In this short, five-page chapter, Jahren takes a quick foray into carbon dioxide. When humans pluck fossil fuels from the depths of the Earth and burn them to create energy, the process releases a heavy dose of carbon dioxide into the atmosphere. This gas would have normally stayed trapped and harmless inside the ground. The carbon dioxide molecule holds onto heat, so when it’s released into the atmosphere in great doses, it warms the atmosphere.

Jahren opens with a discussion of what she perceives to be weather: It’s part wind, part temperature, part sun. These factors are constantly moving and changing, creating complex weather patterns. During her childhood in Minnesota, the winters were uncomfortably cold, but that is now changing: “Minnesota, along with the rest of the Midwest, has become downright balmy since I was a kid, and more and more of what used to be snow now comes down as rain” (135). The increased levels of carbon dioxide in the atmosphere have raised the global temperature by 1.5 °F in the last century, but that fact does not necessarily mean the weather will simply feel warmer.