ve made has become. For instance, it stands to reason that, until very recently, all vertebrate life on the planet was wildlife. But astoundingly, today wildlife accounts for only 3 percent of earth’s land animals; human beings, our livestock, and our pets take up the remaining 97 percent of the biomass. [emphases mine] This Frankenstein biosphere is due both to the explosion of industrial agriculture and to a hollowing out of wildlife itself, which has decreased in abundance by as much as 50 percent since 1970. This cull is from both direct hunting and global-scale habitat destruction: almost half of the earth’s land has been converted to farmland…

Surely we’ve earned our place in the pantheon next to the greatest ecological catastrophes of all time: the so-called Big Five mass extinctions of earth history. Surely our Anthropocene extinction can confidently take its place next to the juggernauts of deep time—the Ordovician, Devonian, Permian, Triassic and Cretaceous extinctions.

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.” …

If we’re really in a mass extinction—if we’re in the [End- Permian mass extinction 252 million years ago]—go get a case of scotch,” he said.

If his power-grid analogy is correct, then trying to stop a mass extinction after it’s started would be a little like calling for a building’s preservation while it’s imploding.

“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—” …

When mass extinctions hit, they don’t just take out big charismatic megafauna, like elephants, or niche ecosystems, like cloud forests. They take out hardy and ubiquitous organisms as well—things like clams and plants and insects. This is incredibly hard to do. But once you go over the edge and flip into mass extinction mode, nothing is safe. Mass extinctions kill almost everything on the planet.

So, good news, we’re not actually in the middle of a mass extinction.  Bad news– that doesn’t mean we’re not wreaking horrible damage on the planet.

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About Steve Greene
Professor of Political Science at NC State http://faculty.chass.ncsu.edu/shgreene

One Response to We’re not in the middle of a mass extinction

  1. R. Jenrette says:

    It’s discomforting to hear that we are not in the midst of a mass extinction but merely in the stage of setting one up with little desire to change course.

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