Abstract
The evolution of coastal hazards in the context of climate change has
been addressed at the regional scale by studying the height and
frequency of extreme sea levels (ESL). However, sea level is not the
only factor determining the hazard changes that can be used at this
scale. Therefore, this article proposes an assessment method of coastal
hazard changes integrating other determinants: geographical
configurations (continental or island), tidal regimes and meteo-oceanic
event types. This method, applied to the coasts of France (mainland and
overseas), reveals significant differences in the evolution of coastal
hazards: coasts subjected to high tidal ranges and storms (e.g.,
Atlantic, English Channel and North Sea) will experience a relatively
moderate evolution of the hazard, thanks to «training» for the future
conditions that present-day high variations constitute. Conversely, the
microtidal shorelines of temperate latitudes (e.g., those of the
Mediterranean) benefit from only a small variability generated mainly by
storm surges, and are therefore poorly prepared for sea level rise. The
situation of the small tropical islands is of particular concern: with
the passage of cyclones these territories are subjected to very
energetic sea states, but by their form, the surges remain moderate,
which constitutes, as well as the low tidal ranges, a limiting factor
for preparing for sea level rise. In addition to this approach at the
regional level, geological, sedimentary and biological evolutions, as
well as local hydraulic phenomena, should be considered to assess at a
finer spatio-temporal scale the hazard changes.