The author would like to thank the following people: Johanna, Alexandra, and Abbie for surviving lockdown together and allowing me to write the fourth edition; Miles Irving for his excellent illustrations; my editors at OUP Jenny Nugee and Latha Menon; all the wonderful staff at UCL, Sopra Steria Group, Sheep Included, The Conversation, and Rezatec Ltd; Richard Betts, Mark Brandon, Andrew Shepherd, Eric Wolff, and other reviewers, for their insightful and extremely helpful reviews of the different editions of this book; and all my brilliant, dedicated colleagues in climatology, palaeoclimatology, geology, geography, social science, economics, medicine, engineering, humanities, and the arts who continue to strive to understand, predict, and mitigate our influence on the climate of our planet.