effect. We have shown relatively precise zero effects across a variety of sensible specifications and ways of measuring exposure to hurricanes. However, it remains possible that particular sub-populations or geographies are in fact experiencing adaptive migration. This is particularly true given that our measure of migration relies on individuals filing tax returns. Very low income or other vulnerable populations may not file returns and so may not appear in our data. The migratory responses of these individuals may therefore be different from what is documented here.

Second, we cannot measure within-county migration. This may be an important dimension of adaptation, as individuals move from more to less-exposed areas within the same county. We cannot capture this form of adaptive migration and so may underestimate the extent of adaptive migration that has occurred between 1992 and 2017. However, recent work utilizing data from U.S. Census tracts finds little to no evidence that migration within U.S. counties has reduced a composite of climate change risk.<sup>26</sup> This result, using aggregate data examining all moves, is contrary to work that focuses on movement after targeted buy-out programs.<sup>25,37</sup> Hence, whether and how migration is a form of adaptation remains an active area of research.

Third, there are many other natural disasters whose frequency will increase as a result of climate change. Our evidence does not indicate that adaptive migration in response to these other disasters is not occurring. Different kinds of disasters may lead to different kinds of migratory responses.

The decision of whether or not to migrate occurs in a specific economic, social, and policy context. It is possible, for example, that our results are driven by existing policy supports and insurance markets that do not fully price-in the effects of climate change, leading people to face lower-than-optimal costs of storm damage.<sup>31,38</sup> Similarly, high-risk areas could be lowering the costs of future hurricanes to individuals by investing in more hurricane-resilient infrastructure and thus lowering incentives for adaptive migration. To the extent that all of these forces are at play, there is a significant role for policy to play in encouraging adaptive responses.<sup>39,40,2</sup> Non-policy changes in economic and social conditions in which the decision to migrate occurs may also change in ways that cause migration to be more adaptive. The increasing prevalence of remote work in the aftermath of the COVID-19 pandemic is one example. If forces like remote work reduce the agglomeration benefits of coastal cities, they may reduce the trade-off between moving to economic opportunity, staying socially connected, and adapting to climate change. The increasing frequency and intensity of storms due to climate change may also make damages a more salient feature of the migration decision in the future.

Future research is needed to understand what factors currently lead to the limited migratory response to hurricanes in the United States. Such research will be useful for informing discussions of managed retreat. The contrast between our results and those focusing on targeted buy-out 14