Scenarios for adaptive flood protection alongside the SSPs for improved climate risk assessment

Abstract

Floods are one of many climate change extremes causing massive economic and non-economic losses and damages. The recent 6th Assessment Report of the IPCC highlights that flooding will be more widespread at 2°C compared to 1.5°C and even more pronounced at higher levels of global warming. To prevent or reduce impacts from flooding, structural measures for flood protection through hard infrastructure are the most common intervention, as they directly manage flood hazards by controlling flow through streams and prevent water overflow. Adaptation options specifically include dikes, flood control gates, weirs, dams, storage and proper waste management. While flood protection could substantially reduce the economic costs of flood events and counts as the most effective adaptation strategy in the water sector to climate change, scenarios for future flood protection are still in their infancy. Consequently, quantitative assessments of climate change (i.e., impact models), which themselves include numerous uncertainties, cannot adequately account for adaptative flood protection in current risk assessments. We propose a Flood Protection Index (FPI) that captures the current level of flood protection across the globe using various data sources. By identifying adaptation-relevant quantitative socioeconomic variables within the framework of the Shared Socioeconomic Pathways (SSPs) and accounting for future climatic risk, we will be able to project five scenarios for flood protection alongside the SSPs. For the first time, we will show how different socioeconomic trajectories could modulate future flood impacts. These scenarios can be included in quantitative assessments of climate change and improve risk assessments in the 21st century.