A Service of The Greening Earth Society   

VIRTUAL CLIMATE ALERT

June 5, 2002 Vol. 3, No. 18

Polar bears are at risk, at least according to a recent online report by The World Wildlife Fund (WWF). The WWF cites human activities as imperiling the bears. Guess which human activity is the most dangerous? It’s energy consumption. It’s not that your lifestyle causes polar bears to currently face difficulties. There’s a total population of 22,000 polar bears that the WWF classifies into about twenty somewhat distinct populations spread across the circumpolar Arctic. Here’s how the WWF rates the status of those sub-populations: forty-six percent are stable, seventeen percent in decline, fourteen percent increasing, and the remaining twenty-three percent are of "unknown" status. So the problem, as the WWF sees it, is not so much with today’s polar bear population, but rather tomorrow’s.

Climate models predict the Arctic will warm in coming decades as the concentration of atmospheric greenhouse gases increases. The warming is anticipated to dramatically reduce the amount of sea ice – important polar bear habitat because it’s where they do most of their hunting.

The WWF report, "Polar Bears At Risk," cites studies that show reductions in both areal coverage and thickness of Arctic sea ice during the past several decades as evidence that model forecasts of coming events are correct. WWF disregards a study by Canada’s Department of Fisheries and Oceans that examines the relationship between sea ice and temperature and concludes, "Overall the possible impact of global warming appears to play a minor role in changes to Arctic sea ice." The Canadians find that changes in wind patterns lead to reshuffling of the ice in the Arctic ocean rather than to a large overall decline.

But the most interesting aspect of the WWF report is what it omits entirely: the relationship between current climate trends and polar bear population.

Figure 1, which is taken from the WWF report, details the location of polar bear populations and their current status. We’ve depicted their status using shading, which was not a part of WWF’s original figure. Figure 2 shows the temperature trends from 1950 to 1995 for Arctic subregions as defined in a recent paper by Rajmund Przybylak and examining Arctic temperature histories.

Notice how in the Baffin Bay region (the area between North America and Greenland), the temperature has been decreasing and the polar bear populations there have been in decline. In the region with the greatest temperature increase – the Pacific region between Siberia and Alaska – nearby bear populations in the North and South Beaufort Sea (just north of Alaska) have risen. Bear population and temperature have been relatively stable throughout the remaining areas. In other words, the observed relationship between temperature and bear population is the opposite of what the WWF report would lead you to believe is to come.

References:

Is Arctic sea ice rapidly vanishing? Fisheries and Oceans Canada - Pacific Region. http://www-sci.pac.dfo-mpo.gc.ca/osap/projects/jpod/projects/arc_thin/thin1.htm

Przybylak, R., 2000. Temporal and spatial variation of surface air temperature over the period of instrumental observations in the Arctic. International Journal of Climatology, 20: 587–614.

Norris, S., Rosentrater, L, Martin, P., 2002. Polar Bears at Risk. WWF International Arctic Programme. http://www.worldwildlife.org/climate/polar_bears.pdf

 

Figure 1. Polar bear population trends (yellow = unknown; green = stable; blue = decreasing; red = increasing), according to information in the World Wildlife Fund report.

 

Figure 2. Temperature trend, 1950 to 1995, for sub-regions of the Arctic (outlined in pink) as determined in a recent study of Arctic temperature trends by Rajmund Przybylak (blue = cooling; red = warming; yellow = no data; green = no significant change).

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Greening Earth Society Virtual Climate Alerts are published periodically in response to news coverage of climate-change advocacy that seeks to portray weather events and hypothetical climate scenarios generated by computer-based climate models as "climate reality." Virtual Climate Alert is coordinated by New Hope Environmental Services of Charlottesville, Virginia.