Polar bears in the Beaufort and Chukchi Seas are spending dramatically more time on land than at any point in the modern tracking record, with up to 50% of some populations now summering onshore compared to a small fraction in the 1980s. The shift, driven by accelerating sea-ice loss that hit a record-low winter maximum in March 2025, is reshaping where and how the Arctic’s top predator hunts, breeds, and survives. The consequences extend well beyond wildlife biology. Longer onshore seasons mean more encounters with coastal communities, declining cub survival, and measurable weight loss in bears that cannot replace their seal-based diet on land.
For Indigenous communities and northern towns scattered along the Beaufort and Chukchi coasts, the new reality is already visible. Bears that once followed retreating ice north now linger near villages, scavenging carcasses, raiding cabins, and occasionally entering built-up areas. Wildlife managers report rising numbers of deterrence events and “problem bear” calls, underscoring how a climate-driven habitat shift is rapidly becoming a public-safety and cultural issue as well as a conservation crisis.
From Ice to Shore: Four Decades of Tracking Data
The clearest picture of this behavioral migration comes from satellite-collar records covering hundreds of adult females tracked across the Beaufort and Chukchi Seas from 1985 onward in both observed and modeled conditions. That dataset shows bears arriving on shore earlier each decade and staying longer as the open-water season expands. According to a detailed analysis by USGS scientists, the average time polar bears spend on land has risen from roughly 20 days to 60 to 70 days, a threefold increase that compresses the window bears have to build fat reserves on sea ice before summer forces them ashore.
A separate open-file assessment extends those projections into the period from 2040 to 2065 for the Southern Beaufort and Chukchi Seas, using coupled climate and habitat models to anticipate how bears will respond as ice conditions continue to deteriorate. That work, published by USGS as a forward-looking scenario set, forecasts continued expansion of the ice-free season and, with it, longer stretches of forced terrestrial living. The pattern is not uniform across the Arctic, but the direction is consistent. Bears that once spent summers drifting on pack ice are increasingly stranded on coastlines where food is scarce and human settlements are close, amplifying both nutritional stress and the potential for conflict.
Why Less Ice Means Hungrier Bears
The assumption that polar bears can simply switch to land-based food has not held up under field testing. A peer-reviewed study conducted from 2019 to 2022 near Churchill, Manitoba, used GPS and video collars along with physiological measures to track what bears actually eat and burn while onshore. The findings, published in a recent issue of a major ecology journal, showed that terrestrial foraging often does not offset the energy costs of living on land. Bears that tried eating berries, bird eggs, or garbage still lost weight at rates comparable to fasting animals. The caloric math is stark. A ringed seal caught on sea ice delivers far more energy per effort than anything available on a shoreline, and there are few opportunities on land for the high-fat diet that bears evolved to exploit.
When ice retreats beyond the continental shelf, bears face a second problem. Offshore multiyear pack ice is poor hunting habitat because seal density drops sharply in deep water far from productive coastal zones. Bears are caught between two losing options: follow the ice into barren deep-water zones or come ashore and burn through fat reserves. One extreme case documented in 2008 illustrates the cost of the first choice. A female polar bear in the Beaufort Sea completed a 687-kilometer continuous swim over nine days, losing significant body mass and her cub in the process. That kind of open-water crossing, once rare, becomes more likely as the distance between productive ice and land grows each summer, compounding the energetic toll already imposed by shorter hunting seasons.
Record-Low Ice and a Shrinking Safety Net
The ice platform that polar bears depend on is disappearing faster than many projections from a decade ago. Multi-year sea ice, the thick older ice that persists through summer, has been shrinking by roughly 13% per decade since satellite records began in the late 1970s. The annual maximum sea ice extent in March 2025 set a new record low, according to joint assessments by NASA and the National Snow and Ice Data Center, meaning the Arctic entered the melt season with less ice than in any previous year on record. That record was not just a summer anomaly; it occurred at the seasonal peak, when Arctic ice should be at its most expansive.
Region-specific monitoring sharpens the concern. The NOAA Arctic Report Card for 2025 documented pronounced sea ice anomalies in the Beaufort and Chukchi Seas alongside slow freeze-up in Hudson Bay, both areas where polar bear populations are already under pressure from nutritional stress and declining body condition. Long-term observers such as Josefino Comiso and George Durner have concluded that summer sea ice and the bears that depend on it may vanish from key regions much sooner than previously expected if greenhouse gas emissions remain high. The U.S. Fish and Wildlife Service formally recognized the species-wide threat years ago when it listed the polar bear as threatened under the Endangered Species Act, citing sea-ice loss as the primary driver through mechanisms including shortened hunting seasons, increased travel distances, open-water risks, disrupted denning, and rising human conflict in its federal listing decision.
Population Declines Already Underway
The demographic damage is not theoretical. Capture–recapture research conducted from 1984 to 2004 in Western Hudson Bay found a clear decline linked to earlier breakup of seasonal sea ice. The study, published in the Journal of Wildlife Management, showed that juvenile, subadult, and older bears suffered the steepest drops in survival as the ice-free period lengthened and body condition deteriorated. Adult females, which drive population growth through cub production and care, also showed reduced survival in years with especially early melt, indicating that the system is losing resilience as environmental variability increases.
Similar warning signs are emerging in the Beaufort and Chukchi Seas, where long-term field programs integrate mark–recapture, aerial surveys, and satellite tracking. A comprehensive USGS data series for Southern Beaufort bears documents shifts in survival, movement, and habitat use consistent with nutritional stress and habitat fragmentation. Complementary work in the Chukchi Sea, archived in another USGS-supported dataset, indicates that even populations once thought relatively stable are now spending more time onshore and traveling farther to find suitable hunting grounds. Together, these lines of evidence suggest that the changes visible today are not short-term fluctuations but the early stages of a long anticipated contraction in both numbers and range.
What Longer Onshore Seasons Mean for People and Policy
As more polar bears are pushed ashore for longer periods, the overlap with human activity will continue to grow. Coastal communities in Alaska and northern Canada are investing in bear-safe food storage, patrols, and deterrence programs to reduce the risk of dangerous encounters, but these measures are ultimately defensive responses to a shifting climate baseline. For Indigenous peoples whose cultures, subsistence practices, and knowledge systems are intertwined with sea ice and marine mammals, the loss of predictable ice seasons and the weakening condition of bears raise deeper questions about identity, food security, and the pace of global change imposed from far outside the Arctic.
Policy responses lag behind the speed of physical change. The threatened status of polar bears under U.S. law provides a framework for monitoring and some protections, but it does not directly curb the greenhouse gas emissions that are driving sea-ice loss. International agreements on climate and Arctic shipping, along with local co-management of subsistence harvests, can ease some pressures at the margins, yet none can substitute for the restoration of a stable ice platform. The tracking records, demographic studies, and climate indicators now converging from the Beaufort and Chukchi Seas point to a simple conclusion: without rapid cuts in emissions that slow and eventually halt the decline of Arctic sea ice, polar bears will spend more of their lives on land, hungrier and closer to people, in a world that offers them fewer and fewer ways to adapt.
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*This article was researched with the help of AI, with human editors creating the final content.
