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