Mr Lilley: To ask the Secretary of State for Energy and Climate Change what the evidential basis is for his Department’s statement that scientific evidence shows that extreme weather events are most certainly intensifying. 
Gregory Barker: The Intergovernmental Panel on Climate Change’s (IPCC) recently published Working Group I contribution to its Fifth Assessment Report (AR5)1 shows there is growing evidence that some types of extreme weather events are intensifying.
The AR5 report concludes that since the mid-2001 century it is very likely that the frequency and/or duration of heat waves have likely increased in large parts of Europe, Asia and Australia, there are likely more land regions where the number of heavy precipitation events has increased than where it has decreased, and the frequency or intensity of heavy precipitation events has likely increased in North America and Europe. The AR5 report also concludes that it is virtually certain there have been increases in intense tropical cyclone activity in the North Atlantic, since 1970. Lack of data or studies limits the ability to draw conclusions on how the intensity of some types of extreme weather events has changed in other regions.
A number of recent studies have shown increased risk of certain extreme weather events happening as a result of climate change due to human-caused greenhouse gas emissions2, 3. The AR5 report concludes it is likely that human influence has more than doubled the probability of occurrence of some observed heat waves in some locations.
1 IPCC, 2013: Summary for Policymakers. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. See Table SPM.1.
2 Peterson et al (Eds) 2013. Explaining Extreme Events of 2012 from a Climate Perspective. Special Supplement to the Bull. Amer. Meteor. Soc, 94 (9), S1-S74.
3 Peterson, T.C., Stott, P. A., Herring, S. (Eds) 2012. Explaining Extreme Events of 2011 from a Climate Perspective. Bull. Amer. Meteor. Soc, 93, 1041-1067. doi: