Climate Science Glossary

Term Lookup

Enter a term in the search box to find its definition.


Use the controls in the far right panel to increase or decrease the number of terms automatically displayed (or to completely turn that feature off).

Term Lookup


All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Home Arguments Software Resources Comments The Consensus Project Translations About Donate

Twitter Facebook YouTube Pinterest

RSS Posts RSS Comments Email Subscribe

Climate's changed before
It's the sun
It's not bad
There is no consensus
It's cooling
Models are unreliable
Temp record is unreliable
Animals and plants can adapt
It hasn't warmed since 1998
Antarctica is gaining ice
View All Arguments...

Keep me logged in
New? Register here
Forgot your password?

Latest Posts


Christy Once Again Misinforms Congress

Posted on 8 August 2012 by dana1981

On August 1st 2012, John Christy once again testified before the US Congress in a Senate hearing on climate issues.  His written testimony is here and his verbal testimony is here.  We previously examined Christy's congressional testimony to the House of Representatives from March 2011 and found it full of incorrect and misleading statements.  This time, Christy repeated many of the same myths and misleading arguments from last year's testimony, and threw in a reference to an incomplete, flawed, unpublished paper for good measure.

Christy's testimony is broken into five distinct climate myths:

1) Disputing the accuracy of the surface temperature record;

2) Exaggerating the discrepancy between modeled and observed global warming;

3) Denying the consensus on human-caused global warming;

4) Cheerleading fossil fuels as the best thing since sliced bread; and

5) Denying that climate change is linked to extreme weather.

We will address the first four myths in this post, while a separate post is devoted to the extreme weather denial of Christy and Co.

Misinforming Congress with Watts' Flawed Unpublished Paper

In his testimony, Christy disputed the accuracy of the surface temperature record (as he also did in last year's testimony).  The accuracy of this record has been confirmed time and time again, and yet Christy refuses to accept the scientific research demonstrating its accuracy.  Worst of all, as Anthony Watts notes, Christy cited the incomplete, unpublished, fundamentally flawed preliminary paper on which Watts and Christy are both co-authors:

"Watts et al. demonstrate that when humans alter the immediate landscape around the thermometer stations, there is a clear warming signal due simply to those alterations, especially at night. An even more worrisome result is that the adjustment procedure for one of the popular surface temperature datasets actually increases the temperature of the rural (i.e. best) stations to match and even exceed the more urbanized (i.e. poor) stations. This is a case where it appears the adjustment process took the spurious warming of the poorer stations and spread it throughout the entire set of stations and even magnified it"

None of the above statements are true.  Christy did finally note that his paper with Watts is "ongoing" and incomplete, mentioning one of the many fundamental flaws in their preliminary paper - its failure to account for changes in time of day temperature station readings:

"This is ongoing research and bears watching as other factors as still under investigation, such as changes in the time-of-day readings were taken, but at this point it helps explain why the surface measurements appear to be warming more than the deep atmosphere (where the greenhouse effect should appear.)"

Yet if the research is incomplete, preliminary, and not reviewed, how can Christy possibly justify referencing it in testimony to Congress?  There is simply no excuse, particularly since major flaws were immediately identified in the Watts pre-publication as soon as it was made public (i.e. see this post by Victor Venema published the very next day).  Christy has misinformed Congress by implying that it has overturned the large body of scientific evidence confirming the accuracy of the surface temperature record.

It's problematic enough that Christy did not recognize the many obvious errors in his preliminary paper with Watts.  While Watts is an amateur, Christy does not have that excuse - he is a climate scientist.  Not only did Christy fail to identify clear fundamental errors in the paper's analysis which completely undermine its conclusion, but he then presented that incorrect conclusion to Congress.

This is an important point, because Christy is constantly claiming that his UAH satellite temperature record is the gold standard, contrary to other research, for example  Mears et al. 2011 and Thorne et al. 2011, which note that the satellite data possibly have outstanding issues, and contrary to the Watts and Christy preliminary paper in which the amount of warming the authors claim is happening in the United States is inconsistent with the amount of warming in the UAH record.  Christy also constantly argues that the surface temperature data sets have a warm bias, including in his testimony to Congress.

Yet in the paper he co-authored on the subject with Watts, Christy apparently did not know to take the first and most critical step of homogenizing the data and removing the climate-unrelated biases introduced by factors like stations moving and time of observation changing.  These are factors which many different scientific groups have investigated using different methodologies, all arriving at essentially the same answer. 

If Christy does not understand this most fundamental aspect about the instrumental temperature record, then he is in no position to dispute its accuracy, especially to the US Congress.

Christy Exaggerates the Model-Data Discrepancy

Christy summarized his criticisms of climate models thusly:

"The average warming rate of 34 CMIP5 IPCC models is greater than observations, suggesting models are too sensitive to CO2."

