According to a recent study that has been submitted on 1st August 2013, rising temperature of the climate has an adverse effect on our behavior. Lets say if the temperature gets hot so do we and that makes more irritated and violent. According to the scientist “For instance, when it gets very hot, there may be changes to individuals’ neurophysiology that makes them more predisposed to violence,” There are some scientific reasons for it including human psychology.
To know more about it :- http://www.thehindu.com/sci-tech/science/rising-temperatures-and-flaring-tempers-linked-says-study/article4981753.ece