Le réchauffement, un poisson d'avril ?

Yesterday morning, while going for daily measurements, I passed a very new track from 2 polar bear cubs with their mother. They are just out of the den and are now discovering their future hunting field. This year, March was much colder than usual. Pack ice and its inhabitants are all the better. Is it the result of our efforts, is climate trend reversing, or are we only having a little occasional cooling? Anyway, during 4 years, we didn't see any half-starved polar bear here. Are we living in a real sanctuary?