Billions in U.S. Funding Hasn’t Convinced Developing World to Ditch Coal

JOHANNESBURG—Wealthy nations are sending tens of billions of dollars to poorer ones for clean energy, the linchpin of a global strategy to cut greenhouse-gas emissions in the developing world.

But two of the most ambitious efforts yet—in South Africa and Indonesia—are now at risk of unraveling, sowing doubts about the rich world’s ability to push developing countries away from coal and other fossil fuels.