There are 20 populations across the Arctic with 20 different stories, but the worldwide average is not increasing. Some populations have experienced steep declines while others have rebounded a little after unregulated hunting was banned in 1973, but that increase is likely to be reversed as the sea ice melts.
One of the most frequent myths we hear about polar bears is that their numbers are increasing. Tales about how many polar bears there used to be (with claims as low as 5,000 in the 1960s) are undocumented, but cited over and over again.
“A common thread with misinformation about polar bears is omitting really crucial pieces of context for interpreting population numbers”, says Dr. John Whiteman. “In the 1950s and 60s, right after World War II, new technology really led to an explosion in hunting of polar bears. This overharvesting certainly drove numbers of polar bears down. We don't know by how much because there were not good population counts back then.”
We do know that some polar bear populations grew after harvest management systems were implemented in Canada, Alaska and Greenland, aerial sport hunting ceased in Alaska, and commercial trapping and hunting was banned across the Arctic. All of these events occurred in the late 1960s or early 1970s, and we know some populations responded as you would expect. Some populations were not being heavily hunted back then and those were probably unaffected by these actions.
However, what happened in the past is increasingly irrelevant. Polar bear habitat is both changing (thinning) and disappearing (loss of sea ice extent) due to global warming at a rate that has never been seen before. Even the most careful on-the-ground management will ultimately fail if polar bears don't have the required habitat.
Polar bears depend on the sea ice surface to efficiently catch their seal prey. A shorter duration of ice cover over their productive hunting areas means less opportunity to hunt. A reduction in sea ice has been statistically linked to reduced stature and weight in polar bears and to lower survival rates of cubs. So, it doesn't really matter that hunting is now largely under control or that we know a lot about other impacts people might have on bears. Without habitat, polar bears will disappear no matter what else we do.
https://polarbearsinternational.org/news-media/articles/are-polar-bear-populations-increasing
