Picture the Arctic and you probably think of a vast, empty frozen wonderland. You probably don’t think about the noise.
But according to a new study published in the journal npj Acoustics, the underwater soundscape is already much louder and more varied than we thought, raising questions about how we monitor and protect its unique environment.
Drawing on a decade’s worth of underwater sound data from Cambridge Bay in the Canadian Arctic, the researchers found that as climate change drives faster ice loss, the region’s underwater soundscape is being reshaped – with potentially severe consequences for wildlife.
“Climate change is amplified more than three times in the Arctic, which means the ice is melting faster, melting sooner and reforming later,” Dr Philippe Blondel, lead author of the study and senior lecturer in the Department of Physics at the University of Bath in the UK, told BBC Science Focus.
“That makes the Arctic more open to human activities – it's easier for ships to travel when there is no ice. The key finding from our article is that ships make noise, but they are not the only ones making noise.”
As well as large ships, whose noise pollution has been the main focus of legislation and monitoring in the past, the researchers found other significant sources included snowmobiles, aircraft and smaller vessels.
Many of these smaller noise sources are invisible to satellite tracking systems, meaning their impacts are routinely missed by models that rely on ship location data alone.
Key Arctic species such as whales and seals rely on sound for everything from communication and navigation to finding food and avoiding danger. As underwater noise in the region increases – both in volume and variety – these vital survival tools are placed under growing strain.
Blondel described it as like standing next to a motorway. “Sometimes you’re just going to have background noise, but then a motorbike might pass by, and that high-frequency noise interferes with your listening to music.
“Then, when a big truck comes past, rumbling at low frequencies, no one can hear what you say.”
In much the same way, one sound source may interfere with a whale trying to communicate with its calf, for example, while another source at a different frequency could scare it away from key feeding grounds.
But the team is not calling for total silence in the Arctic. Instead, Blondel wants environmental policies to cover a broader range of frequencies than the narrow ‘shipping bands’ usually measured in protective frameworks such as the European Marine Strategy Framework Directive.
He also suggested that strict shipping lanes through the ever-more open Arctic, with variable speed limits based on where wildlife is, could be a good way to help reduce harmful noise pollution.
Ultimately, though, enforcement of any such rules will be challenging, as they must target small and large vehicles – and because many different countries border the region.
“My first goal was to show that we must think about all the other frequencies when assessing soundscapes in the ocean – not just the big ships,” Blondel said. “But my main goal is to say we need some kind of framework in the Arctic. We need to find the best way to create these sound guidelines before it gets any worse.”
Read more:
- The Arctic could be free of sea ice by 2035, latest climate model predicts
- Why do we still get major snowstorms in a warming world?
- 10 of the most mysterious places in the oceans
