Something startling is happening in the Gulf of Mexico » Yale Climate Connections

In 2012, the temperature of the Gulf of Mexico began rising along a shocking upward trajectory. 

Climate change is causing oceans worldwide to warm. But that year, summertime sea surface temperatures in the Gulf of Mexico began heating up at about twice the rate seen in the global oceans. The trend has continued into the 2020s, with sea surface temperatures hitting record highs in both 2024 and 2025. The shift has huge implications for the hurricanes that form in the Gulf – and the people who live along its shores and on the islands that dot its waters. 

Hurricanes are heat engines that take heat energy out of the ocean and convert it to the kinetic energy of wind. The maximum intensity that a hurricane can reach increases by about 5-7% per degree Celsius of sea surface temperature increase. So the rise of about half a degree per decade in Gulf sea surface temperatures per decade since 2012 may be causing a 3% per decade increase in the winds of the strongest hurricanes. Because stronger winds cause more destruction, this equates to about a 30% increase in hurricane damage per decade for these strongest storms.

When a hurricane traverses a shallow area of warm ocean waters, its powerful winds churn up cold waters from the depths, cooling the surface and putting the brakes on the storm’s intensification. But when unusually warm ocean waters extend 100 meters or more below the surface, the hurricane’s winds simply stir up more warm water, in some cases allowing dangerous rapid intensification to occur. This phenomenon fueled Hurricane Helene’s furious winds as the storm bore down on Florida in 2024. 

So why have sea surface temperatures been rising so rapidly in the Gulf of Mexico? Will the temperatures keep rising? And what does it all mean for hurricanes? 

Global warming and ocean current changes are to blame

The cause of the Gulf’s warming trend is not just climate change, but also the behavior of a wide ribbon of water called the Loop Current. 

This ocean current transports warm Caribbean water through the Yucatan Channel between Cuba and Mexico, northward into the Gulf of Mexico, in a loop southeastward just south of the Florida Keys – where it is called the Florida Current – and then just west of the westernmost Bahamas. There, the waters of the Loop Current flow northward along the U.S. coast and become the Gulf Stream.

With speeds of about 1.8 mph (0.8 m/s), the Loop Current is one of the fastest currents in the Atlantic Ocean. During summer and fall, its deep, warm waters can provide a huge energy source that fuels rapidly intensifying major hurricanes. Rapid intensification is dangerous because when storms strengthen quickly, they can take people by surprise, leaving little time for preparation or evacuation. 

The Loop Current often bulges out in the northern Gulf of Mexico, where it sometimes sheds a clockwise-rotating ring of warm water that separates from the main current. This ring of warm water – called a Loop Current ring, Loop Current eddy, or warm core ring – slowly drifts west-southwestward toward Texas or Mexico at two to three miles per day. 

The Loop Current pulsates in a quasi-regular fashion, shedding rings every six to 11 months. When a Loop Current eddy breaks off in the Gulf of Mexico at the height of hurricane season, it can provide a vast reservoir of energy to any hurricane that crosses over.

A 2024 paper, Loop Current Eddies as a Possible Cause of the Rapid Sea Level Rise in the Gulf of Mexico, found that in recent years, Loop Current eddies have been growing larger – in fact, their surface area increased by about 50% compared to previous decades. As a result, they’re transporting more warm water into the Gulf, raising sea surface temperatures and sea levels. 

That explains the spike in temperatures. But why are the eddies getting larger? 

A 2023 paper theorized that the huge clockwise-spinning ocean current system spanning most of the North Atlantic Ocean, called the North Atlantic subtropical gyre, had expanded, causing the Loop Current to transport more warm water into the Gulf of Mexico. The authors concluded that about 40% of this shift was from climate change and about 60% was from natural variability. 

They predicted that this effect would die down within the next decade or so, reducing the amount of warm water being transported into the Gulf of Mexico. If they’re right, the rate at which warm water is being delivered to the Gulf will likely decline within the next five or so years, making the Gulf’s rising temperature closer to the global average increase.

A climate regime shift after the 2015-16 Super El Niño?

