World’s oceans hit hottest temperature on record in August

Why This Matters

Key context: <p>Average sea surface temperature outside polar regions was 21.1C on Saturday, latest data finds</p><p>The world’s oceans were hotter than ever previously recorded on Saturday, according to the latest data.</p><p>The average surface temperature was 21.1C, with the <a href="https://www.theguardian.com/environment/2026/aug/19/carbon-pollution-massive-expansion-marine-heatwaves-europe">rising marine heat</a> a stark indicator of the climate crisis. More than 90% of the heat trapped by carbon dioxide from fossil fuel burning enters the oceans.</p><p><a href="https://www.theguardian.com/environment/2026/jul/23/climate-crisis-heat-sucking-soils-dry-extreme-drought-europe-analysis">The Guardian’s climate forum 2026</a><br> On Tuesday 20 October, join Damian Carrington, and our panel of experts – including Professor Andy Haines, Katie White MP, Asad Rehman, Shruti Suresh Gareth Thomas and Amy Fairman for a hopeful and solutions-focused evening. Book tickets <a href="https://www.theguardian.com/guardian-live-events/2026/jun/19/the-guardians-environment-forum-2026">here</a> or at <a href="https://www.theguardian.com/guardian-live-events/2026/jun/19/the-guardians-environment-forum-2026">guardian.live</a></p> <a href="https://www.theguardian.com/environment/2026/aug/24/worlds-oceans-hit-hottest-temperature-on-record-in-august">Continue reading...</a> This development from The Guardian highlights ongoing changes in the sector.