A letter to my students:
Dear Students of Climate Science and Policy 3 CORE 2473,
Sorry for intruding on your vacation. I am trying to give one last lecture. After you turned in your papers, a media brouhaha erupted over emails and files stolen from the servers of the Climate Research Unit (CRU) of the East Anglia University in the UK. Some of these emails are painful for me to read, and commentators have used them to construct a narrative that is quite different from the one I presented in class. I have said repeatedly that science is an open, transparent process. Many say that these emails prove just the opposite. Please bear with me while I examine the four examples most quoted from the stolen trove. I argue that in science, the story is in the scientific literature and not in the email outboxes of a handful of scientists. And that is what I mean by open and transparent.
1) One famous email made reference to papers that the sender intended to exclude from the IPCC Fourth Assessment Report even if it meant that he had to "redefine what peer reviewed literature is." This emailer was a Coordinating Lead Author for Chapter 3 of IPCC 4AR, but the papers in question, it turns out, are discussed at length on page 244 in this chapter. So the IPCC principles of openness and transparency prevailed. The peer-reviewed literature is the peer-reviewed literature, and it was reviewed thoroughly in IPCC. The storyline asserting that the elite excluded contrary papers is not borne out by the actual contents of the Assessment.
2) An email from Kevin Trenberth was highlighted on the Daily Show and on Some Major News Show. Trenberth authored the figure describing energy fluxes in the atmosphere that we used in class and on the midterm. In his vivid language, he said that he is unable to track the energy flows in the atmosphere and that this failure is "a travesty." This quote has been advanced as proof that we really do not know the cause of the warming since 1950 and that Trenberth was confessing his failure secretly to his co-conspirators in the big lie that CO2 warms. Well actually, Trenberth's concern is not secret, he published it in a journal article for all to see in 2009. In it, you can see that the problem he has is with data after 2003. He writes, "Planned adaptation to climate change requires information about what is happening and why. While a long-term trend is for global warming, short-term periods of cooling can occur and have physical causes associated with natural variability. However, such natural variability means that energy is rearranged or changed within the climate system, and should be traceable..." In class, we said that the internal variability was unexplained. Trenberth and others felt that they were making progress on tracking the energy rearrangements that create internal variability. Post 2003 data have frustrated this ambition. He finds it "a travesty" in his email and proposes improvements in the climate information system to address it. There is no confession of a failure to understand the overall trend up, and Trenberth's opinion was not secret. Those reading the literature knew prior to the heist.
3) A programmer's comments in code written to assemble temperature data into a global average temperature trend suggested to many that the CRU data were fudged and that the warming it showed was a lie. The touchstone of science is the replication of important results by others. There are four groups that I know of that are compiling global average temperatures. The HADCRU (Hadley CRU) global average temperatures compare nicely with the results of US NASA GISS, US NOAA NCDC and the Japan Meteorological Service. CRU has been criticized because its data are not completely available. The NASA and NOAA websites provide tons of data and papers explaining procedures. So the record of global surface warming is not dependent only upon CRU's programmer. (P.S. The email snoops did not steal the programmer's notebooks with the commented code. So we do not have a record of how the programmer validated his code or how he recorded the corrections and adjustments to temperatures. The validity of his work is not properly judged by emails and programs ripped out of context. Those who learned all they need to know from the emails already had their minds made up.)
4) The fourth complaint has to do with the presentation of the temperature reconstructions that we looked at in class. Tree rings in particular were discussed. The word "trick" was bandied about. It turns out that the tree ring record differs from the thermometer record after 1960. There is a paper on the subject in Nature in which the authors recommend against using the tree ring data after 1960. Nature 391, 678-682 (12 February 1998). And, guess what, in the reconstructions we looked at, they used measured temperatures after 1960. So the secret trick that the commentators were complaining about was written up in one of the most widely read journals in the world. In general, I do not get tree rings, but Congress asked the National Academy of Sciences in 2006 to report on the temperature reconstructions and their committee "found sufficient evidence to say with a high level of confidence that the last decades of the 20th century were warmer than any comparable period in the last 400 years." It said less confidence could be placed in reconstructions of temperatures prior to 1600, although proxy data does indicate that many locations are warmer now than they were between A.D. 900 and 1600. Proxy data for periods prior to A.D. 900 are sparse, the report notes." As you know from class, I am more interested in the physical role played by greenhouse gases.
We do not need to hack a computer to find the answers to these questions. We need to read the scientific literature. The story is there, not in a handful of in-boxes.
Your papers were very interesting, but it is too bad that no one addressed the impact of the uncertainty in climate sensitivity. You know that IPCC reckons that it ranges from 2 °C to 4.5 °C degrees for a doubling of CO2. We must address the policy implications of that range. The stolen emails do not help that discussion. They were stolen some time ago and released prior to Copenhagen as a distraction. It worked nicely.
Thanks for reading.
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