Understanding the Mysterious Loop Current

By Carlyle Calhoun

Published January 12, 2026 at 3:15 PM CST

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The Loop Current is a powerful ocean current that significantly impacts weather patterns, hurricanes, fisheries, and sea level rise. Despite its importance, it remains little understood. Scientists have joined forces in a huge research collaboration called Understanding Gulf Ocean Systems, or UGOS, to change that.

The amazing science behind understanding mysterious but critical ocean currents. And specifically, understanding the current in our backyard, the Gulf’s Loop Current.

We talk with scientists leading a huge multi-country research collaboration that is going to great lengths and depths to understand the especially unknown Loop Current. We talk about how currents connect us, how they are basically a thermostat for the globe, and why, more than ever before, we need to understand them.

EPISODE CREDITS

This episode was hosted by executive producer Carlyle Calhoun. Our theme music is by Jon Batiste, and our sound designer is Emily Jankowski.

Scientists featured in this episode are paleo oceanographer Audrey Morley from the University of Galway, oceanographer Amy Bower from the Woods Hole Oceanographic Institution, oceanographer Steve DiMarco from Texas A&M, and oceanographer Scott Glenn from Rutgers University.

Sea Change is a WWNO and WRKF production. We are part of the NPR Podcast Network and distributed by PRX. Sea Change is made possible with major support from the Gulf Research Program of the National Academy of Sciences, Engineering, and Medicine. Sea Change is also supported by the Water Collaborative of Greater New Orleans. WWNO’s Coastal Desk is supported by the Walton Family Foundation, the Meraux Foundation, and the Greater New Orleans Foundation.

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TRANSCRIPT

AUDREY: I live in Galway, which is on the west coast of Ireland, so right at the gateway to the North Atlantic. You can probably hear from my accent. I'm not Irish, I'm half French, half German, but I've been in Ireland for the past 12 years.

That’s Audrey Morley. I ask her to describe her adopted Irish home..

AUDREY: We have lots of bogs and, I wouldn't say mountains, but you know, low rolling hills and, um, this coastline is beautiful and wild and there's um, yeah, it's very rocky and green. Lots of stonewalls. Just like what you imagine Ireland to be.

And I was curious about something else I’d heard about the landscape there that surprised me.

CARLYLE: And I heard that there are palm trees there.

AUDREY: Yes, absolutely. I, uh, You wouldn't expect them, but yeah. They are here and they do really well.

Palm trees? In Ireland? I mean look at a map, how is that even possible?

CARLYLE: like if you were to compare where you are in Galway, Ireland to like, if you go straight across the Atlantic to Newfoundland, can you describe how drastically different their weather is?

AUDREY: Absolutely. In Newfoundland, you have freezing temperatures below freezing all through January and February and March. It freezes a lot and you have a lot of snow. In Ireland at the same latitude. The temperatures never. Dip below 40. And that’s on average right?

I called up Audrey, not really to just chat about the weather in Ireland. But to understand why the weather? How the palm trees?

AUDREY: So the reason why we have this mild and wet climate in Ireland is because of the Gulf Stream that turns into the North Atlantic current, and that brings a lot of heat from low latitudes into the North Atlantic. This part of the overall Atlantic mayoral overturning circulation

Or AMOC for short, which is what I’ll be calling it. Audrey is a leading paleo oceanographer studying the AMOC. Picture a map of the North Atlantic ocean, with two big arrows, one pointing north and the other pointing south. The gulf stream is the arrow pointing north -- it carries warm water along the surface of the ocean, from the Gulf all the way to northern Europe, releasing its heat, Then, the water gets cold, sinks, and becomes the other arrow -- it runs back south, along the bottom of the ocean.

AUDREY: so you can think of it like a conveyor belt of, uh, transporting heat north and cold waters back south at depth.

So Ireland can thank ocean currents for their palm trees. And they in fact do.

AUDREY: It is part of, uh, Irish culture. So everybody here knows that the Gulf Stream is important for our way of life.

The Loop Current in the Gulf of Mexico is the starting point, I suppose, of what ends up here in Ireland, right?

CARLYLE: So if we drop a rubber ducky in the Gulf, where would it...

AUDREY:…likely it'll, it'll end up here, but it'll make lots of loop de loops and, uh, lots of, uh, detours before it ends up here, it's the scenic route, um, to, to Ireland.

And so what is happening there is obviously very important. So, for example, if the temperature increases in the Loop current, in the Gulf of Mexico, the more intense the storms are, and the more likely we have hurricane force winds reaching Ireland.

THEME MUSIC

I’m Carlye Calhoun and you’re listening to Sea Change.

Today, the amazing science behind understanding these mysterious but critical ocean currents. And specifically, understanding the current in our backyard, the Gulf’s loop current.

