Overview
- Copernicus recorded a new highest-ever global daily average sea-surface temperature of 21.1°C on 22 August 2026, surpassing the previous daily record from March 2024.
- Experts attribute the spike mainly to long-term greenhouse-gas driven warming with a concurrently developing, unusually strong El Niño adding extra short-term heat.
- Rising ocean temperatures have multiplied marine heatwave days since the early 1990s and have already driven widespread coral die-off that scientists say may indicate a crossed tipping point for some reef systems.
- Warmer seas release more heat and moisture into the atmosphere, weaken the ocean’s ability to absorb CO2, and raise the odds of stronger storms and heavier rainfall for coastal communities; regional impacts already include drought-reduced traffic through the Panama Canal.
- The daily record follows a string of monthly highs this year, including a July 2026 monthly record of 20.96°C, underscoring a continuing upward trend in sea-surface temperatures since observations began in 1979.