Global sea surface temperatures reached a new record for June, highlighting the growing influence of El Niño and raising concerns over the impact of warmer oceans on marine ecosystems, shipping operations and extreme weather patterns.
Data released by the European Union’s Copernicus Climate Change Service (C3S) showed that the global average sea surface temperature climbed to 20.86°C on 21 June, surpassing the previous June record set in 2024. The milestone was independently confirmed by the Copernicus Marine Service, which recorded an average of 21.0°C for the same day using its own monitoring system.
Scientists attribute the latest record to a combination of the developing El Niño event in the tropical Pacific and the long-term warming trend driven by greenhouse gas emissions. While El Niño naturally raises ocean temperatures, researchers say it is unfolding against a significantly warmer climate than in previous decades, increasing the likelihood of further temperature records in the coming months.
Rising ocean temperatures have direct implications for the maritime sector. Warmer sea surfaces can intensify tropical cyclones, increase the frequency of heavy rainfall events, and contribute to more persistent marine heatwaves. They also accelerate coral bleaching and place additional stress on marine ecosystems that support global fisheries.
Beyond the ocean surface, researchers note that heat is continuing to accumulate throughout the water column. Recent studies found that ocean heat content down to a depth of 2,000 metres reached another record high last year, reinforcing evidence that the oceans continue to absorb most of the excess heat generated by human-induced climate change.
Climate scientists also stressed the importance of maintaining global ocean observing systems, including satellites, research vessels, drifting buoys and deep-water monitoring networks, which provide the data used to forecast weather, monitor ocean conditions and improve climate modelling.
