It’s not always true that “the truth will out”.
Scott Johnson has a nice article in Ars Technica describing the outlines of a real scientific controversy.
Many of the trees used for temperature reconstructions grow at high altitudes, where their growth is limited by temperature. For some, a large, sudden cooling could push the tree below the minimum temperature threshold for growth. …
By using a simple model of tree ring growth that simulates artificial records, Mann and his colleagues found that taking this into account could produce hypothetical reconstructions that better matched the climate model predictions.
Many of the dendrochronologists who compile these tree rings records took offense to the idea that they hadn’t noticed such an important error. After all, researchers always cross-check tree ring records with other trees in the area to look for issues like skipped rings and growth variation between individual trees. …
In the published reply by Mann, Fuentes, and Rutherford … the researchers explain why they think it’s possible that missing rings could have slipped past dendrochronologists, despite their cross-checking. They believe that the cold temperatures associated with the eruption would prevent any of the trees in a region from growing. To detect the missing ring, the trees would have to be cross-checked with trees sufficiently far away to have experienced warmer temperatures.
Based on the report itself, I am leaning to Mike’s side. Of course, we don;t really know whether “To the dendrochronologists who submitted their comment, that’s irrelevant until there’s solid evidence for it (which they don’t believe will turn up).” is fair reporting (there’s a possibility of a fair amount of projection here). That position as stated makes no sense. If a plausible improvement in the data model moves the data into closer agreement with a process model, that actually is evidence. The failure to understand this is at the root of the systematic undervaluing of “models”, generally expressed with a sneer by people who don’t like a particular result. But it’s all models.
Even an old-fashioned mercury thermometer is a model. It’s a proxy, not a temperature, whose parameters are expressed by lines marked on a glass tube.
But I’m also struck by the overconfidence in the “truth will out” conclusion.
Eventually, if Mann’s hypothesis is found to be correct, we’ll be able to improve the temperature reconstructions. If, instead, the dendrochronologists are vindicated, that could lead to a different understanding of what the discrepancies mean. Since this is a scientific debate, the data will get the last word—and, right now, the data aren’t in yet.
Well, probably. I suppose we can think of some feasible tests in this case.
But the world needs to understand that science is not all-powerful. In an email exchange, John Mashey quotes the famed applied mathematician John Tukey:
‘The combination of some data and an aching desire for an answer does not ensure that a reasonable answer can be extracted from a given body of data.’
In any case, this pretty much should put the kibosh to any lingering suspicion you may have (I lost mine some time ago) that Mike Mann is a hack. This is a pretty creative and courageous hypothesis to be challenging.
I hope the truth in this matter eventually stops inning. But by its nature this is a question that could stay open for a long time.