He is also invited by mass media on a regular basis to talk about the role of human activity in global warming. In November 2009, he published a new book "New Climate on Earth: Understanding, Predicting, Responding" (in French, ed. Flammarion). In this book, he predicts that due to emissions “"well beyond the worst case scenario"” considered by IPCC projections, a rise in temperatures between 4 and 6 degrees by the end of the century, depending on the selected model. The Copenhague conference failure on the same year made him say that “"if we do nothing, the critical threshold of a temperature rise of 2ºC will be overshoot by 2050."”