It’s still based on the same flawed ecological premise as all previous models – it assumes that sea ice was a naturally stable habitat until human-caused global warming came along. It also uses slight-of-hand maneuvers to correlate declining summer sea ice and declining polar bear population numbers.
Just because they keep repeating the same hype doesn’t make it true.
Posted in Advocacy, Conservation Status, Sea ice habitat
Tagged activist, AGW, Amstrup, Arctic, Atwood, climate warming, decline, ecoregions, emissions, extinction, fallacy, flawed, global warming, greenhouse gas, ice-free, models, polar bear, polarbearscience, population, press release, science, sea ice, sea ice loss, summer, thick spring ice, threat, threatened, USGS, variation
Only half or less of the estimated 2.6% loss per decade of March sea ice extent since 1979 (Fig. 1, below) represents a decline in polar habitat. That’s because several regions with sea ice that are not home to polar bears, like the Sea of Okhotsk, are included in Arctic sea ice totals.
Figure 1. Average monthly Arctic sea ice extent for March 1979-2015 (which includes ice in the Sea of Okhotsk, the Sea of Japan, and the Baltic, where polar bears do not live), shows a decline of 2.6% per decade. NSIDC, March summary 2015.
Both the Sea of Okhotsk and northern Sea of Japan (Fig. 2) have sea ice in winter (which is included in total Arctic sea ice records) but they are not truly “Arctic” – neither is connected to the Arctic by continuous ice, even when the ice is at its maximum extent (nor is the Baltic Sea — in contrast to Hudson Bay and the east coast of North America, which are connected to the Arctic by continuous ice).
Figure 2. Location of the Sea of Okhotsk and Sea of Japan. Insert ice map for March 1979 from NSIDC shows it’s position relative to the Arctic proper.
That lack of connection to Arctic pack ice is probably the main reason that polar bears never colonized the Sea of Okhotsk, even though western Arctic seal species (ringed, bearded, spotted, and ribbon) and Arctic whales (bowhead and beluga) live there. Polar bears don’t currently live in the Sea of Okhotsk and all evidence suggests they never have.
Sea ice maps show that about half of the total ice extent difference between March 1979 and March 2015 was due to a relatively large decline in sea ice cover for Sea of Okhotsk and northern Sea of Japan — regions without polar bears. Surely no reputable scientist or journalist would suggest that the “record low” maximum ice extent for 2015 has any relevance for polar bear health and survival? [or for Northwest Passage travel, for that matter] Sadly, they would.
Posted in Conservation Status, Sea ice habitat
Tagged Arctic, declining sea ice, Derocher, habitat, lost ice, lowest maximum extent, March, misinformation, NSIDC, polar bear, record low, sea ice, sea ice extent, sea ice maximum, Sea of Okhotsk, spring, variation