A favored tactic of denialists is to take the short term behavior of a noisy system to claim that there is no underlying trend. This is most frequently seen in claims that it’s been cooling since 1998 or 2001, when it’s clear that you need at least 20-30 years of temperature data to make meaningful claims about global trends.
Regular readers may remember Bjorn Lomborg using a version of this misdirection to argue that sea levels haven’t been rising recently, and more recently Stefan Rahmstorf’s brutal demolition of Lomborg’s chicanery. Lomborg wasn’t the only person making absurd claims about sea level rise based on a handful of data.
Roger Pielke Sr., too, actually had the chutzpah to claim that sea levels weren’t rising, because at the time 2006 showed a spike relative to more recent years (therefore sea levels will fall incredibly in the future [NOTE: this was hyperbole and not actually Pielke's stated position, see follow up]).
I’d forgotten about Pielke Sr.’s shameful perpetuation of this idiocy until seeing it again on the SPPI site:
This claim was apparently made by Pielke back in June of last year. What was surprising to me about Pielke trafficking in this denialist-type argument was not its dishonesty- he is one of Watt’s biggest supporters after all- but rather its self-defeating nature. Presumably Pielke really isn’t so stupid as to believe that sea levels are in fact falling, and knows that 2006 as an outlier would inevitably be surpassed, illustrating his claim to be both incorrect on its own “merits” and exposing the ludicrous nature of its basis.
Amusingly, the link provided at Pielke Sr.’s blog and the SPPI page is the continuously-updated Boulder sea level data, and sure enough 2006 is no longer the “high water mark”. Pielke’s failure to update his blog and Morano’s republishing of the claim presumably mean that Pielke stands by his assertion, in which case he’s either unequivocally wrong, or deliberately lying.
I eagerly await for Pielke to claim in a year or two that sea level rise is “NOT TRUE… Sea level has actually flattened since 2009″ and again in 2011 or whatever the next short term peak is.
Of course, all this really does is point out how nonsensical the claim was from the beginning. The reason why we look at underlying trends is that simply eye-balling the greatest value doesn’t tell us anything about the general behavior of a noisy system over longer periods of time, and the trend line for SLR hasn’t varied terribly much between Lomborg and Pielke’s claim and the present, even as the maximum value has changed.
Pielke does the same thing with Northern Hemisphere sea ice, claiming that “Since 2008, the anomalies have actually decreased.” He simply picks an extreme outlier minimum and then presents a regression to the mean (itself clearly decreasing) as an increase in sea ice!:
The current extent of NH sea ice is actually below the record 2007 minimum:
Meaning that were I as misleading as Pielke, I would claim that sea ice has melted so much that it’s below its record minimum, implying that this was part of a new trend rather than a temporary wiggle superimposed on the overall decline, which is disturbing enough.
Pielke also claims that there has been “no statistically significant warming of the upper ocean since 2003.” This analysis is based on heat content measured from 0-700m as assessed by Argo float data, which are problematic to put it mildly. Of course if we consider heat content from 0-2000m, the increase shows no such drop off:
The goal here isn’t to say that my short term data are definitive while Pielke, Morano, and SPPI’s are not- but rather to draw attention to the cherry-picked nature of the claims. If your conclusions are so sensitive to their starting or ending points, or data sets used, etc., then chances are you’re not saying much of import.
Hat tip to Brad Johnson for the SPPI page and pointing out that Pielke’s cherry-picking also extended to sea ice.
[UPDATE: From the comments, MapleLeaf points out that the SLR graph doesn't have the inverse barometer adjustment, which can be seen here. In Pielke Sr.'s defense, the CU Boulder sea level home page graphic doesn't show that version either.]
[UPDATE: Pielke has written a response, which I address here.]