I talk with scientists leading a huge multi-country research collaboration that is going to great lengths and depths to understand the especially unknown loop current. We talk about how these currents connect all us. How they are basically a thermostat for the globe. What they mean for hurricanes. And why, more than ever before, we need to understand them.

That’s coming up.

BREAK

Joining me are three leaders in a huge research collaboration called Understanding Gulf Ocean Systems or UGOS.

Amy Bower is a senior scientist at the Woods Hole Oceanographic Institution, Steve DiMarco is a professor of oceanography at Texas A&M, and Scott Glenn is a professor of oceanography at Rutgers.

Welcome, thanks for joining us.

Scott: Thank you.

Amy: Good to be here.

Steve: Happy to be here.

Carlyle:So, let's first explain what this loop current is. And Amy, if we can start with you,

Amy: Sure. The loop current is sort of like a river in the ocean, a river of moving water. It enters the Gulf of Mexico between Mexico and Cuba and flows. Uh, generally northward makes a big loop or a big, uh, bend and turns to the right and exits the Gulf OF Mexico through the Florida Straits. And the Florida Straits are located between Florida, Cuba, and The Bahamas.

Carlyle: Steve, let's kind of build on that. Tell us one other thing that can define what this loop current is.

Steve: Yeah, so it's part of the, uh, air conditioning system of the planet. So it brings the, hot water from around the equator, uh, northwards towards the poles. So, uh, because it's, it's contained, it's in our backyard and it's, uh, it's very localized. It's, it's a spot in the ocean where we can go and, uh, make measurements and do them in a repeatable way.

Carlyle: And Scott, can you, uh, keep helping us define this current.

Scott: Yeah, it's, it's part of the whole global circulation, the global conveyor belt. And this is that piece that goes through the Caribbean and into the Gulf and out through the Gulf Stream over to Europe., this is one of those choke points. It's one of those pulse points where we can monitor it for change and see how it's, um, affecting that global circulation, how it might be changing over time,

Carlyle: So even though this is, you know, this huge powerful ocean current, the fact that it's happening underwater kind of makes it more mysterious and there's a lot we don't know about it, right? So, what do we not know about this current that's really impacting our life, especially for those of us who live on the Gulf Coast or surround the Gulf?

Amy: This is one of the primary objectives of our large collaborative research project that we're working on right now, is to try to predict how this loop current will move around within the Gulf. It doesn't follow the same path all the time. Sometimes this, uh, loop, grows into like a hairpin turn, and then sometimes that hairpin turn, cuts off to form a circular current, we call it an eddy. and that eddy drifts off to the west towards Mexico.And then the loop current itself, retracts back to a more straight current from where it comes into, where it goes out of the Gulf of Mexico. And then that loop current will start to expand again.

Almost like you're filling a balloon kind of,and then after some months that we can't predict yet, it will break off another big chunk, another big circular, current and, that Eddie will drift off to the west. So it's this repeated process of growth and decay that, uh, we really can't yet predict and don't really understand yet. So.

Carlyle : And so the three of y'all, plus a lot of other people involved, have joined together for this big collaborative, and you each have your own expertise. your work is really to kind of demystify this big, important, powerful current. Right? So, let's first talk about your roles in this. Steve, you lead an adaptive surface current sampling team, based outta Texas A&M.

Um, what does that mean?

Steve: Yeah, so we started that, what we were calling the master program or master experiment, uh, as a mini adaptive sampling, uh, experiment to prove to ourselves that we could actually, put that much equipment, different types of platforms that do observational calendars in the same spot at the same time all at once in three different, countries, EEZs. We worked, uh, as a group. There was, uh, 30, 40 people on, uh, weekly calls, with the State Department in the US with councils in, uh, in Mexico and working with the Cubans, the, uh, scientists there. That was, well first of all, it was a amazing experience to do that because it really took a lot of people doing a lot of different things, to pull that off.

So the adaptive part of that was, well, things change. And so you can't just go in with a mindset that I'm gonna make this measurement at this location and, and that's going to give me all the information that I need. We really had to, uh, adapt to whatever the environment was changing towards in order to get the best data set that we could.

Carlyle: So that sounds like complicated work before the complicated science even started.

Amy: That's fair.

Carlyle: So, Scott, tell me about your role in this collaboration.

Scott: Okay. One of the things that I study is hurricanes. And the loop current itself is very warm and it transports a lot of warm water into the Gulf. And we all know that warm water can intensify hurricanes and cooler water can weaken a hurricane.

And the variability in the loop current is so significant, it could be all over the gulf. And you have to be able to forecast that, and you have to be able to have that correctly characterized in the coupled atmosphere. Ocean models. To correctly forecast the intensity of those hurricanes. And so that's the job that I have there.

Carlyle: Amy, you lead a realtime observational system out of the Woods Hole Oceanographic Institution. What does that exactly mean?

