• The world's oceans recorded their hottest June ever, with temperatures reaching 20.98°C.
• El Niño and climate change are prominent contributors to this unprecedented warming.
• Marine heatwaves have affected around 82% of global ocean surface.
• Expectations are set for further temperature records to be broken in the coming months.
• The situation underlines a "deepening crisis" for ocean ecosystems.

According to the European Union's Copernicus Marine Service, the world’s oceans have just experienced their hottest June ever recorded with global average sea surface temperatures reaching 20.98°C, surpassing previous records set in 2023 and 2024. This marked the culmination of six months characterized by sustained marine heatwaves, affecting vast areas of the ocean, which scientists fear could set new highs in the months ahead as El Niño effects amplify temperatures further, according to Le Monde.

The rise in ocean temperatures has implications for extreme weather patterns globally. El Niño, which is known for causing unusually warm sea conditions in parts of the Pacific, has the potential to increase atmospheric heat, subsequently influencing wind and weather patterns worldwide. This can heighten the frequency of extreme weather events such as floods, droughts, and wildfires. Simon van Gennip from Copernicus commented on these developments, indicating that the "onset of a potentially powerful El Niño weather pattern could boost global heat," according to Channel News Asia and Al Jazeera.

This trend towards increasing sea temperatures is regarded as a sign of a "deepening crisis," according to a recent UN scientific assessment, indicating that the oceans are warming and rising at alarming rates. Oceans play a crucial role in regulating Earth’s climate by absorbing approximately 90% of excess heat resultant from human-induced greenhouse gas emissions. Warm ocean temperatures also lead to increased atmospheric moisture, fueling tropical cyclones and extreme rainfall, which raises concerns for animal and coral populations facing the threats of marine heatwaves, as cited in the reports from Le Monde, Channel News Asia, and Al Jazeera.

The first half of 2026 has seen widespread marine heatwaves that impacted about 82% of the world’s oceans. Regions such as the Mediterranean and the equatorial Pacific reported particularly high temperatures, with significant effects on marine ecosystems observed. The Mediterranean reached a new record of 24.3°C, exacerbating conditions for marine habitats, as highlighted by the Copernicus Marine Service. This expanding thermal stress across ocean environments poses serious risks for biodiversity, hence emphasizing the urgent need for climate action, according to Channel News Asia and Al Jazeera.