Oceans hit record temperatures in 2024

As 2024 begins with the hottest ocean temperatures ever recorded, our climate situation is looking pretty dire.

Thred Media
4 min readFeb 22, 2024


The world’s oceans reached the hottest temperatures ever recorded early in 2024, serving as a profoundly concerning indication that the Earth is spiraling toward extreme climate breakdown — if greenhouse gas emissions from human activity do not see radical reductions immediately.

As humanity continues emitting heat-trapping gases into the atmosphere, principally by burning fossil fuels, the oceans have been forced to absorb a staggering 90% of the accumulating excess heat. This has pushed ocean temperatures to unprecedented levels, with experts warning the consequences could be catastrophic.

John Abraham, a professor of thermal sciences at the University of St. Thomas and co-author of the ocean temperature analysis published in Advances in Atmospheric Sciences, said: ‘It’s year after year that we’re setting heat records in the ocean.

The fact that this process is continuing apace every single year is incredibly illuminating for us because it drives home how intrinsically the oceans are connected to global warming and climate change.’

In 2023 alone, the oceans absorbed about 287 petajoules of heat energy — which Abraham points out is equivalent to eight Hiroshima atomic bombs detonating every single second of every single day. The ocean heat content measured in 2023 was a shocking 15 zettajoules higher than figures from 2022.

Analyzing ocean heat data from the surface down to depths of 2,000 meters, the researchers found increased warming across huge expanses of the ocean. But Abraham emphasized that the most pronounced temperature spikes were detected in shallow surface waters. Temperatures here were an average of 0.3°C higher in the second half of 2023 compared to 2022 — what Abraham described as ‘mind-boggling hot’.

Rising ocean temperatures do not bode well for the stability of the climate system and weather patterns. As the oceans grow hotter, more heat and moisture transfer to the atmosphere above through evaporation.

This leads to an escalation in the frequency and severity of extreme weather events across the globe — from deadly heat waves to droughts, wildfires, and intense rainfall that causes devastating flooding.

In 2023 the world endured this chain reaction: scorching heat waves plagued China, Europe and North America; Canada experienced an extreme wildfire season; and countries like Libya, the Democratic Republic of Congo, and Australia were battered by record-shattering rainfall and floods.

Hotter oceans are also irreversibly devastating delicate marine ecosystems like coral reefs. Prolonged exposure to heat causes mass coral bleaching by stripping coral colonies of the algae they need to survive.

2023 saw the worst global coral bleaching event ever documented, impacting a staggering estimated 98% of the planet’s coral reefs. This is an ecological catastrophe, threatening the fisheries and coastal protection that over half a billion people rely upon.

In addition to driving extremes on land, hotter oceans also fuel marine heatwaves — periods when sea surface temperatures spike well above average historical levels for at least five days. The more heat humankind pumps into the oceans, the more intense and frequent these underwater heatwaves are becoming.

While natural fluctuations in ocean currents distribute heat, climate change fundamentally alters these currents. Those flowing from the equator to the poles are strengthening and pushing abnormally high volumes of warm water towards polar regions. This effect was detected across both the northern and southern hemispheres in 2023.

So, when will these worrying ocean temperature and extreme weather trends plateau and begin to reverse? Unfortunately, humanity has already committed the climate system to further warming even if fossil fuel emissions were suddenly halted today.

Alistair Hobday, senior research scientist from Australia’s CSIRO Climate Science Centre, explains: ‘We’re probably locked into [rising temperatures] until around 2050 because the methane and carbon dioxide will have a lifetime in the atmosphere. So even if you turned off the tap today, they’re still going to have an effect.’

However, Abraham cautions there are early signs ocean heating could be accelerating — a trend he says would be ‘concerning’ if validated by more data. Oceans provide invaluable monitoring of the climate crisis, sounding alarms decades ahead of the most severe consequences.

As Abraham concludes, ‘There’s a slight acceleration that we are now starting to detect…but we can’t make the claim that there’s an acceleration until we get more data.’

As the seas grow hotter, extreme weather intensifies, and coral ecosystems collapse, emissions cuts and clean energy deployment must be mobilized rapidly before the Earth is locked into irreversible chaos. The oceans are transmitting a warning to the surface — now humanity must listen, and act.

Originally written by Sahil Pradhan for Thred.



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