Amy: That means that, my group here is responsible for maintaining a fleet of freely drifting floats that wander freely in the ocean down deep, and every so often, every five to 10 days, they actually come up to the surface and go back down again.

And while they make that ascent and descent, they measure the temperature and salinity of the water column that they're drifting in. The Gulf of Mexico is a big place. We can't personally be out there everywhere all the time. So thanks to the technological development of robotics and autonomous systems, we can now send instruments like these floats out into the gulf and let them do the measurements. And we collect the data usually via satellite, um, every time they come to the surface. So we get the data back that way, and between both the profiling floats that I just described and these gliders, which are underwater gliders that make zigzag patterns underwater, and they can be steered and directed to go to different areas.

And so, all this data gets sent back and can then be, um, wrapped into these forecast models and help keep the models on track and, uh, producing more accurate forecasts.

Carlyle: This is so fascinating and I actually have a question later about adventures with your equipment. But, um,

Amy: We got lots of those.

Carlyle: but first, Amy, if it's okay with you, I did want to ask you about a personal experience that's changed your life and also your work. Um, back when you were getting your PhD you got an unexpected diagnosis that meant you would lose your vision. Can youyou talk briefly about what becoming blind has meant for doing this incredibly high level science on the loop current? How have you changed how you access all of these real-time observations you've been talking about, um, that are the basics for your

Amy: science. Yeah, right. I have had to develop new methods, to get access to data. but lucky for me, the, those are available and I've helped to develop some new ones as well.

Amy: I'd say probably the primary tool, uh, for that, that I'm using right now, or tactile graphics where we take a, a plot or graphic showing the data and we can actually make a raised line drawing, uh, of it.

And then I can use my fingers to, figure out what the distribution is.

So, that's a real, help, that's for sure.

Carlyle: are there ways that you experience science differently since you've, since you've lost your vision?

Amy: um, one way I can think of is that I also use, uh, 3D models, especially of the shape of the sea floor and including the Gulf of Mexico. In fact, I've got them right here next to my computer. They're here all the time.

and so I tend to, I think, I tend to think in 3D maybe because of these models more than some of my colleagues maybe do. and so. that's one way that I think I actually can make maybe a bit of a contribution Because the ocean is a 3D environment for

Carlyle: Yes, exactly. But we often don't think about that 'cause we can't see the 3D

Amy: Exactly. Yeah. And almost all the data representations we make are 2D on a piece of paper or on a screen.

Carlyle: So along those lines, you're all coming at this work from different expertise from different institutions, and I've heard your relationship here described as a forced marriage. Uh, what do they mean by that? And do you all feel that's accurate to your relationship?

Amy: oh, that's a good one.

ScottI, I think we're all very good at team building and so, um, maybe, maybe that's a little harsh on us. Maybe.

Scott: Yeah. 'cause like, this is one of the most collaborative groups that you know, I've ever seen, in the years of doing this. And we've all done different kinds of collaborations

but in this case, you know, we've done it all at once with, with a hundred people. And so this was also a big human experiment. And I think we had, you know, good people going into that, that were receptive to this idea. And so maybe it was not as we proposed. Maybe it was forced, but, um, what a wonderful collaboration it has resulted in.

Steve: lemme just chime in because I think oceanography and its history has been not very collaborative like a hundred years ago. It was, you know, you'll see my data when you pry it out of my cold dead hands. And, and, well, well, things, things changed.

It was slow to change, but they, they started changing, I think about 30 years ago when people started realizing what, you can't just hold on to data for your whole lifetime. It needs to be out there. I think really Noah changed that.

You know, the agency, uh, really changed that whole mindset with the integrated ocean observing system, SIU and uh, and the global, uh, initiatives like goose, which is the global ocean observing system, things like that. People realize you really need to get the data out,

I was just, just want to add that it's also very important that we're collaborating with the stakeholders and it's very important. What we're doing for the people that live around the Gulf. And it's not just the US people, it's also Mexico and Cuba. So all three nations, all those people are gonna benefit from this understanding.

Scott: It's a very important time to build that understanding. 'cause the, you know, climate's changing, we have more and more severe weather events. This is a time that we have to be able to improve our understanding and our forecast. And it takes all of us to work together to get that done.

Carlyle: Let's dig into that because I mean, part of this collaboration has been y'all, y'all were faced with a really big challenge, right? There's all of these unknowns with the loop current, you have these different expertise. Everybody kind of came together and said, let's do join forces to understand as much as we can about this current that's impacting very real things for people.

So let's kind of talk about the real things, how we all experience. So loop current,Scott, you mentioned hurricanes.

can you give us some, like examples that we know a lot about on the Gulf Coast. Um, hurricane Katrina, hurricane Ida, these hurricanes that intensified so quickly when they hit hot water in the Gulf. Is that the loop current speaking?

