Background
"Studies indicate," in the words of the authors, "that estuarine systems are particularly sensitive to changing hydrological conditions," and that one of the major purposes of these studies has been to determine "the effects of past centennial- to millennial-scale natural climatic fluctuations" in order to "better predict the impact of present-day and forthcoming climatic changes (and/or anthropogenic activities) on estuary infill." Of "crucial impact" in this regard, in their estimation, "is the impact of storminess within warmer and colder periods on sedimentary patterns through the climatic regulation of (i) coastal wave hydrodynamics and (ii) continental inputs from the Seine river catchment area [in the case of their specific study] during the late Holocene."

What was done
Sorrel et al. linked high-resolution sediment and rock properties of materials found in cores collected from the Seine estuary in northwest France to climatic conditions of the past few thousand years.

What was learned
The five French researchers found that "increased removal and transport of estuarine sediments occurred when winter storm activity greatly intensified over northwestern France," and they report on "four prominent centennial-scale periods of stronger storminess, occurring with a pacing of ~1500 years," which they say are "likely to be related to the last four [of] Bond's [1997, 2001] Holocene cold events," the most recent of which was the Little Ice Age, when Sorrel et al. say that tidal and open marine hydrodynamics exerted "primary control on the sedimentary evolution of the system during 1200-2003 AD." In contrast, they found that "the preservation of sedimentary successions in the outer Seine estuary was maximal [our italics] during ca. 800-1200 AD," which time period they identify as the Medieval Warm Period, when they say that "sediment reworking by waves was considerably reduced."

What it means
In light of these several observations, it should be clear to everyone that earth's climate experiences a millennial-scale cycling of climate with centennial-scale warm and cold periods, and that in northwest France the warm periods are generally associated with less storminess, in contrast to the climate-alarmist claim that warmth generally brings greater storminess to most all parts of the planet.

References
Bond, G., Kromer, B., Beer, J., Muscheler, R., Evans, M.N., Showers, W., Hoffmann, S., Lotti-Bond, R., Hajdas, I. and Bonani, G. 2001. Persistent solar influence on North Atlantic climate during the Holocene. Science 294: 2130-2136.

Bond, G., Showers, W., Cheseby, M., Lotti, R., Almasi, P., deMenocal, P., Priore, P., Cullen, H., Hajdas, I. and Bonani, G. 1997. A pervasive millennial-scale cycle in North Atlantic Holocene and Glacial climate. Science 278: 1257-1266.