Study predicts collapse of Atlantic Ocean current that warms Europe

Climate scientists have known about connections between oceans and the atmosphere for decades, but new research indicates warmer oceans may change ocean currents and atmospheric patterns in a big way.

MPR News chief meteorologist Paul Huttner talked with John Abraham of the University of St. Thomas about shifting ocean currents in the Atlantic Ocean.

The following has been lightly edited for clarity. Click play on the audio player above to listen to this episode, or subscribe to the Climate Cast podcast.

This study finds a higher chance than previously thought that the Atlantic Ocean may see some big changes. What do we need to know here?

There’s what's called a conveyor belt in the ocean, and this is water that travels up the East Coast of the United States and then goes toward Greenland, Iceland and Northern Europe. The water gets cold, sinks to the bottom of the ocean and then it travels backward.

It sort of goes in a like a loop — or a conveyor belt. That passageway of water is really, really important because it brings heat up to Europe, and it’s the reason why England’s temperatures are much more mild.

These scientists discovered that this conveyor belt of water is slowing down, and it will likely stop in the future. It's going to have really crazy consequences for our climate.

If that current were to slow down or collapse, how is that going to affect the weather in Europe?

This event will likely make Europe colder. If this current shuts down, the heat from the ocean won’t go up all the way to Europe. But the paradox is that this is a result of global warming. So, as the Earth warms, we’re going to have some parts of the planet get really, really hot, and we’re actually going to have some parts get colder.

Europe will be one part of the planet that will have this paradoxical outcome of getting colder as the rest of the world gets warmer.

What do you think could happen here in Minnesota? How might it affect our daily weather maps?

It's going to make our weather more wild. We’re going to have more extremes, especially the hot extremes. It’s going to increase temperatures in the Midwest, and it’s going to also make precipitation events more extreme. In Minnesota, we’ve seen this weather whiplash recently — where we go from cold and dry to hot and wet, back to maybe hot and dry — and we go from one extreme to the other. That is going to become even more significant as climate change continues.

But one of the problems we’ve found is what's called a tipping point. And it’s a tipping point where, once you cross it, you can’t stop. It's like a locomotive going down a train track. You can’t just pull the brakes and stop it instantaneously.

So this process has started, and it’s going to evolve over about 100 years. Even if humans take drastic action to reduce greenhouse gasses, that’s not likely going to stop this shutdown of this current.

It looks like we’ve passed over a threshold, and the natural tendency of the ocean is to change its circulation in a way that redistributes heat. It looks like there’s not much we can do to stop it.

The second part of this conversation about shifting ocean currents and climate change will be published next week.