Sir, – Those of us who were welcomed to the Joint Service Defence College with Admiral Guy’s scintillating and provocative opening address, will not be surprised by the challenge in We must keep very calm about climate change (NR 108/2). Having spent my sea-time, whether as DTASO or H, in making measurements, I welcome the call to take account of all observations and analysis to enable us to reach some measure of probability in our policy conclusions. ‘Check, check, and check again’ is the regime for surveyors. The article rightly calls prominent opinion-formers to account. Its own array…