It’s a whale of a problem: Can we lower Arctic noise pollution?

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Rambo Talabong: Hey there. Welcome back to the Scienceline podcast. I’m Rambo Talabong, your host and the Multimedia Editor here at Scienceline.org. Make sure to subscribe to our show — whether that’s on Apple Podcasts, Spotify, Stitcher or another platform that you prefer using.

Talabong: Welcome to the podcast. Today, we’re taking a journey to the Arctic, a place of breathtaking beauty and fragile ecosystems. But beneath the icy waters lies an invisible threat to marine life — noise pollution. Let’s dive into how ship noise is transforming this once-silent sanctuary and what scientists and conservationists are doing to protect it.

Taking us there is Scienceline’s own Kate Callaway. Stay tuned.

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K.R. Callaway: Have you ever wanted to take a trip to the Arctic? Every year, tourists flock to the area to take in the pristine landscape and see the polar bears, seals, whales and other animals that call it home.

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Callaway: But there is something polluting this serene environment and putting marine mammals at risk — something we can’t see.

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Callaway: This pollutant comes from ships that pass through Arctic waters each year on their way to busy ports around the world. It also comes from mining operations and even by wind turbines: And it’s noise.

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Callaway: And it might actually be getting worse. I talked about this with a conservation scientist named William Halliday. He works at Wildlife Conservation Society Canada.

William Halliday: This issue of ship noise is particularly relevant for the Arctic, because sea ice is disappearing at a fairly rapid rate, and that’s making it so that a lot more ships can go to the Arctic now than they could in the past.

Callaway: For tourists who want to take in the Arctic’s pristine landscape, more ships might not sound so bad. 

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Callaway: Expedition cruise ships can be a great way for tourists to learn about Arctic wildlife and conservation. But Halliday says even these small ships contribute to the noise problem.

Halliday: Within the western Canadian Arctic where I work, cruise ships make up about a third of the traffic and so and it’s there’s been a noticeable increase through time. So it’s definitely a concern. Like one of the communities where I do most of my work, Ulukhaktok, which is on the western side of Victoria Island. They had eight ships total come this year, and six of them were cruise ships. So in terms of that very specific local area, the cruise ships are actually the majority of the traffic. When you look within the whole region, they’re not, but they’re definitely going to areas where ships are otherwise not mostly going to.

Callaway: These expedition cruise ships go where no other ships go, which Halliday says is a problem. They bring noise to places that were once much quieter — and where animals are not used to human-generated sounds.

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Callaway: A new study looks at the causes, effects and possible solutions for dealing with noise pollution from Arctic cruise expeditions. The lead author is Fabienne Mannherz, a PhD fellow in the Department for Eco Science at the University of Aarhus. She shared how she first got interested in this topic.

Fabienne Mannherz: Actually, there was a single lecture which we had on underwater noise pollution during my master’s, and then the next day we had another lecture, completely different, on shipping in the Arctic. And suddenly, my brain interlinked those together and like, ‘Okay, if the Arctic is that quiet and shipping puts noise into the ocean. Like, what does that mean for Arctic animals that never have experienced that much shipping noise?’ And that’s kind of how the whole story started.

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Callaway: But, like Halliday, Mannherz said the Arctic is seeing more ships — which almost certainly means more noise. A 2021 Arctic Council report found that ship noise in the Arctic doubled between 2013 and 2019.

Callaway: Mannherz says it’s unclear just how much underwater noise has been increasing in the Arctic. But, she has studied the noise ships — including expedition cruise ships — make there.

Mannherz: The propellers make a lot of sound related to bringing the ship forward. And then there’s something called cavitation. Cavitation is when the propeller spins at a very certain speed, and then it creates tiny, tiny air bubbles due to its high speed. And those air bubbles, they start collapsing, and that creates quite noisy conditions.

Callaway: The amount of noise cavitation makes depends on how fast the ship is going. It can be as loud as a jet taking off.

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Callaway: The noise from cavitation joins noise from engines, generators and even water moving around the ship. 

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Callaway: Halliday compares this noise to living near a busy highway.

Halliday: Think about every time a car passes right like so you get that zoom that goes by. Well, so ship noise is a little bit of a lower pitch than that, a lower frequency, so it’s a bit of a rumble, and it’s so, so much slower, and it can be picked up from so much farther away underwater.

Callaway: All this noise spells trouble for marine mammals. They rely on hearing more than any other sense. For example, Whales’ hearing has evolved to the underwater environment, where sound travels five times faster than it does in the air. Toothed whales hear frequencies up to 180 kHz — much higher frequency sounds than the 20 kHz humans can hear.

Mannherz: So when we think about us, humans or terrestrial animals, they usually rely on things like smell or vision, but all of this is not available underneath the surface. 

