The role of the North Atlantic meridional overturning circulation (MOC) in possible future rapid climate changes is much debated. The U.K. Natural Environment Research Council initiated a program called Rapid Climate Change (RAPID) to investigate this issue, working with international partners. The recent Rapid Climate Change International Science Conference reviewed progress and discussed the scientific challenges in this area, bringing together results from paleoclimatology, modeling, and observational studies.
About 8000 years ago, a sharp drop in temperatures occurred when an outburst from a North American ice-dammed lake (Lake Agassiz) flooded the North Atlantic with freshwater. The event is a possible analogue for potential effects of future North Atlantic freshening from increased precipitation and ice melt. Speakers presented evidence suggesting that the nature of the event is becoming clearer, including the first clear evidence of its impact on the MOC. However, the relationship between the timing of various changes and the lake's outburst needs further investigation.