I was a professional scientist for over 50 years and still have contact with many others; most of them express considerable scepticism about the current orthodoxy of anthropogenic global warming. The repeated use of the snide term “denier” conveys more about those who use it than about those to whom it is applied. Press and other reports constantly confuse three matters which are related but distinguishable: they are climate change, global warming and the effect of man-made carbon dioxide. The climate is certainly changing because it has always changed and always will. The measurement of global warming is based on some questionable observations and some even more questionable averaging calculations, but the reported warming may be real. As to the third item, the effect of man-made carbon dioxide, this is an artefact of computer modelling. Howison states correctly that the atmosphere is a chaotic system; computer models try to accommodate this but none of them has a complete representation of the behaviour of the oceans and their complex interaction with the atmosphere or the part played by solar events. The most misleading claim made by the global-warming zealots concerns the support of the opposition by the “fossil fuel lobby”. Enron was one the biggest lobbyists for the Kyoto Agreement and many major energy companies stand to make billions if they can persuade governments to ration supplies and subsidise the removal of obsolete operations. The international swindle of carbon trading is another dripping roast for the energy suppliers. Dr Peter Dryburgh, Edinburgh