This month’s United Nations Climate Change Conference (COP24) in Katowice, Poland succeeded in producing a rulebook to implement the 2015 Paris climate agreement. Every UN member state signed on. But that will not be enough to head off climate catastrophe. It’s time to call in the engineers. When heads of state convene at the UN next September, the world’s leading engineers should greet them with a cutting-edge framework for global action. Energy transformation for climate safety is our twenty-first-century moonshot. By Jeffrey D. Sachs.