Following the Fukushima nuclear accident, Japan gradually shut down all its nuclear power plants, causing a countrywide power shortage. In response the government launched large-scale energy-saving campaigns to reduce electricity consumption. Exploiting the electricity-saving targets across regions and over time, we show that the campaigns significantly increased mortality, par-ticularly during extremely hot days. The impact is primarily driven by people using less air conditioning, as encouraged by the govern-ment. Nonpecuniary incentives can explain most of the reduction in electricity consumption. Our findings suggest there exists a trade-off between climate change mitigation and climate change adaptation. (JEL I12, L94, L98, Q48, Q54, Q58)