Cultural heritage and sea level rise threat: risk assessment of coastal fortifications in the Canary Islands

Abstract

Climate change impacts on coastal fortifications due to changing groundwater levels, flood risks, or rising sea levels, are threatening the conservation of these assets. Some castles and fortifications have a high level of structural instability due to their high exposure to changing environmental conditions, especially those in direct contact with the sea. This article focuses on identifying the level of risk posed by climate change to coastal fortifications in the Canary Islands. The methodology implemented identifies the exposure and vulnerability of these fortifications, based on a scorecard assigning values of risk to rising sea levels. Four risk categories were selected based on their exposure to either coastal flooding, coastal erosion or coastline retreat, and taking into account its sensitivity through a structural analysis of buildings. There are currently fifteen coastal fortifications from the Early Modern Period in this archipelago and two have been identified as being especially threatened by rising sea levels. Results highlight a need to increase their adaptive capacity, incorporating changes in legislation, including climate change adaptation measures as a basic strategy in cultural heritage management. Options such as the construction of submerged defenses or dikes in order to dissipate the force of the waves could be successful adaptation measures, considered from the perspective of preserving both the landscape and the environment of these historical sites. This assessment provides support to policy makers for the management of coastal fortifications in the context of climate change.