New LiDAR‐Based Elevation Model Shows Greatest Increase in Global Coastal Exposure to Flooding to Be Caused by Early‐Stage Sea‐Level Rise. Issue 1 (2nd January 2023)

• Record Type: Journal Article
• Authors: Vernimmen, Ronald; Hooijer, Aljosja
• Is Part Of: Earth's future. Volume 11:Issue 1(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2023-01-02
• Subjects: ICESat‐2 -- global lowland DTM -- GLL_DTM_v2 -- satellite LiDAR -- coastal flood exposure -- sea‐level rise; Environmental sciences -- Periodicals; Environmental sciences; Periodicals; 550
• DOI: 10.1029/2022EF002880
• Languages: English
• ISSNs: 2328-4277

Abstract

Abstract: The latest projections indicate that sea‐level rise (SLR) is certain to exceed 2 m in coming centuries, and a rise by 4 m is considered possible. Radar‐based land elevation models applied to date suggest that the increase of area below mean sea level, that is potentially exposed to permanent flooding, will accelerate as SLR proceeds, being relatively limited initially. However, applying new and more accurate satellite LiDAR elevation data we find the opposite pattern, with the fastest increase in the area of exposed land occurring in the early stages of SLR. In one‐third of countries most of this increase will be caused by the first meter of SLR and in nearly all within the first 2 m. We conclude that in many regions the time available to prepare for increased exposure to flooding may be considerably less than assumed to date, and that better elevation data will support timely preparations. The global LiDAR lowland DTM (GLL_DTM_v2) elevation data set developed for this assessment is available in the public domain. Plain Language Summary: The latest sea‐level rise (SLR) projections indicate that future sea levels are certain to exceed 2 m and a rise by 4 m is considered possible. Land elevation models applied to date suggest that the increase of land area below sea level will be limited at first but will go faster when SLR continues. When we apply a new and more accurate elevation model we find the opposite pattern, with the fastest increase during the early stages of SLR. In one‐third of countries most of this increase will be during the first meter of SLR, and in almost all within the first 2 m. We conclude that in many regions the time available to prepare for increased exposure to flooding may be considerably less than assumed to date, and that better elevation data will support timely preparations. The global LiDAR lowland DTM (GLL_DTM_v2) elevation data set developed for this assessment is available in the public domain. Key Points: Calculations using radar‐based global elevation models available to date have generally underestimated the extent of lowest coastal areas that are most exposed to sea‐level rise (SLR) A recent lowland elevation model (global LiDAR lowland DTM (GLL_DTM_v2)) derived from only satellite LiDAR data is currently most accurate, we recommend such LiDAR data to be used in SLR impact assessments Applying this model we find that the greatest increase in coastal area below mean sea level will occur in the early stages of SLR, contrary to earlier assessments