Earth in hot water? The sudden warming of the sea has raised concerns

Some researchers believe the jump in sea surface temperatures stemmed from a brewing and possibly strong natural El Niño warming weather condition as well as a rebound from a three-year cooling La Niña, all on top of steady global warming. which is heating the water deep below. If so, he said, this month’s record-breaking ocean temperatures could be the first of many heat records to be broken.

From early March to this week, global average sea surface temperatures rose by about two-tenths of a degree Celsius (0.36 degrees Fahrenheit), according to the University of Maine’s Climate Realigner, which climate scientists use and rely on. We do. That may sound small, but for the average of the world’s oceans – which covers 71% of Earth’s area – to increase that much in such a short period of time, “that’s huge,” said Chris Karnauskas, a climate scientist at the University of Colorado . “It’s an incredible departure from what was already a hot situation.”

Climate scientists have been talking about warming on social media and among themselves. Some, such as Michael Mann of the University of Pennsylvania, quickly dismiss concerns by saying that this is simply El Niño growing on top of human-caused warming increases.

It has warmed especially off the coast of Peru and Ecuador, where most El Niños began before the 1980s. El Niño is a natural warming of parts of the equatorial Pacific that changes weather around the world and increases global temperatures. Until last month, the world has been on the other side, a cooling called La Niña, which is unusually strong and prolonged, lasting three years and causing extreme weather.

Other climate scientists, including National Oceanic and Atmospheric Administration oceanographer Gregory C. Johnson, say it just doesn’t seem to be El Niño. There are many marine heat waves or places of ocean warming that don’t fit El Niño patterns, such as those in the North Pacific near Alaska and off the coast of Spain, he said.

“It’s an unusual pattern. It’s an extreme event on a global scale” that just doesn’t fit with El Niño,” said Princeton University climate scientist Gabe Vecchi. “It’s a big, big sign. to understand it.”

Karnauskas of the University of Colorado took global sea surface temperature anomalies over the past several weeks and subtracted the mean temperature anomalies from earlier in the year to see where the sudden burst of warming is most pronounced. They found a long stretch across the equator from South America to Africa, including both the Pacific and Indian Oceans, was responsible for much of the increase in global temperatures.

Karnauskas said that region warmed by four-tenths of a degree Celsius in just 10 to 14 days, which is highly unusual.

Karnauskas said that part of that region is clearly El Niño, which scientists can confirm over the next few months and they can see it increasing in strength. But the field in the Indian Ocean is different and could be a coincidental independent increase or somehow linked to a larger El Niño, he said.

“We’re already starting on such an elevated background state, a baseline of really warm global ocean temperatures, including the tropical Pacific and Indian Ocean. And all of a sudden you add a developing El Niño and now we’re off the charts.” ,” Karnauskas said.

It’s been about seven years since the last El Niño, and this one was awful. Sarah Purke, an oceanographer at the Scripps Institution for Oceanography, said the world has warmed in that seven years, especially the deep ocean, which absorbs most of the heat energy from greenhouse gases. Ocean heat content, which measures the energy stored by the deep ocean, sets new record highs every year regardless of what’s happening at the surface.

Since the last El Niño, global warming ocean content has increased by .04 °C (.07 °F), which may not sound like a lot, but “it’s actually a tremendous amount of energy,” Purkey said. Said. It’s about 30 to 40 zetajoules of heat, he said, energy equivalent to the size of hundreds of millions of atomic bombs, that leveled Hiroshima.

On top of that warm deep ocean, the scientists said there was an unusual cooling of the world’s surface for three years from La Niña, which acted like a lid on a warming pot. That cover is closed.

“La Nina’s temporary hold on rising global temperatures has been released,” NOAA oceanographer Mike McFadden said in an email.

If El Niño makes its heavily predicted appearance later this year “what we’re seeing now is just a prelude to more records coming in the pipeline,” McFadden wrote.

Karnauskas said what is likely to happen after the heat has been hidden for a few years will be an “acceleration” of warming.