Urban Experimentation as a Driver of Climate Adaptation: A European Review of Climate Shelter in National Adaptation Policies and Practices

This paper investigates how climate shelter initiatives implemented in European cities interact with National Adaptation Strategies (NAS) and National Adaptation Plans (NAP), assessing the degree of vertical integration between local practices and national climate adaptation frameworks. As urban heat increasingly threatens public health and exacerbates socio-spatial inequalities, climate shelters, conceived as networks of safe, accessible public spaces providing thermal comfort and social support, have emerged as innovative adaptation tools; however, their recognition within national policy architectures remains uneven across the EU. This study adopts a qualitative-comparative design structured in three phases: (i) a systematic review of NAS and NAP in the 27 EU Member States through keyword screening and classification of references as explicit, implicit, or absent; (ii) a mapping of climate shelter initiatives across 244 NUTS-2 capital cities; and (iii) an integrative cross-analysis of national frameworks and local implementation patterns. According to our results, only 4 Member States explicitly refer to climate shelters, 11 include implicit references, and 12 show no recognition, while 88 cities implement 97 initiatives, predominantly based on Nature-based Solutions and schoolyard transformations; 5 recurring governance configurations reveal bottom-up, top-down, and hybrid dynamics, demonstrating that local experimentation can anticipate, complement, and potentially reshape national adaptation policies.