Scientists have only rough estimates for many of the 19 polar bear populations because it is both difficult and expensive to census the bears in many parts of the Arctic. That said, they use a working figure of 20,000 to 25,000 bears worldwide.

In the early '60s, the number of bears worldwide plummeted to possibly as low as 6,000 bears due to severe over-hunting. In 1973, the five polar bear nations agreed to ban hunting except by Natives. Polar bear numbers rebounded in the early '80s to possibly as many as 25,000 bears. We lack data on polar bear populations as a whole (and this is one of the key projects that PBI is supporting so scientists can have sound data). But we do have two well-studied populations—Western Hudson Bay and the Southern Beaufort Sea—that are considered representative. The Western Hudson Bay population has dropped by 22% since 1987. The Southern Beaufort Sea bears are showing the same signs of stress the Western Hudson Bay bears did before they crashed: smaller skull sizes, fewer cubs, etc.

Some members of the press take advantage of the complexity by stating that "polar bears are not in trouble—their numbers have doubled since the 1960s." That's a disingenuous statement, of course. There are twice as many bears now, true, but that's because they were severely over-hunted before and when the hunting stopped, they rebounded. But now they are starting to decline and we have two representative populations that illustrate this.