The goal here is to provide a reasoned context and rebuttal regarding distorted views of the ‘ClimateGate’ emails. This is simply done by providing relevant context to statements of interest. The crime: A hacker illegally broke into a computer server at the University of East Anglia involving the Climate Research Unit (CRU). As always, context is key. Once the real context is understood, the emails make sense and the idea of conspiracy, scientific malfeasance, or fraud, is revealed to be unfounded.

Science does not change by opinion.

As with all things, in order to understand what something means, you have to know the context. A fact by itself can easily be spun. When you have the correct context, the spin falls away and what is left is reality, or at least a more reasoned understanding.

On RealClimate: Gavin Schmidt (NASA/GISS) Kevin Wood, (Joint Institute for the Study of the Atmosphere and Ocean, University of Washington) Eric Steig, (Department of Earth and Space Sciences, University of Washington) have provided extensive review in multiple posts. I will attempt to summarize the review here as simply as possible.

When the emails are read in context they reveal that there are no egregious improprieties with regards to the accusations of falsifying or misrepresenting science. The quotes being bandied about carelessly in the media, in support of the denial of human caused global warming, are using the quotes outside of their actual context. This unfortunately gives a false impression that is then used to support the notion that the science is somehow a grand conspiracy.

Back in a little place called reality, the email communications express the normal back and forth of scientists trying to work out complex problems and in some cases their frustrations with those that choose to misrepresent the science (such as Steve McIntyre). The language is casual as one might expect in private communications and expresses real and justifiable concerns involved with those in the denialist campaign.

On April 12, 2010 an expert panel consisting of:

  • Chair: Prof Ron Oxburgh FRS (Lord Oxburgh of Liverpool)
  • Prof Huw Davies, ETH Zürich
  • Prof Kerry Emanuel, Massachusetts Institute of Technology
  • Prof Lisa Graumlich, University of Arizona.
  • Prof David Hand FBA, Imperial College, London.
  • Prof Herbert Huppert FRS, University of Cambridge
  • Prof Michael Kelly FRS, University of Cambridge

concluded after thorough review of the emails and contexts:

“We saw no evidence of any deliberate scientific malpractice in any of the work of the Climatic Research Unit and had it been there we believe that it is likely that we would have detected it.”

Source: The Oxburgh Report

Other Recommended Reading

Nature (International Weekly Journal of Science)

“A fair reading of the e-mails reveals nothing to support the denialists’ conspiracy theories. In one of the more controversial exchanges, UEA scientists sharply criticized the quality of two papers that question the uniqueness of recent global warming (S. McIntyre and R. McKitrick Energy Environ.14, 751–771; 2003 and W. Soon and S. Baliunas Clim. Res., 89–110; 2003) and vowed to keep at least the first paper out of the upcoming Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC). Whatever the e-mail authors may have said to one another in (supposed) privacy, however, what matters is how they acted. And the fact is that, in the end, neither they nor the IPCC suppressed anything: when the assessment report was published in 2007 it referenced and discussed both papers.”

Are the CRU data “suspect”? An Objective Assessment:

CRU data analysis

Source: RealClimate

Comparison of CRUTEM3v data with raw station data taken from World Monthly Surface Station Climatology. On the left are the mean temperature anomalies from each pair of randomly chosen times series. On the right are the distribution of trends in those time series and their means and standard errors. (The standard error provides an estimate of how well the sampling of ~30 stations represents the full global data set assuming a Gaussian distribution.) Note that not all the trends are for identical time periods, since not all data sets are the same length.


There is no indication whatsoever of any problem with the CRU data. An independent study (by a molecular biologist it Italy, as it happens) came to the same conclusion using a somewhat different analysis. None of this should come as any surprise of course, since any serious errors would have been found and published already.

It’s worth noting that the global average trend obtained by CRU for 1850-2005, as reported by the IPCC (, 0.47 0.54 degrees/century,* is actually a bit lower (though not by a statistically significant amount) than we obtained on average with our random sampling of stations.

*See table 3.2 in IPCC WG1 report.