We have previously debunked this myth here, but Christy conveniently provides the data in Figure 2.1 of his own written testimony which completely undermine his point.

fig 2.1

As Christy's figure here shows, the surface temperature data (NCDC, NASA, and HadCRUT4 shown in triangles, squares, and x's, respectively) fall within the envelope of Coupled Model Intercomparison Project Phase 5 (CMIP5) model runs.  Note that Santer et al. 2011 and Thorne et al. 2011 both showed that the satellite temperature trends (also plotted in Christy's Figure 2.1, but which are not directly comparable to surface temperatures) also fall within the model uncertainty range, which Christy neglects to mention.

Christy is correct to note that the model average warming trend (0.23°C/decade for 1978-2011) is a bit higher than observations (0.17°C/decade over the same timeframe), but that is because over the past decade virtually every natural influence on global temperatures has acted in the cooling direction (i.e. an extended solar minimum, rising aerosols emissions, and increased heat storage in the deep oceans).  We're in the midst of a 'hiatus decade', but as Christy's own figure shows, the observed warming is nevertheless consistent with the envelope of model runs, because climate models expect hiatus decades to sometimes occur.

Instead of making this point, Christy misinformed our policymakers by telling them that these results indicate that climate sensitivity is low, and that we should follow the example of North Carolina politicians by suggesting that based on these results we should simply ignore climate model projections and stumble blindly into the future.

Denying the Consensus

Christy also devoted much of his written testimony denying the scientific consensus on human-caused global warming.  In the question and answer session, he disputed the validity of Doran 2009 because relatively few climate science experts had participated (77 of 79 answered that human activity is a significant contributing factor to global warming).  However, this ignores the many other studies with larger sample sizes on the subject, such as Oreskes 2004, Peiser 2006Anderegg 2010, the statements of dozens of scientific organizations including every National Academy of Science with an official position.

Christy espoused various conspiracy theories in his testimony, calling the IPCC 'gatekeepers' and suggesting that a climate contrarian opposition to the IPCC should be funded with taxpayer dollars.  Christy suggested the factually devoid NIPCC report and the fundamentally backwards Michaels Cato report (aptly described by Chris Colose here) as shining examples of the sorts of BS (bad science) that taxpayers should be funding.

However, these groups seem to be obtaining sufficient funding from the fossil fuel industry to pump out their BS reports without additional taxpayer assistance.

Fossil Fuel Energy and Economics Myths

Strangely, Christy concluded both his written and verbal testimony talking about fossil fuel energy and economics rather than climate science - subjects well outside of his area of expertise.  Christy began with the misleading argument that CO2 is plant food, which is a gross oversimplification of a complex issue, and which is frankly an insult to the intelligence of his audience.

He then smoothly transitioned from this oversimplified argument to the myth that CO2 limits will hurt the poor because, he argued, fossil fuel energy is cheap.  In reality, when all costs are taken into consideration, many renewable energy sources are significantly cheaper than fossil fuels.  Ironically, Christy cites concerns about the wellbeing of people in Africa, who are the most vulnerable to the impacts of the climate change his testimony seeks to accelerate.


Per capita emissions vs. vulnerability to climate change, from Samson et al. (2011)

In fact as Peter Sinclair discusses, many Africans have also been taking advantage of solar panels which can pay for themselves in just a few months, are far safer than burning fossil fuels, in addition to being cleaner and better for the climate, and can be implemented far more quickly than waiting for new coal power plants to be built.  Africans are apparently more forward-thinking than John Christy when it comes to energy.


As always seems to be the case when climate contrarians are invited to speak to policymakers (or the public), Christy has done nothing more than repeat a bunch of common and long-debunked climate myths.  Even worse, in doing so Christy referenced the unpublished and incomplete paper he has co-authored with Anthony Watts, which contains numerous fundamental errors that completely undermine its conclusions.  Despite these errors, and despite the fact that the paper has not been reviewed or even submitted to a journal, and despite it contradicting his own satellite measurements which he has held to be the gold standard, Christy presented those wrong conclusions to US Congress.

Unfortunately, one of the two main political parties in the USA only seems interested in propagating climate myths rather than educating themselves about what the body of climate science research tells us.  And just as unfortunately, John Christy seems more than happy to provide them with the desired misinformation.  In fact, during the question and answer session, Christy refused to admit the simple reality that global warming is not a hoax, which makes it very difficult to take anything he says seriously.

0 0

Bookmark and Share Printable Version  |  Link to this page | Repost this Article Repost This


Comments 1 to 23:

  1. Forwarding this article to my senators. Every politician needs to see this, just in case they aren't already aware of Christy's bias.
    0 0
  2. Looking at the model-data discrepancy figure, Christy also seems to have done something odd with the baselines. The surface temperature records are lower than the model values for the entire (and ridiculously short) 1979-1983 baseline period.

