evidence: Yet despite three decades of warnings by the IPCC—and sporadic displays of global coordination—leaders have done far too little, far too slowly to stop further warming. The concentration of carbon dioxide in the atmosphere is now the highest ever recorded when looking back two million years. As the IPCC’s latest report shows, the need for deep and immediate action is clearer than ever. Every ton of emissions reduction matters. Every investment in building resilience matters. [...] To limit warming to 1.5 degrees Celsius by century’s end, we’ll need system-wide changes on a scale never before seen. It means shifting the way we produce and consume energy, from carbon-intensive fossil fuels to clean, renewable energy. It means changing how we manage our land, consume goods and services, store our waste, travel, and even how we eat. [...] Where do we go from here?