Saturday, December 19, 2009

Climate Data Fudge Factor

There is some evidence giving cause for concern:

· There is evidence of dogmatism: ‘The fact is that we can't account for the lack of warming at the moment and it is a travesty that we can't. The CERES data published in the August BAMS 09 supplement on 2008 shows there should be even more warming: but the data are surely wrong. Our observing system is inadequate.’[1] Now it is indeed possible that the data is wrong, but the lack of a continued warming trend (since 1998?) is contrary to the predictions of the models on which IPCC predictions are based, and a common variety of dogmatism is to deny evidence that doesn’t fit your preconceived beliefs.

· There is evidence of arbitrary data manipulation: ‘Another serious issue to be considered relates to the fact that the PC1 time series in the Mann et al. analysis was adjusted to reduce the positive slope in the last 150 years ... At this point, it is fair to say that this adjustment was arbitrary.’[2]

· In the computer code there is evidence of data manipulation conducted in order to get a pre-conceived result.

· Remarks from a programmer writing code indicate serious problems with collection and recording of original data ‘another problem that's based on the hopeless state of our databases’[3]

· For some time there has been controversy over the selective use of data. For a recent example from a Russian institute commenting on the CRU use of Russian data (report here): the continuous data records from Russia which taken in their entirety show warming of 1.4 C since 1860 versus CRU use of only 25% of that data to show 2.06C rise since 1860; the use by CRU of stations with incomplete and interrupted data where such data shows warming versus the omission of stations with complete and continuous data which doesn't.

· More broadly, local scientists in Australia and New Zealand have found broadly constant original temperature data on which a rising official temperature record has been based through the use of methods of data manipulation originating in or influenced by CRU practices. See this discussion of the problems in raw data and controversy over claims of inhomogeneity in that data and adjustments made to produce estimates of historical temperatures from weather stations in Northern Australia: http://wattsupwiththat.com/2009/12/08/the-smoking-gun-at-darwin-zero/

None of these examples demonstrate straightforward dishonesty. For example, all sorts of junk gets left in computer code. People put bits in that they call ‘fudge factors’ because they think they know the broad shape of some other correction process which is not yet coded, so in early drafts a ‘fudge factor’ procedure stands as a proxy for some real adjusting factor. They are, however, evidence that more subtle vices may yet be in play.

Read it all here.

1 comment:

L.A.S said...

Interesting article, Alice, thanks for posting! If you want to check out some of my writing on www.las-digest.com please do, and we could possibly collaborate on a future post.