    I'm guessing that the reason is the 7 years smooth. If those 5 years were hot (80, 81 and 83 were), and the years around them were cool (74-76 and 84-86 were cool), then the 7 year smooth will produce lower values.

    However it's looking as though the baseline period was a careful cherry-pick.
    0 0
  3. Is it easy to get the CMIP5 data for that figure? It would be interesting to look at longer timespans to address the baseline issue, and also to include my new HAD4krig reconstruction (a global version of HadCRUT4 using Kriging).
    0 0
  4. #2 Kevin C - I think you're right about the baselining. If the 1979-83 observations are aligned with the 1979-83 model mean, the graph is skewed. By selecting just 1979-1983 as the baseline, Christy is able to align the model mean with a period (1979-1983) where UAH and other temperature series was running distinctly above the 1979-2012 trend.

    In the graph, there is also the question of how Christy calculated the 1979 datapoint for his running UAH mean. Given the UAH dataset runs from 1979, a centred average on 1979 will only have four points (1979, 80, 81 and 82), instead of the seven that most of the other points would have. The same issue is at the end of the dataset (How many datapoints contrinuted to the 2011 point?) That's a real problem in a graph presented as "7-year running averages". You should only have averages from 1982 to 2008 (Lowess smoothing can fill in the ends, but that's not what's presented).

    Consequence: The observations will run well below the model mean for the entire series, as the baseline period has a disproportionate influence of "El Nino" on the series. By setting the baseline to a peak in the observations (a peak not present by design in a multi-model mean), there is an offset of ~0.1C between the multimodel mean and the observations.

    Aligning the baselines properly over longer periods (at least through a couple of ENSO cycles), and I suspect this offset will disappear. The above graph is thus very deceptive. I can think of many descriptions for people who would produce a graph like this and present it before lawmakers, but I would fall foul of the Comments Policy.
    0 0
  5. #2 and #4 KevinC and skywatcher, I can see why Christy would choose to start the baseline in 1979. It seems a reasonable thing to do as the measurements start then.

    But a bit of thought and some further looking would point out that choosing a starting point for comparison where the multi-model mean ENSO would be zero and the observations are net positive is poor analysis. Similarly if a 7 year mean were baselined using a 4 yr average.

    I suspect that because it helped give Christy the answer he was looking for, he didn't bother to look into it much more - simple confirmation bias. At least I hope that's what he did, rather than actually doing tetests and choosing to mislead Congress.
    0 0
  6. Regarding the model vs observation comparisons, notice that Christy writes:
    "The two satellite-based results (circles, UAH and RSS) have been proportionally adjusted so they represent surface variations for an apples-to-apples comparison."
    0 0
  7. It would be interesting to see what the surface temperature results would look like with the 'corrections' in the Watts/Christy paper... and then compare that to Christy's UAH satellite record and ask him to explain the discrepancies.
    0 0
  8. Excellent analysis as usual but, exactly how much notice do policymakers take of Christy? Are they fooled by him? Do they still see this as a debate?

    As well as the incredible spectacle of a "distinguished professor" (of the FFL-funded University of Abdication) asking politicians to rely upon Anthony Watts, I found his endorsement of the "we skeptics are like Galileo" fallacy and/or victim mentality astonishing.

    As for claiming that fossil fuels are good for us and/or that mitigation is hurting the poor; this is quite simply reality inversion: The problem with inverting reality (31 March 2012).
    0 0
  9. H2O is plant food, too. So, apparently according to Christy nobody can drown.
    0 0
  10. I don't know how Christy selected his baseline period - it's probably a poor choice. That's why I discussed the trends in the post, which I don't believe he mentioned in his testimony. It's very easy to make a misleading graph, but trends are much more difficult to manipulate, other than by cherrypicking start and end points.

    Martin - I'm sure the politicians who invite Christy to speak (Republicans) know exactly what they're going to get. From the question and answer session when Senator Barbara Boxer (Democrat from California) was peppering Christy and exposing some of his myths, it's clear that the other side was not fooled.
    0 0
  11. Off Subject: Are there known financial connections between the FF industry and UAH (or its alumni) that is motivating Mr. Christy's tactics? Or is this a simple case of "saving-face" pride (due to Mr. Christy taking a hard stance years ago, too soon)? ... Snip if this is 'out of line'.
    0 0
    Moderator Response: [DB] General speculations into motivations are generally frowned upon. Specifics get snipped. This is a science-based site and Mr. Christy's science is very much fair game.
  12. Sauerj, like most of the 'skeptics' Christy is ideologically opposed to all forms of government intervention in the environment. Government action is always bad... therefor any problem which would require government action must not really be a problem.

