Newsweek: It was cold in the winter of 1684. Damn cold. So cold, in fact, that a couple of paintings from the time, depicting Londoners gambolling on the frozen River Thames, remain a kind of pictorial shorthand for the depths to which European temperatures can plunge even 330 years later. Earlier this year, those familiar paintings received a fresh airing on the pages of a number of newspapers and websites, carried beneath headlines warning that western Europe was heading for a new little ice age. Research...