Nature Geoscience, Published online: 21 August 2026; doi:10.1038/s41561-026-02038-6 During renewable energy droughts, emissions from fossil-fuel power plants may increase; combined with the stagnant weather typical of such periods, the result is an increased risk of extreme air pollution — as is shown to be the case in China by 2050. However, strategically over-deploying clean energy can cost-effectively sustain electricity generation during these droughts, reducing their impact.