books climate change technology

Book review: Geoengineering, by Gernot Wagner

“The first time I heard about solar geoengineering, I considered the idea nuts. It is.” So begins Gernot Wagner‘s short and finely balanced book on a controversial subject.

If anyone’s wondering where the author stands on the question of geoengineering, the first page makes his position clear. It’s “no solution to climate change”, because it doesn’t get to the root causes and it’s such a massive gamble. Nobody should ever embrace a technical fix with such clear downsides.

Neither does Wagner oppose the idea outright. He’s worked on the economics of it for Harvard and for the Environmental Defense Fund. It’s right to be sceptical about geoengineering – and he suggests almost all scientists working on it are – but it can’t be ignored. As he writes, “one does not need to like solar geoengineering to take the idea seriously.”

That’s exactly where I’d place myself, and why I read the book.

Despite the broader title, which the author apologises for early on, the book is quite specifically about one idea – solar geoengineering. This is the suggestion that some incoming solar radiation could be reflected back into space, and that this would help to cool the planet. There are different ways to do that, some small scale and some large. The book deals with the planetary level interventions, such as spraying aerosols into the stratosphere.

It’s worth looking at in detail because it’s relatively cheap. Not affordable in the way that you or I might measure it, but definitely within the means of several different governments, large corporations, or independent billionaires. That means that somebody is highly likely to attempt it eventually. And for those with a knee-jerk reaction against such large-scale interventions, it’s important to assess the risks and benefits of solar geoengineering against a world of disastrous climate change – not against a healthy world.

Looking at it objectively is difficult because geoengineering gets such strong reactions. It’s a “highly visible and easily distorted” field of science, and so Wagner’s book is very useful at providing an overview of all the things that could go wrong, the possible benefits, and the ethical questions that it raises. Who gets to set the thermostat? And to what? What if it benefits 90% of the world, but makes things worse for the remainder?

The book is admirably clear on all of this. (There was one section on game theory that lost me entirely, but that’s my problem and not Wagner’s.) The author also includes three different scenarios for how somebody might attempt solar geoengineering, which helps to ground the idea in real world geopolitics. And it’s concise too, packing a lot into it’s 160-odd pagecount.

In summary, the book is a really useful guide for thinking through what will become a pressing ethical question in the years to come, while insisting that “there is simply no easy answer”.

One other observation: reading from a climate justice perspective, a nagging question kept coming up as I read. We are on track for a climate crisis that will displace and harm hundreds of millions of people, mostly people of colour. Many will die. In such a context, geoengineering would save lives. Those lives will be in the global south, but it will be the global north that will be best placed to afford geoengineering.

Thinking ahead, there may come a point when the ethical scales will tip. For all the horrendous implications of geoengineering, it may in time be the lesser of two evils. We may come to see it as more wrong not to intervene, with calls from the global south to fund geoengineering as a matter of justice. Right at the end of the book, Wagner raises this question himself.

It makes me uncomfortable to write this, but given these justice implications, it’s not good enough to rule geoengineering out. Now, let’s get on with cutting carbon fast enough and profoundly enough that we never have to do it.


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