According to a new report, the world’s oceans experienced their “warmest June ever observed” and could see further record-breaking highs in the months ahead as El Niño and climate change push temperatures higher.
The findings were released by the European Union’s Copernicus Marine Service, which reported that the global average sea surface temperature reached 21.0 degrees Celsius (69.8 degrees Fahrenheit) in June. The figure surpassed the previous June records set in 2023 and 2024, marking another milestone in a continuing trend of unusually warm ocean conditions.
The European Union’s Copernicus Marine Service said in a statement that the first six months of 2026 “were characterised by persistently elevated sea-surface temperatures and widespread marine heatwaves across much of the global ocean.”
Simon van Gennip, Lead Oceanographer for the Copernicus Marine Service, stated, “Marine heatwaves expanded steadily throughout the period, ultimately affecting around 82 percent of the global ocean.”
“The Mediterranean, the central North Atlantic and the equatorial Pacific all emerged as hotspots, and these regional signals paint a consistent picture of an ocean under sustained thermal stress.”
Simon van Gennip
Scientists say that the record-breaking temperatures reflect the combined influence of long-term human-induced climate change and natural climate variability, including the lingering effects of El Niño. While El Niño is a naturally occurring climate phenomenon that periodically warms surface waters in the central and eastern Pacific Ocean, researchers say greenhouse gas emissions have intensified the overall warming trend, making temperature records increasingly common.
El Nino is marked by unusually warm waters in parts of the Pacific Ocean, releasing more heat into the atmosphere and influencing wind, cloud and weather patterns around the globe. This can raise the risk of weather extremes, ranging from floods in Peru to droughts in parts of Africa and wildfires in Australia.
Land and sea temperatures reached an all-time high in 2024 at the tail end of the last El Nino, and 2026 could be among the warmest years recorded with the onset of the next El Nino this year.
Sea surface temperatures serves as a critical indicator of global climate change. As oceans continue to warm, they influence weather patterns, marine ecosystems and the frequency and intensity of extreme weather events around the world.
Marine heatwaves occur when sea temperatures remain significantly above average for prolonged periods. Such events can have serious consequences for ocean life, including widespread coral bleaching, fish mortality and disruptions to marine food chains. Warmer waters also reduce oxygen levels, placing additional stress on marine species and coastal ecosystems.
Climate scientists warn that unusually warm oceans can contribute to stronger tropical cyclones and hurricanes by providing additional energy to developing storms. Elevated sea surface temperatures can also increase evaporation, influencing rainfall patterns and raising the likelihood of both severe flooding and prolonged droughts in different parts of the world.
The latest findings add to a growing body of evidence showing that Earth’s climate system continues to warm. Recent years have seen a series of record-breaking global air and ocean temperatures, prompting renewed calls from scientists and international organisations for faster action to reduce greenhouse gas emissions.
Researchers are continuing to monitor how ocean temperatures evolve during the second half of the year. Although El Niño conditions are expected to weaken over time, scientists caution that ocean temperatures may remain exceptionally high because of the long-term warming caused by climate change.
Record-breaking Highs In Sea Surface Temperature Expected
According to scientists, the onset of a potentially powerful El Nino weather pattern could boost global heat in the oceans and atmosphere even further in 2026, and into next year.
Carlo Buontempo, Director of the Copernicus Climate Change Service, the EU’s climate monitor, said, “Current conditions could indicate the beginning of a new phase, leading, once more, to uncharted territory.” “With ocean temperatures at these levels and El Nino on the horizon, we are likely to see more temperature records fall in the coming months,” Buontempo added in a statement.
The Copernicus report follows a warning issued in a major UN scientific assessment last month, which declared that the world’s oceans were in a “deepening crisis” as seas were warming and rising faster. Oceans are a key regulator of Earth’s climate because they absorb some 90 percent of the excess heat caused by humanity’s release of greenhouse gases, such as carbon dioxide. Warmer oceans increase moisture in the atmosphere, providing fuel for tropical cyclones and destructive rainfall.
Warmer oceans also play an important role in rising sea levels. As seawater heats up, it expands, contributing to thermal expansion, one of the main drivers of global sea-level rise alongside the melting of glaciers and polar ice sheets. Rising sea levels increase the risk of coastal flooding and erosion, particularly for low-lying communities and island nations.
As global ocean temperatures continue to reach new highs, the findings serve as another reminder of the far-reaching impacts of climate change.
