Question to the Department for Business, Energy and Industrial Strategy:

To ask Her Majesty’s Government, further to the Written Answer by Lord Prior of Brampton on 14 March (HL5780), whether their statement that the increase in global average surface temperatures is not consistent with natural internal variability is supported by evidence that is not based upon computer simulation of the climate.

Our statement reflects the conclusion of the Intergovernmental Panel on Climate Change Fifth Assessment Report that it is virtually certain (>99% probability) that natural internal variability alone cannot account for the observed increase in global surface temperatures. This statement is based on computer model simulations, which capture both the observed magnitude and spatial patterns of warming only when both human and natural forcings are included. Further, reconstructions of past climate variability from records such as ice cores also reveal that recent temperature changes are clearly distinct from natural variability. These records show that temperatures over the last 50 years in the Northern Hemisphere (where records of past climate are most comprehensive) were unusually high relative to the last 1000 years.