Hansen has followed up his “Lights Out Upstairs” outburst with another outburst dismissing critics as “court jesters” with whom he will have no truck. (Lights Out is now cited on the NASA website.) His new jeremiad re-iterated the position of NASA spokesman Gavin Schmidt that U.S. errors “didn’t matter” because the U.S. was only 2% of the earth’s surface. Today I’ll take a look back at Hansen et al 1999 and, especially Hansen et al 2001, the latter entitled “A closer look at United States and global surface temperature change” and being entirely devoted to coaxing a few-tenths of temperature change out of the U.S. record, a matter now said to be unimportant. Hansen also linked interest in the NASA computer programming errors to somehow acquiescing in the “destruction of Creation”.
Hansen’s Recent Jeremiads
Hansen has a collection of his recent jeremiads online here. On August 10, 2007, shortly after NASA had changed their online data for over 1200 US HCN stations and for their U.S. temperature history, Hansen sent an email to reporters and others saying:
Sorry to send another e-mail so soon. No need to read further unless you are interested in temperature changes to a tenth of a degree over the U.S. … My apologies if the quick response that I sent to Andy Revkin and several other journalists, including the suggestion that it was a tempest inside somebody’s teapot dome, and that perhaps a light was not on upstairs, was immoderate. It was not ad hominem, though.
As I will show below, Hansen himself thought otherwise in Hansen et al 2001 – an article which is devoted to nothing but this topic. Update Aug 21 9 am: At its webpage on Hansen’s temperature index, NASA has added the following comment linking directly to Hansen’s outburst – I wonder if it’s covered by the Data Quality Act:
*** What’s New ***
Please see “A Light On Upstairs?” for discussions regarding the changes made on August 7, 2007 for 2000-2006 annual mean, U.S. mean temperatures.
Hansen’s most recent epistle is well worth reading. The proximate occasion of this latest letter is Hansen’s “Y2K” error. He says in the letter (but not at the NASA website) that the flaw affected temperatures in the U.S. “by about 0.15 deg C… only in 2000 and later” and that they patched the program, “thanked the fellow who pointed it out and thought that was the end of it.”
Hansen says that he will not “joust” with his critics, who he regards as mere “court jesters”, since “Creation” itself is at stake:
if we, in effect, destroy Creation, passing on to our children, grandchildren, and the unborn a situation out of their control, the contrarians who work to deny and confuse will not be the principal culprits. The contrarians will be remembered as court jesters. There is no point to joust with court jesters. They will always be present. They will continue to entertain even if the Titanic begins to take on water. Their role and consequence is only as a diversion from what is important.
It’s as though Hansen, who grew up in the 1930s and 1940s, has a Jor-El complex: Jor-El being familiar to young boys of a certain age as Superman’s father who (per Wikipedia):
“was a highly respected scientist on the planet Krypton before its destruction. He foresaw the planet’s fate, but was unable to convince his colleagues in time to save their race. Jor-El was, however, able to save his infant son, Kal-El, sending him in a homemade rocketship to the planet Earth just moments before Krypton’s demise.
Look, there are lots of reasons to believe that climate change is a serious issue: I think that it’s a serious issue. Personally I think that it’s prudent on a number of grounds to generate electricity from nuclear rather than coal or oil – a policy advocated by Hansen here. Even if Hansen is right about all of the proximate effects of increased CO2, no one before him had projected that this would cause the destruction of “Creation” – and, to my knowledge, no such projections are included in even most pessimistic IPCC scenario.
Although Hansen does not specifically mention the “fellow” who brought the error to his attention, he then proceeds into a variety of accusations against his critics:
What we have here is a case of dogged contrarians who present results in ways intended to deceive the public into believing that the changes have greater significance than reality. They aim to make a mountain out of a mole hill. I believe that these people are not stupid, instead they seek to create a brouhaha and muddy the waters in the climate change story. They seem to know exactly what they are doing and believe they can get away with it, because the public does not have the time, inclination, and training to discern what is a significant change with regard to the global warming issue.
The proclamations of the contrarians are a deceit, … The characters in the main drama are big fish, really big fish. But before we get to that matter, I need to expose how the deceit works. Instead of showing the impact of the flaw in our analysis program via a graph such as Figure 1, as a scientist would do (and as would immediately reveal how significant the flaw was), they instead discuss ranking of temperature in different years, including many false statements. We have thus been besieged by journalists saying “they say that correcting your error caused the warmest year to become 1934 rather than a recent year, is that right!?”
The contrarians will be remembered as court jesters. There is no point to joust with court jesters. … Court jesters serve as a distraction, a distraction from usufruct. Usufruct is the matter that the captains wish to deny, the matter that they do not want their children to know about.
In less hysterical tones over at realclimate, Hansen’s colleague and NASA spokesman, Gavin Schmidt, has also minimized the error:
Another week, another ado over nothing.
Sum total of this change? A couple of hundredths of degrees in the US rankings …
NASA spokesman Schmidt also went to the trouble of misrepresenting my role in identifying the specific error. Both at the blog and in my email to Hansen, I specifically identified the error as probably coming from use of one USHCN version prior to 2000 and another version for 2000 and later – a diagnosis confirmed by NASA. Unwilling to even concede me this gruel, Schmidt denied that I even “speculated” as to the cause of the error”
Steve M pointed out where the error came from in his blog posts and his email notifying GISS of the problem. The GISS people simply confirmed that he was correct.
