Tag Archives: data

Published field study observations – not population size – prove polar bears are thriving

There is irrefutable evidence from Barents and Chukchi Sea subpopulations, among others, that polar bears are fat and reproducing well despite marked declines in summer sea ice over the last two decades. These indicators of physical and reproductive health, in any species, are signs of thriving populations. However, these facts negate the premise that polar bears require abundant summer sea ice to flourish, and that creates a problem for polar bear specialists who continue to make that claim (Amstrup et al. 2007; Crockford 2017, 2019).

Enormously fat Chukchi Sea polar bear, USFWS.

In other words, the assessment that polar bears are currently thriving is not based solely on estimates of a slight increase in global population size but on published data gathered from field studies on the bears’ physical and reproductive health.

Oddly, biologists repeatedly turn to data from Western Hudson Bay to drive home to the public their preferred message that polar bear health and abundance are being negatively affected by recent summer sea ice declines. However, they fail to mention that robust field data from many other regions, including the Barents and Chukchi Seas, support the opposite conclusion. Moreover, wherever possible, they mumble under their breath (or leave out entirely) the fact that poor ice conditions could not be blamed for a 27% decline in polar bear numbers in Western Hudson Bay since 2016 — because their own data showed sea ice conditions had been strong!

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Norwegian polar bears continue to thrive in 2019: Svalbard spring study results are in

Results from spring Norwegian fieldwork in the Svalbard region of the Barents Sea are in and they show that despite having to deal with the most extreme loss of summer sea ice in the Arctic, polar bears in this region continue to thrive.

Svalbard polarbear-helicopter-npolar-framcentre

Svalbard polar bear territory (managed by Norway) includes sea ice to the Russian boarder to the east as well as the area around the Svalbard archipelago: the map below is from Aars et al. 2017.

Aars et a. 2017 Figure 1

Observations were collected around Svalbard by a team lead by Jon Aars and Magnus Andersen of the Norwegian Polar Institute between March and May this year, and posted online 4 June 2019. Kudos to them for making their on-going observations and analysis available, in a timely manner for all to see.

Note that Svalbard is the western half of the ‘Barents Sea’ polar bear subpopulation: in recent years, most of the region’s polar bears have been living around Franz Josef Land in the eastern (Russian) sector where Norwegian researchers are not permitted to work.

Barents Sea with Franz Josef Land

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Two technical critiques of the Harvey et al. polar bear Bioscience attack paper

Not much time for blogging, but two technical critiques  of the Harvey et al. paper have recently been posted, which you might like to read at your leisure. I will update this post when I can if more critiques appear plus I’ve provided a list of previous posts (my and others) on this issue.

Polar Bears, Inadequate data and Statistical Lipstick (18 Decemeber 2018, RomanM writing at ClimateAudit)

McIntyre guest blog on Harvey paper photo led_RomanM 18 Dec 2017

Polar bear attack paper invalidated by non-independent analysis” (Cross posted 14 December 2017 at ClimateScepticism from the blog of Shub Nuggarath, 12 December 2017).

UPDATE 19 December 2017: Richard Tol has posted a draft of his critique, which was itself updated 20 December “Lipstick on a bear” in which he concludes:

“In sum, Harvey et al. (2017) play a statistical game of smoke and mirrors. They validate their data, collected by an unclear process, by comparing it to data of unknown provenance. They artificially inflate the dimensionality of their data only to reduce that dimensionality using a principal component analysis. They pretend their results are two dimensional where there is only one dimension. They suggest that there are many nuanced positions where there are only a few stark ones – at least, in their data. On a topic as complex as this, there are of course many nuanced positions; the jitter applied conceals the poor quality of Harvey’s data. They show that these is disagreement on the vulnerability of polar bears to climate change, but offer no new evidence who is right or wrong – apart from a fallacious argument from authority, with a “majority view” taken from an unrepresentative sample. Once the substandard statistical application to poor data is removed, what remains is a not-so-veiled attempt at a colleague’s reputation.”

UPDATED 20 December 2017: Lead author of the Bioscience attack paper Jeff Harvey talked to an Amsterdam newspaper about the backlash to the paper, original Dutch and English translation here.

Fig 3 Sea ice prediction vs reality 2012

Predicted sea ice changes (based on 2004 data) at 2020, 2050, and 2080 that were used in 2007 to predict a 66% decline in global polar bear numbers vs. an example of the sea ice extent reality experienced since 2007 (shown is 2012). See Crockford 2017 for details.

Read a short summary of the paper that Harvey et al. don’t want you to know about here:

Crockford, S.J. and Geist, V. 2018. Conservation Fiasco. Range Magazine, Winter 2017/2018, pg. 26-27. Pdf here.

The paper they don’t want you to read is here:

Crockford, S.J. 2017. Testing the hypothesis that routine sea ice coverage of 3-5 mkm2 results in a greater than 30% decline in population size of polar bears (Ursus maritimus). PeerJ Preprints 2 March 2017. Doi: 10.7287/peerj.preprints.2737v3 Open access. https://doi.org/10.7287/peerj.preprints.2737v3

The paper being criticized (Harvey et al. 2017, in press: “Internet blogs, polar bears, and climate-change denial by proxy”, Bioscience, open access) is available here.  There is a supplementary data file available here and the data for the principal component analysis is available here  and (h/t to R. Tol), the R code is available here

More on this after Christmas but for now a list of previous blog posts of mine and others is provided below. Continue reading