Climate change seems to be an insurmountable problem. Political solutions have so far had little impact. Some scientists are now advocating the so-called 'Plan B', a more direct way of reducing the rate of future warming by reflecting more sunlight back to space, creating a thermostat in the sky. In this book, Mike Hulme argues against this kind of hubristic techno-fix. Drawing upon a distinguished career studying the science, politics and ethics of climate change, he shows why using science to fix the global climate is undesirable, ungovernable and unattainable. Science and technology should instead serve the more pragmatic goals of increasing societal resilience to weather risks, improving regional air quality and driving forward an energy technology transition. Seeking to reset the planet’s thermostat is not the answer.