IPCC error rate: You were expecting something else?

Via the ever-vigilant Stoat, I draw your attention to a letter to the Netherlands parliament from by 55 Netherlands scientists. Along with the usual "the science remains sound" defense of our understanding of anthropogenic global warming, it provides some useful perspective:

The writing of IPCC reports and its quality control remains the work of humans. A guarantee for an error free report is an unachievable ideal, however much an error free report is highly desired

Just as a thousand private emails are bound to include a few intemperate remarks and elucidation of wishful thinking, the thousands of pages of reports that draw on 18,000 sources were bound include a few dubious references. Anyone who finds the current error rate (3 or 4, depending on who's counting) should read Stephen Schneider's Science as a Contact Sport for insight into just how incredible it is that the IPCC quality control process is a rigorous as it is.

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What about the global record? Here, you donât have to take my word for it. A much chastened Phil Jones (the disgraced former Director of the CRU of email fame), in an interview with the BBC on Friday, February 12, 2010, answered a BBC question as follows:

Do you agree that according to the global temperature record used by the IPCC, the rates of global warming from 1860-1880, 1910-1940 and 1975-1998 were identical?

An initial point to make is that in the responses to these questions Iâve assumed that when you talk about the global temperature record, you mean the record that combines the estimates from land regions with those from the marine regions of the world. CRU produces the land component, with the Met Office Hadley Centre producing the marine component.

Temperature data for the period 1860-1880 are more uncertain, because of sparser coverage, than for later periods in the 20th Century. The 1860-1880 period is also only 21 years in length. As for the two periods 1910-40 and 1975-1998 the warming rates are not statistically significantly different (see numbers below).

I have also included the trend over the period 1975 to 2009, which has a very similar trend to the period 1975-1998.

So, in answer to the question, the warming rates for all 4 periods are similar and not statistically significantly different from each other.

So in fact, according to Phil Jones (who strongly believes in the AGW hypothesis) there is nothing unusual about the recent warming either. It is not statistically different from two earlier modern periods of warming. Since these warming periods were before the modern rise in CO2, greenhouse gases cannot have been responsible for those rises.

So my question remains unanswered ⦠where is the anomaly? Where is the unusual occurrence that we are spending billions of dollars trying to explain?

The answer is, there is no unusual warming. There is no anomaly. There is nothing strange or out of the ordinary about the recent warming. It is in no way distinguishable from earlier periods of warming, periods that we know were not due to rising CO2. There is nothing in the record that is in any way different from the centuries-long natural fluctuations in the global climate.

In other words, we have spent billions of dollars and wasted years of work chasing a chimera, a will-of-the-wisp. This is why none of the CO2 explanations have held water ⦠simply because there is nothing unusual to explain.

-cheers

Phil: you fail to notice two things:
1. Phil Jones notes the inability to explain the warming after 1950, and especially since the 1980s, without taking anthropogenic forcings into account

2. The IPCC already discussed the warming before 1950, and all those "It's the Sun, stupid!" suddenly and immediately forget that the sun saw an increase in activity from at least the early 1900s to the early 1970s.

In short, it *is* unusual to see warming in a period where there is no natural forcing that can explain an increase in temperature. Au contraire, the natural forcings point to *cooling*.

"" In short, it *is* unusual to see warming.. ""

No. You just WANT (and NEED for some reason) it to be unusual. FAIL on your part.

-cheers

Given a record that covers 150 years, there are 121 30 year periods that you can choose: what are the odds of finding 4 periods that have comparable trends? Especially if you can choose periods with different lengths, giving you hundreds more options? In other words: cherrypicked.

By turbobloke (not verified) on 13 Feb 2010 #permalink