Part of the dramatic increase in sea surface temperatures since 2016, though, may be from a “super-El Niño” event in 2015-16. Three “super-El Niño” events of approximately equal strength occurred in 1982-83, 1997-98, and 2015-16. According to a 2026 paper, Super El Niño events drive climate regime shifts with enhanced risks under global warming, these events were all responsible for multiple regional climate regime shifts, characterized by an abrupt and persistent transition between alternative stable states in the climate system. One such regime shift after the 2015-16 super El Niño may have been responsible for the abrupt warming of wintertime sea surface temperatures that occurred in the Gulf of Mexico beginning in 2016-17. Over the past 10 winters, Gulf sea surface temperatures have averaged 0.8 degree Celsius above normal; during the previous 10 winters, they were just 0.2 degree above normal. The authors speculated that this regime shift may have contributed to the remarkable number of rapidly intensifying hurricanes observed in the Gulf beginning in 2017.

It remains to be seen whether this year’s evolving El Niño – which could be on par with the three events above – might trigger its own regime shift in the Gulf.

What’s next for the Gulf of Mexico? 

As of May 11, 2026, sea surface temperatures and ocean heat content in the Gulf are at near-record levels, with the sea surface temperatures tied with May 11, 2024, as the warmest on record for the date – over 1 degree Celsius above the 1991-2020 average. The Loop Current shed a ring in February, and it’s now in a regrowth phase, extending northward again. This mode favors the release of another Loop Current eddy during the peak of hurricane season, which would increase the odds of rapid intensification of storms in the Gulf. 

Recent seasonal forecasts from NOAA’s CFS model predict that Gulf sea surface temperatures during the peak of hurricane season will fall short of the records set in 2023-2025.

Longer term, the risk of rapid intensification of hurricanes is rising.

The 2015 paper, Potential impact of climate change on the Intra-Americas Sea: Part-1. A dynamic downscaling of the CMIP5 model projections, warned: “the enhanced warming along the northeastern shelf of the Gulf of Mexico could greatly increase the chance for rapid intensification of hurricanes making landfall across the northeastern Gulf Coast in the 21st century.” 

Only 10 landfalling continental U.S. storms since 1950 have rapidly intensified by at least 40 mph (64 km/h) in the 24 hours before landfall. Five of those storms occurred in the past nine years. 

But so far, there isn’t a clear relationship between the recent spike in sea surface temperatures in the Gulf of Mexico and the total number of rapidly intensifying hurricanes. From 2012 to 2025, 11 of the 29 hurricanes observed in the Gulf underwent rapid intensification. That compares with 14 out of 27 hurricanes during the previous 14-year period, including five during the extraordinarily active 2005 season, when sea surface temperatures were unusually high in the Gulf.

What about the even longer term? According to the latest generation of Intergovernmental Panel on Climate Change models, a moderate global warming scenario would cause a 0.5-1.5 degrees Celsius (0.9-2.7°F) warming of the Gulf during the August-November portion of hurricane season for the period 2036-2065, compared to the historical period 1982-2011. Under an extreme global warming scenario, this warming is predicted to be 1.5-3 degrees Celsius (2.7-5.4°F). 

But NOAA data for the past 10 years shows that the Gulf has already warmed by 0.8 degree Celsius (1.4°F), so the observed warming is decades ahead of where it was expected to be under a moderate global warming scenario. This suggests that sea surface temperatures in the Gulf may be following the extreme global warming scenario.

However, these models are too crude to properly resolve the details of the ocean circulation in the Gulf of Mexico. A 2015 paper, Potential impact of climate change on the Intra-Americas Sea: Part-1. A dynamic downscaling of the CMIP5 model projections, used a detailed NOAA Geophysical Fluid Dynamics Laboratory model to come up with a more sophisticated forecast for the last decade of the century.

Under a moderate global warming scenario, that model predicted that the Atlantic Meridional Overturning Circulation would slow by about 20-25%, causing the Loop Current eddies in the Gulf of Mexico to become less active. 

As a result, the smaller-scale Loop Current eddies would transport less warm water from the Caribbean into the Gulf, resulting in less heat being transported into the Gulf. 

But there would also be less heat being transported out of the Gulf, resulting in the shallow surface waters near the coast from Louisiana to western Florida warming more than 2 degrees Celsius (3.6°F) compared to today.

Such an increase would significantly increase hurricane winds, rain, and storm surge. Since the maximum intensity that a hurricane can reach increases about 5-7% per degree Celsius of sea surface temperature increase, a 2°C warming of water temperatures could cause a 10-14% increase in the winds of extreme hurricanes. This equates to over a doubling in their potential damage. 

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Bob Henson contributed to this post.