is a climatologist
working at the Hadley Centre
. Formerly primarily a climate modeller
, he is currently Managing Scientist, Data development and applications.
His most-cited paper, is "Climate response to increasing levels of greenhouse gases and sulphate aerosols," (J.F.B. Mitchell, T.C. Johns, J.M. Gregory, S.F.B. Tett, Nature 376 : 501-4, 10 August 1995), and of it he says:
- All attempts at detecting and attributing climate change signals need a reliable observed data set and simulations with mechanisms that drive climate change included. In a nutshell, this paper is important because it was the first study to investigate the effect of sulphate aerosols in a general circulation model of the climate system. The experiments simulate the climate back to 1860 (which is when the global records of surface temperature became reliable)... After 1970 our model with greenhouse gases alone begins to depart significantly from the observations. However, when we included sulphate aerosols, which have a cooling effect, the model agreed with the data from the 1930s and onwards. The rapid warming that has taken place since 1970 is, according to the model, attributable to a heating effect from greenhouse gases and a cooling effect from sulphate aerosols.