In the year 2100, tourists will be flying nine times as many kilometres as in 2015, and the average travel distance for all tourist journeys is set to double over the same period. Aviation, 90 percent of which is tourism, must be severely restricted if we are to meet the climate targets. This conclusion was drawn by Paul Peeters, who will be awarded his PhD for his thesis on this subject at Delft University of Technology (TU Delft, The Netherlands) on Wednesday 15 November.