© Press AssociationSome regions of the UK are likely to see more floods, especially in winter.
Launching the UK Climate Projections 2009 report (UKCP09), Mr Benn told MPs that the UK climate will change even with a global deal on emissions.
By 2080, London will be between 2C and 6C hotter than it is now, he said.
Every part of the UK is likely to be wetter in winter and drier in summer, according to the projections.
Summer rainfall could decrease by about 20% in the south of England and in Yorkshire and Humberside by the middle of the century.
Scotland and the north-west of England could see winter rainfall increase by a similar amount.
The government hopes UKCP09 will allow citizens, local authorities and businesses to plan for future decades.
It uses computer models of the world's climate to make projections of parameters such as temperature, rainfall and wind.
Comment: Here is an article covering the discovery of the "new" cloud formations.
The clouds with no name: Harbingers of a mighty storm