CLIMADA v1.4.1: towards a globally consistent adaptation options appraisal tool

Climate change is a fact; therefore, adaptation to a changing environment is a necessity. Adaptation is ultimately local, yet similar challenges pose themselves to decision-makers all across the globe and on all levels. The Economics of Climate Adaptation (ECA) methodology has established an economic framework to fully integrate risk and reward perspectives of different stakeholders, underpinned by the CLIMADA (CLIMateADAptation) impact modeling platform. We present an extension of the latter to appraise adaption options in a consistent fashion in order to provide decision-makers from the local to the global level with the necessary facts to identify the most effective instruments to meet the adaptation challenge. We apply the open-source Python implementation to a tropical cyclone impact case study in the Caribbean, using openly available data. This allows us to prioritize a small basket of adaptation options, namely green and gray infrastructure options as well as behavioral measures and risk transfer, and permits inter-island comparisons. In Anguilla, for example, mangroves avert simulated damages more than 4 times the cost estimated for mangrove restoration, whereas the enforcement of building codes is shown to be effective in the Turks and Caicos Islands in a moderate-climate-change scenario. For all islands, cost-effective measures reduce the cost of risk transfer, which covers the damage of high-impact events that cannot be cost-effectively prevented by other measures. This extended version of the CLIMADA platform has been designed to enable risk assessment and options appraisal in a modular form and occasionally bespoke fashion yet with the high reusability of common functionalities to foster the usage of the platform in interdisciplinary studies and international collaboration.