Scientists at a United Nations conference in Spain called Friday for more research into the sharp rise in ocean temperatures which they warn could have devastating consequences.

"The changes are happening so fast that we are not able to keep pace with the impact," the executive secretary of UNESCO's intergovernmental oceanographic commission, Vidar Helgesen, told AFP on the sidelines of the three-day "Ocean Decade" conference in Barcelona.

"It calls for a much stronger effort to observe and research in real-time and a much closer collaboration between science and policy-making," he said, adding that "tackling ocean warming is a burning issue".

The gathering, which ended Friday, brought together around 1,500 scientists and representatives of governments and environmental organizations to discuss the protection of oceans.

The European Union's climate monitor Copernicus said Tuesday that average sea surface temperatures had set a new record high in March of just over 21 degrees Celsius.

Oceans cover 70 percent of the planet and have kept the Earth's surface liveable by absorbing 90 percent of the excess heat produced by carbon pollution from human activity since the dawn of the industrial age.

 Underestimated future warming? 

 "The ocean has a much greater thermal capacity than the atmosphere; it absorbs much more heat, but it cannot absorb it ad infinitum," said Cristina Gonzalez Haro, a researcher at the Barcelona Institute of Marine Sciences.

Hotter oceans mean more moisture in the atmosphere, leading to increasingly erratic weather -- like fierce winds and powerful rain, and they threaten marine ecosystems that produce almost half of the oxygen we breathe.

One goal of the Barcelona gathering was to try to broaden our knowledge of the warming of the oceans and decipher its implications in an attempt to limit them.

Over 90 percent of the world's oceans experienced heat waves in 2023, which had a direct impact on climate and ecosystems around the world, even those located far from oceans, according to the UN's World Meteorological Organization (WMO).

"We're on a trajectory that has scientists wondering whether we've underestimated future global warming," Jean-Pierre Gattuso, a specialist at the French National Centre for Scientific Research (CNRS), said at the conference.

But scientists warned that the difficulties in implementing major environmental agreements aimed at limiting global warming, such as the 2015 Paris Agreement, do not leave room for optimism.

"Many of us are somewhat frustrated that, despite scientific demonstrations of climate change and its consequences, the implementation of the Paris Agreement is so slow, so difficult, so painful," said Gattuso.

Scientists, however, pointed to some positive signs, such as the adoption last year by UN member states, after 15 years of talks, of a historic treaty that aims to protect oceans and reverse damage done to fragile marine environments by pollution, overfishing, and other human activities.

"Every tenth of a degree counts, every year gained counts, and it's never too late. We absolutely must not lose heart," Gattuso said.