Ocean surface temperatures have reached an unprecedented high for June, setting a new record and signaling a potential shift into "uncharted territory" for the planet's climate, scientists from the Copernicus Climate Change Service have warned. Last month, average temperatures outside polar regions climbed to 20.86°C, surpassing the previous June records set in 2023 and 2024.
This development comes as NASA satellites have confirmed that an El Niño weather phenomenon is underway. El Niño is characterized by warmer water in the equatorial Pacific Ocean and is expected to bring extreme heat to many parts of the globe. Carlo Buontempo, Director of the Copernicus Climate Change Service, stated, "Current conditions could indicate the beginning of a new phase, leading, once more, to uncharted territory." He added, "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."
Over the past three years, global ocean temperatures outside polar regions have consistently been between 0.35°C and 0.73°C warmer than the long-term average. The previous record for June, 20.83°C, was set just last year. Experts highlight that warmer oceans have significant consequences, including retaining atmospheric heat longer, providing more energy for storms, and increasing evaporation, which can lead to extreme precipitation and flooding. Additionally, warmer seas contribute to sea-level rise, ice melt, and stress marine ecosystems.
Professor Simon Tett, Chair in Earth System Dynamics at the University of Edinburgh, noted that these rising temperatures are not surprising, given the continuous increase in atmospheric CO2 from burning fossil fuels. He explained that this human-driven warming is likely being amplified by the emerging El Niño event in the Eastern Pacific.
The World Meteorological Organization (WMO) anticipates above-normal temperatures across nearly all regions globally due to the El Niño event. The most significant heat signals are predicted for southern and western North America, Central America, the Caribbean, Europe, North Africa, and much of Asia. South America's northern regions and Southern Africa are also expected to experience strong warming. Australia's coasts are likely to see warmer conditions, while tropical regions, including Equatorial Africa and parts of Southeast Asia, are forecast to be hotter than average.
Earlier reports indicated that parts of Europe were already experiencing a marine heatwave, with some areas recording sea temperatures up to 6°C higher than usual, particularly in the western Mediterranean Sea off the coast of southern France and along Italy's western coast. The United Kingdom and other European countries recently endured record-breaking heat, while Antarctica experienced unusually mild winter conditions.
Forecast models suggest that the current El Niño could be one of the strongest in decades, potentially comparable to the 1997/98 event, which led to record global temperatures. This intensity could bring wetter conditions to the American Southwest and drought to western Pacific nations. While its direct impact on British weather is indirect, a strong El Niño event could exacerbate global warming effects. Simon Culling, an investigator for the UK’s Tornado & Storm Research Organisation (TORRO), suggested that this could lead to hotter summers in the UK in 2026 and 2027, alongside an increased risk of significant cold spells in the winter of 2026/27.
Grahame Madge, a climate science communicator at the Met Office, previously described the developing El Niño as a potentially significant event, likely the strongest this century and comparable to the 1998 event, which marked a record year for global temperature.
El Niño is one phase of the El Niño-Southern Oscillation (ENSO), a recurring climate pattern across the tropical Pacific Ocean that influences global weather. The pattern shifts between warm (El Niño) and cool (La Niña) phases every two to seven years, disrupting temperature, winds, and precipitation patterns worldwide. El Niño is defined by the warming of sea surface temperatures in the central and eastern tropical Pacific, leading to reduced rainfall over Indonesia and increased rainfall over the tropical Pacific. It also weakens or reverses the equatorial trade winds.
