Energy, Environment, and Climate

Richard Wolfson (W. W. Norton & Co., Inc., New York, 2008) ISBN 978-0-393-92763-4. 532 pp. \$69.47 (paper).

Reviewed by Art Hobson

Reprinted with permission from American Journal of Physics, © 2008, American Association of Physics Teachers.

Courses in energy and the environment are now offered by many U.S. secondary schools and colleges. Wolfson is a Professor of Physics at Middlebury College where he also teaches environmental studies, and his textbook for such a course is the fourth that I know of that is aimed at college non-science students [1]. All of these textbooks are “conceptual,” meaning that they use little or no algebra even though they are strongly quantitative in their use of numbers, proportionalities, graphs, powers of ten, percentages, and probabilities. They all begin with a brief presentation of the physics that will be needed for the remainder of the book, presentations that are too brief to allow the book to qualify as a “physics” textbook but that are usually sufficient to provide the background needed for a textbook limited to energy-related topics. Wolfson's book uses somewhat more algebra than the other books, to the point that many non-science students may be distracted and put off by it.

Wolfson also differs from the other authors in offering a slightly more substantial serving of physics in the opening chapters. However, I must quibble with the way he defines the central concept of “energy.” Wolfson's strategy (p. 22) is to ask students to do deep knee bends for a few minutes, at a rate of one knee bend per second, and to then inform them that “your body is working at the rate of about 100 watts.” This gives students an intuitive, yet quantitative, feel for the watt, and power. He then (p. 37) describes “energy” as “the ‘stuff’ that makes everything happen,” and quantifies this notion with the statement (p. 50) that “if you use energy at the rate of one watt for one second, you've used one joule of energy.” This seems an unnecessarily roundabout way to define energy. The other three books, after defining “work” as the exertion of a force through a distance, just come right out and say that energy is the capacity to do work. This is the correct, complete, and most easily understood definition of this important word.

Quibbles aside, this is a very good book. What I like best about it is its emphasis on global warming (Wolfson prefers the term “climate change” but I've always preferred “global warming” as equally accurate scientifically, and more direct). A textbook needs one or more unifying themes, and global warming - which might well turn out to be the overarching theme of this century--is perfect for a book on energy and the environment. This theme is introduced at the beginning of the book, re-appears at several points, and fully occupies the last five of the book's 16 chapters.

One of many nice details in these five chapters is a quantitative comparison of the greenhouse effect on Venus, Earth, and Mars. Wolfson uses the Stefan-Boltzmann radiation law and the known rate at which solar energy reaches these planets to calculate average temperatures at the three planets' surfaces, neglecting the greenhouse effect. He then notes that the observed surface temperatures exceed the calculated temperatures by 503oC, 33oC, and 0oC, respectively. This excess is the greenhouse effect, and the three values accord nicely with the observed facts that Venus has a thick atmosphere heavily laden with the greenhouse gases H2O and CO2, Earth's atmosphere has a more modest amount of these two greenhouse gases, while Mars has very little atmosphere and even less greenhouse gas. These values also show students that a planet’s atmosphere, and its greenhouse gases in particular, have a major influence on climate.;

Wolfson gives a good presentation of the workings and results of the Intergovernmental Panel on Climate Change. Among those results are estimated values of the natural and anthropogenic “forcings,” or changes in the amount of solar energy reaching Earth's surface, measured in W/m2; major sources of global CO2 emissions; the “global warming potential” of the various greenhouse gases, relative to CO2; the carbon cycle; feedback mechanisms that can dampen or amplify the forcings; Earth's temperature during recent times and over hundreds of thousands of years; nuclear isotopic methods of reconstructing the long-term CO2 concentration and temperature records; the evidence that humans are at least partly to blame for the recent temperature rise; and much more. His presentation of the various IPCC scenarios and future projections based on them is especially enlightening.

The final section of the final chapter, titled “Strategy for a Sustainable Future,” is a welcome and heartening presentation of the Socolow-Pacala “wedge strategy” describing some 15 different ways to combat global warming, all of them based on plausible near-term technology such as carbon capture and storage [2].
The book's central block of 7 chapters covers the various energy resources: fossil (2 chapters), nuclear, geothermal and tidal, direct solar, indirect solar (water, wind, biomass), and a chapter on “hydrogen” in both of its senses: nuclear fusion, and the “hydrogen economy” based on the chemistry of hydrogen. These chapters are uniformly well done; they could have benefited from a careful definition of, and greater use of, the all-important concept of “sustainability.” At the end of the book, Chapter 16 includes an excellent discussion of energy efficiency and conservation, but I think this big topic deserves to be treated as a major source of energy services and to be included as a separate chapter with the other energy sources, right along with direct solar etc.

The pedagogy is quite adequate. The writing is relaxed, personable, and good. The details are correct, insofar as I was able to check them. The text does not emphasize “inquiry” methods, although as in any textbook the end-of-chapter questions could be considered inquiry. Each chapter includes a review of the “big ideas,” terms students need to know, about 10 review questions, about 15 quantitative but non-algebraic exercises, and about four “research problems” that involve library or internet research and, frequently, numerical calculations or estimations.

Any textbook worth its salt should teach something new to the course instructor, and to reviewers. Indeed, I learned several things, such as the distinction between series and parallel hybrid vehicles (p. 120), the meaning of a “combined cycle” power plant (p. 124), a gravitational analogy to nuclear fusion (p. 345), and the comparison of Venus, Earth, and Mars referred to above.

It's an excellent, carefully written, and highly relevant textbook, with a welcome emphasis on global warming--a topic that should in my opinion be part of every introductory physics course.

[1] The other three are Energy: Physical, Environmental and Social Impact, Gordon J. Aubrecht (Pearson Prentice Hall, Upper Saddle River, NJ, 2006), 3rd ed.; Energy: Its Use and the Environment, Roger Hinrichs and Merlin Kleinbach (Thomson Brooks/Cole, Belmont, CA, 2006), 4th ed.; Energy and the Environment, Robert A. Ristinen and Jack J. Kraushaar (John Wiley & Sons, Inc., 2006), 2nd ed.

[2] Robert H. Socolow and Stephen W. Pacala, “A Plan to Keep Carbon in Check,” Scientific American, September 2006, pp. 50-57.

Art Hobson
University of Arkansas

This contribution has not been peer refereed. It represents solely the view(s) of the author(s) and not necessarily the views of APS.