Prehistoric Catastrophe Can Help Us Find A North Star For Climate Peparedness (& Prevention)

I really like camping, hiking, and occasionally taking an e-bike out for a nice ride in the mountains. It would take a truly dull mind to not start wondering, even a little, what caused the terrain to form like it did. Since college, I’ve known just enough about geology to reach what people call the “Peak of Mount Stupid” on the Dunning-Kruger chart. Fortunately, becoming aware that you know almost nothing is enough to get you to fall to the depths of the “Valley of Despair,” where you figure out that you know nothing and can only continue by learning from people who know more than you do.

So, in my spare time, I’ve been trying to do that as I look at the landscapes, like the one in the featured image. I know that a great many millions of years ago, parts of this landscape dropped as the area stretched out. When I took that picture, I was standing on the edge of one of those drop-off zones. Dead ahead, in the distance, you can see the Otero Mesa, a really flat area that has some salt lakes off to the far left (hidden by mountains. Off to the right, you can see some lower-down flat areas, but this other camera angle will give you a better view of what’s down there:

At the very bottom, you can see White Sands National park. This area was formed by lakes that developed in the area, with much of the white sand coming from gypsum that washed out of the mountains. As the ice age lake dried up (this happened several times), the winds blew that gypsum away into giant heaps in the basin floor. At its height, the lake filled nearly the whole lowlands, and even joined with other lakes fed by the Rio Grande (on the other side of the distant mountains) to form a truly giant lake that flooded the whole region’s lowlands.

But, this changed pretty quickly one day between 750,000 and 900,000 years ago, when this giant lake found a weak spot in the mountains that served as the side of the bowl it sat in. First, it trickled out. Then, it managed to cut the side of that weak spot down until the whole lake came gushing out, rapidly cutting a deep canyon and sending all that water into the Gulf of Mexico.

That wasn’t the end of the region’s wacky water woes. Even after people moved into the area, the river kept changing course and creating some pretty nasty floods every time the glaciers gave off a big burst of meltwater up in Colorado. This issue continued for the valley (not shown in these pictures) until a big dam was put in around 1916. There’s an older video that explains a lot more about that here.

The Megacatastrophe Few Know About

This seasonal and multi-year flooding cycle wasn’t something Native Americans couldn’t cope with. The region has had people living in it for tens of thousands of years, and there haven’t been any extinctions, but people in the area came uncomfortably close on one occasion: the Younger Dryas period, starting around 12,800 years ago.

While there’s debate on the causes, one theory is that the whole episode was caused by a comet, which broke up before slamming into the Earth in a number of different places. Whatever the cause, this all happened long before any known writing systems, so we can only know about it from geological records and human artifacts (and the interpretation of that data leaves room for debate).

What we do know is that the lowlands saw regular catastrophic flooding events as glaciers rapidly melted. Even worse, some areas ended up downstream of broken ice dams, and saw absolutely insane floods that destroyed everything and scoured the bedrock. So, if you belonged to a tribe that lived in the lowlands or spent much time there, this was problematic to say the least.

You’d think that maybe moving up into the mountains, where I took the picture from, would be a good refuge, but the comet fragments and then rapid climactic shifts set the forests on fire. This, as we know, makes the forests not very hospitable to life. What about between the forest and desert, like the mountain shelves or the Otero Mesa? Yeah, those were full of thick grass, which also would burn if it wasn’t flooding from unusual rain and burn scars.

Scientists estimate that between 30% and 60% of the human population died during this period. In the southwest, Clovis Culture arrowheads just stop showing up in the ground, and right on top of them is a thick layer of black soot and melted minerals. Everyone didn’t die off, but enough did that a whole culture stopped making things, so they had to have taken a brutal hit from this.

What We Can Learn From This For Today’s Climate Change?

While we aren’t likely to see these sorts of climactic shifts, thinking about the unthinkable is a good way to inspire action. I don’t mean this deceptively, either. Telling people to prepare for things far beyond what we actually expect to see and not telling them that it’s unlikely will only result in people thinking they’re being lied to or that someone is crying wolf.

Instead, we should honestly tell people what’s going on, like the CDC did with itss zombie campaign a few years ago. Sure, that campaign got a lot of attention, and it probably didn’t inspire much preparation for public health emergencies, but we at least know now how to get the public’s attention toward emergency preparedness issues. So, attention grabbing far-out scenarios are good, but only as a first step toward taking more realistic action for more realistic threats.

Perhaps more importantly, getting people to realize that climate shifts killed off around half of the global population, and probably far more than half in the United States, could lead to people just not wanting to go through that kind of trouble at all. Preventing major climate problems is probably where most efforts should lie. Giving people something to aim for (or aim against) would be a good way to accomplish that.

Images by Jennifer Sensiba.