    In almost all cases it is a massive ideological blind-spot rather than any consciously chosen reason.
    0 0
  13. MarkR @5, Christy and Spencer use a 1981-2010 baseline to calculate anomalies for their lower troposphere (T2LT) product. The switch to a very short 1979-1983 baseline is, therefore, anomalous (forgive the pun). As that baseline is not his standard practice, and for very good reason, its use requires explanation. As, apparently, the use of that baseline significantly distorts the comparison between T2LT records and model projections, it is difficult to escape the conclusion that it was a deliberate cherry pick.
    0 0
  14. sauerj @11, Roy Spencer, Christy's collaborator on the UAH satellite data explicitly disavows any fossil fuel, or even private sector funding of his research. Presumably that means that Christy receives no private sector funding for any of their joint research as well. With regard to his projects in which he does not collaborate with Spencer I have no information.

    As DB has pointed out, however, this is a non-issue. The question is the quality of Christy's science, not the nature of his funding. As it stands, his testimony to Congress was very bad science.
    0 0
  15. What I find troubling and puzzling about Christy being listed as a co-author on the awful manuscript is that Christy was once the state climatologist for Alabama. So Christy should be very familiar with time observation bias (TOB) issue and the importance of adjusting for it.

    Now to be charitable to Christy (and the best possible scenario for him ) it may be that Watts included him as a co-author without first consulting with Christy. If someone has not already asked him if this was the case, they need to and Christy needs to clarify the degree of his involvement in analyzing the data and preparing the manuscript.

    Regardless, Christy promoting a seriously flawed and grossly misleading manuscript before Congress is inexcusable.
    0 0
  16. Albatross - I can't imagine that Christy would be referencing the results of a paper on which he's listed as co-author without being intimately aware of the details. In fact I suspect that Christy pressured Watts to release the paper before it was ready because he was afraid Muller would be testifying in the same hearing and he wanted the Watts results to undermine Muller's testimony.

    That's just speculation on my part, but either way, if you're presenting the results of a paper on which you're co-author to Congress, you'd darn well better be very familiar with how those results were generated.

    Though I guess it's true, it wouldn't reflect as poorly on Christy if he were ignorant about the flaws in the paper whose results he presented to Congress. In that case he was just being grossly irresponsible as opposed to being both inept and irresponsible.
    0 0
  17. Dana @16,

    You are probably right. I was doing my best to be as fair as possible to Christy. However, as you note, no matter how one looks at this it reflects incredibly poorly on Christy and those who invited him to testify.

    It is really troubling that "skeptics" and contrarians like Christy are permitted to grossly and repeatedly mislead Congress without any consequence whatsoever. Policy makers need the best science to make informed decisions, not seriously flawed manuscripts such as the one prepared by Watts, Christy and McIntyre.
    0 0
  18. Dana@10 Thanks for the response.

    Albatross@15 Unlike McIntyre (who has disavowed detailed involvement), Christy has self-identified with Watts. This is why his credibility should be heading the same way as President Assad and shares in Standard Chartered...
    0 0
  19. @Moderator response to #11: I think there is considerable evidence that funding matters. This blog rightly focuses on the substance of the science, and discouraging ad hom attacks is entirely appropriate. However, for what it's worth, I don't believe that making funding sources transparent constitutes an ad hom. While not currently popular among researchers, many professional societies have attempted to implement ethical guidelines for funding transparency, given the strong correlation between funding and findings. IMHO, I think revealing the funding of research should be standard practice.
    0 0
  20. @ Albatross on #17: "It is really troubling that "skeptics" and contrarians like Christy are permitted to grossly and repeatedly mislead Congress without any consequence whatsoever. Policy makers need the best science to make informed decisions..."

    Don't make the mistake of assuming that the purpose of congressional hearings is to air the best science. It's just a dog and pony show. With a few exceptions, these people already understand the science, but they are serving a completely different agenda. The scientific community, however much scientists may generally disdain politics, needs to become far more politically savvy. Because this is what you are up against:
    0 0
  21. Richard Lindzen coughs again in the WSJ citing John Christy's Senate Testimony in:

    'Climate Consensus' Data Need a More Careful Look
    0 0
  22. We've got a rebuttal blog post to that WSJ nonsense in the works, Lionel. Look for it next week.
    0 0
  23. Feel free to use my rebuttal to the Wall Street Sixteen Three:
    0 0

You need to be logged in to post a comment. Login via the left margin or if you're new, register here.

The Consensus Project Website



(free to republish)



The Scientific Guide to
Global Warming Skepticism

Smartphone Apps


© Copyright 2014 John Cook
Home | Links | Translations | About Us | Contact Us