The ocean surface has apparently decided that last year's record wasn't quite record-y enough, hitting a new high for June that has scientists reaching for the thesaurus to find fresh synonyms for 'worried.' On 21 June, temperatures outside the polar regions exceeded the already-extraordinary highs observed at the same time in 2023 and 2024, according to the Copernicus Climate Change Service. The EU-funded climate monitor warned that this new peak will likely bring 'consequences for weather patterns, global climate and marine ecosystems' - which is science-speak for 'things are about to get weird.' Timing is everything, and this record arrives just as an El Niño event - forecast to be the strongest in decades - is getting its act together.

When the previous June record was set in 2023, scientists described the trends as 'worrying,' 'terrifying,' and 'bonkers' - terms one rarely finds in peer-reviewed papers but which accurately convey the mood. That record presaged a devastating global heatwave, floods, and storms. Now, the 2023 record has been surpassed, and much of the world is once again seeing temperatures rise in alarming ways. Last month, the UK and many European countries sweltered under new heat records, while Antarctica - yes, Antarctica - experienced unprecedentedly balmy winter conditions. Because why should the ice caps miss out on the fun?

While land temperatures get most of the press, oceans provide a fuller picture of how badly human-caused warming is pushing the climate out of whack. Surface temperatures are influenced by solar radiation, water currents, and the buildup of heat in the depths. Oceans absorb more than 90% of the excess energy in the Earth system, primarily from burning fossil fuels like oil, coal, and gas. That energy imbalance hit a record 23 zettajoules last year - more than double the average of the previous two decades. For context, a zettajoule is a billion trillion joules, and 23 of them is a lot of joules.

As a result, oceans are warming at an accelerating rate. In 2020, the heat added to the oceans was equivalent to about five Hiroshima bombs per second. Last year, it was closer to 11 Hiroshima explosions per second. UN Secretary-General António Guterres has warned that 'Earth is being pushed beyond its limits' - which is diplomatic-speak for 'we are in trouble.' Scientists caution that it's too early to say whether this sea surface heating is temporary or will worsen, since annual peaks usually occur in July and August. But Carlo Buontempo, Copernicus director at the European Centre for Medium-Range Weather Forecasts, warned it could indicate the beginning of a new phase, leading once more into uncharted territory. 'With ocean temperatures at these levels and El Niño on the horizon, we are likely to see more temperature records fall in the coming months,' he said. Copernicus, by the way, is part of the EU’s space programme - because apparently the view from orbit isn't reassuring enough.