Sea-level rise induced change in exposure of low-lying coastal land

Sea-level rise induced change in exposure of low-lying coastal land: implications for coastal conservation strategies

Thiéblemont, Rémi (Bureau de Recherches Géologiques et Minières (BRGM))
le Cozannet, Gonéri (Bureau de Recherches Géologiques et Minières (BRGM))
Rohmer, Jérémy (Bureau de Recherches Géologiques et Minières (BRGM))
Privat, Adrien (Conservatoire du littoral)
Guidez, Romain (Bureau de Recherches Géologiques et Minières (BRGM))
Negulescu, Caterina (Bureau de Recherches Géologiques et Minières (BRGM))
Philippenko, Xénia (Bureau de Recherches Géologiques et Minières (BRGM))
Luijendijk, Arjen (TU Delft Coastal Engineering; Deltares)
Calkoen, F.R. (TU Delft Coastal Engineering; Deltares)
Nicholls, Robert J. (University of East Anglia)

2024

Coastal erosion and flooding are projected to increase during the 21^st century due to sea-level rise (SLR). To prevent adverse impacts of unmanaged coastal development, national organizations can apply a land protection policy, which consists of acquiring coastal land to avoid further development. Yet, these reserved areas remain exposed to flooding and erosion enhanced by SLR. Here, we quantify the exposure of the coastal land heritage portfolio of the French Conservatoire du littoral (Cdl). We find that 30% (~40%) of the Cdl lands owned (projected to be owned) are located below the contemporary highest tide level. Nearly 10% additional surface exposure is projected by 2100 under the high greenhouse gas emissions scenario (SSP5-8.5) and 2150 for the moderate scenario (SSP2-4.5). The increase in exposure is largest along the West Mediterranean coast of France. We also find that Cdl land exposure increases more rapidly for SLR in the range of 0–1 m than for SLR in the range 2–4 m. Thus, near-future uncertainty on SLR has the largest impact on Cdl land exposure evolution and related land acquisition planning. Concerning erosion, we find that nearly 1% of Cdl land could be lost in 2100 if observed historical trends continue. Adding the SLR effect could lead to more than 3% land loss. Our study confirms previous findings that Cdl needs to consider land losses due to SLR in its land acquisition strategy and start acquiring land farther from the coast.

Climate change
Coastal conservation agency
Coastal hazards
Sea-level rise
Shoreline

http://resolver.tudelft.nl/uuid:68dd0f90-d594-4239-b18d-43e3bf48cbde

https://doi.org/10.1007/s44218-024-00041-1

Anthropocene Coasts, 7 (1)

Institutional Repository

journal article

© 2024 Rémi Thiéblemont, Gonéri le Cozannet, Jérémy Rohmer, Adrien Privat, Romain Guidez, Caterina Negulescu, Xénia Philippenko, Arjen Luijendijk, F.R. Calkoen, Robert J. Nicholls