Potsdam, 28 April 2014 – Dear Rob, Many thanks for your letter. You have raised relevant and important questions about approval procedures for the Summary for Policymakers (SPM). We, the three Co-Chairs of IPCC Working Group III (WG III), would like to thank you, first of all, for your tireless work and your excellent leadership in Chapter 13 “International Cooperation: Agreements and Instruments”, in the process of writing the summary documents and during the WGIII session in Berlin. We also thank you for voicing your concerns.