The key evidence relied on by Al Gore, the United Nations and other global warming alarmists is the “hockey stick” graph developed by Mann, Bradley and Hughes. It purports to show that 20th-century warming is unprecedented and that the 20th century was the warmest ever:
The “hockey stick” graph had the virtue, from the alarmists’ perspective, of “getting rid of” the Medieval Warm Period, which had always been acknowledged as the predecessor to the Little Ice Age and our own era, in which temperatures have recovered from the Little Ice Age:
More recent scientific work has thoroughly debunked the Mann “hockey stick” analysis. It has been shown to rest on “collation errors, unjustified truncation or extrapolation of source data, obsolete data, incorrect principal component calculations, geographical mislocations and other serious defects,” as well as “incorrect mathematics.” There are indications, at least, that some of the errors on the part of Mann and his collaborators were deliberate–an instance of the corruption of science by politics and perverse financial incentives that underlies the entire global warming movement.
Andrew Bostom provides an excellent short summary of the significance of the hockey stick and its debunking by more rigorous scientists, which is readily understandable by the lay reader.
If you really want to worry about the climate, consider the fact that we are due for another ice age. I don’t believe there is anything we can do that will control the Earth’s weather, but if anyone seriously thinks that putting more carbon dioxide into the atmosphere will materially raise temperatures, a rational risk assessment would suggest that we emit as much carbon dioxide as possible in hopes of delaying the onset of the far greater evil–the next ice age.
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