Our Oceans Appear to Have a ‘Fever’

Warm Ocean Water Creates a Host of Problems 

If you happen to shout “the water is so warm” when you jump into the ocean during your beach vacation this year, you’re exactly right. 

The National Oceanic and Atmospheric Administration (NOAA) reported in April 2023 that the mean temperature of the ocean’s surface was 21.1 degrees Celsius (69.98 Fahrenheit), which broke the previous record of 21 degrees Celsius (69.8 Fahrenheit) set in 2016. The trouble is that the record has continued to be broken every day for the last 12 months. 

And that entire year of unprecedented heat has scientists worried. 

“It’s not just that it’s an entire year of record-breaking ocean temperatures, it’s the margin that the records are being broken,” said Brian McNoldy, a senior research scientist at University of Miami’s Rosenstiel School of Marine, Atmospheric and Earth Science. 

Climate scientists say most of that record-breaking heat is from human-caused climate change created by the release of carbon dioxide and methane emissions from the burning of coal, oil and natural gas. However, additional heat comes from a natural El Niño weather pattern, a warming of the central Pacific that changes global weather pattern. 

The average sea surface temperature today is about 1.25 degrees Fahrenheit higher than it was from 1982 to 2011, according to the University of Maine’s Climate Reanalyzer. 

If ocean temperatures continue to break records, it could bleach corals, generate more intense and fast-developing hurricanes, drive coastal temperatures up, disrupt fisheries and make extreme rain events more likely. 

That warm ocean water is especially a concern heading into a new hurricane season because warm water gives hurricanes more energy. Forecasters are predicting an active hurricane season for 2024. 

“Nothing surprises me anymore,” said Robbie Berg, a senior hurricane specialist at the National Hurricane Center. “There are still a lot of factors to affect what happens during hurricane season, but even if the Atlantic warms the least between February and September than it has warmed during the same period in the last 40 years, we’d still be at the second warmest on record going back to 1980. It’s going to be hard to get the Atlantic cool at this point.” 

Our planet is also warming 

It’s not just the oceans that are getting warmer. The Earth itself has obliterated global heat records, averaging 13.54 degrees Celsius (56.37 degrees Fahrenheit), breaking the old record from 2016 by about an eighth of a degree according to Copernicus, the Earth observation component of the European Union’s Space program. 

That may not seem like much, but scientists say it’s an exceptionally large margin. 

“It wasn’t just for a month or a season—it was exceptional for an entire year,” said Samantha Burgess, deputy director of the Copernicus Climate Change Service, in a recent interview. “And there are several factors for this, including the El Niño weather pattern and increased solar activity, but by far the biggest factor was the ever-increasing amount of greenhouse gasses in the atmosphere that trap heat.” 

The agency said 2023 was 1.48 degrees Celsius (2.66 degrees Fahrenheit) above pre-industrial times. That’s barely below the 1.5 degrees Celsius limit set by the 2015 Paris Climate Agreement, which nations agreed to in hopes of avoiding the most severe effects of global warming. 

Challenging expectations 

It’s likely the warmer Earth and air temperatures are contributing to the warmer ocean temperatures, but scientists don’t know precisely why sea surface temperatures have climbed so high so fast. 

While air temperatures are warmer, water has a greater capacity to absorb and store heat. In fact, the ocean has absorbed about 90% of the heat created by global warming. 

“It takes a lot of heat to raise water’s temperature, and I do fear there may be something else going on that is causing a long-term change in sea surface temperatures we hadn’t predicted,” said John Abraham, a professor at the University of St. Thomas, who studies ocean temperatures. 

“This is not ideal for a calm hurricane season,” adds McNoldy. “This not only increases the risk of stronger storms and rapid intensification; it also could make the hurricane season even longer.” 

To learn more about how climate change leads to stronger storms, watch this Sci NC interview with MIT climate scientist Kerry Emanuel.