An unknown person recently broke into the CRU's computer system and removed a number of documents. The mysterious cracker then published the data on the Internet. Anthropegenic global warming (AGW) skeptics claim those e-mails and files prove the researchers are attempting to skew the results of their studies to show there is global warming. The CRU asserts that nothing of the sort is going on the documents from the CRU Hack are being taken out of context and they have sound reasons for what is going on behind the curtain.
I suspect the out of context defense will hold in some cases. For example, there is one e-mail where the author uses the word "trick" and skeptics claim this amounts to a nefarious plot. Not true say the researchers, the trick was just an obscure but legitimate mathematic or statistical method. I go with the later, I recall many discussions on how to solve a problem and one person saying "the trick is…". The infamous "hide the decline" is harder to account for without knowing more details of what was being discussed. However, the plain and simple reading of the note is not good for the CRU crew.
A more serious problem is the deletion of data from the CRU's database(s). In my previous post I go over the notion of data outliers. My central point is researchers frequently and rightly exclude certain collected data from analysis. However, generally accepted standards dictates researchers report all raw data and justify data exclusions from further analysis. The inclusion or exclusion of data may be open to debate and further experimentation and that makes good science.
I am aware of a number of justifications for discarding this data. One of them is the raw data went through quality assurance procedures and combined with other sets of data therefore that raw data is no longer needed. That does not pass the smell test, what about those quality processes? Sometimes that justification is combined with the need to save storage space, which does not improve it.
Phil Jones (currently embattled CRU Director) back in October of 2009 states:
The research unit has deleted less than 5 percent of its original station data from its database because the stations had several discontinuities or were affected by urbanization trends. When you're looking at climate data, you don't want stations that are showing urban warming trends, so we've taken them out. Most of the stations for which data was removed are located in areas where there were already dense monitoring networks. We rarely removed a station in a data-sparse region of the world.So, in essence Mr. Jones asserts the missing data tends to register warmer temperatures than what is warranted or that excessive reports from a given area are removed. Those are real justifications open to debate, if only we had the data, we do not and so we have to take Mr. Jones at his word.
This event does not prove or disprove anthropogenic (or otherwise) global warming. It just calls into question the research the promoters of anthropegenic global warming use to support their contentions and policies they believe we need to implement. Further and more rigorous research may indeed uphold the view the earth is warming or it may not.