They could arrive as often as once a year by 2100 if countries continue pumping carbon dioxide and methane into the air at high levels. In western Australia, heat waves as intense as the one in 2011 occur roughly once every 80 years. To this day, the kelp forests, which provide crucial habitat for marine creatures like lobsters, haven’t recovered, said Alex Sen Gupta, an ocean and climate scientist at the University of New South Wales.Īs the sea grows warmer, marine heat waves are more likely to tip temperatures past the threshold at which coral, kelp, and other marine life can survive. The extreme conditions stuck around for about three months, killing shellfish and forcing scallop and crab fisheries to close. It brought so much warmth from the tropics that ocean temperatures in the region rose almost 11 degrees Fahrenheit above normal. One appeared off the west coast of Australia in 2011 when a streak of warm water, some 100 miles wide and 3,000 miles long, surged south. Shifts beneath the surface can trigger heat waves, too. When the wind weakens, the sea temperature tends to rise because warm surface water doesn’t evaporate as easily, and colder water doesn’t get churned up from the deep. Marine heat waves can form in a number of ways, but in general they’re caused by changes in how the air and ocean currents move. “Fish species in particular are great canaries in our collective coal mine.” “That’s the highest water temperature I’ve ever heard of in the ocean,” said Steve Murawski, a fisheries biologist at the University of South Florida who has studied oceans for 50 years. ![]() Scientists predict more fisheries will collapse in coming years as climate change - and the ongoing El Niño weather pattern warming the Pacific - spurs more marine heat waves As a result, six of the last seven Dungeness crab seasons in California have been delayed. The northeastern Pacific Ocean has experienced several hot spells over the past decade - including the Blob 2.0 - and it’s still experiencing one. The economic toll from a single occurrence on fisheries and coastal economies can be as hefty as $3.1 billion. Fish farms in Chile, scallop operations in Australia, and snow crab pots in Alaska have already fallen victim to oceanic overheating. The Blob was the largest and longest-lasting marine heat wave on record. It might also have been an early glimpse of what’s to come. “It occurred in this place where we have some of the best-managed fisheries in the world, and it still created all these impacts,” Free said. To support our nonprofit environmental journalism, please consider disabling your ad-blocker to allow ads on Grist. The acute warming also triggered a toxic algal bloom that disrupted the West Coast’s lucrative Dungeness crab business. In British Columbia and the Pacific Northwest, salmon runs – and the fishing industry that depends on them – floundered. Some 100 million Pacific cod, commonly used in fish and chips, vanished in the Gulf of Alaska during the Blob. It’s not just gulls and sea snails that suffer. Yet marine heat waves can “inject a lot of chaos,” said Chris Free, a fisheries scientist at the University of California, Santa Barbara. ![]() Just a deep-red splotch on a scientist’s map telling everyone it’s hot out there, and perhaps a photo of birds washed up on a faraway beach to prove it. There’s no melting asphalt, no straining electrical grids, no sweating through shirts. What happens on the 70 percent of the planet covered by saltwater is mostly out of sight. A heat wave in the ocean is not like one on land. Over the course of two years, 1 million seabirds died, kelp forests withered, and sea lion pups got stranded.īut you could have easily missed it. The sprawling patch of unusually tepid water in the Gulf of Alaska grew, and grew some more, until it covered an area about the size of the continental United States. Scientists first spotted the Blob in late 2013. This story is part of Record High, a Grist series examining extreme heat and its impact on how - and where - we live.
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