Climate change has had significant effects on brown bear populations, influencing their habitats, behavior, and overall survival. As global temperatures rise and seasonal patterns shift, the ecosystems that brown bears depend on are experiencing rapid changes. These changes disrupt the availability of food sources, which can have a direct impact on the bears' feeding habits and their ability to prepare for hibernation. In some regions, the timing of the availability of key foods, such as salmon during spawning seasons, has become unpredictable. As a result, bears may not be able to accumulate enough fat stores before winter, putting their health and survival at risk.

Additionally, warmer temperatures have altered the natural landscapes that brown bears inhabit. As forest ecosystems shift, bears may find themselves displaced from their traditional habitats, sometimes forcing them into areas that are less suitable for their needs. This can increase competition with other species and humans, leading to more frequent encounters and potential conflicts. These altered habitats also affect the availability of dens, which are critical for hibernation. If bears cannot find proper shelter, they may not be able to enter hibernation properly, leading to further depletion of their energy reserves.

Behavioral changes have also been noted in brown bear populations due to climate change. As food sources become more scattered and less reliable, bears may change their foraging patterns, often traveling further and expending more energy to find enough sustenance. In some cases, this has led to bears moving into urban areas in search of food, which increases the likelihood of human-wildlife conflict. Furthermore, changes in the timing of food availability and hibernation could disrupt their reproductive cycles. Female bears, in particular, may have trouble producing healthy cubs if they cannot find enough food during critical times of the year.

The overall impact of climate change on brown bear populations is complex and multifaceted. As the climate continues to shift, it is likely that bears will have to adapt in ways that could further challenge their survival.