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Smaller Trends and No Acceleration of Mediterranean Sea Levels

Paper Reviewed
Zerbini, S., Raicich, F., Prati, C.M., Bruni, S., Conte, S.D., Errico, M. and Santi, E. 2017. Sea-level change in the Northern Mediterranean Sea from long-period tide gauge time series. Earth-Science Reviews 167: 72-87.

Introducing their work, Zerbini et al. (2017) say that in order "to highlight the important contribution that long-period tide gauge time series can provide to research on climate change, [they] studied the centennial sea-level records of six fairly well documented tide gauges in the Mediterranean," which stations were located at Alicante, Spain, Marseille, France, and Genoa, Marina di Ravenna, Venice and Trieste, Italy. Data from these six stations are among the longest in this region, stretching all the way back to the last decades of the 19th century.

The results of their study are highlighted in the figure below, which depicts the time series of annual mean sea level values and estimated linear trends for each of the six stations, corrected for vertical land movements and other biases inherent in the raw data. With respect to those trends, Zerbini et al. report they are between + 1.2 and + 1.3 mm per year, which linear trend values, they say, are about 0.5 mm lower than the global mean rate over this period published by the IPCC in their latest (AR5) report. Nevertheless, the seven Italian researchers state their estimates are "in perfect agreement with the global findings of Hay et al. (2015) who, using probabilistic techniques, have recently revisited the analysis of global mean sea level since the beginning of the twentieth century [and] estimated a rate of global mean sea level rise equal to 1.2 ± 0.2 mm/year for the period 1901-1990."

Zerbini et al. also investigated/tested for the existence of an acceleration of sea level rise in each of the six Mediterranean station's data, reporting that "our analysis indicates that it is not possible to reliably state the existence of any acceleration, in the area of this study, considering the past 140 years or so, from 1870 through 2012."

The above findings must surely alarm the alarmists, who for more than two decades now have been professing catastrophic future sea level rise for hundreds of millions of inhabitants living in coastal regions across the globe, whereas observations to date show nothing of the sort even appears to be on the horizon.

Figure 1. Time series of annual mean sea level values and estimated linear trends. Adapted from Zerbini et al. (2017).

Hay, C.C., Morrow, E., Kopp, R.E. and Mitrovica, J.X. 2015. Probabilistic reanalysis of twentieth-century sea-level rise. Nature 517: 481-484.

Posted 15 September 2017