Behind the headlines, a struggle between two opposing philosophical visions has shaped the course of international efforts to save the planet from global warming. The liberal cosmopolitanism of the great Enlightenment philosopher Immanuel Kant has been up against the darker vision of an authoritarian global order of great power rivals developed by Carl Schmitt, 'Crown Jurist of the Third Reich'. Clive Hamilton shows how the influence of Schmitt's once-taboo ideas has recently spread around the world – in Trump's America, in Xi Jinping's China, and in Europe with the rise of right-wing populism. His book maps how the actions of these three great powers have defined the course of global climate negotiations. The Kantian vision, best represented by the European Union, has common sense on its side – a threat to everyone that can be solved by collective responses. In practice, however, UN agreements have triggered resistance from surging anti-globalist forces influenced by the Nazi jurist's ideas, a world defined by friends and enemies and where weaker states submit to powerful ones. As the Earth hurtles towards a hot and perilous future, which of these worldviews prevails, Kant's or Schmitt's, could determine humanity's fate.