Email 412, Mar. 2001, Tom Crowley to several Hockey Team members: "It therefore seems that the conveyor is indeed oscillating but the time scale of the larger scale CLIMATE shifts may be more regulated by solar, with volcanism adding some stochastic contribution"

Email 412

ps fyi I counted the average spacing between the warm and cold oscillations in the iron oscillations illustrated by Broecker. Regardless of whether warm or cold are used, the mean spacing is indeed 1.5 k, although the s.d. is 0.4k HOWEVER, the mean spacing between the four main warm phases illustrated by Broecker on the same figure is, believe it or not, 2.15! much closer to the solar peak. This calls to mind the interesting (and clever) Wigley and Raper paper in Proc. Roy. Soc. (1990) indicating that, given the uncertainties in chronology, solar forcing plays a role i n Holocenn climate change. It therefore seems that the conveyor is indeed oscillating but the time scale of the larger scale CLIMATE shifts may be more regulated by solar, with volcanism adding some stochastic contribution. Something like this is worth adding to the proposed Eos piece.