The Shoreline between Nature and Society, a Changing Heritage - Vulnerability of Coastal Ecosystems and Adaptation - page 183

matter, sand and shingles, and mudstones of course, but whose size
allowed for all types of dispersion [PIN 74, VAN 77]. The sandy shores
as they stand today are only the outcome of the transgression in
question coming to an end with, since then, a constant reprocessing of
the matter that tends to correspond to the dominant swells. So that when
humans have frozen the shoreline with heavy structures, they have
introduced noise parameters in the order of nature. Many bitter
experiences on the ground are the consequences of misunderstanding
the mechanisms of transgression itself.
At the dawn of the 21st Century, sea level rise is an element of the
debate on global warming that cannot be denied. In summary, the
temperatures have started to rise since the years 1880, i.e. long before
the massive industrial development of the last decades. The causes of it
are “natural”; we are at the end of the Little Ice Age, although the coal
burning activities of the last 50 years might have played a role in that.
The 20th Century has seen a rise in temperatures of the order of 0.5°C
between 1880 and 1940, then it went down by 0.2°C until the end of the
1960s. The sea level is thought to have risen by about 15 cm including
all the known causes (steric effect, etc.). Should we “fear the worst” as
Roland Paskoff wrote in his controversial topic [PAS 93]? Surely not in
the short term or beyond recent controversies, publicized by the media
and so therefore partly curtailed of their scientific accuracy. At the time,
nothing indicates that more than a 50-cm rise can be expected during
this century; which is disclosed by the latest IPCC report and confirmed
by September 2013 report. Indeed, this report gives a fork included
between 26 and 82 cm for 2100, which has not changed since the 2007
predictions except for the alarmist tone that puts the emphasis on human
responsibilities in the situation. Of course, these curves indicate a
relative acceleration (of 3.2 mm/year), taking into account the
fluctuations arising due to El Niño and La Niña oscillations. However,
it is important to note and discuss the results and the place from which
they have been obtained: the coastlines are a human heritage; they are
becoming increasingly crowded, and the risks are growing accordingly.
Recent catastrophes, the Japanese and Indonesian tsunamis [LAV 11],
and the recent storms in the Atlantic, ring so many alarm bells but there
is no need to anticipate and attempt to predict future changes, because
the risk is very much present.