Implications of energy and CO2 emission changes in Japan and Germany after the Fukushima accident

Highlights: • Post-Fukushima CO₂ emission rises in Japan and Germany were limited despite major cuts in nuclear power. • This was due to record-high renewable power levels and lower/steady total energy use. • However large amounts of emissions and deaths were avoidable if coal and gas were reduced instead of nuclear. • These avoidable impacts will make it harder to meet near-term national mitigation targets. • Major energy users should reduce fossil fuels instead of or before nuclear. -- Abstract: Following the March 2011 nuclear power plant accident in Fukushima, Japan, nuclear power production declined sharply in that country as well as Germany. Despite widespread media coverage of CO₂ emission increases in the first few years afterward, subsequent energy and emission changes and their implications are not well-studied. Here we analyze energy, electricity, and CO₂ emissions data for both countries through 2017. We also quantify the human health and CO₂ implications of two simple yet illuminating scenarios: What if both countries had reduced fossil fuel power output instead of nuclear? And what if the US and the rest of Europe eliminate their remaining nuclear power? We find that emissions increased after Fukushima until 2013 but decreased thereafter due to record-high renewable energy production and lower total energy use. However our "what if" scenarios demonstrate that these two countries could have prevented 28,000 air pollution-induced deaths and 2400 MtCO₂ emissions between 2011 and 2017. Germany can still prevent 16,000 deaths and 1100 MtCO₂ emissions by 2035 by reducing coal instead of eliminating nuclear as planned. If the US and the rest of Europe follow Germany's example they could lose the chance to prevent over 200,000 deaths and 14,000 MtCO₂ emissions by 2035.