Recent acceleration in coastal cliff retreat rates on the south coast of Great Britain
File(s)
Accepted version
Author(s)
Hurst, MD
Rood, DH
Ellis, MA
Anderson, RS
Dornbusch, U
Type
Journal Article
Abstract
Rising sea levels and increased storminess are expected to accelerate the erosion of soft-cliff coastlines, threatening coastal infrastructure and livelihoods. To develop predictive models of future coastal change we need fundamentally to know how rapidly coasts have been eroding in the past, and to understand the driving mechanisms of coastal change. Direct observations of cliff retreat rarely extend beyond 150 y, during which humans have significantly modified the coastal system. Cliff retreat rates are unknown in prior centuries and millennia. In this study, we derived retreat rates of chalk cliffs on the south coast of Great Britain over millennial time scales by coupling high-precision cosmogenic radionuclide geochronology and rigorous numerical modeling. Measured 10Be concentrations on rocky coastal platforms were compared with simulations of coastal evolution using a Monte Carlo approach to determine the most likely history of cliff retreat. The 10Be concentrations are consistent with retreat rates of chalk cliffs that were relatively slow (2–6 cm⋅y−1) until a few hundred years ago. Historical observations reveal that retreat rates have subsequently accelerated by an order of magnitude (22–32 cm⋅y−1). We suggest that acceleration is the result of thinning of cliff-front beaches, exacerbated by regional storminess and anthropogenic modification of the coast.
Date Issued
2016-11-22
Date Acceptance
2016-10-05
Citation
Proceedings of the National Academy of Sciences of the United States of America, 2016, 113 (47), pp.13336-13341
ISSN
1091-6490
Publisher
National Academy of Sciences
Start Page
13336
End Page
13341
Journal / Book Title
Proceedings of the National Academy of Sciences of the United States of America
Volume
113
Issue
47
Copyright Statement
© 2016 National Academy of Sciences.
Identifier
https://www.pnas.org/content/113/47/13336/
Subjects
Science & Technology
Multidisciplinary Sciences
Science & Technology - Other Topics
geomorphology
coasts
cosmogenic radionuclides
erosion
cliffs
NUCLIDE PRODUCTION-RATES
CHALK SHORE PLATFORMS
COSMOGENIC NUCLIDES
SPATIAL VARIATIONS
ROCK
EROSION
VULNERABILITY
ATTENUATION
EVOLUTION
PROFILES
cliffs
coasts
cosmogenic radionuclides
erosion
geomorphology
Publication Status
Published
Date Publish Online
2016-11-07