Ocean Temperatures Become Warmer Amid Record-Breaking El Nino

The first half of 2026 has been marked by a relentless rise in ocean temperatures, with global averages reaching a record 21 degrees Celsius, shattering previous highs recorded in 2023 and 2024.

Carlo Buontempo, Director of C3S, warned that the combination of record-breaking ocean temperatures and a developing El Nino may signal the onset of a dangerous new climate era, with further records likely to be broken in the coming months.

This surge is driven by a potent combination of human-induced climate change and a developing El Nino. 

According to C3S, the world’s oceans absorb more than 90% of the excess heat generated by fossil fuel emissions, an energy intake comparable to the detonation of 11 Hiroshima atomic bombs every second. This immense heat accumulation has triggered widespread marine heatwaves, now affecting up to 82% of the global ocean surface.

The Mediterranean Sea and the equatorial Pacific have been among the hardest hit, pushing marine ecosystems under severe stress. C3S data warns that with these rising temperatures are driving widespread coral bleaching and devastating mass die-offs of marine life.

Friederike Otto, a climate scientist at Imperial College London, emphasised that while El Nino is a temporary phenomenon, climate change will continue to intensify unless fossil fuel emissions are drastically reduced.

C3S also highlighted that these superheated waters are intensifying global weather patterns. Increased evaporation is fuelling extreme rainfall, flash floods, and more powerful storm systems worldwide.

There is a 91% probability that global temperatures will exceed the Paris Agreement’s critical 1.5 degrees Celsius threshold within the next five years, a tipping point that could trigger irreversible climate impacts.

“The world is being pushed beyond its limits,” United Nations Secretary-General António Guterres warned.