Warming Arctic Increases Disease Risks for Polar Bears

As the Arctic warms, polar bears are spending more time on land and facing a greater likelihood of exposure to harmful pathogens. Research indicates that the loss of sea ice and increased interactions with land-based diseases are detrimental to their health.

In a concerning revelation for wildlife conservation, recent research highlights the escalating risks that polar bears face regarding disease as the Arctic region continues to warm. These majestic animals are encountering a range of viruses, bacteria, and parasites that had significantly less impact on them merely three decades ago.

The study, conducted by wildlife biologists, involved a detailed analysis of blood samples drawn from polar bears in the Chukchi Sea area, straddling Alaska and Russia. Researchers examined samples collected from the bears between 1987 and 1994 and contrasted them with samples obtained three decades later, from 2008 to 2017. Notably, the more recent samples showed a marked increase in the presence of immune system indicators that point to infections from various pathogens.

Dr. Karyn Rode, a key wildlife biologist associated with this study, emphasizes that these changes correlate directly with substantial sea ice loss and increased land interactions in the polar bears' natural habitats. The study examined six pathogens in total, including two parasites leading to toxoplasmosis and neosporosis, alongside bacterial infections that cause rabbit fever and brucellosis as well as the canine distemper virus.

Despite the findings showing a rise in these disease-causing agents, Dr. Rode reassures that polar bears are generally resilient regarding disease impact. She indicates, however, that the findings highlight significant ecosystem changes in the Arctic, which could have far-reaching implications not just for polar bears but also for the broader Arctic ecological network.

Polar bear populations, currently estimated at around 26,000 worldwide, primarily reside in Canada but also inhabit regions of the US, Russia, Greenland, and Norway. They are classified as vulnerable by the International Union for Conservation of Nature, with climate change being a fundamental threat to their survival.

Data from previous research suggests that as polar bears increasingly spend time on land due to the diminishment of sea ice—critical for hunting marine prey—their caloric intake is affected. Consequently, these shifts in feeding habits and habitat are likely influencing their exposure to pathogens primarily from affected prey species.

The results of this significant study have been released in the scientific journal PLOS One, underscoring both the immediate and long-term challenges polar bears confront as their icy domain experiences profound shifts in climate and ecology.