Re: Something esle caused by climate change...... crime!
The most surprising thing about that article is Geoffrey Lean's cautious reporting of the claim. It may be related to Lean's fairly enthusiastic endorsement a few years ago (when Lean was working for the Independent) of the claim that switching to unleaded petrol was leading to a significant decline in crime rates around the world:
But I think it's pretty easy to debunk the claim that violent crime rate goes up with temperature from looking at data given for how the historical crime rate has varied in some European countries over the past eight centuries in the paper "Long term historical trends in violent crime" by Manuel Eisner:
The decline in crime rate has been dramatic since the 13th and 14th centuries in England. Table 1 and Figs 1 to 7 give the data. So unless the Medieval Warming Period was much hotter than we've been led to believe, it doesn't look as though the historical crime rate has got much to do with temperature.