Nieuwe onthullingen over hockey stick

Op deze video sprak president Obama in het Huis van Afgevaardigden nog over een 'overwhelming scientific evidendence on climate change'. Een hoongelach brak uit na deze woorden en hij moest er zelf ook om lachen. Maar dat bewijs blijkt toch voor een belangrijk deel op manipulatie van data te berusten. De naast betrokkenen waren zich daarvan terdege bewust. Helaas hielden ze uit collegialiteit hun mond.

Michael Mann, de co-auteur van de hockey stick-grafiek, een temperatuurreconstructie over de laatste duizend jaar, heeft een nieuw boek aangekondigd. Judith Curry heeft daarvan een soort samenvatting op haar blog gezet.

A central figure in the controversy over human-caused climate change has been The Hockey Stick, a simple, easy-to-understand graph my colleagues and I constructed to depict changes in Earth’s temperature back to 1000 AD. The graph was featured in the high-profile Summary for Policy Makers of the 2001 report of the Intergovernmental Panel on Climate Change (IPCC), and it quickly became an icon in the debate over human-caused (anthropogenic) climate change.

I will tell the story behind the Hockey Stick, using it as a vehicle for exploring broader issues regarding the role of skepticism in science, the uneasy relationship between science and politics, and the dangers that arise when special economic interests and those who do their bidding attempt to skew the discourse over policy-relevant areas of science. In short, I attempt to use the Hockey Stick to cut through the fog of disinformation that has been generated by the campaign to deny the reality of climate change. [Noot HL: een stroman – niemand ontkent klimaatverandering.] It is my intent, in so doing, to reveal the very real threat to our future that lies behind it.

Maar dit boek is toch wel de tegenpool van een ander recent boek: The Hockey Stick Illusion van Andrew Montford (alias Bishop Hill). Over dat laatste boek valt het volgende te lezen:

The Hockey Stick reconstruction was led by an ambitious and aggressive young climatologist named Michael Mann of the University of Massachusetts. It was eagerly seized upon by the IPCC. Its prominence made Prof. Mann an academic star and the recipient of hefty research grants. In 2002, Scientific American named him one of "50 leading visionaries in science."

Mr. Montford concludes that the Hockey Stick affair suggests that the case for global warming, far from being settled is actually weak and unconvincing. The implications for policymakers are stark. They have granted an effective monopoly on scientific advice to an organization that has proven itself to be corrupt, biased and beset by conflicts of interest.

Wat moeten we nu van deze conflicterende verhalen denken? De nieuwe serie Climategate e-mails die in de openbaarheid zijn gekomen, biedt een kijkje in de keuken van Michael Mann en laat zien wat zijn collega's over de hockey stick dachten. Ik pik er een aantal krenten uit:

E-mail 2383

if we are going to really get into the paleo stuff, maybe someone(s) ought to have another look at Mann's paper. His statistics were suspect as I remember ...

E-mail 0518

Did Mann et al get it wrong? Yes Mann et al got it wrong. How wrong is still under debate and the ECHO-G/HadCM3 results may be over-exaggerating the variance loss for some model-specific reasons ...

Verder:

1104 Heinz Wanner

I just refused to give an exclusive interview to SPIEGEL because I will not cause damage for climate science.

1656 Douglas Maraun

How should we deal with flaws inside the climate community? I think, that “our” reaction on the errors found in Mike Mann’s work were not especially honest.

0300 Bo Christiansen (on Hockey stick reconstructions)

All methods strongly underestimates the amplitude of low-frequency variability and trends. This means that it is almost impossible to conclude from reconstruction studies that the present period is warmer than any period in the reconstructed period.

3253 Ed Cook

the results of this study will show that we can probably say a fair bit about <100 year extra-tropical NH temperature variability (at least as far as we believe the proxy estimates), but honestly know fuck-all about what the >100 year variability was like with any certainty (i.e. we know with certainty that we know fuck-all).

4133 Johnathan Overpeck

what Mike Mann continually fails to understand, and no amount of references will solve, is that there is practically no reliable tropical data for most of the time period, and without knowing the tropical sensitivity, we have no way of knowing how cold (or warm) the globe actually got ....

288 Wigley

Mike, The Figure you sent is very deceptive ... there have been a number of dishonest presentations of model results by individual authors and by IPCC ...

4241 Wilson

I thought I'd play around with some randomly generated time-series and see if I could 'reconstruct' northern hemisphere temperatures ... The reconstructions clearly show a 'hockey-stick' trend. I guess this is precisely the phenomenon that MacIntyre has been going on about.

3373 Bradley

I'm sure you agree--the Mann/Jones GRL paper was truly pathetic and should never have been published. I don't want to be associated with that 2000 year "reconstruction".

Ook meer in het algemeen:

3066 Thorne

I also think the science is being manipulated to put a political spin on it which for all our sakes might not be too clever in the long run.

Lees verder hier.

Kortom Climategate II onthult dat Michael Mann binnen zijn eigen kring werd bestookt door collega-wetenschappers, die verdacht veel lijken op klimaatsceptici. En dan maar die goedgelovige Obama en andere brave AGWers voorhouden dat er zoiets is als een 'overwhelming scientific evidence on climate change'.

PS, Met dank aan André Bijkerk voor deze tip.