The geography of green innovation

In the last decades, the geography of innovation activity became much more concentrated. By focusing on the metropolitan statistical area of residence of the inventors of patents granted by the United States Patents and Trademark Office between 1976 and 2020, we investigate whether this is true also for "green" innovation, i.e. patents covering mitigation or adaptation to climate change. We find a sharp increase in concentration across areas after the beginning of the 2000s, with areas that are generally more innovative also producing more green patents. Moreover, for an in-depth analysis of spatial dependence patterns, we firstly survey the literature to find tests suitable for comparing spatial patterns and then apply these tests to the data on green patenting in comparison with non-green patenting. We find significant differences between the two phenomena.