The Discovery of Global Warming

  • Spencer R. Weart
Harvard University Press: 2003. 240 pp. $24.95, £16.95, €23.10

In the mid-1990s, as editor of the journal Climatic Change, I was sent a paper outlining the history of the international climate-change assessment process over the previous few decades. The Intergovernmental Panel on Climate Change (IPCC) had recently taken centre stage as the world's 'scientific consensus' on global warming. The article was written by a policy-studies graduate student who had rarely gone to any of the meetings he was reporting on, nor did he know most of the principals whose efforts he chronicled. I wondered how he could possibly get the events and flavour of this evolution of climate efforts remotely right.

Nevertheless, I sent the paper to two senior climate scientists, both of whom had been present at the creation of this evolution of international cooperation in climate assessment. If the student, Shardul Agrawala, could get past these two tough reviewers, he would deserve to be published. I was amazed to receive two rave reviews. “How can someone who never was there do such a good and fair job that it reminded me of parts of this history I had forgotten?” one wrote. The paper was published with a few minor corrections and is now a standard for the history of this effort.

When I was asked by Nature to review Spencer Weart's history of the discovery of global warming, from the nineteenth to the twenty-first century, I was once again sceptical. According to his biography, Weart, a historian of science working at the American Institute of Physics, was not remotely a player in the climate debate. But, remembering my experience with Shardul's article, I began to read his compact little account.

It didn't take long for me to share the amazement of the reviewers of Shardul's paper. Weart's account brought back many forgotten memories of the great scientists I admired in the 1970s and had largely forgotten, including Murray Mitchell, Gilbert Plass and Fritz Moller. He also recounted the discoveries and issues raised by many others with whom I have been, or still am, friends and colleagues. Roger Revelle was my interdisciplinary mentor for 20 years, so I read the account of the work of Roger and his colleague Hans Suess in the 1950s with particular interest. “If just one of these men had been possessed by just a little less curiosity, or a little less dedication to laborious thinking and calculation, decades more might have passed before the possibility of global warming was noticed.”

Getting warm: Roger Revelle (above) and Murray Mitchell were among the first scientists to detect signs of climate change. Credit: E. LAFOND, SCRIPPS INST. OCEANOGRAPHY/AIP EMILIO SEGRÉ VISUAL ARCHIVES/AIP EMILIO SEGRÉ VISUAL ARCHIVES

It is amazing that in such a short book, Weart has managed to stuff in most of the truly important events and characters in the evolution of the global-warming issue. To be sure, I could think of many issues that he left out — such as the need for transient calculations and the pioneers of signal-to-noise ratios in the 1970s who helped to bring about better interpretations of the model results — but Weart manages to cover many of these in an excellent website produced as a companion to the book (http://www.aip.org/history/climate).

My research assistant, Janica Lane, who is helping me to edit my own website (http://stephenschneider.stanford.edu) on the recent history and controversies surrounding climate change, has come across every possible website on climate imaginable, from exaggerated sites of 'deep ecology' non-governmental organizations to the shrill nonsense of 'enterprise institute' anti-warming sceptics and their political apologists in Congress and the business media. “It was such a pleasure to read such a fair and balanced account,” she commented after checking out Weart's website.

In the final chapters of the book, Weart departs from his detached historian role and addresses the modern political problems of climate policy. I found the largely precautionary personal values expressed here to be fair. But best of all, he offers this justification — almost an apology — for his delving into recent events: “The closer an account of events moves toward the present, the less it can be called 'history', and the more it looks like something else — perhaps journalism. The special virtues we seek in a work of history, the long-view perspectives and objective analysis, dwindle. Writers and readers find it hard to pick out which recent developments will really matter in the long run. Worse, opinions about present-day controversies infect views of the recent past with special virulence. Therefore be wary: this concluding chapter can be only a preliminary sketch.”

But I'm glad that Weart did take on the present political climate scene, because he concludes that although scepticism is essential for the health of science, the small cadre of professional 'contrarian sceptics' have been ideological, shrill and way out of step with mainstream science. This historian got it right, both in the past and where the issue is going. I only wish that more of today's journalists and politicians were so careful and insightful.

It is the unwritten duty of a book reviewer to complain about something. So let me do it with full narcissism. In citing my first atmospheric-science paper in 1971, which suggested that aerosol cooling could dominate greenhouse-gas warming, Weart says that the “equations and data were rudimentary, and critics swiftly pointed out crippling flaws”. He is right about the crippling flaws, but what I am most proud of was pointing most of them out first myself in a 1975 paper and in my book written with Lynne Mesirow, The Genesis Strategy (Plenum, 1976). Weart does note a 1992 chapter in which I predicted that an unambiguous greenhouse climate signal would emerge from the climatic noise around the end of the century, but I had first made this point in The Genesis Strategy. Given the IPCC's comments about the “discernible” impact of humans on climate in 1995, I am pretty proud of my 1976 crystal-ball gazing.

But these few personal complaints are trifles. This is a terrific book. For example, despite the polemics today from those who point to uncertainties in climate science as an excuse for inaction, when the usual proposed actions such as carbon taxes would hurt their ideological or clients' interests, Weart recognizes that science operates that way: “Scientists rarely label a proposed answer to a scientific question as 'true' or 'false', but rather consider how likely it is to be true. Normally a new body of data will shift opinion only in part, making the idea seem a bit more or less likely.”

This is a clear statement of the bayesian or subjective probabilistic framework that is becoming the standard for complex assessments of problems such as climate change. I only wish more of my own colleagues were as epistemologically sophisticated about uncertainties and subjective probabilities as this historian (see Nature 418, 476–478; 2002).

Perhaps the finest compliment I could give this book is to report that I intend to use it instead of my own book Coevolution of Climate and Life (Sierra Club Press, 1984) for my climate class. The Discovery of Global Warming is more up-to-date, better balanced historically, beautifully written and, not least important, short and to the point. I think the IPCC needs to enlist a few good historians like Weart for its next assessment.