of the book. After reading their critiques, I stand even more firmly behind my conclusion that the threats to coral reefs from both man-made warming and ocean acidification are unlikely to be severe, rapid or urgent. In the case of acidification, this is underlined by a recent paper, published since my book was written, summarising the results of 372 papers and concluding that ocean acidification `may not be the widespread problem conjured into the 21st century'. The burden of proof is on those who see an urgent threat to corals from warming and acidification. Here is what I wrote (in bold), interspersed with summaries of the scientists' comments and my replies. Take coral reefs, which are suffering horribly from pollution, silt, nutrient run-off and fishing - especially the harvesting of herbivorous fishes that otherwise keep reefs clean of algae. Yet environmentalists commonly talk as if climate change is a far greater threat than these, and they are cranking up the apocalyptic statements just as they did wrongly about forests and acid rain Andy Ridgwell says `I agree that at least for some reef systems, other, and more local human factors such as fishing and pollution may be the greater danger' and Jelle Bijma says `I do agree that, for example, pollution and overfishing are also important problems, some even more important than the current impact of ocean acidification'. It was not therefore accurate of Liz Else to say that the critics accuse me of failing `to recognize that there is