Oceans reach record temperatures at the start of summer – Copernicus sees the beginning of a new phase

Copernicus and the Copernicus Marine Service operate two independent measurement series whose methods are based on local measurements combined with satellite data, including data from the European Space Agency Esa. These methodological differences can lead to slight discrepancies between the values.

Two independent measurement series

According to Copernicus, unusually high temperatures had been measured in several ocean regions in recent months. The climate phenomenon El Niño, which according to the service had only recently emerged, was further amplifying the warming effect.

Carlo Buontempo, Director of Copernicus, stated verbatim: „Die aktuellen Bedingungen könnten auf den Beginn einer neuen Phase hindeuten, die uns erneut in unbekanntes Terrain führen wird. Angesichts der derzeitigen Meerestemperaturen und des sich abzeichnenden El Niño werden in den kommenden Monaten wahrscheinlich weitere Temperaturrekorde gebrochen werden."

Role of the El Niño climate phenomenon

El Niño occurs approximately every few years, primarily in the equatorial Pacific, and according to Copernicus intensifies the consequences of human-made climate change. While the previous record value in 2024 fell within a phase of an already waning El Niño, the onset of the current El Niño was only recently announced, according to the report.

The University of Maine has been recording daily temperature values globally and for individual regions for roughly four decades, also relying in part on satellite measurements. Copernicus experts assume that further records could be broken both in the oceans and in the near-surface atmosphere.

Over the past three years, global ocean temperatures outside the polar regions were between 0.35 and 0.73 degrees Celsius above the long-term average, according to Copernicus. The oceans play a central role in the global climate system, as they absorb the largest share of the additional heat from human-made warming.

Global consequences of ocean warming

The immediate effects of El Niño on Europe are limited according to the report. In regions of the Southern Hemisphere, however, the effects manifest as droughts and floods that hit particularly affected areas.

Copernicus pointed out that ocean warming has far-reaching consequences: the atmosphere remains warm for longer, more energy is stored, and the risk of extreme storms, precipitation, and flooding increases. The service had already expected the record and had pointed to the unusually high temperatures in several ocean regions as well as to the amplifying El Niño phenomenon.

Looking ahead

According to the assessment of the researchers involved, the rising ocean temperatures are likely to have worldwide effects on weather patterns and climate as well as on marine ecosystems. With their independent measurement series, the University of Maine and Copernicus simultaneously provide a double verification of the documented trends.

Overall, the record illustrates – in Copernicus's assessment – that the Earth is entering a new chapter of climate development. Buontempo spoke of „unbekanntem Terrain" and pointed to the likelihood of further records in the coming months.