Tag Archives: Durner

Archive of 2007 USGS reports supporting 2008 ESA listing for the polar bear

The administrative reports used in 2007 to support the decision to list polar bears as ‘threatened’ under the US Endangered Species Act (ESA) in 2008 disappeared from the US Geological Survey website several years ago. I have archived them here in pdf format to make them easy to find for anyone wishing to access the accuracy of the models, data, and assumptions made in 2007.

Amstrup w triplet_Prudhoe Bay 2005_USGS_sm

Steven Amstrup in 2005, then lead USGS polar bear biologist, with triplet cubs, Prudhoe Bay, AK.

This is a housekeeping post meant for future reference. I’ve included citations for the relevant sea ice projection papers used in the models presented in the 2007 documents and a few other related reports from the same time period. Continue reading

USGS ‘treadmill’ paper repeats bogus claim that ice loss harmed polar bears

The newest polar bear science paper making the rounds courtesy the US Geological Survey, is a perfect example of a statistically-significant result with no biological significance. While the results are rather lame, the paper is dangerous because it repeats the disingenuous claim (see Crockford 2017) that Southern Beaufort Sea polar bear numbers declined in recent years due to summer sea ice loss.

polar_bear_rubble_ice_Mike Lockhart USGS_8 April 2011

The USGS authors (Durner et al. 2017) know this harm-from-summer-ice-loss assertion is not true for the Southern Beaufort subpopulation but the more papers they can get into print that say so, the more likely it will be believed — and the less likely readers will check older literature that documents the recent decline in polar bear numbers was due to a three year period (2004-2006) when thick ice conditions in spring made seal hunting a challenge, a repeat of a well-known phenomenon (e.g. Stirling et al. 1980; Stirling 2002) unique to this region that has been documented since the 1960s.

The Durner paper (USGS press releaseIncreased Sea Ice Drift Puts Polar Bears on Faster Moving Treadmill” published online 6 June ahead of print) spins the research results as potentially significant bad news but in so doing reveals how desperate they have become to make the public and their biology colleagues believe that Southern Beaufort polar bears, among others, are being negatively affected by summer sea ice loss (as per Stirling and Derocher 2012).

Durner, G.M., Douglas, D.C., Albeke, S.E., Whiteman, J.P., Amstrup, S.C., Richardson, E., Wilson, R.R. and Ben-David, M. 2017. Increased Arctic sea ice drift alters adult female polar bear movements and energetics. Global Change Biology. DOI: 10.1111/gcb.13746 http://onlinelibrary.wiley.com/doi/10.1111/gcb.13746/abstract [paywalled]

In fact, the Durner et al. paper does not document any harm to polar bears from the proposed ‘treadmill’ effect of more rapidly moving ice for the period 1999-2013 compared to 1987-1998, but instead uses models to suggest bears might have to eat one to three more seals per year to compensate for the extra energy needed to walk against the moving ice. That’s right: perhaps only 1 more seal per year out of the 50 or so they would usually consume (see Stirling and Øritsland 1995). In my opinion, that’s a pretty lame result for what one of the co-authors described as an immense amount of work.

News outlets have essentially used the USGS press release as a click-bait lede for another round of Trump-bashing with respect to the Paris climate change agreement, see here and here: the stories are hardly about polar bears at all. And predictably, polar bear activist and co-author Steven Amstrup (paid spokesperson for Polar Bears International, famous for their “Save Our Sea Ice” campaign) appears to be using the same approach: an up-coming call-in talk radio program at NPR’s Anchorage affiliate KSKA for Tuesday 13 June at 10:00 (Alaska time, see “Talk of Alaska”) is being billed as a discussion of “polar bears, climate change, and the Paris Accord” (h/t AK geologist). Continue reading

Record low sea ice extent and what it means for polar bears…

On Aug. 27, 2012 sea ice extent dipped below the yearly minimum extent reached in 2007.

The sea ice at this point, a five-day average, was 4.1 million km squared and the lowest point reached since satellite records began in 1979. The National Snow and Ice Data Center (NSIDC) thought it was important enough to issue a press release.

There are sure to be more than a few media-hungry folks who will be moaning about the fate of the poor polar bears because of this report. Before people get too hysterical, a bit of rational perspective might be helpful.

Keep in mind that 4.1 m sq. km (Fig. 5) is about the size of Greenland (2.166 m km2) plus Mexico (1.972 m km2), or about the size of India (3.287 m km2) plus Pakistan (0.809 m km2), figures from Wikipedia.

It may be a ‘record’ low, but it’s still a lot of ice: 4.1 m km2 is not anywhere close to an ‘ice-free’ Arctic!

Arctic sea ice melts – or gets pushed out of the Arctic and then melts – every year, leaving various amounts behind. The ice lingering at mid-September adds to next year’s ‘multiyear’ ice.

The maximum extent is usually reached mid-to-late March. Have a look at how this ‘low extent’ developed from the March maximum this year. Even if you’ve looked at some of these maps, you may not have looked at them one after the other. I’ll compare these to the fall maps for 2007, after the Sept. minimum and discuss these in relation to polar bear habitat. Contineu reading