ClimateGate Emails

“lack of warming”

Kevin Trenberth, climatologist at the National Center for Atmospheric Research. He wrote, “The fact is we can’t account for the lack of warming at the moment and it’s a travesty that we can’t.”

Kevin is discussing short term variation that involved natural variation on a year to year basis. It is important to understand that climate is long term (30+ years) while weather and internal variability (weather/natural variability) is considered on shorter time scales.

Trenberth: You need to read his recent paper on quantifying the current changes in the Earth’s energy budget to realize why he is concerned about our inability currently to track small year-to-year variations in the radiative fluxes. – Gavin Schmidt

“Mike’s nature trick” & “hide the decline”

Phil Jones, head of the Climate Research Unit at the University of East Anglia

“I have just completed Mike’s nature trick of adding in the real temps to each series for the last 20 years to hide the decline.”

The term trick in this usage/context means applying a method. Applying various methods is how scientists test different ideas and then compare the results to actual observations. This is normal in the scientific process. Nothing deceptive here.

The paper in question is the Mann, Bradley and Hughes (1998) Nature paper on the original multiproxy temperature reconstruction, and the ‘trick’ is just to plot the instrumental records along with reconstruction so that the context of the recent warming is clear. Scientists often use the term “trick” to refer to a “a good way to deal with a problem”, rather than something that is “secret”, and so there is nothing problematic in this at all. As for the ‘decline’, it is well known that Keith Briffa’s maximum latewood tree ring density proxy diverges from the temperature records after 1960 (this is more commonly known as the “divergence problem”–see e.g. the recent discussion in this paper) and has been discussed in the literature since Briffa et al in Nature in 1998 (Nature, 391, 678-682).

Comment: Steve McIntyre, who you have mentioned on these threads, takes serious issue with your explanation of the “hide the decline” statement. The usefulness of tree-ring data and/or reality of AGW are not the issues here. McIntyre is leveling charges of impropriety and fraud, and quite frankly, his explanation makes a lot more sense than the one posted on this website.

[Response: This is simply false. The ‘decline’ was discussed first in Briffa et al 1998 and the full dataset is available here including data up to 1994. Claims that this was hidden or unavailable are simply untrue. McIntyre is doing a bait and switch with another later update by the same author. – gavin]

Additional Points from

  • Wigley: The concern with sea surface temperatures in the 1940s stems from the paper by Thompson et al (2007) which identified a spurious discontinuity in ocean temperatures. The impact of this has not yet been fully corrected for in the HadSST data set, but people still want to assess what impact it might have on any work that used the original data.
  • Climate Research and peer-review: You should read about the issues from the editors (Claire Goodess, Hans von Storch) who resigned because of a breakdown of the peer review process at that journal, that came to light with the particularly egregious (and well-publicised) paper by Soon and Baliunas (2003). The publisher’s assessment is here.

Update: Pulling out some of the common points being raised in the comments.

  • HARRY_read_me.txt. This is a 4 year-long work log of Ian (Harry) Harris who was working to upgrade the documentation, metadata and databases associated with the legacy CRU TS 2.1 product, which is not the same as the HadCRUT data (see Mitchell and Jones, 2003 for details). The CSU TS 3.0 is available now (via ClimateExplorer for instance), and so presumably the database problems got fixed. Anyone who has ever worked on constructing a database from dozens of individual, sometimes contradictory and inconsistently formatted datasets will share his evident frustration with how tedious that can be.
  • “Redefine the peer-reviewed literature!” . Nobody actually gets to do that, and both papers discussed in that comment – McKitrick and Michaels (2004) and Kalnay and Cai (2003) were both cited and discussed in Chapter 2 of 3 the IPCC AR4 report. As an aside, neither has stood the test of time.
  • “Declines” in the MXD record. This decline was hidden written up in Nature in 1998 where the authors suggested not using the post 1960 data. Their actual programs (in IDL script), unsurprisingly warn against using post 1960 data. Added: Note that the ‘hide the decline’ comment was made in 1999 – 10 years ago, and has no connection whatsoever to more recent instrumental records.
  • CRU data accessibility. From the date of the first FOI request to CRU (in 2007), it has been made abundantly clear that the main impediment to releasing the whole CRU archive is the small % of it that was given to CRU on the understanding it wouldn’t be passed on to third parties. Those restrictions are in place because of the originating organisations (the various National Met. Services) around the world and are not CRU’s to break. As of Nov 13, the response to the umpteenth FOI request for the same data met with exactly the same response. This is an unfortunate situation, and pressure should be brought to bear on the National Met Services to release CRU from that obligation. It is not however the fault of CRU. The vast majority of the data in the HadCRU records is publicly available from GHCN (v2.mean.Z).
  • Suggestions that FOI-related material be deleted … are ill-advised even if not carried out. What is and is not responsive and deliverable to an FOI request is however a subject that it is very appropriate to discuss.

