This Earth Day, dramatic warnings about climate change will be ubiquitous. At his climate summit, U.S. President Joe Biden will undoubtedly repeat that global warming presents an “existential threat.” But most of the hype will be vastly exaggerated. This pervasive climate alarmism is the culmination of persistent eco-anxiety over the past few decades. Already in 1982, the United Nations was predicting that, along with other environmental concerns, climate change could cause worldwide “devastation as complete, as irreversible as any nuclear holocaust” by the year 2000. Needless to say, that...