Environmental efficiency and the role of energy innovation in emissions reduction.

Environmental problems, including extreme weather phenomena, unprecedented global warming, and environmental disasters caused by increasing levels of CO2 and other toxic emissions, along with rapidly increasing economic development and energy consumption, require global development and policies to meet sustainable development goals. The traditional data envelopment analysis (DEA) model has limited practical applicability for measuring environmental performance, as it lacks the computational capacity to deal with undesirable outputs. The current study employs "radial" and "non-radial" DEA technology, and acknowledges the associations of a mathematical foundation to increase the analytical capability of the environmental performance of DEA. Results show that in the measurement of environmental performance analysis, the non-radial DEA model has a higher discriminating power compared to radial DEA. Results show that the average values of radial and non-radial environmental performance are highest for Latin America and the Caribbean, at 0.99 and 0.96, respectively, while the former USSR has the lowest values of 0.22 and 0.32, respectively. The South Asian region shows relatively stable values of about 0.58 to 0.65, and Latin America & Caribbean countries and sub-Saharan Africa also show a stable radial environmental performance ranging from 0.82 to 1.00. These results indicate a considerable difference among the eight world regions.