ClimateGate

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.

• RealClimate: The CRU Hack
  
• RealClimate: The CRU Hack Context
  
• RealClimate:The CRU Hack More Context
• Realclimate: Are the CRU Data suspect - An Objective Assessment
• RealClimate: Jim Hansen's Opinion on the Temperature Data
• RealClimate: Kim Cobb's View - Georgia Tech
• RealClimate: More Independent Views: Myles Allen and Ben Santer
  

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.

Other Recommended Reading

• http://www.desmogblog.com/kevin-trenberth-standing-ipcc-process
• http://www.nature.com/nature/journal/v462/n7273/full/462545a.html

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. 23, 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:

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.

Conclusion:

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 (http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter3.pdf), 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

• Ocean Blips
• Has climate data been destroyed?
  

"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) 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

• http://www.realclimate.org/index.php/archives/2009/11/the-cru-hack-context
• http://www.cgd.ucar.edu/cas/Trenberth/trenberth.papers/EnergyDiagnostics09final2.pdf
  

 "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).

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.

http://www.evolutionnews.org/2009/12/the_decline_they_hid_the_delet.html

[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]

• Real Climate: Simply False
• Real Climate: Simply Presentational

 Additional Points from RealClimate.org

• 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.