Global energy-related carbon dioxide(CO2)emissions pla-teaued in 2019,at 33 Gt,according to a February 2020 report released by the International Energy Agency(IEA)[1].This level-ling off occurred against a backdrop of global economic growth of 2.9％[2].The apparent stasis in emissions belies a multiplicity of emissions increases and reductions resulting from geographical,technological,and commercial swings.It also hides a tale of “two worlds”:a drop in emissions from advanced nations that are tran-sitioning towards clean,renewable energy sources-primarily wind and solar-offset against the growing emissions of poorer nations that continue to increase their reliance on coal,particularly in Asia(Fig.1)[1].