December 6, 2009

Knavish tricks...



If you've paid any attention at all to Climategte, you've heard the damning phrase "hide the decline." But most people don't know what the decline was, or assume, incorrectly that it refers to the decline in measured temps since 1998. Turns out, not so.

Here's a very good piece that explains what was going on, American Thinker: Understanding Climategate's Hidden Decline .These are just a couple of snippets; do do read the whole thing...

...In fact, the decline Jones so urgently sought to hide was not one of measured temperatures at all, but rather figures infinitely more important to climate alarmists – those determined by proxy reconstructions. As this scandal has attracted new readers to the subject, I ask climate savvy readers to indulge me while I briefly explain climate proxies, as they are an essential ingredient of this contemptible conspiracy.

Truth be told — even reasonably reliable instrumental readings are a relatively modern convenience, limiting CRU's global measured temperature database to a start date somewhere in the mid-19th century. That's why global temperature charts based on actual readings typically use a base year of 1850 or somewhere thereabouts.

And yet — most historical temperature charts, including the one Al Gore preached before in An Inconvenient Truth, go way back to 1000 AD. That's where proxies come in.

While historical documents (e,g, ship's logs, diaries, court and church records, tax rolls, and even classic literature) certainly provide a glimpse into past temperature trends, such information is far too limited and generalized to be of any statistical value. So climate scientists have devised means to measure variations in such ubiquitous materials as lake sediments, boreholes, ice cores, and tree rings to evaluate past temperature trends.

They then employ complex computer programs to combine such "proxy" data sampled throughout a region to plot that area's annual relative changes in temperature hundreds or even thousands of years prior. By then combining the datasets, they believe they can accurately reproduce hemispheric and global temperature trends of the previous millennia.

And while reconstructions — as past temperature interpretations from proxy data are called — can differ greatly from one source to another, those generated by the CRU have often been accepted as the de facto temperatures of the past...
[...]

...So not only did conspirators cherry-pick the one series of the four that approximated measured temperatures the longest, they also terminated that series at the point that it too, began to trend down. They then joined it to the actual 1980-1999 temperatures to "hide the decline" in the final product, as that decline created an inexplicable divergence between the reconstructed and measured temperatures. The existence of which challenges the entire series dating back to 1000 AD.

Remember, all of the temperatures prior to 1850 were estimated by computer algorithms and no actual readings exist to prove or disprove those figures. So a relatively short window of opportunity exists to test the programs against observations. Had 20th century measured temperatures continued to align with those recreated as smoothly after 1960 as they did previously, then the programmers could declare their code and hence their millennial temperatures sound. But the divergence, if allowed to stand, instead revealed serious design flaws in the proxy reconstructions. Which suggests that just as the decline was dealt with through trickery, so was the MWP.

And it seems that each time the trick was used, its involvement would be more deeply concealed.

Every multi-volume IPCC Assessment has been accompanied by a relatively brief and highly-politicized Summary for Policymakers (SPM). This synopsis invariably commands the bulk of the media and political attention. Here's the version of the graph depicted prominently on page 3 of the 2001 TAR SPM [PDF], the only version of the report most policymakers and reporters would ever actually see. Notice how they further obscured their chicanery by omitting the series defining legend and the "1988 instrumental value" declaration...
Posted by John Weidner at December 6, 2009 2:10 PM
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