Oceans Are Heating Up and El Nino Will Make It Worse
Even if you hate the beach, live inland and arent bothered by dwindling fish, the latest spike in ocean temperature matters to you. The ocean is like a huge closet where weve been able to store 90% of the excess heat trapped by greenhouse gases. That closet is now stuffed. The latest readings from more than 4,000 buoys around the world show record-breaking sea-surface temperatures from January to March this year. And were on the cusp of an El Nino event a shift in wind patterns and ocean currents that opens the closet door and lets heat and energy spill into our atmosphere. Thats where the heat buried in the ocean comes back to haunt us. The changes in sea-surface temperatures dont sound like much right now theyre about 0.2 degrees C above normal. But it sounds like a lot when expressed as energy added to the system that includes our ocean and atmosphere 40 zettajoules, or sextillions of joules. Thats the equivalent of hundreds of millions of atomic bombs. Its energy that gets trapped in the system by an increasing concentration of greenhouse gases. That energy can manifest as heat waves or storms, said Kenneth Trenberth, a climatologist I met a few years ago at a meeting in Princeton on the El Nino phenomenon. He was then at the National Center for Atmospheric Research in Colorado, and is now an honorary academic at the University of Auckland. While the latest news has focused on new surface measurements, he said, the warming goes deeper. Last year he co-authored a paper showing the ocean is warming down to 2,000 meters. The heat doesnt stay there, thanks to the alternating patterns of wind and currents known as El Nino and its opposite counterpart, La Nina. La Nina has prevailed during the last three years. During this phase, Trenberth said, trade winds push warm equatorial water westward across the Pacific where it piles up by Indonesia. Every two to seven years, that switches to the El Nino pattern. The easterly winds die down enough that the warmer water can slop back toward the Americas. El Nino events can be gentle or fierce, depending on whether strong westerly winds start helping that warm water slosh back across the Pacific, said Kim Cobb, an oceanographer and climatologist at Brown University. But big ones happen roughly every 10 to 15 years. Real whoppers, she said, have occurred in 1972-73, 1982-83, 1997-98 and 2015-16. While El Nino is born in the Eastern Pacific, the change in patterns redistributes heat around the planet disturbing the entire global atmospheric circulation, she said. The cycle of El Nino and La Nina has probably been going on for millions of years, since our continents and oceans reached in their current configuration. Now, however, with rapid overall warming, the cycle might become stronger, and is already creating more extreme conditions. When we think about what sets the thermostat of our planet, it really is our oceans, she explained. Trenberth said that even during the La Nina phase weve seen hot spots in the Pacific that have led to trouble: This was the region that was feeding the atmospheric rivers that flowed into California and produced all the prodigious rains and even snows in the southwestern parts of the United States. Even though theres more capacity for heat deep in the ocean, the water heats up at the surface first, and since cold water is heavier, that can create regions of unhealthy stillness, where normal circulation stops and blobs of stagnant oxygen-depleted ocean grow. Thats why scientists have been observing alarming dead zones in the Gulf of Mexico, which are made worse by nitrate runoff from farms. It affects the phytoplankton, the zooplankton, the fish, the marine mammals and seabirds, Trenberth said. Warming oceans also lead to marine heat waves, which can destroy kelp forests and grasses that provided a home for fish and marine mammals. Trenberth uses the phrase global heating to describe whats going on. Global warming implies increasing atmospheric temperatures, while global heating suggests extra energy sloshing around the whole system that is our atmosphere and oceans. He recently found some old VHS tapes of his interviews in the 1990s, and sent a 1997 interview from the MacNeil/Lehrer News Hour, where he talks about the danger of global heating. Watching it 26 years later, not much has changed in the basic underpinnings of the science. But the climate certainly has. More From Bloomberg Opinion: We Cant Afford Tariffs on Chinese Solar Panels: Mark Gongloff Take Care Before Enlisting the Oceans in the Climate Fight: Lara Williams The Pacific Garbage Patch Is Now Hosting a New Threat: Faye Flam This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners. F.D. Flam is a Bloomberg Opinion columnist covering science. She is host of the Follow the Science podcast. More stories like this are available on bloomberg.com/opinion 2023 Bloomberg L.P.