Keywords: Climate change, global warming, science, science policy

Title: The Hockey Stick Illusion

Author: A W Montford

Publisher: Stacey International

ISBN: 1906768358


For many doubters, the 'hockey stick graph', produced by paleoclimatologist Michael Mann and his co-workers in 1998, was the smoking gun that finally convinced them that CO2-induced global warming was real. It showed a 1000-year reconstruction of temperatures in the Northern Hemisphere that indicated a fairly flat and remarkable record of temperature fluctuations that suddenly shot up late in the twentieth century (like the blade of the hockey stick). For many it was the smoking gun, proving once and for all that the temperature rises in the last decades of were unprecedented and therefore unnatural. What caused this sudden and unexpected rise? CO2 and other greenhouse gases spewed out after the Second World War as the world industrialised massively - or so we were told. The chart was propelled centre-stage, its lead author Michael Mann likewise, particularly when it was used so prominently in the IPCC Third Assessment Report in 2001.

However, there were questions voiced very early on. This new reconstruction seemed to re-write history. The medieval warm period and little ice ages seemed to have disappeared, and there were serious doubts raised as to whether current temperatures really were as unprecedented as they appeared. Stephen McIntyre, a Canadian mining engineer with extensive expertise in statistical analysis, became interested and decided to see if he could reproduce the hockey stick himself. And thus started the 'hockey stick wars' - which rumble on still.

For outsiders trying to understand the issue there is a huge problem. The subject itself is inherently difficult. For example, thermometers were not around a thousand years ago, the instrumental record is relatively short and localised and therefore use has to be made of various proxy records which are used to estimate temperatures. These proxies include tree rings, river sediments, ice cores and so on. Analysis of these disparate data sources is inherently fraught with complication and trying to piece them all together is no mean feat. If this were some arcane piece of academic research it wouldn't matter, but that's not the case - climate change is at the core of contemporary politics, both nationally and internationally.

Andrew Montford, who blogs as Bishop Hill, was a visitor to McIntyre's Climate Audit site and soon started trying to summarise various aspects of the story as it unfolded. His 'Hockey Stick Illusion' provides chapter and verse on the story of Mann, McIntyre and the whole complicated story of whether the 'hockey stick' represents an accurate historical record or a piece of data manipulation that is politically expedient.

Much of the action involves dealing with large datasets, statistical techniques, peer review, who said what to whom and more. It reads more like computer forensics than pop science, but in spite of this it is actually a gripping and interesting read. What emerges makes for grim reading if you are interested in the state of climate science, particularly if you still harbour illusions about the objectivity of the scientific method and the dispassionate role of scientists. Mann and 'team' are shown to be duplicitous, involved in attempts at discrediting their opinions, willing to manipulate the process of peer review and unwilling to admit to using statistical techniques incorrectly.

Of necessity there are some fairly technical topics to be covered, and for the most part Montford does well to explain these so that even those without a grounding in statistics can understand the issues. In particular Steve McIntyre emerges from this book as a the most dogged investigator imaginable - one who is not afraid to challenge the experts and who continues to audit the science to a degree that makes the peer review process appear like a cursory glance. His detective work in puzzling through the obfuscations and evasions are what drive the narrative of the book and which make it such an exciting and engaging read.

It's clear that there are huge question marks about the veracity of the hockey stick. It is also clear that McIntyre, Ross McKitrick and others have made fundamentally correct deductions about the hockey stick and that they have had to fight tooth and nail to get access to publicly funded data sets and computer code. They have pointed out the failings of academic journals and institutions who have either turned a blind eye to dubious behaviour and/or have actively obstructed those who want to dig beneath the covers.

The release of the Climategate emails in November 2009 threw yet more light on the topic, and it should be no surprise that what emerged from the cache of emails showed that the corruption of climate science was truly shocking. Despite the protestations of many of those involved that there wasn't much to see, that it was all a storm in a teacup, what Climategate, and this book show, is that politics subverts science when it comes to climate.

Whether you accept the CO2 theory of anthropogenic global warming or not, this book is essential reading. It cannot be recommended highly enough.

Review © Pan Pantziarka, 2011. Site © London Book Review 2011. Published June 21 2011