Yesterday's post, in which I skated backward through geologic time into the deep past, alluded to a few really bad times the Earth has been through. Episodes of trap volcanism, which make the biggest volcanoes you can think of look like wet firecrackers. Mass extinctions. Asteroid collisions.
Bad as 2020 has been, the planet has seen worse.
A lot worse.
One awful event I didn't mention, however, is the Paleocene-Eocene Thermal Maximum. It occurred about 56 million years ago. The gist is that over a period of maybe fifty thousand years, there was a spike of carbon dioxide injected into the atmosphere -- over 44,000 gigatons (that's 44 trillion tons) of excess carbon dioxide. The result was a greenhouse-effect temperature surge that was on the order of five to eight degrees Celsius, on average, worldwide.
The results were catastrophic, starting with the extinction of close to half of the species of foraminifera, single-celled organisms that form the basis of the oceanic food chain and whose calcareous shells were literally dissolved away by increasingly acidic water. Life eventually bounced back -- it always seems to -- leading to diversification amongst a number of mammalian lineages, including ungulates and carnivores.
But for a while, things were pretty unpleasant. Unbearably hot, a choking, acrid atmosphere laden with carbon dioxide and methane, and oceans like a sweltering vinegar bath.Scientists at Columbia University's Lamont-Doherty Earth Observatory just published a paper this week in the Proceedings of the National Academy of Sciences that looks at why this sudden and catastrophic event occurred. What they found out has two conclusions, one of interest only to folks who like geology, and the other which should terrify the absolute shit out of every human being on Earth.