World sea surface temperatures have broken records every day for the last 12 months.
Oceanographers are increasingly worried.
“Not only is this a record-breaking year for ocean temperatures, but the margin that breaks them is not even close to the previous record,” said Brian McNoldy, a senior research fellow at the University of Miami’s Rosenstiel School. Marine, Atmospheric and Earth Sciences. “That’s what raises a lot of people’s eyebrows.”
According to the University of Maine Climate Reanalyzer, average sea surface temperatures today are roughly 1.25 degrees Fahrenheit warmer than during the 1982-2011 period. This is a massive anomaly that could have significant impacts on weather and ecosystems.
Human-caused climate change likely plays a role, but probably not the only factor, the researchers said. Climate models predict a steady increase in sea surface temperatures, but not as rapidly; Ocean surface temperatures also fluctuate and can be affected by natural climate variability such as El Niño and La Niña.
So scientists don’t yet know exactly why sea surface temperatures are so high.
“I pray we have a year of once-in-a-lifetime warm sea surface temperatures, but I fear something else could happen that causes a long-term change in sea surface temperatures that we haven’t anticipated.” “said John Abraham, a professor at the University of St. Thomas who studies ocean temperatures. “All bets are off now, this is something so unusual that it defies our historical expectations.”
If ocean temperatures continue to break records, this could bleach coral, create more intense and faster-developing hurricanes, increase coastal temperatures, and increase the likelihood of extreme precipitation; scientists had already observed these events in 2023.
Temperatures rose to record levels for the first time in mid-March last year, according to Climate Reanalyzer, which tracks average measurements of sea surface temperature data around the world. The data used to measure these trends dates back more than 40 years and comes from networks of monitoring buoys and robotic devices designed to help meteorologists make weather forecasts.
Abraham suspects that climate change is the main cause of this trend, and that some poorly understood natural ocean processes also play a role.
Average air temperatures are roughly 1.8 F higher today than during 1979-2000, but water has a greater capacity to absorb and store heat; the ocean absorbed approximately 90% of the heat created by global warming. In other words, it was not expected that the seas would warm this much.
“It takes a lot of heat to raise the temperature of the water,” Abraham said.
But both he and McNoldy acknowledged that it is possible for the ocean system to exceed a critical threshold due to global warming.
Last year, some scientists also pointed to El Niño, a natural pattern involving warm ocean water in the tropical Pacific Ocean, as a factor that increases average sea surface temperatures.
But now El Niño is dissipating, so they suspect something else is at play.
“What we’re seeing now leading to high temperatures is something in addition to El Niño and cannot be explained by arguments made six months or 12 months ago,” Abraham said. “Sea surface temperatures are higher elsewhere and far away from El Niño regions.”
McNoldy listed other dynamics that could play a small role, including the weakening of trade winds in the North Atlantic, which has reduced the amount of dust blowing from Africa’s Sahara Desert toward North America. Dust absorbs solar energy over the Atlantic Ocean, so it is possible for more radiation to be absorbed into the ocean.
“That could be a factor, but I don’t have a good sense of being able to quantify it,” said McNoldy.
Some researchers have suggested that changes to shipping regulations could reduce sulfur pollution in ship exhaust, ultimately reducing cloud cover and allowing the oceans to absorb more energy.
“All these little components alone don’t explain what we’re seeing, but maybe together they do,” said McNoldy, but added that he was skeptical of the theory but couldn’t rule it out.
Whatever the cause, high sea surface temperatures can pose serious threats. Abraham said warmer water provides more energy for storms to fuel, so “those that form generally become stronger.”
Warmer waters also increase the risk of rapid intensification, with hurricane winds suddenly intensifying as they approach the coast. Last year, Hurricane Idalia went from a Category 1 to a Category 4 in 24 hours.
Some of the largest sea surface temperature anomalies are in the Atlantic and off the Horn of Africa, where the hurricanes that rock the East Coast of the United States often originate. What’s more, the National Weather Service’s Climate Prediction Center says there’s a 62% chance of La Niña, which is associated with active and damaging hurricane seasons, developing in late spring.
“It’s not ideal for a quiet hurricane season,” said McNoldy, noting that the extra ocean warmth could also extend the season.
Higher sea surface temperatures can also contribute to more intense coastal rainstorms by helping create a wetter, warmer atmosphere, Abraham said.
McNoldy said he’s also concerned about the corals that took a hit last year.
Warm waters caused some of the worst bleaching events ever observed in Florida and the Caribbean Sea; Corals under stress turn white and expel the photosynthetic algae living in their tissues.
“If the anomalies we see now are present in the warmer months, the oceans will be warmer by 2023 and we will see even worse coral bleaching events,” said McNoldy.
Among oceanographers, he added: “We’re all kind of observing something strange happening. At some point, someone will come up with an answer, but I haven’t seen that answer yet.”
This article first appeared on NBCNews.com.