Ocean surface temperatures have reached unprecedented levels, renewing fears about severe heat waves that could hit the world this summer.
According to the European Union's Copernicus Climate Change Service (C3S), the average global sea surface temperature in June was 20.98 degrees Celsius, surpassing the previous record highs set in 2023 and 2024.
The data also showed that temperatures outside the polar regions, on June 21, exceeded the exceptionally high levels recorded at the same time in the past two years.
The service stated that this record caps off six months of near-unprecedented ocean warmth in 2026, with prolonged marine heat waves.
The average sea temperature in the first half of the year was 20.04 degrees Celsius, slightly lower than the record set in the same period of 2024.
The center warned that this new record level could lead to disruptions in weather patterns, imbalances in the global climate , and damage to marine ecosystems, especially as it coincides with the beginning of the El Niño phenomenon, which experts expect to be the strongest in several decades.
The previous record for June, set in 2023, prompted scientists to describe these trends as "alarming," "frightening," and "unprecedented," and it was preceded by a devastating wave of heat, floods, and storms worldwide. Today, that record has been surpassed, and the alarming rise in temperature is once again looming over most of the globe.
Many European countries suffered record-breaking heat waves last month, while Antarctica experienced an unprecedentedly warm winter.
Although attention is often focused on land temperatures, ocean readings provide a more comprehensive picture of the extent to which the climate has been disrupted by global warming caused by human activities.
Sea surface temperature is affected by several factors, such as solar radiation, water currents, and heat stored in the depths.
The oceans absorb more than 90% of the excess energy in the Earth system, which mostly comes from burning fossil fuels such as oil, coal and gas.
This energy imbalance reached a record high last year, at 23 zettajoules ( a scientific unit of measurement for enormous amounts of energy), more than double the rate recorded during the previous two decades.
As a result, the rate of ocean warming is accelerating: in 2020, the heat added to the oceans was equivalent to five Hiroshima-sized bombs exploding every second, while last year that rate rose to nearly 11 bombs per second. UN Secretary-General António Guterres warned that "the Earth is exceeding its limits."
As for the future of this wave, scientists believe it is still too early to judge whether this rise is temporary or will increase, because the annual peaks in ocean temperature are usually recorded in July and August.
But Carlo Pontembo, director of the Copernicus Centre at the European Centre for Weather Forecasting, warned that these figures could herald a new phase leading the world into another climate unknown, saying: "With ocean temperatures remaining at these levels, and El Niño approaching, we are likely to see new heat records broken in the coming months."
