Arguments
The BEST Kind of Skepticism
Posted on 22 October 2011 by dana1981
As Andy recently discussed, the Berkeley Earth Surface Temperature study (BEST) results are in. For those true skeptics among us, the BEST results are not the least bit surprising. It's not a coincidence that the NASA GISS, HadCRU, and NOAA surface temperature datasets show approximately the same amount of warming. Either they all effectively filter out extraneous effects such as from urban heat islands (UHI), or they all don't. However, numerous studies have concluded that these groups do effectively remove the UHI effect, and we have known for a long time that the surface temperature record is reliable.
Thus it's not the least bit surprising that the BEST results have confirmed their accuracy (Figure 1). BEST also confirmed that HadCRUT is biased low, which we already knew. Ironically, although we have known that HadCRUT has a cool bias, and "skeptics" attacked the record in the wake of Climategate, HadCRUT has become the surface temperature record of choice for the so-called "skeptics."
Figure 1: The decadal land-surface average temperature using a 10-year moving average of surface temperatures over land. Anomalies are relative to the Jan 1950 – December 1979 mean. The grey band indicates 95% statistical and spatial uncertainty interval.
As Andy discussed, BEST also demonstrated that rural temperature stations show essentially the same, and in fact even a slightly larger warming trend as urban and more poorly-sited stations (Figure 2). This is consistent with the findings of Menne et al. (2010).
Figure 2: The Berkeley Earth global temperature averages, normalized to zero mean for the period 1950 to 1980.
So for those who consider all the evidence - the true skeptics - the findings of Muller et al. are entirely expected and unsurprising. Then there are those who call themselves 'skeptics', but really are not. In March of 2011, Anthony Watts said (emphasis his):
"I’m prepared to accept whatever result they produce, even if it proves my premise wrong....the method isn’t the madness that we’ve seen from NOAA, NCDC, GISS, and CRU....That lack of strings attached to funding, plus the broad mix of people involved especially those who have previous experience in handling large data sets gives me greater confidence in the result being closer to a bona fide ground truth than anything we’ve seen yet. Dr. Fred Singer also gives a tentative endorsement of the methods....Climate related website owners, I give you carte blanche to repost this."
Not surprisingly, Watts has not adhered to his promise to accept the BEST result. Quite the contrary, in fact:
"Both [Fall et al. 2011 and Menne et al. 2010] (and cited by Muller et al) do an analysis over a thirty year time period while the Muller et al paper uses data for comparison from 1950 – 2010....I see this as a basic failure in understanding the limitations of the siting survey we conducted on the USHCN, rendering the Muller et al paper conclusions highly uncertain, if not erroneous....I consider the paper fatally flawed as it now stands, and thus I recommend it be removed from publication consideration by JGR until such time that it can be reworked....it appears they have circumvented the scientific process in favor of PR."
In short, Watts' complaints are that the BEST papers have been made public prior to undergoing the peer review process, and that their analysis extended 60 years into the past, rather than limiting themselves to the 30-year period during which Watts considers the surfacestation ratings reliable.
There is no validity to these criticisms. Scientific papers are often made available prior to publication (i.e. see arXiv, and by Watts himself), and there's no reason to believe that limiting their analysis to the past 30 years will change the BEST results (though Watts is welcome to try and demonstrate otherwise); obviously the 60-year period includes the 30-year window. To be blunt, Watts is clearly fishing for excuses to dispute the BEST conclusions and continue denying the accuracy of the surface temperature record. Ironically, Watts is attacking a paper which is consistent the results of Fall et al. (2011), on which Watts was a co-author:
"None of our conclusions disagree with those of Fall et al. [2011] or those of Menne et al. [2010]."
Dr. Pielke has also weighed in with his comments on the unsurprising BEST results:
"Unless, Muller pulls from a significanty different set of raw data, it is no surprise that his trends are the same."
Dr. Pielke has long disputed the accuracy of the surface temperature record (including with some unflattering caricatures). His explanation for the various datasets being so similar is that they use the same raw data. However, it is not the accuracy of the thermometers that is in question; rather, the question is whether the thermometer readings are influenced by effects other than global warming, like UHI. Each dataset (including BEST) utilizes different methods to filter out those effects (see Glenn's excellent Of Averages and Anomalies series for details on how they do this), and in that sense they are independent. It's also worth noting that if the surface temperature datasets aren't considered independent, then the satellite datasets (UAH and RSS) that Pielke favors aren't either.
But as it so happens, BEST does utilize raw data which are not included in the analyses of the other groups, as Pielke would have learned had he actually read the papers (or articles about them) rather than automatically seeking a reason to criticize them.
The surface warming is also consistent with the many physical indicators, and the observed amount of warming is consistent with the expected range of climate sensitivity, which itself is based upon many different lines of evidence.
In short, all the evidence has consistently indicated that the surface temperature record is accurate. To continue scrambling for reasons to believe otherwise is not skepticism; refusal to accept overwhelming evidence is denial. Of their paper, Muller said:
"My hope is that this will win over those people who are properly sceptical"
Unfortunately, proper skepticism appears to be in short supply amongst the self-proclaimed climate "skeptics."
On the following version of one BEST temperature graph, it shows a marker labeled "post 1956 rise attributed by IPCC to humans":
Berkeley Earth Results
Does anyone know what is significant about this date? I'm pretty sure it's not when temperature and solar output started going in opposite directions, as that happened later on. Thanks in advance for any info...
Sorry... to make this that much easier, here's the chart minus the extra step of clicking the link:
What I'm hoping to know is the significance of the date 1956 in the comment, "post 1956 rise attributed by IPCC to humans".
dvaytw - 1956 is the point in the BEST analysis where anthropogenic factors took precedence, outweight other forcings. While that particular analysis is (IMO) rather simplistic (no anthropogenic aerosol factors, as far as I can see), it matches fairly well with multiple regression methods such as Lean and Rind, with Granger causality, with other attribution studies, core data on forcings, and modelling with/without anthropogenic forcings:
Roughly since 1960, when long term solar forcing began to drop, anthropogenic greenhouse gases have been the primary forcing change driving up temperatures.
[IPCC modeled temperatures, with/without anthropogenic influences]
Note: The image reference in my previous post should be to the IPCC AR4 report, page 9.4.1.2, not just to the illustration.
KR thanks! What an answer! I've been arguing the same-old same-old with "skeptics" on a podunk expat forum in Taiwan, and wow did you ever just help me slam dunk that debate! I already had the guy on the tip of a spear, and with your post, I just drove it right through his chest (lol), as he made this question central to his alleged "skepticism".
Very sorry if this is off-topic, but in case anyone's interested in seeing the debate, please have a look here:
British Met Service buries new climate-change analysis showing no warming trend - p. 17
dvaytw - You might also look at the excellent summary dana1981 posted in A Comprehensive Review of the Causes of Global Warming, discussing eight or nine different studies of the causes of climate change.
The average attribution of warming to human causes is >100%, as without anthropogenic influences the climate should have cooled. Human driven warming has both counteracted natural cooling and added considerable warming over the last 150 years or so.
KR @111 - that analysis was most recently updated with Wigley and Santer (2012) here, and will be updated with another new attribution study in a post probably next week.