The seas around Europe are hotter than ever. In August, the North Atlantic to the west of France and the UK, along with the North Pacific, registered record sea surface temperatures, according to the EU’s Copernicus service. Scientists say this surge is likely the ocean’s “memory” of the record-breaking heat experienced globally in 2023 and 2024. Since oceans absorb about 90% of excess heat trapped by greenhouse gases, they continue to warm even when air temperatures briefly ease.

According to an article from the Financial Times, these anomalies stand out because the global average was not at its absolute peak. Sea surface temperatures reached 20.82°C in August (excluding polar regions), the third-highest on record for that month, while land averaged 16.6°C. Over the past year, global temperatures have been 1.52°C above pre-industrial levels—close to, but not breaching, the 1.5°C Paris Agreement threshold, which is measured over decades. Still, local extremes paint a troubling picture: marine heatwaves have already fueled catastrophic events, such as the Valencia floods last October, when abnormally warm seas supercharged rainfall.

The implications extend far beyond Mediterranean flooding. Warmer oceans can store immense amounts of energy, intensifying weather systems. Climate scientist Wim Thiery of Vrije Universiteit in Brussels warned that this year’s anomalies could foreshadow more destructive floods. At the same time, reduced summer winds in some northern latitudes may have worsened the heating, as weaker air circulation fails to mix cooler, deeper water with hotter surface layers. The result: the top of the ocean grows progressively warmer.

August also highlighted how shifting seas ripple across global weather. Southern Europe battled extreme wildfires in Spain, Portugal, Greece, and Turkey, while the Baltics and Poland were unusually cool. Beyond Europe, above-average heat stretched across Siberia, China, Japan, and the Middle East, while Australia experienced markedly cooler conditions. Rainfall patterns flipped too—parts of Pakistan, Brazil, Argentina, and southern Africa saw wetter-than-average seasons. Pakistan’s summer monsoon floods have already killed more than 900 people and displaced nearly two million.