Callaway: Mannherz told me about one big problem caused by increased ocean noise. It’s called sound masking.

Mannherz: Sound masking happens if one sound overlaps with another sound, like you can imagine, if you’re sitting in a street cafe and talking to your friend, and then suddenly, a very noisy truck comes by. Then, although your friend might still be talking to you, you might not be able to understand him or her anymore, right? And that can happen for marine mammals when they communicate in a frequency that overlaps with the ones that ships emit.

Callaway: Halliday emphasized that sound masking can be really dangerous for animals underwater.

Halliday: They can’t hear sounds from a predator that’s coming nearby, or sounds from the prey that they’re trying to capture. Or in the case of our toothed whales, the odontocetes that use echolocation clicks, they maybe can no longer effectively hear their own echolocation to find. The food that they’re trying to find. […] There’s also been some studies showing that it impacts the ability of mothers and calves to stay in contact, which could actually lead to decreased health of the calves. […] But then, on top of that, there’s behavioral effects.

Callaway: Halliday says that some Arctic species are extremely sensitive to sound — like Narwhals and Beluga whales. Even if a ship is 50 kilometers away, Narwhals stop what they are doing and freeze — and Belugas might leave the area completely.

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Callaway: These are just some of the scary consequences of noise pollution for marine mammals. But scientists like Halliday and Mannherz say there are things we can do to help — like avoiding the habitats of animals who are sensitive to noise pollution.

Halliday: We know that if you keep a ship out of a sensitive area, that’s a great way to keep the noise out of the sensitive area. Or if you get ships to slow down when they’re going through that sensitive area, then the ships are a little bit quieter, and so that also reduces the noise levels.

Callaway: Or, Mannherz says you can focus on stopping noise at its source.

Mannherz: Refurbishing some elements of a ship, of course, you can measure how loud the propeller, for example, was before it was changed and after it was changed. So we know at least there’s a reduction in the noise levels.

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Callaway: Many Arctic cruise operators are concerned about this too. Melissa Nacke is here to talk about the sustainability guidelines being developed to minimize the footprint of expedition cruises. She is the head of operations at the Association of Arctic Expedition Cruise Operators, or AECO.

Melissa Nacke: That’s actually our mission at AECO, is to ensure sustainable cruise tourism in the Arctic. So that is key and vital to what we do. In AECO, the way we work is that we develop guidelines and standards that typically go above regulatory requirements in many different areas. So this would include things like our mitigation measures around wildlife, around plants, around cultural sites […] all over all over the map.

Callaway: Some of these guidelines match those mentioned by Mannherz and Halliday — like slowing down in sensitive areas for wildlife and making ships quieter. Nacke says one barrier to reducing noise even more is that we don’t yet know which initiatives might help.

Nacke: Underwater noise is a very important area for us. We understand that this is an impact. […] We’ve been working to measure all of the underwater noise that’s produced from our ships, […] and the idea is that we need to get a better understanding of the impact and the noise in order for us to start developing mitigation measures, or continuing to develop our mitigation measures.  

Callaway: Halliday told me he wants to see more governments talking about regulating ship noise. Governments have the ‘final say’ for noise pollution mitigation efforts in their waters, but Halliday says those efforts aren’t a top priority yet.

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Callaway: I asked Nacke what she would say to people who are interested in Arctic expedition cruises but are concerned about noise pollution and conservation.

Nacke: They should be looking into their operator asking, before they book, questions that are important to them, and getting the information. And then, if they decide to take the trip, they should also be asking those questions during their trip and trying to get the information while they’re in those regions about these impacts and getting a better understanding. Ideally, what we want is a tourist that’s going home better educated and understanding the Arctic and the impacts and where we are right now with many issues.

Callaway: Thank you for listening. My name is Kate Callaway. I would like to take a moment to thank my guests, William Halliday, Fabienne Mannherz and Melissa Nacke for their contributions. I would also like to thank Blue Dot Sessions, BBC Sound library and William Halliday for use of music, ambient sounds and other sound effects used in this project.

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Rambo Talabong: Thank you for joining us on this important exploration of Arctic noise pollution. I hope this episode inspires you to think about the unseen impacts of human activity on our planet’s most pristine environments. Until next time, stay curious and keep listening to the world around you.

Talabong: The Scienceline podcast is available on every major platform, so be sure to subscribe wherever you listen. Oh, and if you’d like, maybe give us a rating or review. It helps other people to find our show. Scienceline is a production of NYU’s Science, Health and Environmental Reporting Program. Our theme music is by Jahzzar at the Free Music Archive. And for more information, please visit us at Scienceline.org or shoot us an email at scienceline@gmail.com. See you next time.