The expanse of unusually warm water stretches from Alaska to California, scientists with the National Oceanic and Atmospheric Administration (NOAA) said Thursday. It is the second-largest marine heatwave in terms of area in the northern Pacific Ocean in the last 40 years, after “the Blob.”
What’s causing this year’s marine heatwave? NOAA scientist Nathan Mantua says it is unclear: “It might simply reflect the normal chaotic motion of the atmosphere, or it might be related to the warming of the oceans and other effects of human-made climate change.”
“It’s on a trajectory to be as strong as the prior event,” said Andrew Leising, a research scientist at NOAA Fisheries‘ Southwest Fisheries Science Center in La Jolla, California. He developed a system for tracking and measuring heatwaves in the Pacific Ocean using satellite data. “Already, on its own, it is one of the most significant events that we’ve seen.”
In the 2014 marine heatwave, the system, which stretched from Mexico to the Bering Sea, was blamed for warmer weather on land, miserable feeding conditions for salmon and the sudden deaths of two dozen whales in the Pacific. The “Blob” also caused a toxic algae bloom that disrupted crabbing and the shellfish industry in some areas.
With the earlier marine heatwave, water temperatures peaked at 3.9 C (39.0 F) above average. The NOAA said the water this year has already reached temperatures of more than 2.7 C (36.1 F) above average off the coast of Washington state.
This year’s new marine heatwave is officially being called the Northeast Pacific Marine Heatwave of 2019 and it has started out in a similar way as the blob. It will also take some months to analyze and pinpoint any reasons for this year’s formation.
Right now, researchers are blaming the recent marine heatwave on a persistent weather pattern that began in June: weaker-than-normal winds and a weaker high-pressure system over the wedge of warm ocean between B.C., Hawaii and Washington state, reports CBC Canada.
Normally, in the summer, strong winds churn the ocean, pushing the warm surface waters around and allowing cool, nutrient-rich water from below to rise and take its place. This is not happening this year. Not only has the ocean water become too warm, but without nutrient-rich waters coming to the surface, the heatwave has disrupted the ocean food chain.
This also has an impact on people whose lives depend on the health of the ocean. For example, fisheries managers expected 4.8 million salmon to spawn up British Columbia’s Fraser River, but only 628,000 fish showed up. As a result, commercial fishing operations have shut down, and Fisheries and Oceans Canada has even restricted fishing rights for First Nations.
Depending on how long this new marine heatwave lasts, the consequences could even be worse than what happened last time. In 2015, malnourished sea lion pups washed up on shore in California due to the lack of food, and sea stars wasted away in Washington. In California, the crabbing economy took a $110 million hit.
“We learned with ‘the Blob’ and similar events worldwide that what used to be unexpected is becoming more common,” Cisco Werner, NOAA Fisheries Director of Scientific Programs and Chief Science Advisor, said in a statement.
