Is There a Kuznets Curve for CO2-Emissions?

The history of the environmental Kuznets curve is traced. We estimate how the CO2-intensity of economies is related to GDP per capita and examine the implications for the Kuznets curve. We find mixed evidence for the existence of this curve. In many poor and medium rich countries the CO2-intensity has increased since 1990, while in rich countries it has fallen. In some of those it has fallen at an increasing rate, but in others at a declining rate. If the CO2-intensity converges to a lower limit as countries grow richer the Kuznets curve would not exist.