Oliver Morton The Planet Remade: How Geoengineering Could Change the World Princeton: Princeton University Press, 2016. 440 p. $29.95; $16.95 (pbk.).

Abstract

Geoengineering is “any deliberate technological intervention in the earthsystem on a global scale” (p. 26). The key word in Oliver Morton's definition is “deliberate”: the change occurring has to be one done on purpose, not one that just happens. Humans burning fossil fuels, increasing atmospheric CO2 levels and inducing global warming, is not geoengineering. Their intent had nothing to do with altering CO2 levels or warming the atmosphere. On the other hand, humans introducing into the stratosphere an aerosol mix that creates a thin “veil” that reflects more sunlight back into outer space in order to cool the earth's atmosphere is potentially the twenty-first-century geoengineering exploit par excellence. Something akin to this happens naturally when large volcanoes spewed significant amounts of sulfur dioxide into the stratosphere (Chapter 3). Today David Keith, Professor of Applied Physics at Harvard, is researching which aerosols might work better as veil-makers than sulfur dioxide, which destroys ozone (p. 169); stratospheric field tests will begin soon (http://geoengineering.environment.harvard.edu/). Large-scale sulfur injection was the approach proposed by 1995 Nobel Prize winning atmospheric chemist Paul Crutzen. Yet, many worry that a geoengineering solution to global warming might go awry and trigger great harm. Others worry that its success might compromise global efforts to reduce CO2 emissions. Morton, a science writer and editor at The Economist, covers both sides of this debate but concludes that limiting the rise in global air temperature to 2 degrees Celsius by the end of the century will require geoengineering. His examination of past, present, and future global CO2 emissions (Chapters 8 and 9) makes him seriously doubt whether emission controls alone could do the job. His recommendation (Chapter 12) is to gradually introduce a reflecting veil in the stratosphere while simultaneously pressing for greater efforts to control CO2 emissions. To those who object to the very idea of humans “remaking” the planet through geoengineering, he notes (Chapter 9) that this has already happened. Early-twentieth-century crop yields were much lower than today due to the limited amount of fixed nitrogen in the soil. A century ago Haber and Bosch developed an industrial process that took inert nitrogen from the atmosphere and produced fixed nitrogen fertilizer. Vaclav Smil has calculated that half the nitrogen atoms currently in the world's food have originated in a Haber–Bosch converter (p. 195). Today's 1.5 billion hectares of cropland, which produce enough food to feed over 7 billion people, would have been able to feed only half as many without Haber-Bosch's early geoengineering feat. Morton credits it with creating “room in the earthsystem for the global demographic transition to play itself out” without causing needless suffering and disruption (p. 206). Stratospheric veil-making, he contends, can provide a similar way of sidestepping needless suffering during the twenty-first century's challenge of ending a destructive reliance on fossil fuels.