Trends and cycles in CO2 emissions and incomes: Cross-country evidence on decoupling

This paper provides cross-country evidence on the relationship between growth in CO2 emissions and real GDP growth from 1960 to 2018. The focus is on distinguishing longer-run trends in this relationship from short-run cyclical fluctuations, and on documenting changes in these relationships over time. Using two filtering techniques for separating trend and cycle, we find that long-run trends show evidence of decoupling in richer nations—particularly in European countries—but not yet in developing economies, and that there is stronger evidence of decoupling over the 1990 to 2018 sub-period than over the earlier 1960 to 1989 sub-period. There is also a strong cyclical relationship between emissions and real GDP growth in both advanced and developing economies, and the strength of this relationship has not weakened much over time. The cyclical relationship is largely symmetric: emissions fall about as much during recessions as they rise during booms. The transition to a low-carbon economy will thus require continued progress not only in bringing down trend emissions, particularly in developing economies, but also in taming the increase in emissions that occurs during the boom phase of the business cycle.