Canadian political scientist Thomas Homer-Dixon explains why human civilization must make a transition from fossil fuels to low-carbon energy sources—not just because of climate concerns but also because conventional oil is declining in production and becoming increasingly difficult to extract. He describes the political climate in Canada, where conversation about global warming—and especially about the oil sands in Alberta—is now widely viewed as unpatriotic and pointless. Homer-Dixon envisions a potential wake-up call to humanity in the form of a climate shock to global food-production systems, triggered by extreme weather events, and he sees increasing evidence for a connection between environmental stresses and civil conflicts. He calls for accelerated research on energy technologies, such as ultra-deep geothermal power, and for new research on how to restructure economies and social institutions. According to Homer-Dixon, the climate change problem might ultimately reside as much in our heads as in the external world. His latest work focuses on mapping the “mindscape,” a virtual space within which most of the world’s people are clustered in a few ideologically polarized groups. Vast, unexplored regions of the mindscape, he says, may offer new ways of thinking about problems such as climate change and new ways of living together successfully in the future.