The European Central Bank published Working Paper No 3155 by Michael Koetter and Alexander Popov examining whether electoral success by Germany’s Green Party is followed by changes in pollution outcomes. Using regional data from 1990–2018, the paper finds that emissions decline when Green politicians are in positions of influence, with effects differing by the level of government. When the Greens are the first or second party in county elections, estimates show reductions in locally hazardous pollutants and in carbon dioxide (CO2), including a 5.1% fall in combined carbon monoxide, nitrogen oxides and sulphur dioxide emissions, a 9% fall in total suspended particulates, and an 8.8% fall in CO2. By contrast, when the Greens are part of a state governing coalition, the decline is concentrated in CO2 (4.2%) with no statistically significant effect on the local pollutant measures. The primary channel appears to be lower output in more carbon-intensive sectors rather than improved emissions efficiency, with only weak evidence of lower CO2 emissions per unit of output and stronger evidence of contraction in sectors such as mining and utilities, manufacturing and construction.