Influence of El Niño on the variability of global shoreline position

Abstract

Coastal zones are fragile and complex dynamical systems that are increasingly under threat from the combined effects of anthropogenic pressure and climate change. Using global satellite derived shoreline positions from 1993 to 2019 and a variety of reanalysis products, here we show that shorelines are under the influence of three main drivers: sea-level, ocean waves and river discharge. While sea level directly affects coastal mobility, waves affect both erosion/accretion and total water levels, and rivers affect coastal sediment budgets and salinity-induced water levels. By deriving a conceptual global model that accounts for the influence of dominant modes of climate variability on these drivers, we show that interannual shoreline changes are largely driven by different ENSO regimes and their complex inter-basin teleconnections. Our results provide a new framework for understanding and predicting climate-induced coastal hazards.

Role of Atmospheric Indices in Describing Shoreline Variability Along the Atlantic Coast of Europe

“…Global studies of shoreline change based on satellite‐derived shorelines (SDS) are becoming increasingly common (Almar et al., 2023; Ghanavati et al., 2023; Luijendijk et al., 2018; Mentaschi et al., 2018; Vousdoukas et al., 2020); however, concerns have been raised regarding satellite‐derived global applications (Cooper et al., 2020; Zăinescu et al., 2023). To explore links between shoreline response and modes of climate variability, robust methodologies for deriving shorelines involving wave and/or tide corrections (Castelle et al., 2021; Vos et al., 2023) or time‐ and spatial‐averaging techniques (Castelle et al., 2022; Warrick et al., 2023) must be applied.…”

“…Based on SDS, Almar et al. (2023) recently claimed that interannual shoreline changes at the global scale are largely driven by different ENSO regimes and their complex inter‐basin teleconnections, including along the Atlantic coast of Europe. Noteworthy, the authors used uncorrected SDS data at 0.5° spaced transects.…”

“…However, the typical time-and space-averaging windows and type of water-level correction are essentially site-specific (Konstantinou et al, 2023), which challenges such global application. Based on SDS, Almar et al (2023) recently claimed that interannual shoreline changes at the global scale are largely driven by different ENSO regimes and their complex inter-basin teleconnections, including along the Atlantic coast of Europe. Noteworthy, the authors used uncorrected SDS data at 0.5° spaced transects.…”

“…Since wave height variability is strongly linked to coastal dynamics, it can therefore be hypothesized that atmospheric indices are also linked to coastal change. Almar et al (2023) used this hypothesis on a global scale by developing a conceptual global model based on satellite-derived shoreline (SDS) positions from 1993 to 2019 and a variety of reanalysis products. They argue that global interannual shoreline changes are largely driven by different ENSO regimes and their complex inter-basin teleconnections, but reported correlations for the NE Atlantic appear weak.…”

Satellite-derived sandy shoreline trends and interannual variability along the Atlantic coast of Europe

“…Another limitation of previous SDS studies at regional to global scales is that shoreline change characteristics are typically averaged geographically [i.e. latitude, longitude, country, continent 1,33,34] or at too-coarse a spatial resolution [34], which cannot capture the variability of shoreline response at the scale of the coastal environments. A large body of literature based on field data shows that coastal settings, such as coastline orientation with respect to the dominant wave climate [e.g.…”