by Every day for the past 12 months, the world’s sea surface temperatures have broken records.
Ocean scientists are becoming increasingly worried.
“It’s not just a full year of record ocean temperature, but the margin it’s breaking — it’s not even close to the previous record,” said Brian McNoldy, a senior research associate at the University of Miami’s Rosenstiel School. the Sea, the Atmosphere and the Earth. “That’s raising a lot of people’s eyebrows.”
Average sea surface temperatures today are about 1.25 degrees Fahrenheit higher than they were from 1982-2011, according to the University of Maine Climate Reanalyst. It is a massive anomaly that could have significant effects on weather and ecosystems.
Human-caused climate change is likely to play a role, researchers said, but it is likely not the only factor. Climate models predict a steady, but not rapid, rise in sea surface temperatures, and ocean surface temperatures also fluctuate and can be affected by natural climate variability, including patterns such as El Niño and La Niña.
So scientists don’t know exactly why sea surface temperatures are rising so high.
“I pray that we have one year in our lifetime of warm sea surface temperatures, but I fear that there may be something else going on that is causing a long-term change in sea surface temperatures that we did not predict. ,” said John Abraham, a professor at the University of St. Thomas who studies the temperature of the ocean. “All bets are off now, this is unusual, it’s defying our past expectations.”
If ocean temperatures continue to break records, that could erode corals, generate more intense and fast-developing hurricanes, raise coastal temperatures and make precipitation more likely — events scientists have already observed in 2023.
Temperatures reached record highs in mid-March last year, according to the Climate Reanalyzer, which tracks averages of sea surface temperature data around the globe. The data used to measure these trends goes 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 the trend, and some poorly understood natural ocean processes are also playing a role.
Average air temperatures are about 1.8 F higher today than they were from 1979-2000, but water has a greater ability to absorb and store heat – about 90% of the heat created by global warming is absorbed by the ocean. Therefore, it was not expected that seas would heat up so much already.
“It takes a lot of heat to raise the temperature of the water,” Abraham said.
However, both he and McNoldy acknowledged that global warming may have caused the ocean system to pass a critical threshold.
Last year, some scientists also pointed to El Niño, a natural pattern associated with warm ocean water in the tropical Pacific, as a factor in raising average sea surface temperatures.
But now El Niño is spreading, so they suspect something else is at play.
“What we see now driving high temperatures is something other than El Niño and it cannot be explained by the arguments given six months ago or 12 months ago,” Abraham said. “Sea surface temperatures are higher elsewhere and far from El Niño locations.”
McNoldy listed other dynamics that may have played a small role, including the weakening of the North Atlantic trade winds, which reduced the amount of dust blown from Africa’s Sahara Desert toward North America. Dust absorbs the sun’s energy over the Atlantic Ocean, so it is possible that more radiation is being absorbed into the ocean.
“That could be a factor, but I don’t have any sense of being able to quantify it,” McNoldy said.
Some researchers have also suggested that changes in maritime shipping regulations could reduce sulfur pollution in ship exhaust, ultimately reducing cloud cover and allowing the oceans to absorb more energy.
“These small components alone don’t explain what we’re seeing, but maybe in a combined sense, they do,” McNoldy said, though he’s skeptical of the theory but can’t rule it out. the count.
Whatever the reason, higher sea surface temperatures can pose dire threats. Warmer water provides more energy to storms, so “the ones that form tend to get stronger,” Abraham said.
Warmer waters also increase the risk of rapid intensification — when hurricane-force winds suddenly increase near the coast. Last year, Hurricane Idalia went from Category 1 to Category 4 in 24 hours.
Some of the biggest anomalies in sea surface temperature are in the Atlantic and off the Horn of Africa, where the hurricanes that hit the East Coast of the United States often originate. Additionally, the National Weather Service’s Climate Prediction Center says there is a 62% chance of La Niña — associated with active and damaging hurricane seasons — developing in late spring.
“It’s not ideal for a calm hurricane season,” McNoldy said, noting that additional ocean heat could also add to the season.
High sea surface temperatures can contribute to more intense coastal rainstorms, as well, Abraham said, by helping to build a moister and warmer atmosphere.
McNoldy said he is also concerned about corals, which took a hit last year.
Warm waters have caused some of the worst bleaching events ever observed in Florida and the Caribbean, with stressed corals turning white and expelling the photosynthetic algae that live in their tissues.
“If the anomalies we’re seeing now are in place during the warm months, the oceans will be warmer than 2023 and we’ll see even worse coral bleaching events,” McNoldy said.
Among the ocean scientists, he said: “We are all watching something strange happen. At some point, someone will come up with an answer, but I haven’t seen that answer yet.”
This article was originally published on NBCNews.com
