Thread by @sarahkaplan48

56 million years ago, the Earth heated up faster than any time in its history — except the present. Now @NMNH paleontologist Scott Wing is looking at the past to understand what our future might hold

Here are a few lessons from that ancient catastrophe:
washingtonpost.com/news/speaking-…

1. Extinctions.

Global warming made the oceans more acidic and decreased the availability of oxygen in some areas. That triggered mass die offs of tiny, single-celled creatures called foraminifera, which have calcium carbonate shells — a lot like today's corals.

2. Dwarfing.

Mammal fossils from the PETM suggest that warmer climates made creatures up to 30 percent smaller. Why? It's thought that the smaller bodies were better at shedding heat.

3. Dramatic shifts in landscape.

The Bighorn Basin, which Scott Wing studies, looked a lot like the southeast US before the PETM. It was lush, swampy full of sycamores and palm trees. But all that changed when the weather got warmer.

During the PETM, Wyoming became hot and arid. Fossils from this period come from plants that usually grow in dry, toasty climates in Central America.

Also, weather got really wild. Geologists find evidence of increased torrential rainstorms and intense floods. Sound familiar?

4. Very hungry insects.

Scott also finds increased damage from insect bites on leaves from this period — and the possible explanation is fascinating. Wing thinks that all the excess carbon in the atmosphere actually made plants less nutritious.

How would that work? Well, I wasn't able to get into it in the story, but studies of modern crops suggest that plants exposed to higher levels of atmospheric CO2 contain less protein and fewer nutrients like iron and zinc.

Oops, meant to link to a big study from 2014: nature.com/articles/natur…

What does this mean for us? Should we be looking out for shrinking horses? Not yet. The amount of carbon released during the PETM (up to 7 trillion tons) is 10x greater than what we've added to the atmosphere. We'd need to burn Earth's entire fossil fuel reservoir to match it.

BUT - humans are also increasing atmospheric carbon levels at a pace 10x faster than what happened in the PETM.

And the consequences we're already beginning to see are "eerily familiar," Wing says.

"This is not the apocalypse," Scott told me. "This is growing up as a species."

“Science has finally gotten us to a point where we have some idea of what the consequences are of the things that we do. Can we use that knowledge in something that starts to approach a wise way?”