{"id":42622,"date":"2026-06-12T07:15:00","date_gmt":"2026-06-12T14:15:00","guid":{"rendered":"https:\/\/www.lifeandnews.com\/articles\/?p=42622"},"modified":"2026-06-14T23:23:48","modified_gmt":"2026-06-15T06:23:48","slug":"el-nino-is-back-and-ocean-temperatures-are-already-near-record-highs-that-can-spell-disaster-for-fish-and-corals","status":"publish","type":"post","link":"https:\/\/www.lifeandnews.com\/articles\/el-nino-is-back-and-ocean-temperatures-are-already-near-record-highs-that-can-spell-disaster-for-fish-and-corals\/","title":{"rendered":"El Ni\u00f1o is back, and ocean temperatures are already near record highs \u2013 that can spell disaster for fish and corals"},"content":{"rendered":"\n

Dillon Amaya<\/a>, National Oceanic and Atmospheric Administration<\/a><\/em><\/p>\n\n\n\n

It\u2019s official: El Ni\u00f1o is back<\/a>. By late fall 2026, forecast models give a 2-in-3 chance of a strong-to-very strong El Ni\u00f1o affecting the weather, climate and ocean temperatures across the planet.<\/p>\n\n\n\n

El Ni\u00f1o is the climate system\u2019s biggest player and one side of the El Ni\u00f1o-Southern Oscillation, or ENSO<\/a>. It\u2019s the heads to La Ni\u00f1a\u2019s tails.<\/p>\n\n\n\n

During El Ni\u00f1o, a swath of ocean stretching 6,000 miles (about 10,000 kilometers) westward off the coast of Ecuador warms for months on end, typically by 2 to 4 degrees Fahrenheit (about 1 to 2 degrees Celsius). A few degrees may not seem like much, but in that part of the world, it\u2019s more than enough to completely reorganize wind, rainfall and temperature patterns all over the planet.<\/p>\n\n\n\n

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Marine heat waves can trigger coral bleaching. Alexis Rosenfeld\/Getty Images<\/a><\/figcaption><\/figure>\n\n\n\n

I\u2019m a climate scientist<\/a> who studies the oceans. With an El Ni\u00f1o expected to strengthen through the summer and fall<\/a>, water temperatures will heat up even more. It\u2019s time to start preparing.<\/p>\n\n\n\n

How does El Ni\u00f1o affect the planet?<\/h2>\n\n\n\n

No two El Ni\u00f1o events are exactly alike, though we\u2019ve seen enough of them that forecasters have a pretty good idea of what\u2019s likely to happen<\/a>.<\/p>\n\n\n\n

People tend to focus on El Ni\u00f1o\u2019s impact on land, justifiably. The warm water affects air currents that leave areas wetter or drier than usual. It can ramp up storms in some areas, like the southern U.S., while tending to tamp down Atlantic hurricane activity<\/a>. https:\/\/www.youtube.com\/embed\/wVlfyhs64IY?wmode=transparent&start=0 How El Ni\u00f1o forms. NOAA.<\/p>\n\n\n\n

El Ni\u00f1o can also wreak havoc on the many marine ecosystems that support the world\u2019s fishing industries, including coral reefs<\/a> and seagrass meadows<\/a>.<\/p>\n\n\n\n

Specifically, El Ni\u00f1o tends to trigger intense and widespread periods of extreme ocean warming known as marine heat waves.<\/p>\n\n\n\n

Global ocean temperatures are already near record highs<\/a>, so El Ni\u00f1o-induced marine heat waves could push many sensitive fisheries to a breaking point.<\/p>\n\n\n\n

What is a marine heat wave?<\/h2>\n\n\n\n

A marine heat wave is just that: a \u201cwave\u201d of extreme heat in the ocean, not dissimilar to an atmospheric heat wave on land.<\/p>\n\n\n\n

At their smallest, marine heat waves can inundate local bays and coves<\/a> with hotter-than-normal water for a few days or weeks. At their largest, marine heat waves like the Northeast Pacific Warm Blob<\/a> of 2013-2014 can grow to gargantuan proportions, with regions three times the size of Texas<\/a> experiencing ocean temperatures 4 to 6 F (about 2 to 3 C) above average for months or even years.<\/p>\n\n\n\n

Warm water might not seem like a big deal, especially to surfers hoping to leave their wetsuits at home. But for many marine organisms that are highly adapted to specific water temperatures, marine heat waves can make living in the ocean feel like running a marathon<\/a>.<\/p>\n\n\n\n

For example, some fish increase their metabolism in warm waters by so much that they burn energy faster than they can eat, and they can die. Pacific cod declined by 70% in the Gulf of Alaska in response to a marine heat wave. Other impacts<\/a> include bleached corals, widespread harmful algal blooms, decimated seaweeds and increased marine mammal strandings. All told, billions of U.S. dollars are lost<\/a> to marine heat waves each year.<\/p>\n\n\n\n

Marine heat waves flare up for a variety of reasons<\/a>. Sometimes, ocean currents shift warm water around. Sometimes, surface winds are weaker than normal, leading to less evaporation over the ocean and warmer waters. Sometimes, cloudy places just aren\u2019t as cloudy for a few months, which lets more sunlight in and heats up the ocean. Sometimes, both weaker winds and fewer clouds happen at the same time, producing record-breaking marine heat waves<\/a>.<\/p>\n\n\n\n

How does El Ni\u00f1o fit in?<\/h2>\n\n\n\n

In the climate system, El Ni\u00f1o is king. When it dons its fiery crown, the entire planet takes notice, and the oceans are no exception. But the likelihood of increased marine heat wave activity during El Ni\u00f1o depends on where you are.<\/p>\n\n\n\n

Along the U.S. West Coast during El Ni\u00f1o, surface winds that normally blow from the north tend to subside. This weakens evaporation and slows upwelling<\/a> of colder, deeper water. That increases the chances of coastal marine heat waves. California waters are already extremely warm<\/a>. El Ni\u00f1o could make things even hotter for longer.<\/p>\n\n\n\n

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