The rate of ocean warming has almost doubled since 2005, warns the European Copernicus Observatory

Warmer waters bring more violent hurricanes and storms, with their attendant destruction and flooding.

The oceans, which cover 70% of the earth’s surface, play the role of regulator of the earth’s climate. In this context, the confirmation of an unprecedented acceleration in the rate of their warming should not be taken lightly. “It has been increasing steadily since the 1960s. And since around 2005, the rate of ocean warming has doubled”said oceanographer Karina Von Schuckmann, who presented the 8th report on the state of the Copernicus oceans on Monday September 30. Gold, “Ocean warming can be considered our sentinel of global warming”.

In detail, the oceans have warmed by 1.05 watts per m2 since 2005, compared to 0.58 watts per m2 in previous decades, according to the report. This warming can be explained by the fact that the oceans have absorbed since 1970 “more than 90% of the excess heat in the climate system”, caused by massive emissions of greenhouse gases by humanity, demonstrated the work of the Intergovernmental Panel on Climate Change (IPCC).

In addition, more than a fifth of the world’s ocean surface experienced a severe heat wave in 2023, this report reports. However, warmer waters bring more violent hurricanes and storms, with their attendant destruction and flooding. The month of September was also marked by intense precipitation, such as super typhoon Yagi which swept across Asia, deadly floods in the Sahel, Nepal and Europe, and even Hurricane Helene in the south. east of the United States… Although it is still too early to link with certainty all these deadly events to climate change, the network of scientists World Weather Attribution (WWA) has already shown that the rains which hit Central and Eastern Europe are “by far the strongest ever recorded” in the region.

The warming of the oceans is also accompanied by an increase in marine heatwaves. More widespread, marine heat waves also tend to become longer, with an average annual maximum duration which has doubled since 2008, from 20 to 40 days. Marine heatwave episodes can lead to migrations and episodes of mass mortality of species, degrade ecosystems, but also reduce the capacity of ocean layers to mix between the bottom and the surface, thus hindering the distribution of nutrients. They can also “have implications for fish productivity”, impacting fishing, the oceanographer further underlined.

Finally, the Copernicus report also notes that the acidity of the oceans, which absorb a quarter of the CO2 emitted by human activities, has increased by 30% since 1985. Above a certain threshold, the acidity of the sea ​​water becomes corrosive to the skeletons and shells of corals, mussels, oysters, etc. This threshold, considered as a “planetary boundary”should be crossed “in the near future”, according to a report published in mid-September by the Potsdam Institute for climate impact research (PIK).

Since the 19th century, the average temperature of the Earth warmed by 1.1°C . Scientists have established with certainty that this increase is due to human activities, which consume fossil fuels (coal, oil and gas). This warming, unprecedented in its speed, threatens the future of our societies and biodiversity. But solutions – renewable energies, sobriety, reduced meat consumption – exist. Discover our answers to your questions on the climate crisis.