I’ll not comment on the anthropogenesis of global warming for fear of being labeled one who believes the earth is flat, but I will comment on the impending extinction of the polar bear. It is claimed by advocates of the current warming crisis that temperatures now are the highest in recorded history. That claim is correct, if one recasts it to say “the highest in the history of recorded temperatures”, but we have only been recording temperatures for a couple of hundred years. The Wells’ data, using over a hundred proxies (such as tree ring growth) suggests no “medieval warm spell” – but anecdotal and archeological evidence show that a thousand years ago the temperatures (in the northern hemisphere, and particularly the North Atlantic region) were higher than today. Given the choice between the “proxies” and the anecdotal (wine grapes in England that had the French objecting to the competition) and the archeological (kitchen middens with remnants of the grains and animals husbanded – and those in Greenland) I’ll take the latter.
One can’t define the length of the medieval warm spell as one can’t say what is normal – the following centuries led us into the “mini ice age” in Europe – but it doesn’t matter. There is evidence of a “warm spell” in early Roman Britain, but not as well documented. Settlements found in the Orkneys and northern Scotland from some 5 to 6 thousand years ago, settlements of an unknown people who had a civilization that built relatively sophisticated dwellings suggest that the climate there was warmer then than now (and there is evidence that those peoples disappeared by migrating south as the climate cooled).
OK, what about Polar Bears? Even if one doesn’t accept all the proposed warm spells it would be difficult to claim that there were none. The medieval one is estimated to be about 300 years long, but I’m sure there have been significant others. If the current melting of the polar ice cap threatens the polar bear with extinction then we must assume that the polar bear has evolved since the last warm spell – or that the polar bear evolved millions of years ago and has survived a number of meltings. It is not as if the polar bear could migrate to a colder area, that could have applied to the wooly mammoth whose range was in the colder levels of the temperate region. The mammoth could move north, the plar bear had no further north to go.
Personally I think the current panic on global warming is an example of poorly used statistics and a “bandwagon effect” among scientists – we’ve seen that effect before. But that personal opinion doesn’t invalidate my comments above. I will have more to say on the statistical usage in modern science in another posting.