With this book's first edition (2007) Cambridge University Press kindly afforded a couple of pages as Appendix 4 to allow a brief summary of the IPCC's 2007 assessment (AR4) at the book's final page-proof stage: that assessment literally came out a couple of months before this book's first edition was published. This time the IPCC's 2013 assessment (AR5) will come out several months after this edition sees light of day and so I now use this appendix in a different way.
In the course of lectures and encounters following this book's first edition I have invariably been asked a number of questions as to my personal thoughts, as opposed to recounting the climate science and policy developments. Other than commenting on likely prospective research and policy analysis avenues, in the main I have shied away from answering, especially as most people have expected me to be predictive: what will happen to such and such in coming decades? And of course nobody can predict the future. Having said that, I do have some personal thoughts on climate science and policy. Given that there has been interest in my own take beyond that of appraising the literature, I now make a couple of points in this short appendix, quite separate from the main body of the text: I do not wish to contaminate my earlier (hopefully) sober review of the science and policy with wilder personal musings.