Telegraph: It is, perhaps, the most contentious wiggly line in the history of science. Starting in the year 1000 it depicts global temperatures in wobbly, but overall decline until round about the beginning of the last century, then rearing sharply upwards, ending much higher than at any time in its thousand year span. Quickly dubbed the 'hockey stick' since the long decline looks (sort of) like the stick's handle and the rapid rise (more or less) like its blade it has been at the heart of heated debate...