Global CO2 efficiency: Country-wise estimates using a stochastic cost frontier

► We estimate global environmental efficiency in line with the Cancun vision, using a stochastic cost frontier. ► The study covers 170 countries during a 10 year period, ending in 2007. ► The biggest improvements occurred in Europe, and efficiency falls in South America. ► The efficiency ranking of US and China, the largest emitters, deteriorated. ► In 2007, highest efficiency was observed in Africa and Europe, and the lowest around China.