{"id":512613,"date":"2026-04-04T13:55:07","date_gmt":"2026-04-04T13:55:07","guid":{"rendered":"https:\/\/www.newsbeep.com\/uk\/512613\/"},"modified":"2026-04-04T13:55:07","modified_gmt":"2026-04-04T13:55:07","slug":"record-high-ocean-temperatures-off-southern-california-raise-fears-of-prolonged-marine-heatwave-us-news","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/uk\/512613\/","title":{"rendered":"Record high ocean temperatures off southern California raise fears of prolonged marine heatwave | US news"},"content":{"rendered":"

For more than a century, shoreline stations operated by the Scripps Institution of Oceanography<\/a> have measured water temperatures along the California<\/a> coast. This year, they are flashing a warning sign.<\/p>\n

Over the last three months, several stations have repeatedly posted record-breaking daily high temperatures \u2013 with the La Jolla station<\/a> registering temperatures a full 10F above historical average at one point last month.<\/p>\n

The waters of southern California historically warm every few years as tropical currents make their way north, a phenomenon known as El Ni\u00f1o. But the marine <\/a>heatwave that started last fall wasn\u2019t caused by tropical currents. Instead, a high-pressure atmospheric system \u2013 think of calm, sunny days \u2013 has perched above southern California, warming both air and sea above historic levels. The same phenomenon has helped fuel a ferocious California heatwave on land.<\/p>\n

The extended ocean warming has drawn comparisons to \u201cthe Blob\u201d, a three-year marine heatwave caused by similar prolonged high-pressure conditions a decade ago that devastated marine life<\/a>. The next few weeks are likely to determine whether this marine heatwave fizzles out or evolves into something more Blob-like, scientists say.<\/p>\n

\u201cThe biggest concern is how the year plays out,\u201d Andrew Leising, an oceanographer with the National Oceanic and Atmospheric Administration, said. \u201cWe could be looking at much larger impacts next fall and winter, if it stays warm and then it\u2019s followed by a strong El Ni\u00f1o.\u201d<\/p>\n

It\u2019s typical in the spring for shifting atmospheric conditions to generate north-westerly winds that push warm surface water back out to the open ocean, allowing cooler water from below to rise to the surface \u2013 a phenomenon called upwelling. Upwelling brings nutrient-rich water from the depths to the surface, feeding the phytoplankton that play a crucial role in supporting much of California\u2019s marine life.<\/p>\n

Over the last few days, high water temperatures have cooled somewhat, raising the prospect that the heatwave may be dissipating already. It will take more time, however, to know for sure that the heat is clearing.<\/p>\n

\u201cThe expectation right now is that likely the waters down to even southern California should start cooling a little bit into next month, but it\u2019s not a guaranteed thing,\u201d Leising said. \u201cThe concern is the sequence of events and how they unfold.\u201d<\/p>\n

Prolonged ocean heat has a devastating impact on phytoplankton and can cause harmful algal blooms. Those changes can wreak havoc on many forms of marine life, from sea lions and dolphins, to shore birds and halibut<\/a>. The Blob years led to one of the worst Dungeness crab seasons in recent history, said Melissa Carter, a researcher at the UC-San Diego Scripps Institution of Oceanography.<\/p>\n

Such heatwaves are becoming more common and lasting longer, partly because of the slow warming of the oceans driven by the climate crisis, and partly because of atmospheric changes that scientists are still struggling to understand.<\/p>\n

\u201cThe question is what\u2019s causing us to have these extreme warm temperatures?\u201d Carter said. \u201cWhat are the drivers? That\u2019s what we\u2019re trying to find out.\u201d<\/p>\n

What concerns Carter is that once these high-pressure systems establish themselves in an area, they create a \u201cfeedback loop\u201d that tends to reinforce warm, calm conditions, making upwelling less likely to occur, she said.<\/p>\n

\u201cIf these systems do become that strong and persistent, where they come every year, it can have the potential to shut down upwelling,\u201d Carter said. \u201cEverything we think of related to the health of the ecosystems of the west coast could be forever altered.\u201d<\/p>\n

The lingering ocean heat offers a few upsides, though they pale in comparison with the costs. The warmer water temperatures bring tuna far closer to shore, making it easier to fish for them. Surfers and swimmers have also enjoyed warmer water through the winter.<\/p>\n

\u201cI enjoy being in the water when it\u2019s a marine heatwave,\u201d Carter said. \u201cBut our ocean should not be a swimming pool. Nothing can live in a swimming pool. That\u2019s not what we want.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"For more than a century, shoreline stations operated by the Scripps Institution of Oceanography have measured water temperatures…\n","protected":false},"author":2,"featured_media":512614,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[22],"tags":[1397,90,56,54,55],"class_list":{"0":"post-512613","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-environment","8":"tag-environment","9":"tag-science","10":"tag-uk","11":"tag-united-kingdom","12":"tag-unitedkingdom"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts\/512613","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/comments?post=512613"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts\/512613\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/media\/512614"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/media?parent=512613"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/categories?post=512613"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/tags?post=512613"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}