Something remarkable—and troubling—unfolded in Panama’s Gulf in early 2025. For the first time in at least four decades, the Gulf’s famed seasonal upwelling simply didn’t show up. This natural phenomenon, a kind of oceanic elevator for nutrients and cool water, usually transforms the region between January and April. But this year, the deep, cold water that typically surges to the surface and jump-starts the marine food chain stayed put, leaving scientists, fishers, and conservationists scratching their heads—and, frankly, sounding the alarm.
According to a new study published in Proceedings of the National Academy of Sciences and led by Aaron O’Dea of the Smithsonian Tropical Research Institute (STRI), this is no small blip. “The 2025 season broke the pattern in clear ways,” O’Dea explained, noting that the event disrupted one of the Gulf’s most reliable ocean patterns. Researchers recorded not just a lack of the usual cold-water pulse, but also a steep decline in productivity during the months when the system is usually most vibrant. The upshot: marine ecosystems and the people who depend on them are feeling the strain.
So, what exactly is upwelling? In Panama, it’s a seasonal process driven by strong northerly winds that push the sun-warmed surface waters aside. That allows deeper, nutrient-rich water to rise—a shot of fertilizer for phytoplankton, which in turn feed everything from tiny fish to the largest predators. This annual nutrient bonanza supports fisheries, cools nearshore waters, and even helps protect coral reefs from the worst effects of heat stress. “Upwelling hotspots punch above their size,” Earth.com reported, “producing food and jobs by feeding forage fish that in turn support larger species targeted by coastal fleets.”
The numbers tell a stark story. Historically, Panama’s upwelling kicks off around January 20 and lasts about 66 days, with surface temperatures sometimes dipping as low as 58.8°F (about 14.9°C) and typically below 66.2°F (19°C). But in 2025, surface temperatures stubbornly refused to fall below 77°F (25°C) until March 4—a full 42 days later than usual. And even then, the cool spell lasted just 12 days, an 82% reduction from the average, with the minimum temperature hovering at a balmy 73.9°F (23.3°C). That’s a dramatic shift, and it didn’t go unnoticed by those who rely on the Gulf’s bounty.
The culprit? It all comes back to the winds. The study found a 74% drop in northerly wind events, with those that did occur relaxing 25% more hours than usual. While the wind speeds themselves weren’t weaker when they did blow, they simply didn’t show up often enough to do the job. “The headline is not that winds were weak when they blew, but that they did not blow often,” the study’s authors emphasized. This lack of wind energy meant the ocean’s stratified layers remained stubbornly in place, blocking the usual nutrient surge.
Why did the winds slacken? The answer points to larger climate forces at play. The Intertropical Convergence Zone (ITCZ)—a belt of thunderstorms and shifting winds near the equator—moves seasonally and influences the Panama Low-Level Jet (PLLJ), which normally drives the offshore winds responsible for upwelling. In 2025, La Niña conditions may have nudged the ITCZ northward, weakening the wind jet’s strength. Yet, as the Smithsonian Tropical Research Institute notes, past La Niña years didn’t cause such a total failure. This suggests that climate change may be amplifying these shifts, disrupting wind systems more frequently and more dramatically than before.
“This event shows how quickly climate effects can hit basic ocean functions,” one researcher told PNAS. The consequences ripple out in all directions. Without upwelling, primary production plummets, weakening the food chains that support both commercial and small-scale fisheries. Local fishers, who have relied on these waters for generations, are already feeling the pinch with lower catches. The economic and social stakes are high, as coastal communities depend on robust fisheries for food security and livelihoods.
The impact on coral reefs is equally concerning. In Panama, reefs such as those in Coiba National Park typically benefit from the cooling effect of upwelling, which can reduce the risk of coral bleaching—a stress response that occurs when corals lose their symbiotic algae under heat. Without the usual cold-water influx, reefs are left exposed to prolonged warm temperatures, raising the odds of bleaching and long-term damage. A 2023 review described how the upwelling Gulf of Panama tends to run cooler and more nutrient-rich than the Gulf of Chiriquí, shaping different coral growth trajectories under today’s warming. But with the 2025 upwelling failure, even these “refuge” reefs may be at risk.
The 40-year record makes the 2025 event stand out like a sore thumb. Comparing long-term satellite sea surface temperature data and three decades of on-site measurements, the study found clear gaps in wind forcing and water mixing. Offshore wind speeds were far below normal, and water layers stayed stubbornly stratified. Spanish-language reports echoed the warning, calling the upwelling failure a wake-up call on climate impacts to ocean processes.
It’s not just Panama that’s vulnerable. The Gulf of Papagayo in Costa Rica experiences a similar upwelling, driven by the same wind patterns. If these trends continue, local fisheries and tourism—especially those tied to healthy reefs—could see similar disruptions. “If the failure of Panama’s upwelling repeats, fishers may need to adjust timing, gear choices, or target species for leaner seasons,” according to Earth.com. Reef managers may also need to develop localized alerts, treating upwelling corridors as temporary refuges that can disappear without warning.
What comes next? Scientists are calling for better monitoring in tropical regions to catch these changes early. Improved wind tracking, finer sea surface temperature mapping, and more robust links between physics, plankton, fish, and reefs are all on the wish list. Models and moored sensors can help close the gap, giving both researchers and communities the information they need to adapt.
Panama’s government and scientific community are already mobilizing for more research to pin down long-term trends. Local groups are watching closely for signs of recovery next season. But the big question remains: Will the Panama Low-Level Jet return to its usual rhythm, keep sputtering, or swing unpredictably between extremes? Only time—and more data—will tell.
The 2025 failure of Panama’s upwelling stands as a stark reminder that climate shifts aren’t just abstract global trends. They hit close to home, reshaping food security, economies, and ecosystems across Central America. For now, everyone from fishers to scientists is keeping a wary eye on the horizon, hoping that this year’s anomaly doesn’t become the new normal.