World ocean temperatures set new record

The temperature at the ocean surface rose to 20.96 degrees Celsius on Friday (4 August), according to data from the European Union's climate observatory. The previous record was 20.95 degrees Celsius in March 2016, according to the EU's Copernicus Climate Change Service.

According to scientists, the oceans have absorbed 90% of the excess heat generated by human activities since the dawn of the industrial age.

This excess heat continues to build up as greenhouse gases—mainly from the burning of oil, gas, and coal—continue to build up in Earth’s atmosphere. Globally, average ocean temperatures have regularly broken seasonal heat records since April.

“Ocean heatwaves are a direct threat to some marine life,” said Piers Forster of the International Climate Centre at the University of Leeds. “We have seen coral bleaching in Florida as a direct result and I expect there will be further impacts.”

Warming of the oceans is predicted to have other impacts on marine life, including the migration of certain species and the spread of invasive species.

This could threaten fish stocks and thus undermine food security in some parts of the world. Warmer oceans are also less able to absorb carbon dioxide (CO2), exacerbating the vicious cycle of global warming.

And higher temperatures caused by El Nino tend to warm ocean waters even more. Scientists expect the worst effects of the current El Nino to be felt by the end of 2023 and continue into the following years.

“While there are certainly short-term factors, the main long-term cause is the build-up of greenhouse gases in the atmosphere caused by human activity, primarily the burning of fossil fuels,” said Rowan Sutton, director of climate research at the University of Reading.

On Monday, a temperature of 38.3 degrees Celsius - as hot as a bathroom hot tub - was recorded off the coast of Florida, which is considered a world record high.

Last week, the surface water of the North Atlantic rose to a record high average temperature of 24.9 degrees Celsius, according to provisional data from the US National Oceanic and Atmospheric Administration (NOAA).

The Mediterranean Sea broke its daily heat record in early July with an average temperature of 28.71 degrees Celsius, according to Spain's leading marine research center.

According to a 2019 report by the Intergovernmental Panel on Climate Change (IPCC), marine heatwaves have more than doubled in frequency since 1982. By 2100, they could be 10 times more frequent than at the beginning of the 20th century if polluting emissions are not reduced.

The use of coal, oil and gas is expected to be at the heart of debate at the upcoming United Nations climate talks, dubbed COP28, scheduled to take place later this year in Dubai.

Mai Anh (according to AFP, CNA)

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