Does It Make Sense to Treat Solar Geoengineering Like Nuclear Weapons Testing?

Last week, the New York Times reported on a nascent U.S. government effort to build a detection system for solar geoengineering. Also known as solar radiation modification (SRM) or stratospheric aerosol injection (SAI), this is the idea of dumping a bunch of tiny sulfur particles high up in the stratosphere as a way of reflecting a small amount of sunlight back into space to help cool the planet; volcanos do this naturally, humans do a chunk of it by accident, and as the world warms there is an increasing interest in doing another chunk of it on purpose.

The idea, though, remains intensely controversial, as it has been for decades at this point. A full-scale deployment would likely alter weather patterns, including crucial monsoon seasons, offering up winners and losers even if the overall effect would be a decline in average temperature; and some say that decline would give bad actors an excuse to keep emitting, keep drilling, keep burning. And so, the early detection system: it makes sense to be able to tell if someone out there just goes ahead and does it without warning.

There is some logic here, in that the act of SRM would not likely be a grossly obvious one. I have written before about how it is cheap enough for small countries or even a few rich people to get it off the ground, and some modified planes in the sky dusting the stratosphere with sparkly dust isn’t the kind of thing you can see out your window. But the comparison offered by the Times is an odd one: nuclear weapons testing detection systems.

Test ban treaties function, one expert told the Times, because of the global ability to detect a test when it happens. But on a certain level, placing SRM in that same basket cedes the entire argument to the side insisting it is per se dangerous. A nuclear weapons test is an aggressive act; its result has zero potential to do anything except harm. There is no question that SRM has some harms associated with it; but the whole point is that it also has benefits, and the debate, at root, is on whether it will reduce overall human suffering and whether we, collectively, have the right to make that call.

There is also the question of secrecy. An early detection system — which, it should be stressed, is only costing about $1 million per year so far, spread out across various agencies, so it’s not as if this is some giant boondoggle dragging scientists and agencies away from more important things — is only needed, of course, if someone would engage in SRM without telling the world. This is, I suppose, possible — it just depends on motivation.

The planetary savior types who might do it will certainly crow loudly; a country or alliance who starts geoengineering with the tacit (or, less likely, explicit) hope it can in fact delay an energy transition probably would want to advertise as well. Think Saudi Arabia and its all-out push against climate action, and you get the idea. But any party that earnestly just wants to reduce its climate change impacts a bit while the world gets on with the painfully slow march away from fossil fuels might conceivably want to keep this in the dark. Why give those delayers any excuse?

I have long suspected that there are some secret geoengineering research programs out there — China is rich enough, practical enough, and still reliant on fossil fuels enough to at least be doing some preliminary work on the particulars. The logical question that follows from an early detection system, though, is what happens when it hits the mark? Okay, we detected a big pulse of sulfate aerosols lobbed to 60,000 feet above the Sea of Japan. What now? Start a war with the world’s biggest emitter for trying to cool the planet down a bit?

Again, its more a question of framing than anything else. As SRM gets more and more likely, building out the surrounding capacity for detection, monitoring, anything to make such an effort more transparent, seems like a reasonable idea. But this isn’t a nuke test, and comparing it to one probably only makes talking about the idea harder than it already is.