Hypotheses on a Mediterranean Sea regime shift in the late 1980s.

A comparative study of biological and physical time series in the eastern and western Mediterranean Sea for the period 1960s to 2005, combined with a literature review, finds that all point out to an abrupt period of change in the late 1980s that involved circulation and pelagic systems. We show, using regime shift detection methods, evidence that the Mediterranean Sea underwent a climate shift in the late 1980s. An extension of this analysis to larger scale climate indexes (NHT and NAO), shows that they changed around that time. We hence hypothesize that the Mediterranean shift is part of a larger, hemispheric change, and is related to other shifts recorded during the same period in all other European seas