What would Aldo Leopold think about geoengineering?

Corresponding with the accelerating crises of climate and biodiversity loss has been a call in contemporary environmentalism to think and act at planetary scales to address a planetary problem. One prominent proposal, stratospheric aerosol injection (SAI), would attempt to replicate the cooling effect of volcanic eruptions by tactically injecting reflective particles into the atmosphere in an attempt to reverse global warming. This article first constructs a new case for SAI on behalf of the wild, an idea that has appeared in passing within several influential arguments for solar engineering but has not received widespread endorsement. I then introduce the reader to Aldo Leopold’s land ethic and defend one interpretation that is supported by mainstream interpreters in the literature, drawing the reader’s attention to the important role that a human/nature parallel plays in Leopold’s moral reasoning and the value he places on preserving biodiversity. Then, I apply this framework to SAI and argue that it poses an intractable dilemma for ‘geoengineering for the wild.’ I provide a novel reading of Leopold’s famous essay “Thinking Like a Mountain” and argue it illustrates the importance of two distinct forms of intellectual humility in his thought. Then, I present the dilemma. It appears when one answers a simple question: is it better for SAI to “work” or “fail?” As I will discuss, this question is too simple, but it is revealing. I will argue in what follows that from a Leopoldian outlook both success and failure in solar geoengineering should deeply trouble us. This constitutes 'the climate engineer's dilemma.'