The global polar bear population is currently about 26,000, according to the International Union for Conservation of Nature (IUCN). That's a rough estimate, but scientists have determined with 95% certainty that between 22,000 and 31,000 polar bears exist on Earth today.
These polar bears are divided into 19 subpopulations around the Arctic, although not very evenly. Some polar bear populations number fewer than 200 individual bears, while others consist of more than 2,000.
Polar bears live in areas that fall under the jurisdiction of five countries: Canada (Labrador, Manitoba, Newfoundland, Northwest Territories, Nunavut, Ontario, Québec, Yukon); Denmark (Greenland); Norway (Svalbard, Jan Mayen); Russia (Yakutiya, Krasnoyarsk, West Siberia, North European Russia); and the U.S. (Alaska).
Here are the 19 subpopulations of polar bears, along with an estimated size and trend for those with sufficient data:
|Barents Sea||2,600||likely stable|
|Chukchi Sea||2,900||likely stable|
|Davis Strait||2,200||likely stable|
|Gulf of Boothia||1,600||likely stable|
|Kane Basin||350||likely ⬆|
|M'Clintock Channel||300||very likely ⬆|
|N. Beaufort Sea||1,000||likely ⬇|
|S. Beaufort Sea||900||likely ⬇|
|S. Hudson Bay||800||very likely ⬇|
|Vis. Melville Sound||150||unknown|
|W. Hudson Bay||900||very likely ⬇|
Are polar bears endangered?
Polar bears do face potentially existential threats, at least in some places. At the same time, however, a few populations have rebounded in recent decades from overhunting last century, leading some people to argue polar bears are actually thriving throughout their range. The late U.S. Sen. Ted Stevens of Alaska, for one, said in 2008 "there are now three times as many polar bears in the Arctic than there were in the 1970s," a claim that has periodically resurfaced since.
Polar bears are listed as "Vulnerable" on the IUCN Red List of Threatened Species, a designation they first received in 1982. They are protected by the Agreement on the Conservation of Polar Bears, a multilateral treaty signed in 1973 by the five polar bear nations listed above. It prohibits unregulated hunting of polar bears, along with using aircraft or large motorized vehicles to hunt them, and compels member states to take appropriate actions to preserve the ecosystems that sustain polar bears.
Countries with polar bear populations have also passed laws enacting various protections for the bears. In the U.S., for example, polar bears are protected partly by the Marine Mammal Protection Act of 1972 — which prohibits the "take" of polar bears and other marine mammals without federal approval — but also by the Endangered Species Act, since they were listed as a "Threatened" species in 2008.
If the polar bear population has really grown so much since the 1970s, though, why is there so much concern for the species? Why still classify them as vulnerable or threatened today? For one thing, despite the encouraging rebound of some populations, there is little evidence to suggest polar bears are thriving overall.
That's partly because we don't have enough long-term data on polar bears in general, especially for certain areas. It's true that a few populations have grown since receiving stronger legal protection, and several seem reassuringly stable. But even if scientists are correct that about 26,000 wild polar bears exist today, we don't have many historical benchmarks to help us put that in perspective. Those who doubt their current plight often claim only 5,000 polar bears were left in the 1960s, but as environmental journalist Peter Dykstra has reported, there is little scientific evidence for that number, which one expert called "almost certainly much too low."
At least four polar bear populations are likely in decline, according to the IUCN Polar Bear Specialist Group (PBSG), but we have too little data to establish trends for another eight populations, and too little to even estimate a population size for four of those. And while their specific status is more muddled than the overall outlook for climate change itself, there is significant evidence to suggest many polar bear populations are in peril.
How is climate change affecting polar bears?
To understand why polar bears are vulnerable to climate change, you have to know what polar bears eat — and how they get it. Polar bears are apex predators and a keystone species in their Arctic habitats, and their favorite food by far is seals. They specifically target ringed and bearded seals due to their high fat content.
Polar bears spend about half their time hunting, typically by stalking seals from the sea ice and ambushing when they surface to breathe. They often travel long distances and wait hours or days for a single seal, and while only a fraction of their hunts succeed, it's generally worth the trouble for such fatty food.
Polar bears are considered marine mammals, but while they are excellent swimmers, they are outmatched against a seal in the water. Sea ice is instrumental to their hunting strategy, and it's now dwindling due to rising temperatures in the Arctic, which is warming at roughly twice the rate as the planet overall.
Arctic sea ice naturally waxes and wanes with the seasons, but its average late-summer minimum is now shrinking by 13.2% every decade, according to the U.S. National Oceanic and Atmospheric Administration (NOAA). The oldest Arctic sea ice — frozen for at least four years, making it more resilient than younger, thinner ice — is now in steep decline, NOAA adds. This oldest ice comprised about 16% of the total ice pack in 1985, but it's now less than 1%, representing a loss of 95% in 33 years.
In 2019, Arctic sea ice tied for its second-lowest extent on record. This decline is bad for several reasons, since Arctic sea ice performs key services for Earth like reflecting solar heat and influencing ocean currents. It's even more directly important for polar bears, since less sea ice can mean fewer chances to catch seals.
The effects of climate change vary by location, and sea-ice decline seems to be affecting some bears more than others so far. Western Hudson Bay had roughly 1,200 polar bears in the 1990s, for example, but that has since fallen to about 800, and as Polar Bears International (PBI) notes, trends in their body condition, survival and abundance have been linked to sea-ice conditions. Bears in Southern Hudson Bay have also suffered a 17% decline since 2011-2012, according to PBI, and their body conditions have similarly been linked to a longer ice-free period.
Most other subpopulations are either considered stable or lack sufficient data, but many will likely also face dire challenges from the loss of sea ice in their habitats.
Some polar bears might be able to adapt, but their options likely will be limited. Even if they can exploit new food sources on land, they could face competition or conflict with established residents like brown bears and people. Polar bears are also slow to adapt, as the World Wildlife Fund notes, due to their low reproductive rate and long time between generations. That doesn't bode well given the speed of modern climate change, which is already happening too quickly for many species to adapt.