By WWF-Canada’s Brandon Laforest and WWF Arctic’s Melanie Lancaster
Polar bears in some parts of Canada are getting fatter and more numerous according to recent survey results from two of the world’s 19 polar bear subpopulations.
Scientists found that recovery efforts are paying off and the bears have, at least temporarily, responded well to changes in Arctic sea ice. This is reflected in their body conditions — bears are fatter than they were in the mid- to late-1990s — and increasing or stable in population over the past two decades.
The two polar bear subpopulations — M’Clintock Channel and Gulf of Boothia — are neighbours found in the central Canadian Arctic territory Nunavut. The former subpopulation has increased from around 325 bears in the late 1990s to 716 today while the Gulf of Boothia subpopulation has remained mostly stable at around 1500 bears.
Local actions contribute to population recovery
The population increase in M’Clintock Channel is, in part, the result of good adaptive management in Nunavut. M’Clintock Channel polar bears are co-managed by governments and local Inuit communities.
Co-management includes regulating how Inuit can sustainably harvest polar bears according to their rights and traditions while ensuring the long-term health and sustainability of the population.
A combination of science and Inuit knowledge was used to trigger management actions in the early 2000s in response to a marked drop in polar bear numbers in M’Clintock Channel.
Inuit agreed to decrease their harvest for several years to allow the population to grow while contributing their knowledge and observations to monitoring the bears’ recovery, and this decision-making process has paid off.
Ice shapes life
We know polar bears need sea ice for almost all aspects of their lives — to hunt seals, find mates, and generally get around. Sea ice is to polar bears what forests are to orangutans: essential habitat.
For these northern polar bear subpopulations, thick, old sea ice has dominated until recently due to climate change. This ice is called “multiyear sea ice” because it has survived the summer melt over many seasons.
Up to four meters thick, old sea ice is like a heavy blanket on the ocean’s surface, blocking sunlight from reaching the water underneath and limiting algal growth. Algae form the base of the Arctic Ocean food web, sustaining everything from tiny bugs to fish, seals and polar bears. Without light, there is limited food for the bears.
Old is replaced by new
Scientists say that bears in M’Clintock Channel and Gulf of Boothia are in better shape, in part, because of lighter sea ice. For these northern polar bear subpopulations, the past three decades have seen a complete transformation of the seascape.
Old sea ice is being replaced by ice that melts and forms anew each year and there is more open ocean. This “opening” of the ocean means higher productivity: more algae, zooplankton, fish and seals — and better hunting opportunities for polar bears.
Going, going, gone?
Amongst the deluge of depressing climate change-related news, these findings for polar bears are heartening. But scientists say this upswing is temporary. In September 2020, sea ice hit its second-lowest extent in recorded history.
The Arctic’s icy visage — something we’ve taken for granted as an eternal feature of the polar regions — will continue to disappear over the coming decades. Along with it will likely go these small wins that we are currently seeing for polar bears.
While less sea ice in this part of the Arctic has led to more food for polar bears, it also means the bears in these subpopulations are losing their permanent ice platforms from which to hunt all year. Recent estimates suggest completely ice-free summers in the Arctic as early as 2030. Such a change would have monumental impacts on the Arctic marine ecosystem, including polar bears.
It was the action of local people in central Nunavut that contributed to the recovery of the M’Clintock Channel subpopulation, but not all polar bear conservation issues can be solved in the Arctic.
Unless we as a global community drastically reduce greenhouse gas emissions, by the end of this century we may lose all but a few polar bear subpopulations in and around the top of the world.