IGBP-SCOR Workshop: Ocean acidification — modern observations and past experiences

PAGES News, Vol.14 • No 3 • December 2006 W or ks h op R ep or ts Despite these initially encouraging results, signifi cant problems remain. The most important and one that was repeatedly raised was that of chronology. The off set (around 200 years) in the terrestrial dates for the Agassiz drainage and the ice core chronologies, while within error bars, is still quite signifi cant. Other carbon-dated records in the ocean sediment or on land are aff ected by a carbon-dating plateau around this time, which suggests the need for more work on alternate dating techniques, such as tephrology, for cross-correlating the different records. Other questions are more subtle. The North Atlantic has a very complex and dynamic circulation on decadal to multi-decadal timescales, and modern observations do not support the notion that all of this variability can be associated with a single quantity (such as the overturning streamfunction). Fitting the disparate ocean records into a wider and more complex picture is not easy and work is clearly required to improve that. And fi nally, improved and higher resolution data from the tropics and sub-tropics—particularly in Asia—are going to be needed to resolve the amplitude of any far-fi eld response. The latest results and initial modeling work strengthen the panel’s initial view that this event is a key target for Holocene paleoclimatology and that it may prove helpful in providing tests of climate models and infl uencing their development. That potential has yet to be fully realized.