It will be interesting to see where Mann takes this. He has been criticized for getting the “shaft” of his hockey stick wrong (no pun intended). Part of that was discounting the Medieval Warming Period, but the scholarly research on the existence of that is tough to ignore (even though Mann et al did their best to discredit it).
My guess is, he’s scrambling for an explanation that will fix his shaft (again, no pun intended).
Wonder if he’ll proactively release ALL data and code used to arrive at his conclusions...? If not, he’s learned nothing from ClimateGate about doing science.
The work can't be peer reviewed without that.
It sounds to me like he's using NOAA's prediction for the coming El Niño to nicely fit CRU's junk science of the past, as well as linking the currently predicted warming from El Nino to AGW.
From the NWS Climate Prediction Center:
THE TEMPERATURE OUTLOOK FOR DJF 2009-10 INDICATES AN ENHANCED LIKELIHOOD OF ABOVE AVERAGE TEMPERATURES FOR MUCH OF THE WESTERN HALF OF THE CONUS AND ALASKA, AND ESPECIALLY SO IN THE NORTHERN ROCKIES ALONG THE CANADIAN BORDER.
BELOW NORMAL TEMPERATURES ARE LIKELY FROM CENTRAL TEXAS ALONG THE GULF COAST TO THE MID-ATLANTIC.
Voila! Regional variations! The MWP was but an El Niño anomaly -- and Mann has those tree rings to prove it! (After massaging the data a bit.)
Looking forward, the AGW cultists can then rejoice in those "above average" temps in the west and north (while ignoring Texas, et al) which will prove the accuracy (after some adjustment) of those cracker-jack "state-of the-art climate models" interpretation of "how human-caused climate change ... impact this key climate pattern."