2024 Churchill Barber Symposium

Hudson Bay in Canada supports two of the world’s polar bear populations considered most immediately threatened by climate change. The bears in the Western Hudson Bay population are considered to already be experiencing a steep decline in numbers. A Government of Nunavut report showed the population dropped by more than a quarter between 2016 and 2021.

In the face of numbers like these, it is important to understand not just what’s happening to the bears, but also to understand projections for sea ice, an important hunting platform for the bears. The sea ice changes, and other associated changes driven by climate change, also affect the whole food web in the bay. As the top predator, the fate of polar bears is linked to any changes in that food web, from algae that grow under the ice to ringed seals, the bears’ favorite food.

Two years ago, Polar Bears International responded to local concerns about the future ecology of the bay by helping organize the first Churchill Barber Symposium. The symposium, held in Churchill, brought together experts from a number of fields to combine and share their knowledge. It was named in honor of the late Dr. David Barber. His work on sea ice and the ecology of Hudson Bay, and his commitment to building research infrastructure and programs in Churchill laid the basis for the symposium.

Sobering forecast for Hudson Bay polar bears

The second Churchill Barber symposium was held in August 2024, and attended by a variety of academics and local people over two days. One of the presenters, Dr. Julienne Stroeve, spoke of the research she led that was spurred by the first symposium. This research, to which PBI staff made a contribution, coupled ice and snow modeling with the conditions necessary for ringed seals and polar bears to thrive. The modeling of future snow and ice for the Hudson Bay was also corrected by comparing model projections to actual measurements taken over the past several years. Stroeve said that this makes their projection of how much ice will be lost more conservative than some other projections.

As Stroeve explained, 180 days off the ice is seen by polar bear specialists as a critical threshold for polar bears. Longer than that, and their chances of survival diminish, as they’re less able to find enough food on land. The current international commitments to reducing greenhouse gas emissions would result in 2.7 degrees of warming. “As we get closer to that 2.7 target, then we might start seeing some big consequences…certainly as we go further in time and we warm more you’re going to get to the point where you have too many ice-free days and the bears are fasting for too long to be able to survive. At 2.7 the fasting period will exceed 183 days in Western Hudson Bay, and that’s about 200 days in Southern Hudson Bay by that level of warming.”

Compounding the problem for Hudson Bay’s polar bears is the likely fate of their favorite food, ringed seals. Stroeve says that the team’s modeling showed a decrease not just in ice, but in snow cover also. The seals need thick enough snow to make the dens where they have their pups. The models show precipitation in the Hudson Bay region increasingly falling as rain, rather than snow.

New Churchill Marine Observatory

Dr. Feiyue Wang, Project Lead for the Churchill Marine Observatory and Professor at the University of Manitoba also spoke at the symposium, following the observatory’s official opening earlier in the week. The observatory provides important infrastructure and a research focus for delving into the future of the Bay. Wang laid out the focus of some of that research. Much of it will also be driven by climate change, but following the assumption that what is bad for bears will be good for shipping. The port of Churchill has long been seen as a potential “third seaway”, a port for shipping grain, minerals and other commodities from Central Canada. It has never really capitalized on that potential due in part to long periods when ice has made shipping difficult. Wang believes that the shipping route from Churchill may well expand with less sea ice, and the potential of other infrastructure being built to channel trade to the port. He sees part of the mission of the observatory as helping understand the marine environment and the potential impacts of any spills from increased shipping.

A second day of the symposium was more geared to the academics present as they delved deeply into topics as diverse as the potential of airships in the north to improving remote sensing of sea ice conditions. In all, 15 presenters shared their knowledge with each other, and with an online audience. Planning has already started for a third symposium, two years from now.

Clive Tesar is a Lecturer in Northern Studies at Carleton University in Ottawa, and a policy and communications consultant. We works with Polar Bears International on coexistence issues.