This chapter examines connections between climatic determinist accounts of civilization and the tendency toward climate reductionism in recent writings on climate change and future societal collapse. It examines the writings of a sequence of key historical figures, notably, Hippocrates, Ibn Khaldūn, Montesquieu, and Buckle. Thereafter the work of a range of late nineteenth and early twentieth-century American writers including the chemist-historian John William Draper, geographers Ellsworth Huntington and Ellen Semple, and medical practitioners William Petersen and Clarence Mills are reviewed. Scrutiny of their pronouncements reveals the intimate connections such figures perceived between climate and health, wealth, war, eugenics, temperament, and civilization more generally. The essay foregrounds continuities between these proposals and the writings of some contemporary commentators on climate and economics, and on the implications of climate change for the future of human society.