[Response: Not so. He saw the jump but did not speculate as to the cause. – gavin]
Hansen et al 1999, 2001
The principal argument at realclimate and in Hansen’s jeremiads against the materiality of the U.S. errors is that the U.S. is only 2% of the earth’s surface. Hansen also argued that in 2001, he stated that 1934 was slightly warmer than 1998; so that, even though NASA online figures as of July 2007 showed that 1998 was warmer than 1934, Hansen claimed that he was for 1934 before he was against it, a claim that I do not dispute.
One of the realclimate posters picked up this trivialization of an interest in U.S. history as follows:
Again, if somebody is really interested in improving worldwide data, spending most of their effort chasing 2% USA Lower-48 is very weird. Reasonable, well-informed people can and do disagree about good procedures, but much of this thread seems right out of the Philip Morris GEP or Data Quality Act playbooks, and it does not help good science…
It is interesting to contrast their present view on the immateriality of U.S. temperature history with their position in Hansen et al 1999 and Hansen et al 2001. The two figures are shown on a common scale in the re-plot below (courtesy of digitization by Hans Erren). As you see immediately, in 1999, Hansen reported that 1934 was 0.6 deg C warmer than 1998. Further, there was actually a negative trend in U.S. temperatures since the 1920s. However, this negative trend for the period since the 1920s had been replaced by a flat trend in the 2001 figures. For the period since 1880, the earlier report had a flat trend, the later report a temperature trend of about 0.32 deg C per century (with, as noted above, a flat trend since the 1920s.)
While Hansen and Schmidt now decry the immateriality of U.S. temperature history, this was definitely not the position of Hansen et al 2001. The entire purpose of Hansen et al 2001 was to provide a re-statement of U.S. temperature history, eliminating the inconvenient negative trend since the 1920s in the earlier publication. The heavy lifting for this re-statement had been done by co-author Tom Karl at NOAA, whose adjustments for time-of-observation and “station history” led to the re-statement of U.S. results reported by Hansen et al. The first sentence of the abstract stated:
The purpose of the present paper is to document the changes that have been made in the GISS analysis of surface temperature change subsequent to the documentation of Hansen et al.  and to use this new analysis for a closer look at the United States and global temperature change.
In the running text, they observe ( a quote cited by a poster at realclimate):
Although the contiguous U.S. represents only about 2% of the world area, it is important that the analyzed temperature change there be quantitatively accurate for several reasons. Analyses of climate change with global climate models are beginning to try to simulate the patterns of climate change, including the cooling in the southeastern U.S. [Hansen et al., 2000]. Also, perceptions of the reality and significance of greenhouse warming by the public and public officials are influenced by reports of climate change within the United States.
Another reason is, of course, that there are far more temperature histories reaching back to the 1930s from the U.S. than anywhere else (more on this on another occasion). The adjustments did not include allowance for HO-83 thermometers known to have a positive bias on readings for a number of stations in the 1990s.
In any event, a few years ago, Hansen et al thought that a re-statement of U.S. results, amounting only to an upward re-statement of about 0.32 deg C per century was worth publishing. However, it seems that an error amounting to a downward step of 0.15 deg C is immaterial. I’m sure that Jor-El’s engineering was more precise than this.
Here’s another interesting graphic showing the difference between Hansen 2001 and Hansen 1999 (from the digitized versions – I’ll try to get original versions to ensure that the comparison here has not been affected by digitization artifacts: however the graphics is a vector graphic and Hans Erren’s digitization is probably pretty good.)
There are several very interesting aspects to this graphic. The total increase in the smoothed version is 0.35 deg C: thus whatever trend exists in U.S. temperature since the 1930s exists entirely because of Karl’s adjustments, adopted here by Hansen (Karl) et al. Second, aside from this inserted trend, look at the size of the differences for individual years: the 95% range in differences is -0.38 deg C to +0.39 deg C.
If the U.S. temperature history of Hansen et al 1999 is regarded as an estimate of the history in Hansen et al 2001, it is obviously not a very good estimate: despite having histories from over 1200 stations, the 2-sigma confidence was only about plus-minus 0.38 deg C. It’s worth pondering what type of error distribution for 1200 stations would give rise to such high error. Any i.i.d. assumption for errors in the 1999 estimates would give a pretty tight error interval. Since the “true” errors were much higher than such estimates would have been, this would show that the actual error distribution in 1999 was tremendously far from i.i.d. Indeed, this serves as rather a pretty illustration of non-i.i.d. errors in a pretty simple situation.
Note (Tuesday): Gavin Schmidt emailed me last night observing that Hansen et al Figure 6 shows U.S. temperature history on a meteorological year basis (DN) while Hansen et al 2001 page 22 shows US temperature history on a calendar year basis and that there is a more precise comparandum in Hansen et al 1999 Plate A2. I’ve asked Hans Erren to digitize this figure and will re-issue the Figure below when I obtain that data.
Hansen, J.E., R. Ruedy, Mki. Sato, M. Imhoff, W. Lawrence, D. Easterling, T. Peterson, and T. Karl, 2001: A closer look at United States and global surface temperature change. J. Geophys. Res., 106, 23947-23963, doi:10.1029/2001JD000354.
A closer look at United States and global surface temperature change http://pubs.giss.nasa.gov/docs/2001/2001_Hansen_etal.pdf