I have posted that it is my present position that the atmospheric climate is altered through the engine of ocean temperature change and not the other way around. What this chart shows is how variable the energy content of the
Atlantic actually is and that key lows and highs are expressed in the historical record rather convincingly.
Disappointingly, it is not clear from this that the process is particularly cyclic at all. We do not have the rest of the Holocene here to play with, but the apparent 1100 cycle may simply not exist or it may exist but be imprecise in terms of period. Again we need the whole Holocene and we also need to correct for the Bronze Age possibly sustained by the lack of desertification.
The present regime tells us of a consistent heat content that has not changed in fifty years and that the resolution is too poor to pick up short term changes.
We now have pretty consistent evidence that more heat is entering the
Arctic at a constant annual inflow. It is also clear that this increase may be very difficult to detect in either the sedimentary record or with ocean temperature records. It is not too hard to imagine that the surplus heat is represented by an obscure diversion of currents somewhere and undetected.
However, real climate change came with gross changes in the temperature of the north Atlantic Gyre and that is surely a lagging indicator at best, while temperatures associated with the
Gulf Stream would lead. Atlantic Ocean Sediments Confirm Roman & Medieval Periods Warmer, Peer-Reviewed Research Determines
Read here. View full map source here and/or click on image to enlarge. From the Sargasso Sea, researchers worked with a combination of "biweekly hydrographic data, a long history of sediment trap collections to document the rain of particles from the sea surface to the seafloor, and exceptional deep sea cores of sediment" to reconstruct sea surface temperatures stretching back some 3,000 years. The empirical evidence confirms that the
Bermuda sub-tropical area experienced warmer temperatures during both the Roman and Medieval warming periods versus modern temperatures. (click on image to enlarge)
"The core-top data indicate temperatures of nearly 23 degrees, very close to the average temperature at Station S over the past 50 years. However, during the Little Ice Age of about 300 years ago sea surface temperatures were at least a full degree lower than today, and there was an earlier cool event centered on 1,700 years ago. Events warmer than today occurred about 500 and 1,000 years ago, during the Medieval Warm Period, and it was even warmer than that prior to about 2,500 years ago."
"These results are exciting for a few reasons. First, events as young and as brief as the Little Ice Age and the Medieval Warm Period have never before been resolved in deep sea sediments from the open ocean. Because the
Sargasso Sea has a rather uniform temperature and salinity distribution near the surface, it seems that these events must have had widespread climatic significance. The Sargasso Sea data indicate that the Medieval Warm Period may have actually been two events separated by 500 years, perhaps explaining why its timing and extent have been so controversial."