Scott: Yes. Katrina was the one that really made the point, it rapidly intensified when it went over the warm water, the loop current. And that's when it was really first noticed that it's not just the temperature of the surface of the water, but it's also the subsurface water.

How thick is that warm water? How much heat content is in that water to keep fueling that hurricane? And that's what started a lot of the activity to make sure we had the loop current correct. in the coupled models for the hurricanes. And so every single one of those hurricanes has its own specific story.

With the loop current and the interactions with it, how it could be intensified over warm water, or it could be weakened over cold water. And we saw that with hurricanes like

Helene and Milton as they came across. And Helene, it came up and it intensified all the way into the coast, but in the process, it cooled the water, it cooled the ocean behind it.

And so then when Milton came by, it went over that cooled water. And even though it came in strong, it was weaker than what it would've been. And so those interactions we saw during this experiment. how that loop current affected the hurricanes and how the hurricanes affected the loop current.

Carlyle: It is so crazily important. 'cause I think we're all obsessed when we're watching the news of hurricanes, everybody's looking at the path, where's it gonna go? Where's it gonna go? But we're rarely talking about, you know, is it gonna hit the loop current and therefore is it going to intensify it so much more?

And so therefore, do people need to evacuate versus not?

Scott: yeah, so not only are we looking, not only are we plotting the map of the hurricane, the forecast hurricane track, but also the map of the loop current andwhat's the heat content of that current. And also things like the Mississippi River plume.

And by plume you mean you mean the fresh water of the Mississippi coming

water from the Mississippi River plume being infected south underneath the tracks of the hurricanes by the loop current. So it's affecting the circulation of the whole gulf and bringing warmer, colder water, fresher saltier water underneath the forecast path of that hurricane. And we have to know that to get an accurate forecast of intensity.

Carlyle: Amazing. So it's not just hurricanes though, right? That are impacted by the loop current. I mean fisheries, this was something I didn't know much about before. Um, either Amy or Steve who wants to speak kind of, how the loop current impacts fisheries.

Amy: Certainly different species of fish need different climates to live in and thrive in warmer water or colder water, more oxygenated water, less oxygenated water. And so, where the loop current is located will determine where certain marine organisms thrive and where they don't .

Carlyle: So for real life, use of this data, you know, fishermen, what they can look at this and say, oh, you know, instead of burning all this diesel to go in this direction, I can assume that I'm gonna catch a lot more fish in this location because that's where the loop current is, or that's where the colder water is.

Is that how it would work in real life?

Amy: Yeah. Yeah, yeah, yeah, exactly. Um. especially for the loop current, especially the big pelagics like, uh, swordfish tuna, they are very affected by the temperature of the water and they will not go into cold water if they can help it cooler water.

Carlyle: And Steve, maybe you can speak to this, um, for a long time. My understanding is that the industry most involved in the science of understanding the loop current was the oil and gas industry. Why are they so interested in the loop current?

Steve: Yeah, so they have to drill, right? So when they put out, the big rigs, and especially in, in deep water, they have to put a drill string down from the surface all the way to the ocean bottom. And, and so that's a big pipe. Uh, and when a current goes by, that's something like the loop current or one of the associated eddies,

the oil and gas industry need to know. When is that current gonna go by my oil rig? Because The friction of the current rubbing against that metal can cause vibrations, which can fatigue the metal, which can cause a break, which we don't want that to happen. Right? You don't wanna have a, a big break during, uh, an operation 'cause it could lead to a spill and an environmental disaster.

So the oil and gas industry really needs to know. 'cause what they'll do is if a current exceeds about, uh, a knot and a half, so a nautical mile per hour, 1.5 nautical miles per hour, if it exceeds that, they'll stop operation.

I see. And it's unpredictable enough that you can just have peaceful waters way down deep, and then all of a sudden the loop current hits you and the the speed of the water passing by this equipment is all of a sudden disruptive,

Steve: Right.

Carlyle: Okay, so so I wanna back up to something that we've mentioned a couple times, um, is Eddie's, um, so I think most people think of eddie's like in a river. You know, when you see kind of that swirling whirlpool. Is that what eddies are in the loop current?

And why? Why are we so interested in eddies?

Amy: Yeah, sure. Um, eddies in the ocean are somewhat analogous to a swirl you might see in a river, a swirl of water, except they much, much, much larger.

These eddies in the ocean are large swirling currents that take up an area the size of Rhode Island or bigger actually. And they are important because they are basically a little piece of the loop current. So they have that very warm water, uh, from the tropical Atlantic inside of them, and they sort of wander across the gulf, uh, after they're formed.

And if a hurricane goes over one of them, as was the case with Hurricane Katrina, the hurricane can extract energy from that warm water enclosed in the Eddy and intensify incredibly.

