Introduction to Modern Climate Change

By Bryan Walker 23/11/2011


I wouldn’t normally seek a text book for review, but a pre-publication recommendation described this one as excellent reading for any lay person interested in the subject. I’d also seen the author, Andrew Dessler, in an television interview which I wrote about, which was further encouragement. The book is An Introduction to Modern Climate Change. Dessler is a climate scientist but he’s also versed in the politics of the matter, having worked as a Senior Policy Analyst during the Clinton administration. His text book, a little unusually, covers both the science of climate change and the policy response to the issue.  It makes excellent sense to consider them together.

The science carries such grave implications for human welfare that it demands policy responses. Dessler sets much store by an electorate educated in both the science of the changing climate and the steps that are needed to avoid its worst consequences in the future.  Not all of the electorate is likely to become as educated in the science as this book allows, but the broad scientific outline on which the book is based is certainly capable of wide dissemination across the community.

Dessler has deliberately avoided advocacy, placing his faith in a dispassionate presentation of the facts. That’s an entirely appropriate stance for a university text book, respecting the rationality of academic discourse. Whether such approaches can prevail against the unreason rampant in some sectors of society on this issue is perhaps moot, but Dessler firmly believes that an unbiased assessment of the facts will bring the majority of people to see, as he does, that climate change poses a serious risk which we should head off by reducing our emissions of greenhouse gases.

The book’s material comes from a one-semester paper for nonscience majors at Texas A&M University. It assumes no prior knowledge of any field of science, though does assume a knowledge of simple algebra. This doesn’t make it lightweight. The science section of the book is thorough and demanding, while always well-explained and accessible to any general reader prepared to devote time to follow it. The policy section lays out the possible solutions dispassionately. Chapter summaries and end-of-chapter problems for students to address all aid in consolidating the reader’s grasp of the material as it develops.

I occasionally found myself wondering how the Governor of Texas, so confident in his denial of climate science, would fare if he took this undergraduate course in his own state’s oldest public university.

I occasionally found myself wondering how the Governor of Texas, so confident in his denial of climate science, would fare if he took this undergraduate course in his own state’s oldest public university. It’s a measure of the extraordinary torrent of denial that has accompanied the development of climate science that Dessler’s opening chapter on the distinction between weather and climate should include a section to explain the book’s credentials as a communication of the great weight of expert scientific opinion represented by the IPCC reports.

The science section of the book first examines the evidence that the climate is warming. There follow clear explanations of some basic concepts: the physics of electro-magnetic radiation and how it explains that greenhouse gases warm the planet;  the carbon cycle, our perturbation of it, and how this helps our understanding of what happens to carbon dioxide after it is emitted into the atmosphere;  the role of time lags, radiative forcing and feedbacks; climate sensitivity.  Finally the science section pulls together the abundant evidence that it is the increase in greenhouse gases due to human activities which is responsible for the present-day warming.

Dessler communicates well with the non-scientist, as I can attest, being one myself. The progression is clear, the high significance of feedbacks in the process is well-explained, the absence of alternative factors to account adequately for the warming fully explored. One is left highly respectful of the patient discovery which over time has built up such a clear understanding of the climate consequences of our exploitation of fossil fuels.

The book then moves to the future projections of the science. Dessler provides a very useful summary of the sometimes confusing body of alternative scenarios in the IPCC literature and how they are projected to affect future levels of atmospheric carbon dioxide. One feature he highlights among the projections is that unevenly distributed growth scenarios, where the rich get richer and the poor remain poor, result in higher atmospheric emissions than those where similar economic growth is more evenly distributed. Across the scenarios, predictions of warming by the end of the century range from 1.8-3.6 degrees. He includes at this point a reminder that climate change does not stop in 2100.

The likely impacts are serious and probably negative for human society. Warming may not be uniform but will overall increase every decade, precipitation distribution will change and more rainfall will come in heavier downfalls, sea level will rise and the oceans will become more acidic. Poor countries are likely to have a harder time adjusting to the impacts than wealthy countries. Lurking in the background is the possibility of abrupt changes, low-probability but high-consequence events.

What we do about climate change is discussed under the three headings of adaptation, mitigation and geoengineering. Lags in the climate system mean that there is climate change ahead to which we can only adapt. Mitigation options are explained, with special attention paid to the market-based approaches through a carbon tax or a cap-and-trade system. Geoengineering is broken into two categories — solar radiation management and carbon cycle engineering — and noted as a last-ditch approach.

A brief history of climate science and politics follows, ranging from Arrhenius to the IPCC for the science and on the political side describing the Framework Convention on Climate Change and the Kyoto protocol.  It leads into a final discussion of the action required to keep below 2 degrees of warming, a target, he points out, that has been arrived at through political compromise not scientific analysis.

The book is exemplary in its clarity and completeness. It is a reminder once again of how solid the science of climate change now is, and of how seriously its projections of the future, with all their attendant uncertainties, should be taken in our policy formulations. But how many more reminders will we need? Dessler’s presentation may be measured, but it’s not difficult to sense the mounting urgency behind his exposition.

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