This article establishes empirically that a persistent culture of "rugged individualism," captured by exposure to the American westward-moving frontier from 1790 to 1890, undermines pro-climate perceptions, environmental performance, and climate change preparedness across counties in the United States. It also demonstrates that individualism is associated with environmental underperformance at the state level, making it more difficult to mitigate the far-reaching consequences of changing climate conditions. To establish external validity of the subnational evidence, I use a global sample of up to 97 countries and provide suggestive evidence that individualism creates barriers to climate change responses worldwide.