The pace at which oceans are warming has almost doubled since 2005 as global temperatures rise because of human-caused climate change, a report from the EU monitor Copernicus said Monday.

"Ocean warming can be seen as our sentinel for global warming. So it has increased continuously since the 60s and since about 2005, the rate of ocean warming has doubled," oceanographer Karina von Schuckmann from Copernicus Marine Service told reporters.

Over the past two decades, the pace of ocean warming jumped from a long-term rate of 0.58 watts per m2 to 1.05 watts per m2, according to "The State of the Ocean Report" by Copernicus.

The oceans, which cover 70 percent of earth's surface, are a major regulator of the climate and act as a carbon sink by drawing greenhouse gases from the atmosphere.

The IPCC, the expert panel of climate scientists mandated by the United Nations, says that since 1970, oceans have absorbed some 90 percent of the excess heat caused by these planet-warming emissions.

Copernicus said its report detailed "record-breaking ocean temperatures, marine heatwaves stretching down to the deep ocean, unprecedented sea ice loss and rising levels of heat stored in the ocean".

In 2023, more than 20 percent of the global ocean surface experienced at least one severe to extreme marine heatwave, it added.

These degrade ecosystems and upset the delicate balance of nutrients in the ocean, while warmer waters lead to more violent hurricanes, storms and other extreme weather events.