Cold water on hot temperatures

Here's some Science Reading for delegates sunning themselves on Bali's beaches between sessions at the IPCC's latest talk-fest that will have them spluttering into their daquiris.

One of the IPCC's earliest blunders was the promotion of the so called "hockey stick" temperature graph -- it was the most dominant graph in the first three IPCC reports and in all their scare stories -- a graph that ramped up late-twentieth century surface temperatures and obliterated the medieval warm period, producing a hockey stick-shaped graph for the temperatures of the last millennia, with a large, scary uptick at our end of the line saying to productive human beings "It's All Your Fault!". 

Steve Mcintyre and Ross McKitrick between them put the hockey stick out to pasture, demonstrating that poor methodology and reliance on unreliable tree ring data rendered the IPCC's favourite graph meaningless: they showed that any figures run through the algorithm producing that hockey stick shape would have produced that hockey stick shape.  Any figures at all, from the incidence of cancer in rats to Britney Spears' fluctuating panty size.

The IPCC quietly dropped the hockey stick (and here's how the figures look now).  But the IPCC now has a new star in their apocalyptic firmament: a new graph -- the very first graph in the IPCC's latest official pre-Bali "synthesis" report on climate science (a report summarised here) -- a graph that as Terence Corcoran describes in the National Post "purports to show temperatures soaring over the last 25 years. The recent jump, the IPCC says, is 'very likely"due to man-made carbon emissions."

But research by Ross McKitrick and Patrick Michaels suggests this baby should also be put to bed: their research suggests the land-based temperature record on which the IPCC's new baby is based is irretrievably contaminated.  Summarises McKitrick,

In a new article just published in the Journal of Geophysical Research -- Atmospheres, a co-author and I have concluded that the manipulations for the steep post-1980 period are inadequate, and the [IPCC's] graph is an exaggeration. Along the way, I have also found that the United Nations agency promoting the global temperature graph has made false claims about the quality of its data...

The IPPC has tried to brush away concerns for years about data having been contaminated by unreliable surface station management (which appear to have been collecting temperatures of the world's car parks) and increasing industrialisation and urbanisation around many of the world's temperature collection stations.  Michaels and McKitrick charge that these concerns have been inadequately and even dishonestly addressed, and their new research confirms them as real.  Writing in Canada's National Post, McKitrick concludes:

Our new paper presents a new, larger data set with a more complete set of socioeconomic indicators. We showed that the spatial pattern of warming trends is so tightly correlated with indicators of economic activity that the probability they are unrelated is less than one in 14 trillion. We applied a string of statistical tests to show that the correlation is not a fluke or the result of biased or inconsistent statistical modelling. We showed that the contamination patterns are largest in regions experiencing real economic growth. And we showed that the contamination patterns account for about half the surface warming measured over land since 1980.

In other words, we have confirmed, on new and stronger grounds, that the IPCC's global surface-temperature data is exaggerated, with a large warming bias. Claims about the amount of surface warming since 1980, and its attribution to anthropogenic greenhouse-gas emissions, should be reassessed using uncontaminated data. And governments that rely on the IPCC for advice should begin asking why it was allowed to suppress earlier evidence of this problem.

The ball appears to be back in the court of the IPCC -- and it looks like they might have been aced.