Carlyle: and in fact eddies are so important. They're named like hurricanes, right? And this part kind of cracked me up. So there, there've been all kinds of Eddie names. Can y'all tell me like, who have been some of these Eddies,

Steve: There's been Eddie Murphy. Oh ha. You know Eddie V? Eddie Van Halen. Oh, great. You know, Edison,

Carlyle: Eddie Edison?

Scott: One thing I think we're finding is that we need more names out there because, uh, the name Eddies are the big eddie's, the big clockwise eddies that are shed by the loop current. But we're finding out in this experiment that those smaller eddies are important. There's a whole cascade of eddies scales from the big to small, and some of them turn clockwise, some of 'em turn counter clockwise. And we're finding that we have to know something about all of them all at the same time to improve the forecast.

Amy: This a focal point of our research, is the Yucatan Channel itself. And, um, we call it like a boundary…It's a boundary of the Gulf of Mexico. It's a, and, and the, the, the signals come through that channel have: a, probably have a major impact on how the loop current evolves.

Carlyle: Yeah. And I just feel like taking a moment here to be amazed with you all, that the, the whole planet works like this, that we're, we're looking at this huge movement of water that is all in, uh, relationship with each other and with us. I mean, it impacts humans and, and agriculture and… everything.

And so I, I read something about, um, it takes a thousand years for this water to move through all of the currents in the ocean. But it sounds like what you're saying is not all water moves the same. Right? Can somebody explain this a thousand years thing to me?

Amy: That's the timescale of the global circulation. Right? it might be multiple thousands, but, uh, yeah, on the order of a thousand years, right? Where if you take a, a, a, a little volume of water off the east coast of the US and it's gonna move with the currents around the whole globe, and it will be moved in part by the AMOC or the meridian overturning circulation, this. set of currents that really encircle the globe and also move volumes of water vertically as well. And so it's like a radiator system in a house, really, uh, or a plumbing of, of some kind. And it can take a thousand years or more for one volume of water to transit that whole plumbing system of the world. Ocean.

Steve: We actually published a paper on this a few years ago, and it, uh, was like, what is the, uh, the ventilation rate of the abyssal golf, right? That's the deep Gulf uh, ventilation means how long does it take to replace all the water that's there right now?

and we use radio chemistry to do that. So, radioactive isotopes of, uh, various parameters in the ocean to do it. And it's about 150 years. So it takes about 150 years to fully replace the deep, uh, water that's in the Gulf of Mexico.

Carlyle: That's amazing. I don't know if we have the time for you to explain all of the science of that, but that sounds very cool. Um, so I did want to get into, the adventures of science on this project. So as we've kind of touched on, you all have all of this. incredible equipment spread across the Gulf.

You've got floats, you've got the most dense number of floats in the world, in fact are in the Gulf. Um, you've got underwater gliders.

Y'all tell me about what it's like to fly one of these gliders, and maybe if you can tell me about a particularly adventurous voyage.

Steve: uh, think wheel of fortune every, every time the glider comes to the surface,

It starts with getting a text message from the glider that the gliders at the surface and the, the bell that rings sounds a lot like the Wheel of Fortune. bell ding, ding, ding, ding, ding, ding. And it goes off.

and so they get that phone call. Uh, 'cause the glider can only communicate when it's at the surface, so they, so, uh, when it's subsurface, we kind of know where it is.

Uh, but it's just, you know, it's, it's under the surface. We can't communicate with it. So it comes to the surface. It says, I'm here, I'm at the surface and I'm doing okay. And, uh, and if the pilot sees that message, they're like, okay, we'll continue doing what you're doing, or go to this location, or,

if there's there's issues, then we have to go get the glider. one of the big problems in the Gulf of Mexico, which nobody else on the planet has this problem except in the golf and everyone, uh, in your audience would probably, know what Shark Week is.

We have an issue with gliders in the Gulf that. Attract remora, that's fish that kind of suckers onto the bottom of a shark and follows it around and it's in a symbiotic relationship with the shark.

It turns out that they really love gliders too in the Gulf, and the problem is they can prevent the glider from making it all the way to the surface. So we have to do things in the Gulf to, to mitigate that and, uh, and keep it from remora attacks. That's what we call them. And, uh, and if they, if it keeps the glider from, make it to the surface, the glider can panic, abort the mission, and then we have to go get it.

Carlyle: What do you mean? Go get it under Why you go fish it out?

Steve: Yeah, we have to find it because if it aborts the mission, it means that it'll eject weight, uh, come to the surface, and once it does that, it can never go back down. And if it's a hundred miles offshore, we have to go get it, or we'll lose the glider. And the gliders are expensive, so we don't wanna lose any gliders.

Carlyle: So those were more just looking for a free ride, however they can

Steve: That's all they're doing. They are doing, that's exactly what they're doing.

Scott: Scott, do you, do you have a Yeah,

We have plenty of stories of adventures like that where, you know, shark attacks, um, you know, they can be very quick, giant squid attacks. They can be very prolonged and keep a glider underwater for, for some time. So there are those hazards like that, that we worry about, but we're getting very good at mitigating those.

