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New climate change study on Arctic warming outlines future uncertainties for Alaskan fisheries

Boats covered in snow sit in a partially frozen Kodiak harbor. (Photo by Kavitha George/KMXT)
Boats covered in snow sit in a partially frozen Kodiak harbor. (Photo by Kavitha George/KMXT)

A report published earlier this month in the journal Communications Earth & Environment outlines that the Arctic – including parts of Alaska – is warming four times faster than the rest of the world due to climate change. Researchers had previously believed the Arctic was warming twice as fast as other parts of the globe. Mike Litzow is the Director of the Kodiak Lab for NOAA Fisheries. He spoke to KMXT’s Kirsten Dobroth about how that could – and may already be having – an effect on coastal communities and Alaskan fisheries.

Editor’s note: This conversation has been edited for length and clarity. Mike Litzow is also on KMXT’s Board of Directors, which does not direct news coverage.

Kirsten Dobroth: I wanted to kind of back up and talk about what we already know or knew about climate change in the Arctic, and in waters off of Alaska and how that area is warming compared to other parts of the world.

Mike Litzow: What we already knew about the Arctic was that it was warming faster than the rest of the globe. So, that’s something that climate scientists call Arctic amplification. And in terms of Alaska, and Alaskan fisheries that really plays out for the Bering Sea. And in particular the northern Bering Sea, that area that’s seasonally ice covered is where you’re seeing the most rapid changes, the most rapid loss of sea ice, the most rapid warming in Alaska. And then also, it’s the place where you’ve seen some of the biggest fisheries challenges and fisheries changes to date.

KD: There was a time when extreme weather events, it was more hypothetical that maybe they were tied to climate change. And now we have ways of looking at human caused climate change and these extreme weather events and understanding that they are driving each other or connected.

ML: That’s right. So that’s a part of climate science called attribution science. And it used to be that we knew there was a trend in the climate that’s caused by humans. But we couldn’t tell if an individual, say, low sea ice year was related to human activities. And that’s changed. So now, as these really warm years come across our observational horizon, we can make pretty good determinations about how much of a human contribution there is. So, for the Bering Sea in particular, we can see that human fingerprint arising as early as the 1960s, and 1970s. And it’s gotten to the point where since the early 2000s, we’ve been in these temperatures that you can only explain with human activity in the Bering. The Bering has just gotten much, much warmer, much more quickly than the Gulf of Alaska, and that does seem to be part of that Arctic amplification.

KD: What are some of the changes that we’re seeing in fisheries in Alaska because of that?

ML: The really noteworthy immediate response in the Bering was watching the pollock and the cod go north really fast. So, the oceanographers always told us fisheries scientists that we should expect winter sea ice to be in the northern Bering Sea for the rest of our lifetimes. And then suddenly, that wasn’t true. We got a couple of years where there was no sea ice all the way up to the Bering Strait in March in the depths of winter. And then the next summer, when we went out and did our bottom trawl survey, we found pollock and cod way north – like up north of St. Lawrence Island, where they never had been before. And the Russians have had commercial fisheries for pollock in the Chukchi Sea in recent years, which is totally off the hook in terms of how the system used to behave. That’s a big initial consequence.

Then the other big fisheries impact that we’re seeing is snow crab; around the Arctic, snow crab exists in the Atlantic and in the Pacific Arctic, and they always exist in places that are seasonally ice covered. And as the southeast Bering Sea has lost its seasonal ice cover, we’ve seen these big, outsized declines in snow crab, and that’s having huge ongoing impacts on the fishery that are playing out right now. That’s that’s the other really big consequence that we’re tracking.

KD: So, when you’re looking at some of these changes in fisheries, and also at some of these extreme weather events, whether it’s marine heat waves or loss of sea ice, and then you look at this new research that came out, how does that affect your work? Does it factor into it at this point? Or how do you interpret that information?

ML: Yeah, that’s that’s a good question. So, I guess that comes to like the perspective that we have at NOAA Fisheries, we’re fishery scientists, and we’re not climate scientists. So, we try to use the lessons of climate science, obviously, to understand what’s happening with these fisheries. But that study was more about recognizing where we are – four times faster than the global average, that’s something. And then that question of whether it’s internal variability, and we should expect it to ease over time or whether it’s underappreciated consequences of global warming that the climate models don’t get. So, I guess, big picture as we go forward: we know the direction that human activities are taking the climate, but the details are important and the details are really hard to resolve until they play out. The future is a very hard thing to study. So, I guess that, to my mind, that’s the biggest lesson for fisheries scientists is just how much uncertainty remains for us. And really that uncertainty goes either way, you know, things could change more slowly than we think they’re going to, but they can also change more quickly than we think we’re going to. And really, I guess, if you just look at what’s happened since 1979, things have changed more quickly than we thought they should.

KD: And for all of us who are not scientists and live in coastal communities, or maybe make our livelihood off of fishing, whether that’s commercial or subsistence, what is the takeaway? Like, what can we take from this information and from this discussion?

ML: We naturally evaluate risk in a system based on what we know. If I’m a set netter in Kodiak, and I’ve been set netting for 20 years, I’ve had my good years, I have my bad years, and they formed this sort of envelope of expectations. And that’s true of anyone who’s operating in any fishery around Alaska. I think one of the big takeaways is that that lived experience, that historical experience of what we should expect is increasingly not relevant to what’s actually happening. And so that’s one of the biggest lessons is giving up on that past experience and trying to understand where we are and how different this current climate is from what we knew even a decade ago.