Difficult to take this serious
I would suggest that
* Increasing disparity of wealth ( Rich get richer, poor get poorer)
* Insatisfaction with Governements.
* Corporate Theft. ( Silverstein cough cough)
Were more more likely to cause Murder and Robbery than that that might arrive from a change in climatic conditions.
( Rape is a subject I won't include as it's probably very, very difficult to determine the reasons but I am not sure that Climatic Conditions are the major factor, ymmv)....