Uh, it's not the early days of these vehicles We kind of know what the hazards are, and they've become much more robust and much more adept at saving themselves. Uh, they're much smarter than they used to be. Uh, and so now the adventures are not about like, what disaster are we trying to, uh, recover from. It's more about where do we want to go? What do we wanna discover? What strong, severe current environments do we want to go into? Can we get into that Eddie and get back out again? Can we live through that storm and, and, and get the data that's critical for these models during that, that intense hurricane?

Carlyle: So let's talk about why all of this hard to get data is so valuable.

Steve: yeah. So the, the models allow us to look into the future. Right. So, so it makes us have. Better mechanisms to predict. and right now, like we're doing all the quantification of that.

it's like, well, if we're only, you know, 5% better, making a prediction, is it worth it to put millions of dollars of equipment into the ocean? My intuition right now is, yeah, it's gonna be worth it because it's gonna impact people's lives. Uh, it's gonna help with economies, it's gonna help with fisheries, it's gonna help with water quality.

There's many, many different aspects. It's gonna help with.

Carlyle: Yeah. And I wanna get to kind of, um, the future of ch big changes with our ocean currents. I think if people have heard of the AMOC, which is the Atlantic Ma, anybody wanna say that?

Amy: Sure. Atlantic Meridian Overturning Circulation. AMOC.

Carlyle: Thank you Amy. Um, so the times that ocean currents are in the news, it's. Quite often about the AMOC and how it's changing because of climate change. Um, there's a lot of news about it slowing down, about predictions for it collapsing.

And of course this has huge consequences for the world, for agriculture, for the whole climate of Europe. I mean, as you all started off talking about these currents are impact our climate, they impact all kinds of things. So what are you all learning?

What do you all know about the loop current and how climate change is impacting it?

Amy: In terms of the Gulf of Mexico and climate, one of the loudest signals or changes in the Gulf is the warming Uh, the Gulf of Mexico is warming more rapidly than other parts of the ocean. This has a secondary impact of increasing sea level in the Gulf of Mexico,

Carlyle: And the loop current is involved somehow in the, in sea level rise. And the rapidity of that, I guess.

Amy: Yeah. It's bringing in warmer water, certainly. Yeah. transported the water that it is transporting into the Gulf is warmer than in the past

Carlyle: Mm-hmm. Which takes up more volume, which leads to..

Amy: higher sea level. Yes. Mm-hmm.

Carlyle: Are there any, last thoughts that you would like to leave our listeners with that can, maybe either shed light on your fascination with the Loop Current or anything that we haven't covered that y'all would like to share?

Amy: Yeah, I, I have been thinking about one thing, I wanted to make sure that we mention our very, engaged colleagues from Mexico, who are contributing to the YUGOS program extensively. They are also operating gliders in the Yucatan channel in the Caribbean, right at the entrance to the Gulf of Mexico, where the Yucatan current, which becomes a loop current, where it's right entering is such an important place, and they've been, uh, maintaining amazing, glider operations there for some time now.

Another, observing system that they have maintained since I think 2002, over 20 years now. And, uh, that's provided an incredible, uh,treasure trove of observations at the same place, which is so valuable, uh, to have a long time series like that. they also, run very sophisticated numerical models.

Uh, that add to the suite of other models that are run mainly in the US and also in Europe that we are using regularly, and that we're adding our observations to, to improve their forecast ability. Uh, uh, so they are really valued partners in Yugos.

Steve: we're working with the Cubans as well. In fact, every time the glider goes into the Cuban EEZ, we have to send an email to the, uh, the Cuban military saying, we're in your water, and we’re going to be here for 2 or 3 days or longer…

Carlyle: I mean, just to make your work even more complicated. You're doing diplomacy, you're going deep underwater, you're flying gliders. What are you all not doing?

Steve: Right.

Scott: And, and all that data goes to those countries. And so we know the scientists in Cuba, we see them at international meetings. We know the scientists in Mexico. They all have access to that data because it takes this full community to build that understanding, uh, to benefit the people.

Steve: Yeah. All one ocean. All the people. All the people. It's one ocean around the Gulf of Mexico,

Carlyle: Yes. And we are all connected as, as you all said, one ocean. And I want to thank you all for joining us and also for, you know, all of your work to understand this, uh, vital science that's, that's helping inform us. and I wanna thank you for your time.

Amy: Thank you

Steve: Thank you very much.

Scott: My pleasure.

CREDITS

Thanks for listening to Sea Change! This episode was hosted by me, executive producer Carlyle Calhoun. The episode was fact-checked by Garrett Hazelwood. Our theme music is by Jon Batiste and our sound designer is Emily Jankowski.

