I commented in a post a couple of days ago that we should probably avoid risking the Arctic warming by 10 degrees or more and that the only way that I thought this could be achieved was by avoiding raising atmospheric CO2 concentrations much higher than they are today. There was, however, a suggestion in a comment that this wasn’t strictly true as it could be achieved through geo-engineering, in particular releasing SO2 particles into the upper atmosphere which would then act to increase our albedo.
There’s one immediate issue with this idea, which is that it would act to cool the planet by reflecting more sunlight back into space, but it wouldn’t influence, for example, ocean acidification. There is, however, a more subtle issue that is explained more clearly in this article than I can probably do here (H/T afeman). I’ll do my best to summarise, though.
There’s a rather unfortunate narrative that sometimes rears it’s ugly head in the climate debate, which is essentially that climate change is some kind of conspiracy to take over the world and impose some kind of socialist utopia (I’m paraphrasing, but it’s along these kind of lines). Personally, I think this is nonsense, but even if some do have this goal, it’s all rather unlikely. We can’t really force sovereign nations to not generate energy via fossil fuels. If they can access fossil fuels, then there’s doesn’t seem to be much that could be done to stop them from using it. So, as I see it, any global reduction in CO2 emissions would have to be done through some kind of global agreement, rather than through simply imposing rules on sovereign nations.
This, however, isn’t strictly true for geo-engineering. If we consider injecting SO2 into the atmosphere, it will have a global effect. It may well cool the planet back down to an “acceptable” average, but there will be some areas that suffer, and others that benefit. One could imagine a scenario where there’s global agreement and that those who will suffer agree to the process because of the overall benefit. On the other hand, they may choose to oppose the idea. However, this may not matter. A global superpower, who would benefit from the process, might carry on regardless; effectively imposing their will on the rest of the planet.
Of course, I think we should avoid the risk of getting to a point in the future where we might be forced to consider intentionally geo-engineering the planet (rather than doing it unintentionally, as we are now). If, however, we got there, there’s every chance that this could happen against the wishes of many sovereign nations. So maybe those who worry about a single government making decisions for the entire globe, are right to be worried, but for very different reasons to those that they currently have. Of course, maybe we’ll be lucky; climate sensitivity will be low; ocean ecosystems will adapt to increased ocean acidification; and the changes to our weather from polar amplification will be beneficial, rather than detrimental. However, assuming this without considering the risks that climate sensitivity will be high; that a warmer climate will have negative effects on agriculture; that changes to our weather will have many detrimental effects; that ocean acidification will damage ecosystems; and that we might be forced into taking the kind of action that we’d probably rather avoid, just seems rather silly.