evidence: Depopulation and associated challenges for US cities by 2100 [...] Finally, it is worth noting that many of these demographic transitions are made within the context of accelerating climate change. Climate change can and will intersect with these demographic changes in multiple ways. For example, it can impact fertility by changing human behaviour and affecting migration patterns within countries (e.g. from rural to urban areas) and between countries (e.g. from poor to rich countries)19. These climate change-related shifts in migration patterns can exacerbate ongoing population shrinking and ageing, for example by influencing younger people to out-migrate from already rapidly ageing areas, accelerating thus population shrinking in some areas13,20,21. [...] In this sense, different ageing and shrinking countries and regions will very likely adapt through various context-specific social and economic measures. In some countries there are already discussions about the possibility of a ‘depopulation dividend’ through interventions such as the above linked to economic revitalization activities, i.e. ‘achievement from depopulation of positive gains that contribute to socio-cultural, political–economic, and environmentally sustainable living’109 (see example of ‘depopulation dividend’ for Sado Island in Japan, Supplementary Table 3).