­­Reviewed by Michael M. Gunter, Jr., Rollins College

Kerry Emanuel offers a concise overview of the science of climate change and deftly explains the difficulties of communicating its complexities to the general public.


What We Know about Climate Change (2nd ed.), by Kerry Emanuel, The MIT Press, 2012, 128 pp.

What We Know about Climate Change (2012) offers a concise and non-intimidating overview of the science of climate change while deftly explaining the political difficulties involved in communicating its complexities. In less than 100 pages Emanuel offers a tightly scripted summary of the basic science of climate change, noting that broad scientific consensus on human activity as the significant causal agent is still met by obstinate global warming skeptics and ill-informed elected officials within the United States. A professor of atmospheric science in the Department of Earth, Atmospheric and Planetary Science at MIT, Emanuel was named by Time magazine in May 2006 as one of the “100 People Who Shape Our World.” This second edition covers eight chapters with a new section about the prospects of confronting climate change using adaptation, mitigation and geo-engineering.

The first two chapters introduce the dynamic nature of our 4.5 billion year-old planet, from Wegener’s continental drift to the advance and retreat of huge ice sheets over millennia, all while emphasizing that our civilization developed during a period of exceptional climate stability over the last 7,000 years. The second chapter explains greenhouse physics and the central role of water vapor in trapping more and more heat. In essence, the warmer the atmosphere, the more water vapor evaporates, with the extreme end result akin to the planet Venus where the oceans are depleted and an average surface temperature of 900 degrees Fahrenheit cooks everything.

The real strength of this book is in later chapters that effectively flesh out the link between science and the politics of climate change, emphasizing the difficulty of communicating climate science to the general public. For example, in chapters three and four, Emanuel explains that while evidence clearly exists that our climate is changing, exactly how much it will change remains uncertain. Climate modeling distinguishes “climate noise” which occurs in short spurts of less than 30 years from the frightening shifts underway since industrialization. It forecasts more intense storms, droughts and floods as well as rising sea levels and acidification. These changes are already underway, but positive feedback loops, with their very negative impacts, continue to challenge climate models. For instance, despite millions of lines of computer instructions, climate models cannot yet simulate critical heat-transferring dynamics involving cumulus clouds. These clouds, typically only a few miles wide, are simply too small to fit into current models that are segmented into 50 mile horizontal blocks.

Like many before him, from Ross Gelbspan to Michael Mann, Emanuel notes that fossil fuel interests have capitalized on these uncertainties, taking a page out of the tobacco lobby playbook to confuse the electorate and stall transition away from a carbon intensive economy. To his credit, though, Emanuel does not restrict his finger pointing to conservatives and the Republican Party. He also notes that liberals need to rethink nuclear power and that journalists, with their “attraction to controversy,” have done a woeful job reporting on climate change to date, actively abetting climate change skeptics in the process.

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