What was done
The authors derived proxy temperature records from two deep-sea sediment cores recovered from the Tyrrhenian Sea in a study that provides new insights into the climatic variability of the region encompassing the Mediterranean basin during the termination of the last great ice age and throughout the Holocene.

What was learned
Sbaffi et al. report that seven main cold events with an average duration of 650 years occurred during the last 12,000 years, while they provide evidence suggesting that as many as ten may have occurred over the last 14,000 years.  Consequently, the climatic oscillations they discovered would appear to have a period of between 1400 and 1700 years.  They also note that the timing and intensity of these oscillations are "in good agreement with others previously identified in the Mediterranean basin."  Specifically, they report that in both the western and eastern Mediterranean basins, "evidences of Holocene climate instability have been interpreted as implying 1-2°C variations in sea surface temperatures (Rohling et al., 1997; De Rijk et al., 1999; Cacho et al., 2001; Sbaffi et al., 2001) and these fluctuations are considered to be closely linked with the more extended events observed in the north Atlantic Ocean," citing, in this regard, "the original 1500 year cycle highlighted in north Atlantic studies of the late 1990s (O'Brien et al., 1995; Bond et al., 1997; Campbell et al., 1998)."

What it means
The authors' discovery of these millennial-scale climatic oscillations in the area of the Mediterranean basin "testifies," in their words, "to their wide distribution in an area previously thought to be characterized by Holocene climatic stability," and they thereby give added weight to the conclusion of Bond et al. (2001) that they are likely global in extent and solar-induced, as described in our Editorial of 28 Nov 2001.

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., Chezebiet, 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 climates.  Science 278: 1257-1266.

Cacho, I., Grimalt, J.O., Canals, M., Sbaffi, L., Shackleton, N.J., Schonfeld, J. and Zahn, R.  2001.  Variability of the Western Mediterranean Sea surface temperature during the last 30,000 years and its connection with the northern hemisphere climatic changes.  Paleoceanography 16: 40-52.

Campbell, I.D., Campbell, C., Apps, M.J., Rutter, N. and Bush, A.B.G.  1998.  Late Holocene ~1500 yr climatic periodicities and their implications.  Geology 26: 471-473.

De Rijk, S., Hayes, A. and Rohling, E.J.  1999.  Eastern Mediterranean sapropel SI interruption: an expression of the onset of climatic deterioration around 7 ka B.P.  Marine Geology 153: 337-343.

O'Brien, S.R., Mayewski, A., Meeker, L.D., Meese, D.A., Twickler, M.S. and Whitlow, S.I.  1995.  Complexity of Holocene climate as reconstructed from a Greenland ice-core.  Science 270: 1962-1964.

Rohling, E.J., Jorissen, F.J. and de Stigter, H.C.  1997.  200 years interruption of Holocene sapropel formation in the Adriatic Sea.  Journal of Micropaleontology 16: 9-108.

Sbaffi, L., Wezel, F.C., Kallel, N., Paterne, M., Cacho, I., Ziveri, P. and Shackleton, N.  2001.  Response of the pelagic environment to palaeoclimatic changes in the central Mediterranean Sea during the Late Quaternary.  Marine Geology 178: 39-62.