As Arctic sea ice melts, human activity is making the ocean louder, impacting marine wildlife that rely on sound. (Unsplash/Hubert Neufeld)Climate change is having a profound impact on the Arctic. We know that the region is warming significantly faster than the global average, resulting in the melting of sea ice and disrupted habitats.But climate change is also affecting the Arctic in ways few people may consider. It is making the Arctic Ocean a noisier place. For the region’s wildlife, this increasingly noisy environment is having profound impacts on their lives.Anyone who lives in an urban environment knows how tiring it can be. Living next to busy roads is exhausting, with constant noise, day in, day out. The same is true in the Arctic Ocean, where melting sea ice is making way for increasing human activity. This is even more important in water, where animals use sounds to communicate, to navigate and to find prey, or avoid becoming prey.Recent research on fish sounds explains how sound can be used for marine conservation. We should avoid introducing loud sounds in the oceans because it changes the soundscapes the animals have evolved to live in, and because it affects them directly. And just like air pollution, sound pollution knows no borders.Ocean observatories can record these sounds and tell us how loud they are, how long they last and how they affect their surroundings. This is important because the world is changing rapidly, especially in the Arctic, and human impacts are increasing.Newly published research, conducted by colleagues and me, used 10 years of underwater observations from 2015 to 2024 to quantify the impacts of ships and other sources of loud sounds in Iqaluktuuttiaq (Cambridge Bay), Nvt., on the local environment and to examine the best ways to measure their effects on local soundscapes. We found some surprising facts, making us look (or rather, listen) to the Arctic in different ways.Sound is essential underwaterStudies show that ambient sound levels in the Arctic seas are currently very low, and that marine life will therefore be more sensitive to any increase. Ships are the second loudest source of underwater sounds after seismic prospecting and pile-driving. As the Arctic opens up to human activities, ships are bound to be a big part of it. But it is not only ships. We found that loud sounds include many other sources: snowmobiles, machinery, aircraft. These sounds vary with the season. In winter, when there is full ice cover and no ships, snowmobiles can affect sound below the ice.In summer, when there is little to no ice cover, many of the loud sounds come from smaller vessels that are not legally required to carry GPS transponders. They are not picked up by satellites, but they are sizeable contributors to sounds underwater. Other sounds come from machinery, and even from aircraft flying nearby. Like shipping, these sounds should also be part of monitoring and regulating underwater noise in the region.Because many smaller ships do not use satellite transponders, modelling sound impacts from satellite tracking is an insufficient way to gauge how much noise human activity is generating. That means assessments of underwater noise must be based on actual measurements in the field.Long-term measurementsDeploying instruments at sea, especially in the Arctic, is challenging and expensive, and therefore generally possible only for short periods. Ocean Networks Canada has been measuring sound in the oceans around Canada for 20 years. They have installed ocean observatories around the country, in particular in Iqaluktuuttiaq. In partnership with local communities, they aim to provide the scientific measurements necessary for evidence-based actions and initiatives.Their Ocean Data Portal is a dream come true for scientists: 64,000 sound measurements per second, for years on end, complemented in season with local ice profiling. We also used local weather data from Nav Canada, satellite charts of regional ice cover from the Canadian Ice Service and ship tracks from the Arctic Ship Traffic Database operated by the Arctic Council. As there is so much data, and because we wanted to contrast two very different seasons, we focused our studies on the months of May, when there is full ice cover and no shipping, and August, when there is little to no ice and more shipping activity. Arrival of a cruise ship in an Arctic harbour. Ships are major contributors to underwater noise in the region. (Philippe Blondel) We did this for 10 years in a row and analyzed the sounds loud enough (more than 10 decibels louder than the weekly background) for long enough (over one minute), identifying where they came from and what frequencies they extended into. There were many surprising sounds.For example, we could hear footsteps on the ice and snow, the unsuccessful revving up of an engine, followed by something that sounded like kicking, and walking back on snow and ice. These sounds were not loud enough to be an issue. More often, we could hear noise from machines, either on boats or on shore. This sometimes lasted for a long time. What surprised us was hearing aircraft every now and then. The sounds of the propellers, presumably passing close to our hydrophone. There were many other sounds, including those of marine wildlife, but we focused on sounds loud enough to possibly impact these animals because they were too loud or lasted long enough to be a nuisance.Our research shows that impactful sounds in this part of the Arctic vary between summer and winter. In summer, where the water is mostly open, this noise can extend to higher frequencies over one kilohertz. Conversely, in winter, when there is no shipping and ice cover isolates the waters below from a lot of sounds, these loud sounds show a span of frequencies lower than one kilohertz. These variations with ice cover and in the frequencies to monitor should be included in the future Arctic baselines.Improving data collectionRegulations often focus on frequency bands associated with large ships in deep waters (third-octave bands centred on 63 hertz and 125 hertz, to be precise). The European Marine Strategy Framework Directive is often cited as a model, used in Canada and elsewhere. Using the right frequencies is important when considering baselines.Canada and other Arctic countries are ideally placed to collect the evidence that can define an Arctic marine strategy framework directive. This becomes more urgent as the climate changes, the Arctic opens to human activities and pressures on Arctic resources grow. Together, we can make a more sustainable ocean. There is much to do, and I am looking forward to working more with Canadian scientists and Arctic communities.Philippe Blondel receives funding from UK Research and Innovation (UKRI), through the Engineering and Physical Sciences Research Council (EPSRC) and the UKRI Horizon Europe Guarantee. Access to the Arctic Ship Traffic Database used in the underlying study was funded by the Department for Science, Innovation and Technology, as part of the United Kingdom- Arctic Council Working Groups – Research and Engagement Scheme 2024/25, working with the Arctic Council Working Groups, Norwegian Ministry of Foreign Affairs and the NERC Arctic Office. Philippe is sometimes consulted by Ocean Networks Canada on technical matters related to passive acoustic monitoring.