Climate change due to production of carbon dioxide, methane, and other greenhouse gases poses the greatest and most urgent threat to the world. The Paris Agreement is too weak a response to save our children, but it is at least a start in focusing global leaders on the issue. The US should ratify the treaty then work within that framework to strengthen it and accelerate the move towards carbon-neutral economies. With the rapid reduction in costs of solar and wind electricity, and of batteries both for transport and power grids, much of the necessary technology already exists. Selfishly, does the US choose to be a leader in this transition, oor abdicate that to China?