In the meantime, read about why peer-review is a necessary but not sufficient condition for science to be worth looking at. Also, before you conclude that the emails have any impact on the science, read about the six easy steps that mean that CO2 (and the other greenhouse gases) are indeed likely to be a problem, and think specifically how anything in the emails affect them. – Gavin Schmidt

Update: The piece by Peter Kelemen at Columbia in Popular Mechanics is quite sensible, even if I don’t agree in all particulars.

Further update: Nature’s editorial.

Further, further update: Ben Santer’s mail (click on quoted text), the Mike Hulme op-ed, and Kevin Trenberth.

Myths vs. Facts: Denial of Petitions for Reconsideration of the Endangerment and Cause or Contribute Findings for Greenhouse Gases under Section 202(a) of the Clean Air Act

Myth: The University of East Anglia’s Climatic Research Unit (CRU) emails prove that temperature data and trends were manipulated.

Fact: Not true. Petitioners say that emails disclosed from CRU provide evidence of a conspiracy to manipulate data. The media coverage after the emails were released was based on email statements quoted out of context and on unsubstantiated theories of conspiracy. The CRU emails do not show either that the science is flawed or that the scientific process has been compromised. EPA carefully reviewed the CRU emails and found no indication of improper data manipulation or misrepresentation of results.

Myth: The jury is still out on climate change and CRU emails undermine the credibility of climate change science overall.

Fact: Climate change is real and it is happening now. The U.S. Global Change Research Program, the National Academy of Sciences, and the Intergovernmental Panel on Climate Change (IPCC) have each independently concluded that warming of the climate system in recent decades is “unequivocal.” This conclusion is not drawn from any one source of data but is based on multiple lines of evidence, including three worldwide temperature datasets showing nearly identical warming trends as well as numerous other independent indicators of global warming (e.g., rising sea levels, shrinking Arctic sea ice). Some people have “cherry-picked” a limited selection of CRU email statements to draw broad, unsubstantiated conclusions about the validity of all climate science.

Myth: The CRU emails and several errors found in the most recent IPCC report undermine the credibility of the IPCC Fourth Assessment Report.

Fact: The IPCC’s primary conclusions are based on an assessment of thousands of individual studies and collective insights from the comprehensive climate science literature. Although many errors were alleged, EPA confirmed only two errors. The small number of documented errors are not central to IPCC’s main conclusions or to EPA’s Endangerment Finding. In a report of such magnitude, a few errors do not undermine the credibility of the entire work of the IPCC. The process used by the IPCC stands as one of the most comprehensive, rigorous, and transparent ever conducted on a complex set of scientific issues.

Myth: EPA misstepped when it did not do its own scientific analysis of climate change to inform the Endangerment Finding and instead relied on existing scientific assessments.

Fact: EPA relied on major scientific assessments, including reports from the U.S. Global Change Research Program, National Academy of Sciences, and IPCC, because they represent the best available information to determine the state of climate change science. These assessments are designed to address the breadth and scope of all published literature and undergo multiple levels of rigorous review. This approach ensures that EPA benefits from the depth and strength of thousands of climate scientists.




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