The debate might seem too trivial to care about, but as authors Simon Lewis and Mark A. Maslin demonstrate, the stakes are very high indeed. They show that scientists since the 18th century have recognized human influence on the face of the earth. What we have learned since then, and especially in the past 50 years, shows our influence has grown only greater; we just don’t want to admit it, because then we’d have to try to clean up the mess we’ve made.