The author, Michael E. Mann, is an expert on reconstructing past climate variations from records stored in natural systems, such as the annual growth rings in trees, the chemical composition of water in ice cores from Greenland and Antarctica, and the chemistry of layers deposited in tropical corals or stalactites from caves. His research has concentrated on documenting and understanding climate variations over the last one to two thousand years by extracting common climate signals from multiple different records, first for the northern hemisphere and then for the whole globe. His graduate study at Yale University in the United States in the early 1990s identified natural long-term variations in the Northern Hemisphere climate, using longer data records and new methods to extract information from the data.

Mann never imagined that his research would push him out of the ivory towers of academia into the cut-and-thrust world of politics, commentators, and lobbyists. But it certainly did, and this book describes his experiences over the last two decades as a climate scientist, as a communicator, and as a target of frequent attacks. Mann was subjected to what he describes as the ‘Serengeti strategy’, in which predators ‘look for the most vulnerable animal at the edge of a herd’. In his case the predators were climate change ‘confusionists’, politicians and commentators who wish to confuse the public understanding of climate change science and delay action on reducing industrial emissions of green-house gases.

The reason for these attacks was that Mann led a ground-breaking series of studies in the late 1990s that described Northern Hemisphere temperature variations over the last thousand years and showed that the warmth of the latter part of the twentieth century was very unusual, likely warmer than any time in a thousand years, including the so-called Medieval Warm Period. The graph of the average temperature shows a wobbly but steady decline over nine hundred years followed by an abrupt rise in the twentieth century, a shape not unlike a hockey stick, the label that has been used to describe it ever since. This research was singled out for attack because it clearly showed that the warming in the twentieth century was unusual in the long-term context, and it was one of the figures featured in the Summary for Policymakers of the Third Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), published in 2001.

I have known Mann for many years, as a fellow lead author in the IPCC 2001 assessment and as the joint author of a research study comparing his estimates of past natural climate variations with estimates from global climate model simulations and instrumental observations from across the globe. I have also co-authored research papers with Ben Santer and Phil Jones, two other figures in the Climate Wars who feature in this book because they have also been subjected to attacks from climate change confusionists.

This book is well written and tells a remarkable story that is likely to be of interest to a wide range of readers. It opens a window onto the work of a research scientist studying climate variability and climate change, providing glimpses of the mundane activities as well as the excitement of new discoveries. It provides readily understandable details of how past climate variations are reconstructed from a range of natural records, of the techniques used in palaeoclimatology.

The book describes the scientific method: investigate a scientific question by testing an hypothesis; analyse the results; and submit the report describing the data, the analytical approaches used, the results, and the conclusions to a scientific journal where it will be subjected to critical assessment by independent experts, a process called peer review. If the study is considered to be new, interesting, and without flaws, it will pass this peer review and be accepted for publication in a scientific journal. Peer review is not infallible, but it is the best available system for ensuring the quality of scientific research. Mann’s research, as described in this book, has resulted in many peer-reviewed scientific publications that have stood the test of time, as the results have been confirmed and extended in a range of studies around the world.

Unfortunately, the frightening aspects of this story are the details of the Climate Wars, of the repeated attacks on Mann’s research by climate change confusionists. Commentators with no scientific expertise, ranging from politicians such as Republican congressman Joe Barton from Texas, Virginia Attorney General Ken Cuccinelli, or Republican Senator James Inhofe from Oklahoma, to blog writers Stephen McIntyre and Marc Morano, have repeatedly promulgated misinformation and sought to launch formal investigations into Mann’s research, claiming professional misconduct or worse, even though it had been peer reviewed and confirmed by other scientists. They found a group of media reporters and commentators ready to repeat these claims without question and to amplify them. The blogosphere and some media outlets can be very effective echo chambers for communicating misinformation.

The illegal hacking of emails from a mail server for the Climatic Research Unit at the University of East Anglia in late 2007, now called Climategate, and their subsequent release through blogs, were cited as evidence of a conspiracy among climate scientists such as Mann, Santer, Jones, and others, including myself. It was claimed that there was suppression of evidence contrary to global warming and emphasis on evidence that supported global warming due to human activities. After three independent official assessments of the Climategate emails in the United Kingdom, there have been no findings of misconduct or a conspiracy, just findings of normal scientific research and the occasional use of misleading words in private emails, which had then been selectively quoted to discredit the scientists and their research.

Multiple separate assessments of Mann’s research methods and findings have also been undertaken by the US National Academy of Science and the Pennsylvania State University. Again, they found no evidence of misconduct and confirmed the findings of his research, as have many subsequent peer-reviewed scientific studies.

This book provides Mann’s views on the Climate Wars. There are several other great books that describe related aspects of the Climate Wars: Naomi Oreskes’ Merchants of Doubt: How a Handful of Scientists Obscured the Truth on Issues from Tobacco Smoke to Global Warming (2010) and Stephen H. Schneider’s Science as a Contact Sport: Inside the Battle to Save Earth’s Climate (2009). While there isn’t yet a book written by a scientist on the Climate Wars in Australia, there are two relevant books that describe the politics and the role of the media and vested interests in delaying action on climate change in Australia: Guy Pearse’s High and Dry: John Howard, Climate Change and the Selling of Australia’s Future (2007) and Clive Hamilton’s Scorcher: The Dirty Politics of Climate Change (2007).

One of the fascinating aspects of The Hockey Stick and the Climate Wars is its selection of quotes used at the start of each chapter. They are all very relevant and interesting, but one of my favourite quotes and perhaps the most important one is missing. Charles Darwin, after his own battles over public misunderstanding of his science, wrote in the sixth edition of On the Origin of Species: ‘Great is the power of steady misrepresentation; but the history of science shows that fortunately this power does not long endure.’

Mann finishes the book on a similarly positive note, suggesting that he senses a turning of the tide in the Climate Wars. I am not so sure that this is the case in Australia. With the introduction of legislation setting a price on greenhouse gas emissions from human activities, the Climate Wars have heated up here, with coordinated misinformation campaigns from politicians, from media commentators such as Alan Jones and Andrew Bolt, and from geologists with vested interests such as Ian Plimer and Bob Carter. I hope that steady misrepresentation loses and that science wins the Climate Wars quickly, as further delays in actions to reduce greenhouse gas emissions lock in even more global warming.

CONTENTS: JULY–AUGUST 2012