At the start of summer, the world’s surface oceans have never been as warm as they have been this year. On June 21, the measurements from the EU climate program Copernicus were 20.86 degrees and the Copernicus marine service was 21.0 degrees Celsius, above the previous record values for this day from 2023 and 2024.
In these two years, the climate change service measured 20.83 degrees Celsius and the ocean service measured 20.9 degrees Celsius for the deadline. Since these are two independent series of measurements, there are slight deviations between the two. Both systems rely on local measurements combined with satellite data, including from the European space agency Esa.
El Niño amplifies the effect of climate change
Copernicus emphasized that the record was to be expected given the unusually high temperatures recorded in several ocean regions in recent months and the natural climate phenomenon that is currently occurring El Niño enhance the effect.
An El Niño, which occurs every few years, especially in the equatorial Pacific, exacerbates the consequences of man-made climate change. The effects are particularly felt in regions in the southern hemisphere with droughts and floods. For Europe, the direct consequences are limited.
Earth heading into “unknown territory”
Copernicus director Carlo Buontempo emphasized: “Current conditions could indicate the beginning of a new phase that will once again take us into unknown territory. Given current ocean temperatures and the looming El Niño, more temperature records are likely to be broken in the coming months.”
The Copernicus experts assume that further records could be broken both in the oceans and in the near-surface atmosphere. At the time of the previous 2024 record, the then El Niño was already fading, while the start of the phenomenon was only recently reported this year.
A record with consequences
The warming of the oceans has far-reaching effects, emphasized Copernicus. Higher ocean temperatures kept the atmosphere warmer for longer and caused more energy to accumulate – increasing the risk of extreme storms, precipitation and flooding.
According to Copernicus, in the past three years, global ocean temperatures outside the polar regions have been between 0.35 and 0.73 degrees Celsius above the long-term average.
Oceans are important climate buffers
Data from the University of Maine’s “Climate Reanalyzer” platform also supports Copernicus’ measurements. For June 21st, the platform shows an average sea temperature of 20.97 degrees – a week later this value was at the same level on June 28th. The university has been recording daily values globally and for individual regions for around four decades, which are also based, among other things, on satellite measurements.
The oceans play an important role in the global climate. Oceans absorb most of the additional heat from man-made global warming.
