The term "nuclear winter" was commonly used in the 1980s and represented a scenario where a nuclear war could profoundly alter the earth's climate through injection of aerosols into the stratosphere, which could be considered a highly extreme example of human activity altering the earth system. Paul Crutzen, in his Nobel Prize speech, said that this concept is politically important as it "magnifies and highlights the dangers of a nuclear war and convinces me that in the long run mankind can only escape such horrific consequences if nuclear weapons are totally abolished by international agreement". While nuclear war is hopefully something that we will never experience, it is highly interesting to return to this topic four decades later, after the major advancements in the science of aerosol-climate interactions that have occurred in the meantime (partly motivated by an exploration of geoengineering concepts), and improvements in our abilities to model the agricultural and economic impacts of climate change. The conclusions of the paper by Robock et al. offer a sobering reminder of the manifold dangers of this type of warfare to the earth system and society.