Geoengineering – to do or not to do?

Climate change remains an uncomfortable topic. Politicians continue to state it is such an important problem, and then fail to do anything sufficient to solve it. There seems to be an idea amongst politicians that if everyone drove electric vehicles, all would be well. Leaving aside the question as to whether over the life of a vehicle the electric vehicle actually emits less greenhouse gas (and at best, that is such a close call it is unlikely to have any hope of addressing the problem) as noted in my post

the world cannot sustain then necessary extractions to make it even vaguely possible. If that is the solution, why waste the effort – we are doomed.

As an article in Nature (vol 593, p 167, 2021) noted, we need to evaluate all possible options. As I have remarked in previous posts, it is extremely unlikely there is a silver bullet. Fusion power would come rather close, but we still have to do a number of other things, such as to enable transport, and as yet we do not have fusion power. So what the Nature article said is we should at least consider and analyse properly the consequences of geoengineering. The usual answer here is, horrors, we can’t go around altering the planet’s climate, but the fact is we have already. What do you think those greenhouse gases are doing?

The problem is that while the world has pledged to reduce emissions by 3 billion t of CO2 per year, even if this is achieved, and that is a big if, it remains far too little. Carbon capture will theoretically solve some of the problems, but it costs so much money for no benefit to the saver that you should not bet the house on that one. The alternative, as the Nature article suggests, is geoengineering. The concept is to raise the albedo of the planet, which reflects light back to space. The cooling effect is known: it happens after severe volcanic eruptions.

The basic concept of sending reflective stuff into the upper atmosphere is that it is short-term in nature, so if you get it wrong and there is an effect you don’t like, it does not last all that long. On the other hand, it is also a rapid fix and you get relatively quick results. That means provided you do things with some degree of care you can generate a short-term effect that is mild enough to see what happens, and if it works, you can later amplify it.

The biggest problem is the so-called ethical one: who decides how much cooling, and where do you cool? The article notes that some are vociferously opposed to it as “it could go awry in unpredictable ways”. It could be unpredictable, but the biggest problem would be that the unpredictability would be too small. Another listed reason to oppose it was it would detract from efforts to reduce greenhouse emissions. The problem here is that China and many other places are busy building new coal-fired electricity generation. Exactly how do you reduce emissions when so many places are busy increasing emissions? Then there is the question, how do you know what the effects will be? The answer to that is you carry out short-term mild experiments so you can find out without any serious damage.

The other side of the coin is, if we even stopped emissions right now, the existing levels will continue to heat the planet and nobody knows by how much. The models are simply insufficiently definitive. All we know is that the ice sheets are melting, and when they go, much of our prime agricultural land goes with it. Then there is the question of governance. One proposal to run small tests in Scandinavia ran into opposition from a community that protested that the experiments would offer a distraction from other reduction efforts. It appears that some people seem to think that with just a little effort this problem will go away. It won’t. One of the reasons for obstructing research is that the project will affect the whole planet. Yes, well so does burning coal in thermal generators, but I have never heard of the rest of the planet being consulted on that.

Is it a solution? I don’t know. It most definitely is not THE solution but it may be the only solution that acts quickly enough to compensate for a general inability to get moving, and in my opinion we badly need experiments to show what can be achieved. I understand there was once one such experiment, although not an intentional one. Following the grounding of aircraft over the US due to the Twin Tower incident, I gather the temperatures the following two days went up by over a degree. That was because the ice particles due to jet exhausts were no longer being generated. The advantages of an experiment using ice particles in the upper atmosphere is you can measure what happens quickly, but it quickly goes away so there will be no long term damage. So, is it possible? My guess is that technically it can be managed, but the practical issues of getting general consent to implement it will take so long it becomes more or less irrelevant. You can always find someone who opposes anything.