Global Sea Surface Temperatures Hit Record Highs in June

Global sea surface temperatures reached a record 20.86 degrees Celsius (69.55 degrees Fahrenheit) on June 21, according to the European Union’s Copernicus Earth observation program. This peak, announced July 1, surpasses previous records and signals increased risks for extreme weather, flooding, and marine ecosystem stress as a newly declared El Niño develops.

The Copernicus Climate Change Service reported the June 21 measurement beat the previous record of 20.83 C (69.49 F) set in 2023 and 2024. An independent dataset from the Copernicus Marine Service corroborated the warming trend, reporting temperatures of 21.0 C (69.8 F).

Carlo Buontempo, director of the Copernicus Climate Change Service at the European Centre for Medium-Range Weather Forecasts (ECMWF), stated that current conditions may signal a shift into uncharted territory.

With ocean temperatures at these levels and El Niño on the horizon, we are likely to see more temperature records fall in the coming months.

Carlo Buontempo

Why are ocean temperatures reaching record levels?

A developing El Niño in the Pacific Ocean is driving the current heat spike. El Niño is the warm phase of a natural climate cycle.

The Copernicus Climate Change Service reports that this El Niño is likely to reach levels that have not been seen in decades. This natural cycle is interacting with an already warming world, creating a compounding effect on sea surface temperatures.

The service added that it remains to be seen whether these temperature spikes are temporary or indicative of longer term trends.

Which regions saw the highest temperature spikes?

Ocean warming has not been uniform across the globe. The most significant temperature increases occurred in the Mediterranean, the Baltic Sea, the coasts of Northern Canada, and specific bands across the Pacific.

Data from the European Space Agency shows that temperatures in the Mediterranean on June 29 were up to 8 C (14.4 F) higher than the average recorded between 1990 and 2020.

What are the risks of warming oceans?

Elevated sea surface temperatures directly impact atmospheric conditions and global weather patterns. Higher ocean temperatures keep the atmosphere warm for longer periods and provide additional energy to storms.

Representatives from the Copernicus Climate Change Service identified several primary risks associated with this warming:

• Increased evaporation, which enhances the potential for extreme precipitation and flooding.
• Acceleration of ice melt and subsequent sea level rise.
• Severe stress on global marine ecosystems.

The interaction between the record June temperatures and the strengthening El Niño suggests that more temperature records will likely fall in the months following the July 1 announcement.