This year, global sea surface temperatures hit an unusual record high.
Data from the European Center for Medium-Range Weather Forecasts shows that every year, sea surface temperatures follow a predictable pattern: they get cooler during the summer, rise in early fall, dip again in winter, and then peak in early spring.
But in 2023, the data shows that the pattern changed. After the early spring peak, sea surface temperatures didn’t dip much—they just kept rising. They are still following the same seasonal cycle of highs and lows. But for the past year, the entire cycle has broken records.
The data goes back to 1979. Every day for the past year, we’ve seen global average sea surface temperatures that are higher than anything on record. And this year’s temperatures have all been higher even than last year’s record highs.
KDLG’s Meg Duff sat down with Rick Thoman, a climate specialist with the University of Alaska Fairbanks, about those abnormal temperatures and how they might be impacting Bristol Bay.
KDLG: When you look at the global average, what's going on there? And what have ocean temperatures been like in Bristol Bay?
Rick Thoman: Well, that is a great question. Over the past year, of course, we've had El Nino in the tropical Pacific. But as you note, globally, the world's oceans are exceptionally warm.
Alaska has been something of an exception, particularly the Eastern Bering Sea and the North Central Pacific Gulf of Alaska have not been especially warm over the last year. And in fact, the Eastern Bering Sea, including Bristol Bay, this spring water temperatures are significantly cooler than normal.
Now we'll see how this relatively mild weather pattern that we're in affects those sea surface temperatures. They're likely to rise and so won't be as far below normal, but that'll be pretty shallow right at the surface. Once a storm comes along or two and helps mix up that water, they would probably go back to normal.
Alaska has not been entirely on its own. There are other parts of the world that have not been in that record warmth or near record warmth sea surface temperatures. But in the northern hemisphere, around Alaska is one of the notable regions where the water temperatures are near or even a little bit below the long term normal.
KDLG: Even though sea surface temperatures are lower here, is there any impact we could see from those higher global ocean temperatures on the weather?
Thoman: “That is a great question, and the answer is definitely we could see some impacts. The most obvious and direct way that we would see that: although ocean temperatures in Bristol Bay, Gulf of Alaska, Eastern Bering Sea are below normal, in the north central Pacific, so south of the Aleutians, ocean temperatures are way above normal, part of that global picture.
That area, of course, is close enough that once storms get going, whether it's a midsummer storm or as we move in later into the season, warmer ocean temperatures mean more evaporation from the ocean surface. That can feed into storms and—when all the other pieces come together—produce higher precipitation amounts than would have otherwise occurred. So the potential for big rain storms goes up when the global oceans are warming, just because we're getting more evaporation off of the ocean into the air.
KLDG: What can folks out on the water expect in terms of marine conditions this season?
Thoman: Well, certainly, many people remember last summer's fishing season in Bristol Bay as a pretty dismal season! Lots of clouds, lots of rain. There were certainly some stormy episodes, especially for the time of year, of course.
Little bit of a different pattern, at least, set up right now across the region. The outlook from NOAA’s Climate Prediction Center for July will be issued here tomorrow. Early indications are that we will see a continuation of the Climate Prediction Center’s outlooks for increased chances for above normal precipitation and below normal temperatures.
That would imply the potential for more storminess than average. But will it be more stormy than last year? That is an open question.
Last year was pretty remarkable in that regard for the Bristol Bay region, and much of South Central and Western Alaska overall. So hopefully we won't be at that level, but the current outlook would favor more storminess, more rain, more clouds than would be typical for the region for July.
KDLG: Thanks so much Rick.
Thoman: You bet!
Get in touch with the author at meg@kdlg.org
