In his analysis of his hockey stick temperature reconstruction, Michel Mann claimed that his results were robust to changes in certain weighting factors. Humorously, Steven McIntyre demonstrates that it is robust because when you do the math, the weighting factors actually cancel out of all the equations. In effect, Mann was saying that y =3x/x gives the answer “3″ robustly for all values of x (well, except zero). True, but scientifically meaningless. But worrisome when a scientist has to run numerous simulations to discover the fact. I presume he thought his weighting factors were actually doing something in his model.

“3x/x” captures the situation exactly. To be fair, Mann himself did not claim that the changes were “robust” to weighting factors; his claims were to things like all dendroclimatic indicators; he himself never mentioned that he used weighting factors. This particular issue was raised by Wahl and Ammann. Again to be precise, they didn’t make the claim of robustness about the weighting factor L (using the nomenclature of the post) where the claim is trivial but true, but about the weighting factor P where the claim is false. This is the Team after all.

Its my tamino impression.

Why bother; The climate only matters on 30 year time scales.

Somebody ought to tell the people working with the monthly and yearly anomalies to not bother with this weather stuff.

Jan version: 2007 87 63 59 66 55 53 51 56 50 55 46 39 Year 57
Apr version: 2007 86 63 60 64 55 53 51 56 50 55 49 40 Year 57

I didn’t check other years.

I have absolutely NO idea what you just said. You are taking this entire controversy to a place outside of my areas of expertise, and thereby marginalizing the worth of my contributions to the discussion. As I am a person of worth and intellect and moral correctness, to exclude my input in favor of a technocrat’s formulas is entirely wrong, and works to show only that you have valued and weighted the wrong inputs and influences in your results-driven propogandizing.

Clearly, your ad hominum, math-centric attacks on Mr. Mann’s work cannot detract from the essential TRUTH of what he tells us. Mann shows us our evil, and your attempt to use these outlandish, inscrutable MATH problems to discredit him fails to address, much less impeach, the core of his work.Mann is post-math!

In any professionally managed engineering program, no previous version of data would just be discarded or overwritten. The older version would be archived and a change notice issued detailing the reason(s) for the update. This change notice would have to be approved by an authorized official before any modification to the current data could be done.

Perhaps GISS is doing this and has the older versions safely archived with their change notices.

In any case, if you are using this data, it seems wise to check for the latest data fairly regularly. Don’t assume you can just go in, add the most recent value, and use that only.

Thanks