Sea Change is a WWNO and WRKF production. We are part of the NPR Podcast Network and distributed by PRX.

Sea Change is made possible with major support from the Gulf Research Program of the National Academy of Sciences, Engineering, and Medicine. Sea Change is also supported by the Water Collaborative of Greater New Orleans. WWNO’s Coastal Desk is supported by the Walton Family Foundation, the Meraux Foundation, and the Greater New Orleans Foundation.

We’ll be back in two weeks.

Imagine Ireland. Lush green rolling hills. Towering cliffs along the coast. Lots of sheep. Cozy pubs. And of course,

INTERVIEW: palm trees. Yeah there everywhere.

ME: palm trees in Ireland?

(how are there palm trees in Ireland?)

INTERVIEW: something about the weather. It’s really never cold. Rarely snows.

https://www.theirishroadtrip.com/best-cork-pubs/

Red Fox Inn, which is part of the Kerry Bog Village. Located just outside the town of Kilorglin along the Ring of Kerry,

The segment in the fourth episode of Blue Planet II used the true story of the 28,800 bath toys that fell from the cargo ship Ever Laurel to explain the nature of global ocean currents. The toys, which were designed without holes and thus floated indefinitely, washed up on shores from Alaska to South America to Europe over many years.

In 1992, a cargo ship lost a container of 28,000 rubber ducks in the Pacific Ocean, which were carried by ocean currents to various locations around the world, including Alaska, Hawaii, and eventually the Atlantic. These "Friendly Floatees" became a scientific tool, helping oceanographers study marine currents by tracking their long and unexpected journeys

https://www.iflscience.com/28000-rubber-ducks-accidentally-embarked-on-an-epic-ocean-current-study-in-1992-58342

Science has come a long way!

Here’s a conversational introduction for your podcast episode about ocean currents, highlighting their global importance—and why palm trees surprisingly grow in Ireland. Short video clips that could be woven in include NASA’s “Perpetual Ocean” visualization, PBS’s “How Ocean Currents Work,” and TED-Ed’s “How do ocean currents work?” as engaging audio-visual companions.[1][2][3]

Imagine stepping off a plane in Ireland: rain-washed hills, rugged coastlines, sheep dotting the meadows—and wait, are those palm trees? Not exactly the image that comes to mind when thinking of the Emerald Isle. Yet along parts of western Ireland’s coast, you’ll find the unmistakable silhouette of palm-like trees swaying in the Atlantic winds. How on Earth do these tropical-looking plants thrive so far north? The answer: a story of invisible highways and planetary circulatory systems, threading their way beneath the ocean’s surface.

Welcome to today’s episode, where we dive into the life-and-death importance of ocean currents—the mighty, silent sculptures reshaping climates, delivering warmth and nutrients, and, every so often, surprising us with something as improbable as palms in Ireland’s gardens.[4][5][6]

Let’s set the scene: Ireland and Newfoundland, Canada, sit at nearly the same northerly latitude, but their winters couldn’t be more different. Newfoundland suffers classic North Atlantic chills, while Ireland’s west coast enjoys mild, almost gentle winters. Why? The Gulf Stream—a warm, swift Atlantic current—acts like a conveyor belt, transporting heat north from the Gulf of Mexico, hugging the Irish coast, raising temperatures, and making the air just cozy enough for those faux-palms (technically Cordyline australis, a cabbage palm from New Zealand) to flourish.[5][7][4]

But ocean currents don’t just hand out beach days and palm trees. They regulate weather patterns, fuel the cycles that bring rain to fields, steer hurricanes, and keep the global ecosystem humming. You could even say they “stir the pot” for all planetary life. Like arteries in the body, they circulate heat, oxygen, and nutrients—if you could peer beneath the water’s surface, you’d witness rivers within the ocean, racing in looping, interlaced patterns. NASA’s “Perpetual Ocean” animation brings this to dazzling life: swirls, eddies, and current streams, pulsing in sync with the Earth’s rhythms. It’s more hypnotic than a lava lamp, but far more consequential.[8][9][10][11][1]

Still, these underwater highways are more than picturesque. The Gulf Stream decides if Europe freezes or thrives. Other currents—the Kuroshio near Japan, the Humboldt off South America—influence everything from monsoons to fisheries to the habits of migratory species. Ocean currents bind oceans together, knitting together distant places in ways most folks never notice. In PBS’s “How Ocean Currents Work” and TED-Ed’s “How do ocean currents work?” you can hear and see the basics explained with a storyteller’s flair: rubber ducks drifting thousands of miles, warm and cold streams colliding, salt and wind fueling the marine conveyor belt. Quick audio clips from these can audibly set the scene for listeners.[12][13][2][3]

But here’s the kicker. Ocean currents are now under threats—by climate change, melting ice, and shifting winds. The same force that helps palm trees root in rocky Irish soil could see their climate-magic disrupted. Scientists warn that changes to these currents could bring far-reaching consequences: altered storms, failing fisheries, and yes, even threats to those improbable Irish palms.[7][14]

So, as we embark on this episode, let’s wander from Ireland’s palm-studded baysides through the ocean’s pulsing highways—unpacking how these hidden forces bind our climates, our coastlines, and our fate. Along the way, we’ll share short clips and sounds: the rush of currents, snapshots of global animations, and stories of plants and people shaped by these planetary currents.

