Global sea surface temperatures broke records in June: temperatures of up to 21°C were recorded in the ocean on 21 June – exceptionally high global sea surface temperatures that will have an impact on marine ecosystems, weather patterns and the climate across the entire planet.
This was reported on Wednesday by the Climate Branch (C3S) and the Ocean Branch (CMEMS) of the European Earth observation programme Copernicus.
The new record for this time of year had been expected. Over the past three years, the ocean between 60 degrees north latitude and 60 degrees south latitude (meaning outside the polar regions) has been between 0.35°C and 0.73°C warmer than the long-term average.
Additionally, since mid-May, sea surface temperatures in the Pacific Ocean around the equator have been rising, which may indicate that El Niño is developing.
After all, this weather phenomenon occurs when the ocean water in the central and eastern parts of the Pacific Ocean becomes warmer than normal. This happens on average every two to seven years and usually lasts for nine to 12 months. El Niño is associated with higher global temperatures.
El Niño
The World Meteorological Organisation (WMO) of the United Nations (UN) reported on 2 June that there is an 80% chance of El Niño developing between June and August.
The National Oceanic and Atmospheric Administration (NOAA), the US agency for meteorology and oceanography, officially confirmed the onset of El Niño on 11 June.
The deviation of global sea surface temperatures from the norm for this time of year reached a record high in June. According to data from the climate service, the sea surface temperature on 21 June was 20.86°C, slightly higher than the 20.83°C recorded in 2023 and 2024.
On 21 June, the ocean service recorded a sea surface temperature of 21°C, 0.1 degrees higher than in 2023 and 2024.
Uncharted territory
Higher sea surface temperatures keep the atmosphere warm for longer, fuel storms and increase evaporation, thereby raising the risk of extreme rainfall and flooding. Ocean warming also causes sea levels to rise further and accelerates ice melt.
In warmer seas, marine ecosystems come under pressure. Coral reefs, for example, will bleach and die off more quickly. Higher sea surface temperatures are also linked to more frequent and intense marine heatwaves, which disrupt marine ecosystems and affect fisheries and the economies of coastal regions.
"Current conditions may signal the start of a new phase that is taking us into uncharted territory once again," said C3S Director Carlo Buontempo. "With ocean temperatures at this level and El Niño on the horizon, we are likely to see even more temperature records broken in the coming months."
