Ocean temperature on the verge of a new record
According to the Copernicus monthly bulletin, the global average ocean surface temperature In March it reached 20,97 ºC, a figure that excludes polar areas to focus on areas where observations are more continuous and comparable over time.
That value is barely one tenth below the record recorded in the same month of the previous year, which confirms that the ocean It continues to accumulate heat very quicklyFar from being an isolated spike, it is linked to the last three years, cataloged as the hottest on record on a planetary scale.
For Europe, this excess heat stored in the sea represents a key background factor: the ocean acts as a gigantic energy reservoir that it conditions air temperatures, the formation of storms, the intensity of rainfall and the duration of heat waves affecting countries such as Spain, France, Italy or Portugal.
Transition to a new episode of El Niño
Copernicus warns of the recent evolution of ocean temperatures points to a likely transition towards El Niño conditionsThis natural phenomenon is associated with the large-scale warming of the waters of the equatorial Pacific, with chain effects on the global climate that extend over several months.
The most recent El Niño episode, which unfolded between 2023 and 2024, turned those two years into the warmest ever recordedWith the climate system still marked by that excess of energy, the possible activation of a similar new event is generating concern in the scientific community.
The World Meteorological Organization (WMO), the leading authority on climate prediction, had already indicated that the opposite phase, La Niña —linked to cooler ocean temperatures— is weakening. In early March, the UN agency estimated around a 40% probability that typical El Niño conditions would develop before July.
These types of estimates are not a certainty, but they serve as a guide for European and national meteorological services, such as AEMET in Spain, to refine your seasonal projectionsIf El Niño is confirmed, episodes of heat, droughts or torrential rains could intensify in different areas, depending on how the phenomenon interacts with the atmospheric situation over the Atlantic and the Mediterranean.
Impacts of ocean heat: sea level and extreme weather events
The excess heat absorbed by the oceans isn't just a matter of statistics. When water heats up, it expands, which directly contributes to the sea level riseThis thermal expansion adds to the water input from melting glaciers and ice sheets, amplifying the risk of coastal flooding.
In the European context, this combination translates into greater pressure on the low coastal areasThis includes densely populated areas of Spain, France, the Netherlands, and Italy. Spring tides, intense storms, and Mediterranean gales are more likely to breach dikes, seafronts, and protective systems when the average sea level is higher.
Ocean warming also reinforces the marine heat wavesThese are prolonged periods in which the water temperature is well above normal. These episodes weaken key ecosystems such as coral reefs and kelp forests, and in the case of the Mediterranean, serious impacts on sensitive species have already been detected.
Added to all this is an increase in the intensity of certain extreme weather phenomena, such as more torrential rains and more powerful cyclones in different regions of the planet. Although the exact influence varies by area, recent reports indicate that the warmer ocean provides extra energy to storms, which can lead to episodes of more severe damage and flash floods.
Between the land and sea surfaces, Copernicus places the month of March in the fourth place among the warmest Since reliable records have been kept, there has been an anomaly of around 1,48°C above the average for the pre-industrial period (1850-1900). This historical reference point is used to assess the extent to which the planet is moving away from the temperature targets of the Paris Agreement.
The Arctic is experiencing record lows in sea ice
The Copernicus bulletin doesn't just focus on the state of the oceans; it also confirms that the extent of Arctic sea ice This winter, the northern hemisphere reached record lows once again. The recorded ice cover remains at a level similar to last year's record.
These data coincide with the analyses of the NSIDC, a US institute specializing in monitoring the polar regionswhich had already warned that Arctic ice continues to lose extent and thickness. Less ice means more exposed dark water, which absorbs more solar radiation and heats up more quickly, fueling a vicious cycle of melting and further warming.
The evolution of the Arctic is closely linked to the European climate. Changes in ice distribution and in the temperature contrast between the pole and mid-latitudes can affect the atmospheric circulationaltering the trajectory of storms and anticyclones that condition the weather in Spain and the rest of the continent.
In recent years, various studies have linked the weakening of sea ice with a higher frequency of persistent weather patterns, such as prolonged heat waves or periods of almost stationary rainfall, phenomena that have a major economic and social impact in Europe.
The picture painted by the Copernicus data, with oceans very close to their maximum temperaturesThe risk of a return of El Niño and record-low Arctic ice point to a climate system under intense pressure. For Spain and Europe as a whole, these signs mean the need to prepare for potentially more extreme summers, more vulnerable coastlines, and more intense weather events, while the scientific community insists that a rapid reduction in emissions is key to preventing these record-breaking conditions from becoming the new normal.
