Inventing Green: Environmental Shocks and the Long-Term Reorientation of Innovation

How are preferences for innovation formed, and what determines the long-run direction of technological change? This paper shows that early-life exposure to environmental accidents can durably reorient inventive effort decades later, even in the absence of targeted policy. I study radioactive fallout from the 1986 Chernobyl nuclear accident across Sweden, exploiting plausibly exogenous variation in local exposure driven by rainfall. Combining municipality-level fallout data with Swedish patent records from 1967 to 2021, I find that more exposed areas experienced a persistent increase in green patenting, with no change in total patenting. The effect emerges only in the early 2000s, and is driven by individuals exposed during childhood: matching inventor-level data with detailed administrative records, I show that individuals exposed to fallout during their formative years are more likely to enter the patent system as green inventors and to begin their inventive careers with green technologies, consistent with a cohort-based entry mechanism. A simple model of directed technical change with formative exposure rationalizes these findings. In addition, the paper shows that green patents originating from more exposed areas do not have a lower number of citations than other patents, suggesting that the results are not driven by low-quality innovations.