29 November 2009

CRU on Global Temperature Data

The Times had an article yesterday reporting the old news that CRU did not have in its possession the original station data from some locations that comprise its global temperature index. I am quoted in the Times article as follows:
“The CRU is basically saying, ‘Trust us’. So much for settling questions and resolving debates with science,” he said.
The quote comes from a blog post I put up last August when CRU announced that it did not have some of the original station data. Here is the full context of my quote:
CRU has in response to requests for its data put up a new webpage [NOTE: Apparently this page is no longer up on the CRU emergency server] with the following remarkable admission (emphasis added):
We are not in a position to supply data for a particular country not covered by the example agreements referred to earlier, as we have never had sufficient resources to keep track of the exact source of each individual monthly value. Since the 1980s, we have merged the data we have received into existing series or begun new ones, so it is impossible to say if all stations within a particular country or if all of an individual record should be freely available. Data storage availability in the 1980s meant that we were not able to keep the multiple sources for some sites, only the station series after adjustment for homogeneity issues. We, therefore, do not hold the original raw data but only the value-added (i.e. quality controlled and homogenized) data.
Say what?! CRU has lost track of the original data that it uses to create its global temperature record!? Can this be serious? So not only is it now impossible to replicate or reevaluate homogeneity adjustments made in the past -- which might be important to do as new information is learned about the spatial representativeness of siting, land use effects, and so on -- but it is now also impossible to create a new temperature index from scratch. CRU is basically saying, "trust us." So much for settling questions and resolving debates with empirical information (i.e., science).
Today I received an email from a climate scientist of CRU-email fame complaining about my quote in the Times. He says that the national meteorological services have the original data, suggesting that I was misrepresenting the situation. I replied to him as follows:
I would suspect that there are some very profound disciplinary differences in the handling of data here between the community I am from and yours. If, for instance, an economic research unit were releasing analyses of global economic activity in support of policy claimed to not hold the original country data -- instead saying, well the countries have it -- that would be highly problematic.

My advice to you and your colleagues is that the defense that you present in your email to me is not a very good one. Rather, I suggest instead being open and simply saying that in the 1980s and even 1990s no one could have known that maintaining this data in its original form would have been necessary. Since it was not done, then efforts should be made to collect it and make it available (which I see CRU is doing). Ultimately, that will probably mean an open-source global temperature record will be created. If you believe -- and I see no reason to suspect otherwise -- that such an open-source analysis will confirm the work of Jones et al., then you should be welcoming it with open arms.
Obviously, CRU should have taken these steps long before the present circumstances, but regardless, they are now moving towards greater responsiveness and transparency. When the data is available in its original form those skeptical of climate science can then do the temperature math themselves out in the open where everyone can see their work. If the global numbers come out as CRU has presented over the years, then it will strike a blow to skepticism about global temperature trend records produced by CRU and restorse a good deal of credibility to this area of climate science. At that point, the fellow who emailed me and his colleagues can rightly boast of their integrity and say "told ya so." Until then, a defensive, circle-the-wagons approach is probably not the best course of action. But old habits die hard.