These findings have implications for what we all must do to prevent disaster. An ECS of 3°C means that if we are to limit global warming to below 2°C forever, we need to keep CO2 concentrations far below twice pre-industrial levels, closer to 450 ppm. Ironically, if the world burns significantly less coal, that would lessen CO2 emissions but also reduce aerosols in the atmosphere that block the sun (such as sulfate particulates),
so we would have to limit(=reduce!) CO2 to below roughly 405 ppm.