Environmental efficiency of Japanese regions before and after the Great East Japan Earthquake

This study measured the environmental and energy efficiency of 47 regions in Japan for the period 2005–2017, which was before and after the Great East Japan Earthquake (GEJE) in March 2011, using the slacks-based measure data envelopment analysis model. Our model had comprehensive inputs and outputs: seven inputs (labor, capital, coal, oil, gas, renewables, and electricity), one desirable output (gross regional product), and four undesirable outputs (CO2, SOx, NOx, and dust). In our results, before GEJE, the mean environmental efficiency deteriorated from 0.529 in 2005, 0.518 in 2008, 0.501 in 2011, and 0.464 in 2014 but improved to 0.527 in 2017. Iwate, Miyagi, and Fukushima in the Tohoku region were severely damaged by the earthquake, but these areas were inefficient even before the disaster. Tokyo's environmental efficiency deteriorated from unity in 2005 and 2008 to 0.839 in 2008 and 0.698 in 2011 and then improved back to unity in 2017. We also presented potential reduction ratios for energy and undesirable outputs. To examine the determinants of efficiency, we regressed the efficiency on influencing factors using the panel Tobit model. Gross regional product per capita and tertiary industry share were positively correlated with environmental efficiency. This implies that the development of the service sector is more helpful for transitioning to a sustainable society compared with other sectors.