I like Roger, I like a lot of his writing, I loved his book, and he always gives me good interviews. But I have to disagree here.
There is a big problem with the media reporting of the new paper. It contains a fundamental error which (apparently) originates in the NSF press release and which was furthered by public comments by scientists.How is this "startling?" They say in their paper that it's not robust:
In a belatedly-posted FAQ to the paper, which appeared on Real Climate earlier today, Marcott et al. make this startling admission:
Q: What do paleotemperature reconstructions show about the temperature of the last 100 years?Got that?
A: Our global paleotemperature reconstruction includes a so-called “uptick” in temperatures during the 20th-century. However, in the paper we make the point that this particular feature is of shorter duration than the inherent smoothing in our statistical averaging procedure, and that it is based on only a few available paleo-reconstructions of the type we used. Thus, the 20th century portion of our paleotemperature stack is not statistically robust, cannot be considered representative of global temperature changes, and therefore is not the basis of any of our conclusions.
Without filling data gaps, our Standard5×5 reconstruction (Fig. 1A) exhibits 0.6°C greater warming over the past ~60 yr B.P. (1890 to 1950 CE) than our equivalent infilled 5° × 5° area-weighted mean stack (Fig. 1, C and D). However, considering the temporal resolution of our data set and the small number of records that cover this interval (Fig. 1G), this difference is probably not robust.(Emphasis mine.)
- on the first page, right-hand column, they explicitedly note their reconstruction stops at "100 yr B.P," and their "present" is defined as 1950 CE.
- The graphs on page 2 have the blade in different colors, and the captions make it clear these aren't their results.
- On the last page: they write, "Our results indicate...." which is not the same as writing "Our results show...." Anyway this is the discussion portion of their paper, and what's wrong about discussing how their results look in light of the recent instrumental record?
For the same reason, the press release, which is setting the context, is going to address what every journalist is immediately going to want to know: what does this say about today's warming? Not, what does this categorically prove -- there is no such thing -- but what does this say, what does it "indicate?" Because here we have this 11,000 year reconstruction, and on the other hand we have the instrumental record over the last 130 years or so, so what do they say together? It would be irresponsible (and a waste of taxpayer-funded research) not to say something about the broader context in an issue of this importance.
So it seems to me that
(a) the scientists made it clear in their paper their results were not robust for 1850 CE onward
(b) they addressed, in their discussion and in interviews, the immediate question on everyone's mind: so how do your results compare to today's warming?
And today's warming looks pretty darn troubling, and my cynicism is wondering if that's what almost all of the paper's post-publication criticism is trying to suppress by any means necessary (although my guess is that's not Roger's motivation, which (I'm guessing) he sees along this line).
Update: I made much this same comment on Roger's blog, and he responded here.