Some time in the near future… global emissions of planet-warming greenhouse gases might finally stop rising and head into long-term decline. …Once it does, some analysts think the politics, psychology and even the financing of climate action could shift profoundly. …I have to say this thought did not occur to me in November, when research emerged showing that there is a 70% chance that global emissions will start falling in 2024. …Economist Nat Keohane, a former Obama White House adviser who is now president of the Center for Climate and Energy Solutions think-tank… is remarkably bullish about the impact of a decline. “I think that would be an extraordinarily powerful political and psychological moment,” he told me. …A global peak in emissions will be a big turning point, but not nearly enough to contain warming now hitting levels never recorded before. Years of steep and prolonged falls will be needed after that.