The heating of seas across Spain and the globe shows no sign of slowing, and the situation is moving into uncharted territory. This week the waters around the Iberian Peninsula recorded a startling spike, with temperatures on Monday, April 10, running 3 degrees Celsius above typical levels for this time of year, according to the Copernicus Climate Change Service, the European Union’s earth-observation program.
In a post on a social network, the State Meteorological Service noted that Spain’s sea waters already marked a historic temperature high in 2022. Last year, sea temperatures reached their strongest levels since the start of the agency’s historical series in 1940.
Indeed, more than 94 percent of days in 2022 saw above-average sea-surface temperatures in the Mediterranean. Heatwaves in the atmosphere were mirrored at sea, contributing to one of the hottest summers in recent memory. Far from easing, the trend persisted into autumn and remained through mid-winter, as the Center for Environmental Studies reported in its quarterly bulletins.
Spanish seas among those with the highest temperature rise verified.
On August 11 last year, the Valencia buoy recorded 29.62 ºC, an all-time high at that point, according to regional media notes. The previous record, set on August 7, 2015, stood at 28.65 ºC. Experts stress the Mediterranean’s increasing tropicalization and warn about escalating risks to marine ecosystems and coastal comfort.
Above 30º in the Mediterranean
For some time the Alicante Climatological Laboratory has described the Valencia coast as reaching a simmering state. This is driving temperatures above 30ºC across many Mediterranean zones. Warming in the deepest layers signals a dangerous mix that threatens coastal livability, as CEAM highlighted in recent findings.
Evolution of temperature anomalies in the Spanish seas recorded by AEMET shows a sustained pattern of warmth extending through recent seasons.
The intense marine heatwave in the Mediterranean during the 2022 summer and autumn persisted into December and into parts of January. In February the values remained high across most of the basin, though a gradual decline began. At numerous locations, temperatures reached around 18ºC, with record anomalies nearly doubling prior seasonally adjusted values in several spots.
Alarm signals around the world
The NOAA, the United States National Oceanic and Atmospheric Administration, reported on its official platform that sea temperatures exceeded 21ºC in some basins. Meteorologists and climate scientists globally warned that oceans are entering unknown territory. The ongoing rise in ocean heat is a clear signal tied to climate change, illustrating effects that were already visible and are continuing to unfold.
The consequences for marine life are sharp and immediate, affecting species distribution, breeding cycles, and ecosystem balance. Observers note that past decades began with a steady rise in average sea temperature, and recent figures show the trend accelerating even in regions traditionally marked by stability.
More than forty years have passed since ocean averages reached such elevated levels. If this trajectory continues, accumulated ocean warming may persist even if emissions are curtailed, potentially influencing atmospheric conditions for decades to come. An added factor is the El Niño phenomenon, which could intensify heat globally this summer. When El Niño drives a pronounced rise in seawater temperatures, already-record-breaking waters run the risk of further intensification, compounding current anomalies.
El Niño, short for the Southern Oscillation, refers to fluctuations in Pacific Ocean temperatures linked to atmospheric changes. This natural cycle influences climate patterns far beyond the equatorial region, shaping weather in multiple continents. Forecasters warn that warmer atmospheric conditions combined with sea-surface anomalies could amplify extreme weather events in various forms—from heatwaves to heavy rainfall—across different regions.
Meteorologist Francisco Martín emphasizes the unpredictability of outcomes given the unprecedented level of marine heat accumulation. He notes that heat stored in seawater must release somehow, frequently manifesting as severe weather events. A growing consensus points to greenhouse gas emissions as the primary driver, with atmospheric CO2 levels reaching new highs in recent months. Researchers also observe a direct link between rising air temperatures and heat transfer into the upper 100 meters of the ocean basins, the globe’s warmest layer in many regions, according to climatologist Jorge Olcina of the University of Alicante.
The science remains clear: ongoing warming at sea is a symptom of broader climate change, a trend that carries wide-ranging implications for oceans, weather systems, and human communities. While models continue to improve, experts agree that immediate action to reduce emissions and adapt to changing marine conditions is essential to limit future impacts.
Notes for readers: ongoing monitoring and research are essential as scientists compile new data to understand the evolving dynamics of ocean heat content and its global consequences. The information cited here reflects findings reported by national meteorological services and major climate research centers. [Citations: NOAA, CEAM, AEMET, Copernicus, and regional press reports cited for context.]