The dizzying increase in ocean temperatures is alarming scientists, who are calling for more research into the changes taking place and fearing devastating effects on the climate as a whole.
“Changes are happening so quickly that we are not able to monitor the impact,” recognizes Vidar Helgesen, executive secretary of the Intergovernmental Oceanographic Commission of UNESCO, for whom “addressing ocean warming is urgent “.
“A much greater effort of observation and research in real time is necessary,” he told AFP at the Ocean Decade conference which ends Friday in Barcelona and brought together 1,500 scientists , representatives of States or organizations.
The temperature of the oceans, which cover 70% of the Earth and play a key role in regulating the global climate, reached a new absolute record in March, with an average of 21.07°C measured on the surface, excluding areas near the poles. , according to the European Copernicus Observatory.
This overheating, which has been getting worse month after month for a year, threatens marine life and leads to greater humidity in the atmosphere, synonymous with more unstable weather conditions, such as violent winds and torrential rains.
Capacity not “infinite”
According to specialists, the oceans have absorbed 90% of the excess heat caused by human activity since the start of the industrial era. Marine environments, which produce nearly half of the oxygen we breathe, have allowed the Earth’s surface to remain habitable.
“The ocean has a much greater heat capacity than the atmosphere, it absorbs much more heat, but it cannot absorb it infinitely,” warns Cristina González Haro, researcher at the Institute of Sciences of the sea of Barcelona.
According to a reference study published in January, the oceans will still have absorbed a colossal amount of energy in 2023, capable of boiling “billions of Olympic swimming pools”.
One of the major objectives of the Ocean Decade (2021-2030) is to try to broaden knowledge on warming and to decipher its multiple implications, in an attempt to limit them.
“There is still a lot we don’t know about the oceans. We have only mapped about 25% of the planet’s seabed and, at the same time, we need to map and monitor changes occurring due to climate change live,” emphasizes Helgesen.
According to the World Meteorological Organization (WMO), a UN agency, more than 90% of the planet’s oceans experienced heat waves at some point in 2023, with a direct impact on the climate and ecosystems across the entire planet… regardless of the distance that separates them from the sea.
“We are on a trajectory that raises many questions among scientists and we wonder if we have not underestimated future global warming,” warned Jean-Pierre Gattuso, specialist at the National Center for Scientific Research, in Barcelona. (CNRS) French.
Everything counts
The difficulties in implementing major international environmental agreements, such as the Paris Agreement concluded in 2015 to try to limit global warming, do not, however, invite optimism, according to scientists.
“Many of us are somewhat frustrated to see that, despite the scientific demonstrations of climate change and its consequences, the implementation of the Paris Agreement is so slow, so difficult, so painful. “It doesn’t bode well” for the future, lamented Mr. Gattuso.
However, researchers point to some positive signals, such as the adoption in 2023 by UN member states — after 15 years of discussions — of a historic treaty to protect the high seas.
“If I could send a message to policymakers, presidents, prime ministers or business leaders, I think it would be: ‘take a moment out of your busy schedule and look into the eyes of your children and grandchildren,’” urged Mr. Helgesen.
A call relayed by Jean-Pierre Gattuso: “every tenth of a degree counts, every year gained counts and it is never too late. There is absolutely no need to demobilize.”