Fossil fuel burning to blame as oceans hit hottest temperatures, scientists say

04 August 2023 , 20:43

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Dr Kathryn Lesneski (Image: Florida Keys National Marine Sanctuary)

The world’s oceans have reached their hottest-ever recorded temperatures amid climate change, figures show.

The average daily global sea surface temperature has hit 20.96 C, beating the 2016 record of 20.95 C, the EU’s climate change service Copernicus found. Researchers at Copernicus said the record-breaking highs were part of a trend of drastic increases in global temperatures.

Oceans help to regulate the global climate by soaking up heat. They also drive weather systems, and organisms in them produce half the Earth’s oxygen. But warmer water has less ability to absorb carbon dioxide, leaving more in the atmosphere. It also speeds up the melting of glaciers, causing sea levels to rise.

Hotter oceans can also disturb marine life and upset food chains. Prof Mike Burrows, who is monitoring impacts on sea shores with the Scottish Association for Marine Science, said: “It is sobering to see this change happening so quickly.”

A scientist in diving gear inspects coral (Getty Images)

Dr Samantha Burgess, of the Copernicus Climate Change Service, said oceans should be warmest in March, not August. She added: “The fact that we have seen the record now makes me nervous about how much warmer the ocean may get between now and next March.”

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She added: “The more we burn fossil fuels, the more excess heat will be taken out by the oceans.” That in turn means it will take longer to stabilise the oceans, and return them to their previous state, she added.

Dr Matt Frost, of the Plymouth Marine Laboratory in Devon, said: “We are putting oceans under more stress than we have done at any point in history.” The record breaking temperatures follow marine heatwaves this year including in the UK, the North Atlantic, the Mediterranean and the Gulf of Mexico.

In June, temperatures in UK waters were 3C to 5C higher than average. In Florida, sea surface temperatures hit 38.44C last week. Dr Kathryn Lesneski, monitoring a marine heatwave in the Gulf of Mexico for the National Oceanic and Atmospheric Administration, said: “The water feels like a bath when you jump in. There is widespread coral bleaching at shallow reefs in Florida and many corals have already died.”

Amy-Clare Martin