Polar bears have not been harmed by sea ice declines in summer – the evidence .

By steven d keeler | Sep 01, 2013


Polar bear numbers overall have increased, despite the appearance of a ‘stable’ global population since 2001 and significant declines in Arctic sea ice coverage in summer.

While it will come as a great consternation to the likes of the world wildlife federation, greenpeace, the sierra club and the national geographic, arctic polar bears are not paying attention to past predictions of gloom for the species.

The global population estimate generated by the PBSG (20,000-25,000 bears, as of July 2013) has been virtually unchanged since 2001, giving the impression that declines in some subpopulations have been offset by increases in others. However, adjustments to a few subpopulation estimates (primarily changing estimates that had formerly been included in the total to zero (0), without adjusting the total downward) suggest that the actual numbers must have increased by 2650 to 5700 bears since 2001. These increases in total polar bear numbers have occurred despite declines in the amount of sea ice remaining in September (Fig. 1 below) and a trend to earlier dates for the summer breakup of sea ice in regions such as Hudson Bay and Davis Strait.



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