Tag Archives: correlation

Explaining abundant polar bear sightings on the East Coast as an upshot of sea ice loss is absurd

Last week, a senior producer at CBC News, in order to concoct a timely story for ‘Earth Day’, attempted to explain the high number of sightings of polar bears this April in Newfoundland and Labrador, compared to the last two years, as a consequence of climate change and its handmaiden, loss of Arctic sea ice.

Title: ‘With an extinction threat looming, no wonder polar bears are at our door — and on the roof: there’s a grim reason why polar bears have been frequently showing up in coastal communities’. CBC News, 23 April 2022

The problem with this narrative is that the East Coast had much reduced sea ice in 2021 and virtually no polar bear sightings in Newfoundland and none in Labrador. There was more ice in 2020 than 2021 but also few bears. This year, ice extent was similar to 2020 for most of the region but polar bear sightings were up considerably.

In fact, the two years with the most sightings and problems with polar bears since 2008 were 2017 and 2018: in 2017, sea ice was exceptionally thick in April (although average in extent) and by June the sea ice was so thick and enduring that the Newfoundland fishing fleet couldn’t get out for spring openings; 2018 was another year of average sea ice extent and had even an even larger number of sightings than 2017, in Newfoundland especially (Crockford 2019:32). This suggests the sea ice vs. polar bear correlation on the East Coast since 2008 – if there even is one – may be the opposite of that stated in the CBC article: less ice usually means fewer bears onshore in Newfoundland and Labrador and more ice often means more bears.

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Baffin Bay polar bears are abundant and the population is stable, study scientist admits

An article by CBC News today (3 March 2020) is a surprisingly well-balance report on a recently published paper by Kristin Laidre and colleagues on their work on Baffin Bay polar bears that I discussed last month. It presents the Inuit perspective that polar bears are currently abundant in the area and the population stable despite less summer sea ice and some documented declines in body weight and at least one scientist conceded this is indeed true.

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Fat polar bear, summer 2012 near Thule, NW Greenland (Baffin Bay subpopulation). Robin Davies photo.

However, the CBC writer still left out the most critical caveat included in the paper about the study: that factors other than changes in sea ice could have affected the body condition and litter size data that the authors documented but they didn’t look at anything except sea ice. This automatically means the conclusions are scientifically inconclusive.

See some quotes below from the CBC article and the caveat from the paper. Continue reading

New paper says Baffin Bay polar bears may have been affected by less summer sea ice

A new paper on Baffin Bay polar bears reports data on body condition and litter sizes collected as part of a major study of the region completed in 2013 compared to sea ice declines since the 1990s; based on a computer model, the authors predict that in 37 years time (if sea ice declines continuously), the incidence of twin litters could “largely disappear.” However, no decline in population numbers was predicted and a critical caveat acknowledges that factors other than changes in sea ice could have affected the body condition and litter size data the authors analyzed, which means the conclusions are scientifically inconclusive.

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Fat polar bear, summer 2012 near Thule, NW Greenland (Baffin Bay subpopulation). Robin Davies photo.

The last (2013) polar bear population survey of Baffin Bay (SWG 2016) generated an estimate of almost 3,000 (2,826; range 2,059-3,593), which means that regardless of some slight changes in body condition and litter size over the last two decades (which may or may not have been caused by loss of sea ice), there are currently a lot of bears in Baffin Bay.

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Churchill problem bears and early breakup dates in WHB: The 1983 & 2004 anomalies

In this part of my critique of Stirling and Parkinson (2006), regarding breakup dates in Western Hudson Bay (see Part I here), I will show that these authors also left out critical data.

Figure 1. A bear is transported to Churchill’s polar bear holding facility, from a 2011 Huffington Post article “Polar Bear Prison.”

Figure 1. A bear is transported to Churchill’s polar bear holding facility, from a 2011 Huffington Post article “Polar Bear Prison.”

Their correlation between number of problem bears in Churchill and breakup dates for WHB worked because some very inconvenient data were simply left out: problem bear data for 1983 and 2004.

Inclusion of that information would have shown 1983 and 2004 were two of the worst years for polar bear problems in recent history despite being late breakup years (1983 also had the last human fatality from a polar bear attack). They could have explained why they did not use the data but they did not — they simply left it out.

Amazingly, this work is being touted as “evidence” that global warming is harming Western Hudson Bay polar bears.
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