Overview
- Two independent Copernicus systems confirmed new peak global sea surface temperatures on June 21, reporting about 20.86°C and 21.0°C respectively, beating June records set in 2023 and 2024.
- Researchers attribute the record to the long-term rise in ocean heat from greenhouse gas emissions layered with the onset of El Niño, which releases extra heat from the Pacific to the atmosphere.
- Copernicus data show widespread marine heatwaves in the first half of 2026 that affected roughly 82 percent of the global ocean, with the Mediterranean averaging about 24.3°C and seeing heatwave exposure of about 98 percent of the basin.
- Warmer seas increase evaporation and storm energy, raise sea levels by thermal expansion, and stress marine life including mass coral bleaching, with regional risks such as floods in Peru, droughts in parts of Africa, and wildfires in Australia reported as possible outcomes.
- Forecast models indicate El Niño may strengthen later in the year, making more temperature records likely, but scientists say the key uncertainty is whether June’s spike will be a short-term overshoot or the start of sustained unprecedented ocean warmth.