“Humanity is on thin ice,” UN Secretary-General António Guterres said during a video message in March 2023. “And that ice is melting fast." Guterres was responding to the AR6 Synthesis Report from the United Nations Intergovernmental Panel on Climate Change (IPCC), which warned of “a rapidly closing window of opportunity to secure a livable and sustainable future for all.” To keep temperature rise to 1.5°C and avoid a cascade of climatological catastrophes—flood, drought, famine, disease, species extinction, and many, many others—the world must cut greenhouse gas emissions in half by 2030. [...]