In 2050, approximately 66 % of the total population of the 26 European coastal countries lived in coastal regions (Iglesias-Campos et al., 2015 and Forzieri et al., 2017). Concretely, in Canary Islands the phenomenon of ?littoralisation? is linked to the growth of old urban area as well as to the construction of new ones in coastal areas not previously occupied in last decades. Actually, human transformed coastlines in Canary Islands is a reality and the anthropic pressure on them is patent, receiving, in 2017 up to almost 20 thousand tourists per km of coastline, in the case of Tenerife and Gran Canaria. In addition, we must not lose sight of the fact that the islands have a high population density rate, being much higher in coastal areas, both because of the economic and tourist activities and because of the island orography that prevents the expansion inland or inland areas. As a result, it is known that losses from sea flooding in European coastal cities are likely to increase in the future if no further adaptive actions are taken. Without adaptation measures, the losses modelled would be EUR 31 billion in 2100. The objective of the LIFE COSAdapta project is to provide a validated adaptation solution to sea level rise in island and outermost territories, which share similar characteristics. To this end, during the project, a prototype of an innovative adaptation measure codesigned with participatory processes will be implemented in Quintanilla (Covenant of Mayors for Climate and Energy) . The prototype is based on the re-conceptualization of tidal pools into tidal pool-reef, a more holistic and adaptive view of cultural elements on islands. The multifactorial validation of the prototype will allow the project to provide a new measure of coastal adaptation in the Nature-Based Flood Defense (NBFD, within Nature-Based Solutions) group in addition to a new cataloging of coastal blue infrastructures.

Research team