Changes to Gulf Stream could mean colder summers, more intense storms in N.L., researcher says

A new study on the ocean's currents suggests the Gulf Stream, located 200 miles off the shores of Newfoundland and Labrador, may soon reach a tipping point that could affect climates around the world.

The study, titled "Observation-based early-warning signals for a collapse of the Atlantic Meridional Overturning Circulation," was published in the Nature Climate Change journal.

Bradde Young, a professor in the department ofphysics and physical oceanography at Memorial University, said the Gulf Streambrings warm water into the Atlantic, while also cycling in cooler water from the Earth's poles.

"If nothing else moved the heat around, the equator would be way warmer than it is, and the poles would be way colder," de Young told CBC Radio'sOn The Go onFriday.

"But two things move the heat around:the atmosphere does it by swirling winds and the ocean does it by causing the warm water [to be] carried poleward. The Gulf Stream helps to keep the North Atlantic warmer and then that cold water cycles back."

Oceanographers have been working to measure the water-moving currents for decades but are often presented with challenges due to how fast the Gulf Stream moves, de Young said.

But as oceanographers take a more direct approach and look to data of the past, he said, the newly released study shows the planet's circulation system could be moving to a place where lesswarm watergets carried into the Atlantic.

LISTEN| Brad de Young talks the Gulf Streamwith the CBC's Ted Blades:

"The system likes tobe in the warm place or the cold place, and it jumps between the two. That happens naturally, and we don't entirely know why.We know some of the things that can do it, and a massive fresh water event is one of the things that can turn it off," he said.

"The big story and the reason that people have really been paying attention to it in the last 30 years is because we know that there's a lot of melting of glacial ice. There's suggestions that that melting fresh water would play that role, and cap the system and shut it off."

System changes could mean colder weather, more intense storms

If the current system brought less warm water into the northern Atlantic, de Young said, it could result in parts of North America, Greenland and Europe becoming colder and southern regions becoming warmer, which could lead to droughts around the world.

In the context of Newfoundland and Labrador, he said it could bring a cooler summerbuta more intense winter season.

"The problem with that is more than just a little bit of cooling.If you think about the temperature difference between the equator and the pole, that's going to get much bigger, because you have a cooler North Atlantic and a warmer, now tropical region," he said.

"There is a little bit of evidence to support this ishappening, because the only place we really see a cold blob in the surface ocean at the moment is between Greenland and Labrador."

While de Young said there isn't a true way to measure the probability of an event like this happening, data suggests the scenario is more likely to happen than it was 150 to 200 years ago.

"The short answer is we know that it can happen," he said. "We don't really have a way to measure what the probability is. But we know the changes that we're making are more than likely to trigger it than if we left the ocean alone," he said.

"This recent study suggests the planet as a whole was kind of leaning toward making this change, and the concern is that the things we're doing pushes that leaning towardfalling over."

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