Oceans are breaking heat temperatures daily. What’s behind the trend?

Everything from hurricanes to sea life could be altered by the warming waters.

By Sarah Asch & Sean SaldanaApril 15, 2024 3:10 pm,

The ocean has broken temperature records every day for more than a year so far. This trend shows no sign of changing in 2024. 

The sea has continued to beat previous temperatures by wide margins. In fact, the whole planet has been relatively hot for months, according to a lot of different data sets.

So why exactly is this happening? 

For answers, the Texas Standard was joined by Andrew Pershing, vice president for science at Climate Central, a nonprofit communication and research group. Listen to the interview above or read the transcript below.

This transcript has been edited lightly for clarity:

Texas Standard: Why are we seeing ocean temperatures breaking records right now?

Andrew Pershing: Well, the number one reason is because we are living on a warming planet. We have too much carbon dioxide in the atmosphere. We’re trapping a whole bunch of heat, and 90% of that heat is getting stored in the ocean. So that’s first and foremost why we see, year after year, the ocean keeps setting these records.

But this year we’re seeing a few things getting added on top of that, perhaps. We have an El Niño that’s kind of waning now. That’s boosted temperatures a little bit more. And there are also some interesting hypotheses out there about how some changes in things like aerosol pollution over the Atlantic may be allowing things to warm up even more on top of that global warming signal. 

Why might that aerosol pollution be an issue now?

So this is really interesting.

So, you know, aerosol pollution are particulates like from the tailpipes of diesel trucks or, in this case, really big ships. There’s been a real global effort to reduce emissions because they’re bad for humans to breathe them. But one of the side effects is that those particles are actually a little bit reflective. So they tend to have a cooling effect. And so if you reduce those particulates, you can actually get a little bit of warming.

So there’s some hypotheses out there that that may be driving a bit of the signal that we’re seeing, especially in the North Atlantic.

So this signal, as you called it, how much of a temperature increase does it represent in the short term? 

So, you know what we’re looking at are temperatures around the world, averaged over the planet, they’re about 1.4 degrees above kind of the average conditions – what we would have expected in, say, the 1990s. And that those temperatures are even higher in certain places.

So one of the places that I think we’re all in the U.S. really keeping our eye on, is this kind of tropical, Atlantic waters that are the source waters for hurricanes. That’s the energy that’s going to make hurricanes into the powerful storms that they become. 

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What about the Gulf of Mexico?

So the Gulf of Mexico is definitely warmer than normal than what you would expect. It doesn’t stand out globally as like one of the glowing hot spots that we see on the planet, but definitely the waters off of Texas and Louisiana seem to be running about almost two degrees Fahrenheit above normal.

Could this be the sort of thing that is a blip on the radar? Just something that, looking in the short term, we see maybe increases, decreases yearto year that may fall within this range?

Well, you know, this is a long term trend. It’s one that the scientific community understands really, really well.

Like, the best signal that we have to track global warming on the planet is the amount of heat stored in the ocean. And that just ticks up year after year after year, because we keep trapping more heat on the planet.

But then on top of that, on top of that long term trend, you do have bumps and wiggles of years that maybe are a little bit above the trend and years that are a little bit below the trend, and maybe this is a year that stands above that long term trend. But what that means is that in 5 or 10 years, we will catch up to that and a normal year and will feel like this. 

We could probably talk for the rest of the show about the impacts of this trend, but what are some that stand out most for you as far as the upshot – the effects for the ocean and us?

So, you know, the big one that we’re going to watch is the impact on the hurricane season. And so we’re talking about a more active hurricane season as we switch into a La Niña. Then you add the warmer oceans underneath it, and that means that you’re going to get more frequent storms, and the storms are more likely to become big and powerful.

I’m an oceanographer. I love spending time in the ocean. And, you know, the thing that really tugs at my heart are looking at the pictures of coral reefs. We really are seeing warming in really critical places like the Caribbean, like the Great Barrier Reef. And so the reefs in those ecosystems are going to start to really, really feel it this year. And that’s going to be some sad stuff to watch.

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