Ready to dive in? Let’s set sail on the invisible rivers that keep our world turning.

Recommended companion clips:

NASA’s “Perpetual Ocean,” captivating visualization of surface currents (audio from the pulsing patterns)[11][1]
PBS’s “How Ocean Currents Work,” accessible segment on climate impact (voiceover and sound effects)[2]
TED-Ed’s “How do ocean currents work?” for story-rich scientific explanation (clips about drift and climate)[3]

Use these audio-visuals between segments to enhance the sense of movement, mystery, and life carried by the world’s oceans.

⁂

Now please add on to this by transitioning from the larger idea of all ocean currents and how they are the conveyor belt of the world to the loop current in the Gulf. Include a description of how the loop current connects to the larger currents and the general route it takes through the Gulf of Mexico. Please preview why the loop current is so important but also mysterious--it's not well understood.

Transitioning from the mighty ocean conveyor belt—the great systems that move heat, life, and weather around the globe—let’s bring things close to home, to the Gulf of Mexico, where one of the world’s most fascinating currents quietly circulates: the Loop Current.

Picture this: while that “conveyor belt” begins with the Gulf Stream sweeping warmth up the Atlantic and giving Ireland its improbable palms, a key section of this global system originates much farther south. Warm waters from the Caribbean rush between the Yucatán Peninsula and Cuba, surging northward into the wide basin of the Gulf. There, they don’t just drift aimlessly—they perform a sweeping arc, flowing north towards Louisiana before looping southeast, creating a bold semicircle that bends back toward the Florida Straits. It’s a constantly shifting route, with this flow sometimes surging farther north, other times retreating south, but always serving as a powerhouse in the Gulf’s watery heart.[38][39][40]

This is the Loop Current—a river within the sea. When it exits the Gulf off Florida's tip, it transforms into the Florida Current, which soon joins its big sibling, the Gulf Stream, carrying vital warmth up the U.S. East Coast and on to Europe. So, the Loop Current is not just a Gulf feature: it's a crucial feeder into the current that shapes weather and climate for millions far beyond the Gulf itself. Without it, that great conveyor belt would sputter, and the climate dial on both sides of the Atlantic would shift.[39][41]

But here’s where the mysterious part comes in: the Loop Current remains one of the least understood and most unpredictable of the world’s major currents. Its route can change dramatically, sometimes spinning off giant, warm “loop eddies” that can drift for months and supercharge hurricanes, then vanishing just as quickly as they appeared. Unlike the steady march of the Gulf Stream or the rigorously mapped currents elsewhere, the Loop Current defies easy forecasting. Some summers it plunges deep into the Gulf toward the mouth of the Mississippi; in other years, it hugs the southern edge, creating baffling patterns for scientists, fishermen, and forecasters alike.[40][42][38][39]

That uncertainty makes the Loop Current both vital and vexing. It feeds into hurricane strength, shapes regional fisheries, and sits at the crossroads of energy infrastructure and ecological productivity. In the next segment, we’ll peel back the layers of the Loop Current: how scientists study it, why it’s the wild card in the Gulf, and why understanding it is key to everything from hurricane prediction to the future of the Gulf Coast.

Stay tuned—the secrets of the Loop Current are just beginning to unfold.

⁂

Give a 45–60 second spoken transition script linking global conveyor belt to the Loop Current

Here’s a 45–60 second spoken transition linking the global ocean conveyor belt to the Loop Current:

We’ve just explored how this vast conveyor belt weaves through every ocean on the planet—moving heat, nutrients, and even the rhythms of our weather from continent to continent. But let’s zoom in now, to a single stretch of the world’s waters that plays an outsized role in both the global system and the communities along our Gulf Coast: the Loop Current.

Think of the Loop Current as a powerful link in that endless chain—a warm surge flowing up from the Caribbean, looping north through the Gulf of Mexico, then ducking through the Florida Straits to help power the mighty Gulf Stream. The same current that keeps Irish gardens green and European winters mild actually gets much of its strength from this tropical river within the Gulf. And yet, while the Loop Current is a vital artery in our planet’s circulation, it remains one of the most mysterious. Its twists, turns, and hidden energy shape hurricanes, fisheries, even our understanding of the Gulf itself—and scientists are still working to unlock its secrets. Let’s take a closer look at what makes the Loop Current tick, and why so much depends on its hidden flow.[47][48][49]

⁂