Challenging polar bear fearmongering about Arctic sea ice extent for March 2015

Here are some facts to counter the misinformation and fearmongering being spread via twitter by a polar bear biologist who is getting carried away with his conservation activism.

Arctic Sea ice extent March greater than PB habitat_April 12 2015

Following up on my last post, I note that Arctic regions with sea ice but not polar bears were about 0.32 mkm2 below last year’s March average extent – which means the total ice decline from 2014 (0.4 mkm2) represents only a slight decline in polar bear habitat, most of which is in the Barents Sea (and due primarily to the state of the AMO, not global warming).

Sea ice extent for the Sea of Okhotsk and Baltic Sea combined (both areas without polar bears)1 were about 0.6 mkm2 below average this year for March. Average extent for March (according to NSIDC) is 15.5 mkm2, which means this year’s extent (14.4 mkm2) was 1.1 mkm2 below average, of which less than half (0.5 mkm2) was “lost” polar bear habitat.

IUCN Polar Bear Specialist Group biologist Andrew Derocher has been saying this is a “huge loss for polar bears” (see below): rational analysis of the facts show it is not.

Derocher tweet 2015 April 10_re March seaice and PB habitat

In fact, the area of polar bear habitat decline from average in March 2015 was about the size of Spain alone (~0.5 mkm2) and most of that was a predictable loss of Barents Sea ice, which has in recent years been strongly impacted by the negative state of the AMO. That’s meant a few challenges for Barents Sea polar bears but it’s nothing they haven’t experienced before and most bears seem to be adapting.

Derocher’s attempt to spread misinformation about the 2015 record low March extent in relation to polar bear habitat was the second within a week — it followed on the heals of another tweet he sent a few days earlier (copied below), which I countered here:

Derocher tweet 2015 April 7 claims March ice is polar bear habitat

Footnote 1. Area of sea ice without bears:
Area of Baltic Sea = 0.40 mkm2 [last froze over entirely in 1987]
Area of Sea of Okhotsk = 1.6 mkm2 [last froze over entirely in 1979]

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