Climate Fault Lines argues that climate politics is transforming. As global warming's effects materialize, a new political cleavage is emerging between people, businesses, and governments in places that stand to lose from higher temperatures and less vulnerable areas that could even benefit. Our book brings together models from geosciences, economics, and political science to theorize and test how these climate cleavages emerge and affect politics. We find that climate change's unequal effects produced polarizing responses within countries and in international relations.