Rosanne D'Arrigo killed the hockey stick

Email 2013

Know anything about the "divergence problem" in tree rings? R D'arrigo talked to the NRC yesterday. I didn't get to talk to her afterward, but it looked to me that they have redrilled a bunch of the high-latitude tree rings that underlie almost all of the high-res reconstructions, and the tree rings are simply missing the post-1970s warming, with reasonably high confidence. She didn't seem too worried, but she apparently has a paper just out in JGR. It looked to me like she had pretty well killed the hockey stick in public forum--they go out and look for the most-sensitive trees at the edge of the treeline, flying over lots and lots of trees that are lesss sensitive but quite nearby, and when things get a little warmer, the most-sensitive trees aren't anymore, and so the trees miss the extreme warming of the recent times, and can't reliably be counted as catching the extreme warmth of the MWP if there was extreme warmth then. Because as far as I can tell the hockey stick really was a tree-ring record, regardless of how it was labelled as multiproxy, this looks to me to be a really big deal. And, a big deal that may bite your chapter... --Richard