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The Potential Collapse of AMOC 2 min read

The Potential Collapse of AMOC

I learned about The Atlantic Meridional Overturning Circulation and how it inspired 'The Day After Tomorrow.'

By Cary Littlejohn

This is just one of those stories I couldn't get out of mind after I heard it.

How Changing Ocean Temperatures Could Upend Life on Earth - The Daily
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The whole thing is worth a listen, but it's the second half that lodged itself in my brain. It starts with clips from a pretty forgettable movie, The Day After Tomorrow (which, somehow, is 20 years old, apparently).

In the film, Dennis Quaid's character suggests that changes to the North Atlantic current could be to blame for massive aberrant weather events. Though I remembered the ice-age conditions that defined the majority of the film, I'd forgotten that it was supposedly caused by changes to ocean currents.

Even if the film weren't largely forgettable, I'm not sure I would have thought it was a scientifically sound theory as a story engine. But as it turns out, that part of the film, if little else, wasn't so far out there.

I didn't know about the Atlantic Meridional Overturning Circulation, or AMOC, as the episode calls it. But apparently it's a big deal.

It was cool to learn about how AMOC takes warm water to the north and cold water to the south, and in a sense, helps regulate things as we know it. AMOC, though, is slowing down, and one of these days (nobody is sure when, though the episode says the consensus seems to be it's a long way off) it might collapse entirely.

If it continues to slow (or collapses entirely), twin weather-related terribles happen: Colder water stays in the north, driving down temperatures there, making it a much colder place to live (possibly colder than it was before the Industrial Revolution when humans started emitting greenhouse gases, possibly like roughly 12,800 years ago when AMOC last collapsed and brought on an ice age), and warmer water stays in the south, fueling stronger storms and more rainfall near the equator. These could have dramatic effects on humans living in these areas.

Even though it's likely way in the future, I couldn't stop thinking about this possibility, these trickle-down effects that make so much sense when the science is explained and would have such massive consequences. Maybe it was the movie comparison that made it so visual in my head, but it's one of stickier podcast episodes I've listened to in a while, especially on climate issues.