More seriously, the problem with using polar bears anti-global warming evidence is that (a) data is anyway not totally perfect, so the total numbers are only estimates, (b) Climate change remains more of a longer-term threat than a short-term one, although the extent Arctic Sea ice is decreasing on average, so this pressure will only continue to grow, and (c) until recently, hunting of polar bears was a far greater threat, and even after it was banned or heavily restricted it took some time for the populations to recover.
The Climate Change pressure on polar bear populations is therefore only a subleading effect, but it is real, and likely to dominate in the near-ish future.