'Too much warming': Polar bears in Hudson Bay could go extinct by 2030s if global temperatures continue to increase

Climate change impacts on polar bears Churchill's polar bear population could go extinct within the next three-and-a-half decades if temperatures continue to climb

If certain goals that are in the Paris Climate Accord aren't met, the existence of polar bears in the Hudson Bay may come to an end.

This is according to a new report entitled "Ice-free period too long for Southern and Western Hudson Bay polar bear population if global warming exceeds 1.6 to 2.6C." The report was written by researchers from multiple institutions in North America and overseas, including the University of Manitoba.

The report found if global temperatures pass the 2C warming limit, polar bears in Hudson Bay could go extinct as early as the 2030s.

"So what happens if we get to that 2C, if we're right at that limit? Well, our research is showing that based on these model projections, it looks like that at that level, we're kind of in this grey area for polar bears in Hudson Bay," said Alex Crawford who is an assistant professor in the Department of Environment and Geography at the U of M, and is also a co-author for the paper.

"At that level, it's probably too much warming for the southern Hudson Bay population."

If temperatures get to the 2.2 to 2.6C range, Crawford said that will likely have detrimental impacts on the western Hudson Bay polar bear population.

If temperatures continue to rise, the report said the number of days that Hudson Bay is covered in sea ice would decrease, which would affect the polar bear population as well as the ring seals – one of the main food sources for polar bears.

"Those ring seals are also dependent on the sea ice. They form dens deep in the snow that form up on top of the sea ice. So really, the loss of the polar bears is a sign that we're losing the ring seals."

What does a global temperature increase mean? 

When asked what a 2C global temperature rise would look like, Crawford said it is something that can't just be compared to the last several years, he said it is a generational change noticed over time.

"In order to really get a good sense of what the change looks like, it's usually helpful I think, to think about yourself and then think about grandparents at the same age. You start putting it in that context, a place like Winnipeg or a place like Churchill, Manitoba is seeing several more days that exceed 30C than your grandparents experienced when they were your age, and we're experiencing several fewer days that get below -20C than when your grandparents were that age."

He said that may not seem like a lot in someone's day-to-day life, but it can mean a lot to species like polar bears or other animals that are common in other parts of the world.

"If you start talking about the polar bears, well for them, there's another thing that matters, and that is how long Hudson Bay is covered with sea ice. In the past, it was covered with sea ice for most of the year, about eight months out of the year. Today, it's covered with ice more like seven, maybe six-and-a-half months out of the year. And that change is really big."

If the sea ice, ring seals and polar bears were to disappear, Crawford noted other mammals may start to frequent Hudson Bay more – such as harbour seals and killer whales.

What could be done to prevent this? 

Crawford said after individuals review the data, the question needs to be if we need polar bears in Hudson Bay and if they are important.

If the answer is yes, then the decisions that are made need to be decisions that prevent other changes like the loss of sea ice Crawford said.

He points out that people can do their part to lower emissions and reduce their carbon footprint, but steps need to also be taken at the government level – specifically federal and international governments.

"That requires the elected officials in a place like Canada valuing things like health and sustainability over things like profit. And that isn't necessarily a decision that every politician wants to make or that every voter wants to make. That's why it's hard for me to say what you have to do, but it is something I can say, 'Well if you want to do this, these are the sorts of steps that seem necessary.'"

While this is localized to the impacts climate change has on polar bears and Hudson Bay, Crawford said this report could easily be used for other areas around the world that have an identity based on a specific ecosystem.

"If you go down to southern Florida, part of their identity, if you go to places like Biscayne (Bay) or the Dry Tortugas, are the coral reefs that are around. That's another ecosystem that is impacted by climate change, it's part of their identity."

He said the best way to look at climate change is to see how it could impact local areas close to you, instead of on a larger global scale.