Global costs of protecting against sea-level rise at 1.5 to 4.0 °C

Abstract

Sea levels will rise, even with stringent climate change mitigation. Mitigation will slow the rate of rise. There is limited knowledge on how the costs of coastal protection vary with alternative global warming levels of 1.5 to 4.0 °C. Analysing six sea-level rise scenarios (0.74 to 1.09 m, 50th percentile) across these warming levels, and five Shared Socioeconomic Pathways, this paper quantifies the economic costs of flooding and protection due to sea-level rise using the Dynamic Interactive Vulnerability Assessment (DIVA) modelling framework. Results are presented for World Bank income groups and five selected countries from the present to 2100. Annual sea flood damage costs without additional adaptation are more influenced by socio-economic development than sea-level rise, indicating that there are opportunities to control risk with development choices. In contrast, annual sea dike investment costs are more dependent on the magnitude of sea-level rise. In terms of total costs with adaptation, upper middle, low middle and low income groups are projected to have higher relative costs as a proportion of GDP compared with high income groups. If low income countries protected now, flood costs could be reduced after 2050 and beyond. However, without further adaptation, their coasts will experience growing risks and costs leaving them increasingly reliant on emergency response measures. Without mitigation or adaptation, greater inequalities in damage costs between income groups could result. At country level, annual sea flood damage costs without additional adaptation are projected to rapidly increase with approximately 0.2 m of sea-level rise, leaving limited time to plan and adapt.

Global-scale analysis of socioeconomic impacts of coastal flooding over the 21st century

“…The present analysis considers the adaptation strategy in the form of coastal protection by structural measures (e.g. dikes), similar to previous analyses (Nicholls, 2002;Hinkel et al, 2014;Lincke and Hinkel, 2018;Nicholls et al, 2019;Tamura et al, 2019;Tiggeloven et al, 2020;Vousdoukas et al, 2020;Brown et al, 2021). Coastal protection by structural measures is commonly applied in impact studies because it delivers more predictable safety levels against coastal extremes (Vousdoukas et al, 2020) to estimate the future costs of adaptation.…”

New LiDAR‐Based Elevation Model Shows Greatest Increase in Global Coastal Exposure to Flooding to Be Caused by Early‐Stage Sea‐Level Rise

“…Nine near‐global DEMs that are available in the public domain with some of them previously being applied in global and local assessments of flood risk (Brown et al., 2018, 2021; Haasnoot et al., 2021; Jevrejeva et al., 2018; Kirezci et al., 2020; Koks et al., 2019; Neumann et al., 2015; Nicholls et al., 2021; Schuerch et al., 2018; Zhang et al., 2019), are compared with the GLL_DTM_v2. These are SRTM v4.1 (Jarvis et al., 2008), MERIT‐DEM (Yamazaki et al., 2017), CoastalDEM v2.1 (Kulp & Strauss, 2021), TanDEM‐X (Rizzoli et al., 2017), Copernicus DEM GLO‐30 v2020‐02 (Airbus, 2020), FABDEM (Hawker et al., 2022), NASADEM v1 (Crippen et al., 2016), ASTER GDEM v3 (Abrams et al., 2020), and ALOS AW3D30 v3.2 (Tadono et al., 2016).…”

“…The radar‐based SRTM was the first GDEM and is still most commonly used in global coastal SLR impact assessments to date (e.g., Brown et al., 2021; Jevrejeva et al., 2018; Nicholls et al., 2021; Schuerch et al., 2018; Syvitski et al., 2009) despite having low vertical accuracy by any measure (Vernimmen et al., 2020). The MERIT GDEM is also often used in global and regional assessments (Haasnoot et al., 2021; Kirezci et al., 2020) but while having somewhat improved accuracies compared to its source SRTM it still cannot be used with high confidence in SLR assessments (Gesch, 2018; Hooijer & Vernimmen, 2021).…”

Future sea level rise dominates changes in worst case extreme sea levels along the global coastline by 2100

“…Coastal zones contain large human populations, significant socio-economic activities and assets, and fragile ecosystems. With climate change and sea level rise coastal communities face increasing risk of more frequent and severe coastal inundation, leading to huge economic losses (Jevrejeva et al 2018, Abadie et al 2020, Vousdoukas et al 2020, Brown et al 2021, IPCC 2021, 2022. While the focus of sea level change studies tends to be on quantifying the rate and magnitude of mean sea level rise, most threats of coastal flooding are governed by a combination of extreme sea levels (ESLs) due to storm surges and waves, and sea level rise (Vousdoukas et al 2018, Kirezci et al 2020, Tebaldi et al 2021.…”