IEEE Spectrum December, 2007 - 51

RESOURCES
Fire and Ice
this book puts the global
warming controversy in a
very small nutshell
revieWeD By m. grAnger morgAn

BooKs

on Amazon.com, this book looks
like any other: attractive cover, nice
promotional blurbs. Imagine my surprise when my copy arrived: 12 by
18 centimeters, 85 pages, wide margins, and only about 140 words to the
page. Still, I am a great fan of kerry Emanuel's
previous semitechnical book, the beautifully produced Divine Wind: The History and
Science of Hurricanes (oxford, 2005), so I
sat down to read the seven brief chapters
with interest. I was not disappointed.
Emanuel, a professor of atmospheric
science at MIT, explains how and why the
climate system has varied enormously over
geologic time scales, and he does so in language so clear and concise that any college
grad should be able to understand. With
echoes of robert Frost's apocalyptic poem
"Fire and Ice," he outlines why, despite these
great swings, Earth has never careened
into a permanent deep freeze or become
overheated, as in the case of venus, whose
surface is hot enough to melt solder.
Next comes a clear explanation of planetary heat balance and the greenhouse
effect, with a discussion of the central
role of water vapor and clouds, a topic too
often glossed over in descriptions for lay
readers. Then, using the analogy of the
paths traced over time by leaves falling
into a turbulent brook, chapter 3 provides
a masterly explanation of chaotic systems
and why there is an inherent limit to how
far ahead we can forecast the weather.
This chapter is less successful in moving
from the moment-by-moment characterization of weather to the more stable average values that make up climate.
chapter 4, which discusses climate
models, includes the only plot in the book,
comparing the output of a climate model
based on "natural" radiative forcing with
one to which human emissions of greenhouse gases and aerosols have been added.
only the latter successfully replicates the
past three decades of climate records. The
author conveys this conclusion clearly in
a diagram (despite the reference to "colored curves" in what is, in fact, a black-andwhite plot).
having laid out the basics, in chapter 5

the author explains why even a modest
increase in average global temperature
may-by melting ice sheets, thus raising
sea level-intensify droughts, floods, hurricanes, and other disasters. These changes
would, of course, have a profound impact
on the things people value.
The final two chapters describe in a brief
and balanced way the nature and sources
of the political controversy that has swirled
around the issues of climate science. There
is a good discussion of the self-correcting
nature of the scientific method, and of how
virtually all serious climate scientists now
agree that the average atmospheric temperature is rising and that human activities
are contributing to this trend. It also makes
clear that sorting out some of the additional
details will probably involve uncertainties
that are irreducible on the time scale of the
geophysical experiment we're running with
planet Earth. There is also an appropriate,
if brief, discussion of the interest-group
politics that have complicated public discourse, notably the role played by the handful of professional deniers who are forever
being quoted by scientifically naive journalists seeking "balance."
unfortunately, the final 15-page afterword by two other scholars was quite a
letdown and detracted from the book's
overall effectiveness. Judith Layzer, an
assistant professor of environmental policy
at MIT, and William Moomaw, a professor of
www.spectrum.ieee.org

MIT PrESS

What WE KnOW abOUt ClimatE ChangE
by Kerry Emanuel, mit Press,
Cambridge, mass., 2007; 85 pp.;
US $14.95; iSbn-10: 0-262-05089-7

http://www.Amazon.com http://www.spectrum.ieee.org

Table of Contents for the Digital Edition of IEEE Spectrum December, 2007