“What keeps me up at night – quite literally, frankly – is the fear that we might be slithering toward deploying solar geoengineering without having done the hard work,” writes author of Geoengineering: The Gamble, Gernot Wagner. Despite the lackluster writing in this book, readers will take away one main point: Geoengineering should scare you, too. 

But what is it, exactly, that the world is ‘slithering’ towards anyway? Some people think geoengineering is necessary, considering the threat of climate change. Every decade since 1880, the Earth’s temperature has increased by 0.14°F (0.08°C), and twice that following 1981 (0.32°F / 0.18°C). The results are palpable, with record breaking heat, water scarcity, and more powerful hurricanes all around the world. And scientists predict that the worst is yet to come.

Solar geoengineering, or solar radiation modification (SRM) may provide the quick ‘techno-fix’, as Wagner calls it, the world needs. Wagner defines SRM as “a largescale, deliberate intervention to cool the planet by sending a small fraction of sunlight back into space” (5). In other words, this is not about everyone painting their roofs white to reduce heat absorption. Nor does accidental geoengineering, such as ocean temperature reductions from ship emissions, make the cut. 

What makes the cut is Wagner’s focus: a form of SRM in which sulfates are released high in the atmosphere. By deliberately adding sulfate aerosols to the high altitude windstream, they can spread across the globe. The result: a theoretical mirror over the world, reflecting some of the solar energy that heats the planet back into space. 

Sound too good to be true? That’s because it is. Wagner dives into 20 reasons why. From failing to address ocean acidification and less sunlight for solar energy, to ozone depletion and unintended climatic consequences, Wagner summarizes previous research on the deleterious impacts of SRM. As a tool for solving global warming, Wagner remains adamant that what the world really needs is more research to confirm if these pros outweigh the risks. In the meantime, he emphasizes that only serious carbon dioxide emissions reductions will help prevent the need for geoengineering.

Wagner outlines many questions that need to be resolved before SRM is deployed.  He ponders who should be in charge of an SRM project, when might it be best to start one, what would happen if there are unintended consequences, and ultimately, why are people so misinformed on SRM. Wagner takes a stab at some answers, creating fictional accounts of a future world where the government is in charge of SRM versus individuals around the globe. He brings in the stories of his fellow researchers to emphasize the importance of ongoing research to prevent misunderstanding, and even muses on the nature of science itself as a self-correcting force. 

Wagner’s knowledge and thoroughness is evident. He knows SRM like the back of his hand, which makes sense. Wagner’s specialty is climate economics and he is a founding executive director of Harvard’s Solar Geoengineering Research Program. 

Despite Wagner’s expertise, however, the organization of the book is difficult to follow. It reads as more of a stream of consciousness rather than a careful examination of SRM. Wagner is also repetitive–rather than bringing up important points for emphasis, Wagner instead makes the same writing moves over and over again. These include long, difficult to follow sentences, the phrase “[word] does the work” employed dozens of times, and the same examples used ad nauseam. While brief, Geoengineering: The Gamble is still longer than it needs to be. 

If you look past mediocre writing, Wagner’s book offers a nuanced, in depth, and worldly introduction to the potentials of solar geoengineering for good and bad. Considering the current state of the climate, Wagner’s contention that geoengineering is a matter of “not if, but when,” makes this book a helpful read for anyone concerned about climate change.