The Sixth Extinction

Species are mortal too.

They appear, they die out. Some quickly, some slowly. Sharks are an old species. Sharks appeared 450 million years ago. Humans, two million. Homo neanderthal is gone already. How will homo sapiens do?

The Earth’s fossil record shows five mass extinctions, in which many or most species disappeared over a few months or centuries. The first four are mysterious. We don’t know for certain what caused them.

The Fifth Extinction we know about. 66 million years ago, an asteroid the size of Manhattan slammed into the Yucatan peninsula in Mexico.

The energy released was like a hundred million atom bombs. The Earth’s forests burned down. A vast tsunami swamped every coast on the planet. 75% of species died. The Fifth Extinction was as sudden as they get.

Mass extinctions are part of the life of the planet. We are now nearing the end of the Sixth, the Holocene extinction.

The Holocene extinction is us. Humans are the first species to become the apex predator on both land and sea. We have already extinguished almost as many species as the asteroid did. The extinction started centuries ago. We just noticed.

Species loss is now hundreds of time faster than the ‘background’ rate over the millennia. Some of this is now widely known. We have hunted lions, tigers and whales near to extinction. We have almost emptied the oceans of fish. Warming from our carbon emissions is melting the ice polar bears live on.

But the Sixth Extinction is not recent. Species loss has been accelerating for centuries. It matches the spread of humans. Species disappear as we farm and build. Where humans flourish, other species disappear.

Climate change is the closing paragraph of a story that began before we started writing.

Yeast in a warm container of nutrients consumes all the food then dies in its own waste. Any animal that sees its species double in a lifetime has cause to worry.

Of course, humans are not yeast. We’re talking about it.

But that’s about all we’re doing. There are ways to soften the end of the Sixth Extinction. Although polar bears won’t survive, there are things we could do so humans might. But we’re not doing those things. Nothing remotely like them. As a species we don’t seem to have whatever that takes.

The next decades will see species of life disappearing faster and faster. The human population will crash. What we do right now determines how soon, how far and how fast.

We’re not doing much; expect it to get ugly.

Further reading

“What killed the Neanderthals?”, Luke Mitchell, London Review of Books, 36, 9, 8 May 2014: review of The Sixth Extinction: An unnatural history by Elizabeth Kolbert
The Dark Mountain Project “a network of writers, artists and thinkers who have stopped believing the stories our civilisation tells itself.”

Update 2021

A sci-fi drama Nightflyers follows an Earth mission launched to contact an alien spacecraft passing through our solar system. The aliens have so far ignored all attempts to make contact. When the Earth mission heads towards it, the alien craft turns away. The human xenobiologist explains:

That’s an intelligent species. To them we just look like a parasite trying to escape a dying host.