Marine heatwaves can wreak all sorts of havoc in Alaska: last year, a marine heatwave in the North Pacific ocean fueled Typhoon Halong, which devastated Alaskan communities. This summer there could be an extra hiccup: a strong El Niño event is likely according to the World Meteorological Organization, which could make the effects of a heatwave even worse.
El Niño events happen as a result of slower trade winds along the equator, which slows down the upwelling of cold water from deep in the ocean and causes overall warmer water conditions.
“We’re expecting a massive El Niño this year," said Alaska Fisheries Science Center Director Bob Foy during a commercial fisheries trade show in Kodiak on April 16. "And it’s going to be larger than usual, it’s going to make its way to Alaska, we’ll probably see the effects of it this summer.”
The El Niño event could hit as another marine heatwave is brewing. Marine heatwaves happen when the temperature of the ocean is 4-5 degrees Fahrenheit higher than the baseline average for that area. According to research from the University of Alaska, Fairbanks, temperatures in the Gulf of Alaska have been generally trending upwards over the past fifty years, with an average increase of around 0.2 degrees C per decade. But marine heatwaves across the Pacific have hit even higher temperatures, and have become more frequent since the mid 2010s.
“Recent ones have elevated temperatures up to eight degrees Fahrenheit over normal," said Rick Steiner, a former University of Alaska professor and current marine conservation biologist with his consulting business called Oasis Earth.
“There's a fear now in the physical oceanographic community that all of these ocean temperature elevation phenomena will eventually combine into a permanently warmer ocean system," he said, "so the shorter term impacts will become permanent.”
Steiner said that because the ocean is normally so stable in temperature, even one degree of difference can have big impacts, especially on the cold tolerant species that live in Alaska, like Pacific cod and snow crab.
According to NOAA data, there has been a marine heatwave impacting the west coast of the lower 48 since the end of last year. And there’s been one along the Aleutian Islands at the same time. Jennifer Questel, an oceanographer and zooplankton ecologist at the University of Alaska, Fairbanks College of Fisheries and Ocean Sciences, told KMXT that preliminary data from her department indicates temperatures in the Gulf of Alaska last winter were warmer than average, which means there will likely be another marine heatwave in the area this summer.
Combined, Steiner said the El Niño and marine heatwave could create very dangerous conditions in Alaska waters in the coming months.
“Unfortunately, every one of these ocean heat phenomena amplifies each other," he said. "No one can predict with any degree of certainty that all of that will happen this summer in Alaska, but it's a possibility. And I believe, looking at the trends and trajectories over the last few months, it's a probability.”
The Blob, which was a massive warming event that decimated sea life during the mid 2010s, also happened during a combined El Niño event and marine heatwave. Questel said it’s “quite possible” an event similar to the Blob happens this year.
Steiner said it’s important that Alaskans keep an eye out for unusual things that are typically caused by marine heatwaves–like dead seabirds or fish along the shore and emaciated marine mammals– and report any sightings to Fish and Game or NOAA.
