Quick notes:

  • AMOC is a series of currents that move warm water north

  • Oceanographers have noticed the AMOC currents slowing down recently

  • Other times the AMOC has slowed down? Right before major world weather shifts

Picture it: you’re lounging on the beach with a cold drink in your hand and the soothing waves of the ocean lapping up against your toes. The breeze is in your hair, and the smell of salt is in the air. Enjoy this moment, because if scientists’ predictions are right, we might not be able to enjoy our ocean (or our world) for very much longer.

What is AMOC, and why is it warning us about the ocean?

AMOC stands for Atlantic Meridional Overturning Circulation; it’s a series of currents that move water throughout the world’s oceans, so AMOC itself isn’t actually warning us about anything. Researchers that study AMOC, however, have some pretty big news: there isn’t as much movement in the oceans today as there has been in the past. And that’s probably not good.

Wikimedia

Currents of warm water usually move through the ocean kind of like machine parts move through a factory on a series of conveyor belts. Warm water moves from the heat of the tropics north into the North Atlantic ocean. When the water cools down, some of it evaporates, giving the remaining water a higher salt content. This salty water drops to the bottom of the ocean, spreads out, and, if it’s lucky, ends up towards the top again where it can soak up the sun’s rays and get all nice and toasty again. And trust me, we want this to keep happening.

Since 2004, oceanographers have been studying AMOC and other ocean circulation systems, and they’ve noticed a slowdown of the currents. And although it might not change our lives drastically in the near future, the ocean might have more to tell us than meets the eye.

What happens if the ocean’s circulation system actually stops instead of just slowing down?

The current system of currents creates climate. When the warm water is distributed throughout the world’s oceans, energy moves all over and gives us weather and habitable living temperatures. Should the AMOC come to a grinding halt, our weather patterns and temperatures might be in for a drastic shift.

There isn’t as much movement in the oceans today as there has been in the past. And that’s probably not good.

That being said, even AMOC-focused scientists aren’t completely sure what would happen if our common currents slowed or stopped. Since oceanographers have only been studying AMOC for about 15 years, they can’t say for sure if the slowing of the AMOC is even a widespread, world-changing trend.

But back to the potentially bad news. There is evidence that there have been major changes in AMOC and ocean currents before… like right before the last ice age. Could it be possible that changes in the ocean current are hinting at a massive change in world weather? Scientists don’t think it likely, but they’re still watching AMOC, just to be sure.

Don’t worry: it’s not quite time to panic and run from the beach with your towel trailing. But do keep an eye on those ocean headlines, because those great big bubbling bodies of water know more about our planet than we do.

A deeper dive — Related reading from the 101

Why a discovery at the bottom of the Mariana Trench is bad news for us all | Science101

The ocean has more secrets than just how it moves. We’re affecting the ocean in more ways than we even know.

-Climate change isn’t the only thing killing our coral reefs | Science101

While climate change might be partially to blame for changing the ocean currents and for killing coral reefs, there’s more to the story than meets the eye (or the thermometer). 

The north pole is moving, should we be worried? | Science101

The oceans aren’t the only changing parts of our world, and most of us don’t even know.