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Decadal to Centennial Variability in the North Atlantic
Reference
Black, D.E., Peterson, L.C., Overpeck, J.T., Kaplan, A., Evans, M.N. and Kashgarian, M.  1999.  Eight centuries of North Atlantic Ocean atmosphere variability.  Science 286: 1709-1713.

What was done
The authors conducted a high-resolution study of sediments in the southern Caribbean that were deposited over the past 825 years.

What was learned
The record revealed substantial variability of both a decadal and centennial nature, which suggested that climate regime shifts are a natural aspect of Atlantic variability.  Relating these features to other records of climate variability, it was concluded that "these shifts may play a role in triggering changes in the frequency and persistence of drought over North America."  Another finding of note was a strong correspondence between the up-and-down changes in North Atlantic climate and similar changes in 14C production rate, which is accepted as a valid measure of changing solar activity.  In the words of the authors, this finding "suggests that small changes in solar output may influence Atlantic variability on centennial time scales."

What it means
This paper adds to the accumulating store of knowledge that illustrates the fact that variability is the name of the game when it comes to earth's climate.  It shows that climate change is natural, and that one of the natural drivers of this natural change is the naturally-occurring variability of solar processes.  So what's new?  Nothing under the sun.


Reviewed 15 February 2000