For those of you who have read the previous blog entries in this series, you’ve already seen some very compelling reasons to study geoengineering.  From a scientific perspective, this topic is fascinating, not only in its own right, but also as a tool to reveal the basic inner workings of the climate system.  As a physical scientist, this appeals to me immensely.  It also has vast social, political, psychological, ethical, and governmental implications which are equally fascinating, very important, and so complicated and intricate that I am reluctant to comment on them, despite the (correct) insistence by my colleagues that I won’t be able to maintain this reluctance for long.  But however compelling these reasons may be, and any number of researchers could completely justifiably spend the extents of their careers focused on these problems, they don’t answer the question posed to me:  “Why do I study geoengineering?”  In my opinion, the answer is simple (perhaps overly so), practical, and yet powerful and awe-inspiring every time I consider the implications:  I worry we’ll have to do it.

Inside this statement are actually three worries.  First, the effects of anthropogenic climate change may be painful.  Even on the “low” end of warming in projections of future climate change under business-as-usual emissions, the effects have the potential to be severe.  The only permanent way to reduce the effects of anthropogenic climate change is to mitigate emissions of greenhouse gases, an expensive, time-intensive process on which society has shown little progress.  (Carbon Dioxide Removal methods also show promise in alleviating the effects of climate change, but they are also expensive and slow, and their capacity is likely dwarfed by emissions rates, at least at present.)

It stands to reason that we might want to alleviate these effects, which leads me to my second worry, in that we would implement geoengineering.  (I’m only talking about Sunlight Reduction Methods in this context.)  Regardless of whether geoengineering would be deployed as an emergency measure or as a strategic part of a portfolio of responses to climate change (perhaps the latter is more likely), this invites a host of issues, such as how do we geoengineer, how much, and to do what?  The decision to geoengineer is replete with vast implications that, when unpacked, have little to do with science and much more to do with people’s value systems.  I remain skeptical as to whether these questions can be answered.

Regardless, for the purpose of progressing the narrative, let’s assume a decision could be made regarding what climate impacts society might want to achieve with geoengineering.  This invites my third worry:  we might geoengineer poorly.  Perhaps our calculations are incorrect, and geoengineering doesn’t do what we want it to do.  Perhaps we underestimate the consequences, which turn out to be much more severe.  Or perhaps one of Donald Rumsfeld’s “unknown unknowns” (this comes up at literally every geoengineering meeting I attend) emerges.  And the list can go on ad infinitum.  The point being, there is sufficient uncertainty in both the expected climate response to a particular method of geoengineering and our ability to implement it with both the accuracy and precision necessary to achieve our goals that our ability to geoengineer “well” is not a given.

Everything I’ve said thus far sounds very pessimistic, which was not my intention when I sat down to write this post, so let me clarify.  I worry about these things because they are unknown.  But that means the past few paragraphs are not statements of hopelessness, but rather, statements of intent.  And this is where my work enters the picture.  I can’t speak for the motivations of my fellow researchers, but I research geoengineering because these things need to be known.  Certainly, we will never know everything, and we may never even know enough to geoengineer successfully (whatever that means), but I want to do my part.  And I get to enjoy myself along the way, because let’s face it – it’s a privilege to work on one of the most interesting, exciting, important topics out there with some of the smartest people in the world.