Arctic Underwater Noise Requires Smarter Limits

For years, the Arctic dampened a great deal of human noise. Dense sea ice stopped waves, restricted vessel traffic and kept numerous industrial developments at a distance. That former tranquillity is disappearing rapidly.

As the ice recedes, human activity is increasing, bringing more vessels, aircraft and snowmobiles. This movement creates an often overlooked consequence: underwater noise that travels across the ocean and remains after an engine has gone.

Sound and Arctic life

Beneath the surface, sound is as important as vision is on land. Numerous Arctic species depend on it for navigation, communication, finding prey and avoiding danger.

Human-generated noise in the water makes these signals more difficult to detect. Whales and seals can abandon areas they would usually use for feeding or migration, or alter their behaviour in ways that demand extra time and energy.

The consequences are felt by people as well. Hunting and fishing continue to supply food in many northern communities. When noise drives animals from established areas, journeys may take longer and become less predictable.

It can also interrupt seasonal patterns that hunters understand closely, creating further pressure in regions where harsh weather already imposes serious constraints.

The real sources of Arctic noise

Large ships are an obvious source, and they certainly contribute. Yet today’s Arctic soundscape also contains smaller noise sources that satellite tracking does not always capture.

Snowmobiles travelling across coastal ice, aircraft flying overhead and small boats operating near communities all contribute to the underwater sound environment.

This distinction is important, as different machines create different types of noise. Certain sources generate higher-frequency sounds than those typically covered by the frequency bands on which regulators concentrate.

Monitoring that covers only a limited band can therefore overlook a substantial share of the noise experienced by animals and people.

A decade of Arctic listening

Researchers from the University of Bath tackled this issue through ten years of measurements gathered in Arctic Canada.

Their latest study presents a workable method for tracking underwater noise in an environment where ice, weather and shifting human activity can transform conditions between seasons.

Among the study’s most distinct results is that ice cover has a major effect on sound levels. Regulations devised for open waters farther south may consequently be unsuitable for polar seas.

The Arctic differs not only in its wildlife and shipping activity, but also in its physical processes. Ice may obstruct, scatter or alter sound, meaning a single universal standard is unlikely to fit.

Revising Arctic noise limits

The research identifies a clear policy challenge. Certain environmental systems, including the European Marine Strategy Framework Directive, use low-frequency “shipping bands” to assess underwater noise pollution.

The Bath researchers say these bands no longer reflect present-day Arctic conditions, which involve a broader range of vessels, activities and frequencies.

In response to this disparity, the team calls on international organisations and authorities responsible for establishing, revising and enforcing underwater-noise regulations to reconsider the thresholds applied in Arctic waters.

The aim is not to create entirely new targets without basis. Instead, it is to record what is genuinely occurring across a broader frequency range and make decisions according to Arctic conditions, rather than assumptions drawn from lower latitudes.

Opening waters, increasing noise

The Arctic is moving into a new phase, with climate change advancing there at about three times the global average.

As melting ice opens waters that were once inaccessible, shipping corridors are widening, air traffic is rising and more small vessels are entering the area for tourism and resource exploration.

Industrial activity close to shore is also likely to increase, including mining and drilling, together with growing geostrategic pressures.

“These changes are increasing the intensity and variety of underwater sounds, which can travel hundreds of kilometres through cold northern waters,” said Dr. Philippe Blondel, the study’s lead author.

“All these sources contribute noise that affects local ecosystems, wildlife, and the subsistence activities of Indigenous communities.”

Smarter limits rather than silence

Dr. Blondel made clear that his team was neither seeking nor considering complete silence in Arctic waters necessary. “Some sounds, like the small fishing vessels used by locals, can have negligible impacts,” he said.

“Other [human-made] sounds are small compared to the loud background noise of ice melting or fracturing, or they do not affect the hearing of local animal species, meaning they too are acceptable.”

Since the effects of sound differ, Dr. Blondel said monitoring needs to encompass a broad spectrum of frequencies while taking account of how impacts vary by season and ice cover.

The significance of a sound depends on more than its volume: its timing and its overlap with Arctic conditions are equally important.

Listening to the Arctic

The decade-long research demonstrates that underwater sound offers a sensitive, dependable means of identifying human activities that do not leave evidence in satellite records.

This acoustic record supplies direct evidence that can enable regulators to tailor noise rules to actual Arctic conditions, which change with the seasons and the extent of ice cover.

The work also drew on years of measurements gathered by Ocean Networks Canada at its community observatory in Cambridge Bay (Ekaluktutiak), Nunavut.

With interest in the Arctic continuing to increase, the researchers said effective management will require the monitoring of frequently neglected sound frequencies and recognition of seasonal ice dynamics.

The study underlined that regulators need evidence collected within the Arctic rather than models designed for lower latitudes.

In a region undergoing such rapid change, the straightforward principle is also the demanding one: continue listening, listen across a wider range, and allow the Arctic’s own data to define the standard.

The complete study appeared in the journal npj Acoustics.