Climate change is a global threat requiring global action, so it’s essential that the U.S. join, and preferably guide, worldwide cooperative efforts. Among Biden’s first acts should be notifying the United Nations that the U.S. will rejoin the Paris Agreement — a global framework for carbon abatement, advanced by the U.S. and then abandoned by Donald Trump. Its targets need to be made more ambitious, and the U.S. should lead not by exhortation but by example.

An ambitious target for clean power is crucial, and a fast transition is feasible. The cost of clean energy from sources such as wind and solar has fallen dramatically and is still falling. In many cases, clean power is already cheaper than electricity from fossil fuels, even without taking its huge environmental and health benefits into account. Hydrogen, a storable fuel, is poised to become the next significant clean power source. Battery technology is improving all the time. And with new and better energy infrastructure, the U.S. can build a smart power grid. Clean power is within reach.