But he does explain a key practical problem with the concept, as follows:
We would have to keep on managing the insolation for millennia or until someone finds a cheap way to remove carbon dioxide from the air. The largest danger is thus that humanity gets into trouble over these millennia and would no longer be able to keep the program up, the temperature would jump up quickly and make the trouble even worse. Looking back at our history since Christ was born and especially the last century, it seems likely that we will be in trouble once in a while over such a long period.I am surprised that he does not also consider that natural disasters effectively beyond human control might put a serious hole in maintaining the necessary work - a seriously large asteroid strike, for example, would have economic and society disrupting consequences that I doubt anyone can forecast. While it won't likely be the end of humanity (it's a big planet), and the dust it throws up would initially cool the place, perhaps to crop destroying and famine inducing levels, when the sky clears enough again the world economy may take a long time to recover before large scale geo-intervention can resume. This scenario would involve initial disaster from sudden darkness and lingering cold weather, to a reversal where the temperature climbs rapidly to dangerously high levels.
This danger could also be an advantage, just as the mutual assured destruction (MAD) with nuclear arms brought us a period of relative peace, the automatic triggering of Mad Max would force humanity to behave somewhat sensibly and make people who love war less influential.
My impression is that the main objection from scientists against geo-interventions is their worry about creating such an automatically triggered doomsday machine. Those people seem to think of a scenario without mitigation, where we would have to do more and more Solar Radiation Management. While carbon dioxide accumulates in the atmosphere over millennia, the stratospheric particles (after a volcanoes) are removed after a few years. So we would need to keep adding them to the stratosphere and if we do not reduce greenhouse gas emissions increasingly many particles.
I would much prefer to not have the dangerously high temperatures a possibility.
And besides, at an ecological level, no one knows how ocean acidification is going to pan out. Lots more algae, sometimes of the poisonous variety; key crustaceans in the ocean food chain (pteropods) dying out; oxygen low areas of the ocean that can support little sea life of any variety - these are all realistic predictions of increased CO2 in the atmosphere and oceans, and keeping the temperature down alone won't solve them.
So, I will remain a skeptic of this band-aid approach to dealing with climate change and CO2 emissions.
I would also have wished we would not need the band-aid and was in favour of drastic action in 1990. We did do some, but not enough.
ReplyDeleteIf you can convince your Australian conservative colleagues to take reducing CO2 emissions as seriously as European conservatives, we could still keep the band-aid as small as possible.
Assuming technology improves and we would know of the asteroid more than half a year in advance, the band-aid might even have a small advantage. We could rip it off before the asteroid strikes.
We did not have such strikes in the last millennia, they are rare in the full history of the Earth. So the chance of one hitting us while we do this is small. A program to find and destroy them could still be worthwhile because the consequences are so large.
That was also the reason why I wanted to do something about climate change in 1990. The small probability that it is really bad is a big part of the total risk.
Hi Victor, thanks for your comment.
ReplyDeleteAlthough I did only mention asteroid strikes, it was just one example. I am sure you would be aware of the various other potential natural disasters talked about over recent years by the likes of Nick Bostrom: super-pandemics (either natural or via genetic engineering); a return of massive volcanism (with the US destroying potential of Yellowstone perhaps the most obvious concern); and potentially large crop failures under AGW before effective geo-engineering has time to kick in.
My worry is not the disaster is large enough to threaten humanity per se - but large enough to hurt economies enough that they can't keep maintaining the geo-engineered shield. Because they do sound like expensive projects.
The costs of solar radiation management is a few percent of the GDP of The Netherlands, a small country in area, but mid-sized economy for the WEIRD countries. That is a lot of money, but would be something we could keep up as long as civilization is maintained (and such a doomsday machine would be a motivation to maintain civilization, the benefits of which the American right does not seem to appreciate.) A smaller problem, like the destruction of America, would be manageable.
ReplyDeleteIf there were a problem before geo-engineering kicks in, the temperature jump would also be small.
It would naturally have been better to have had a situation in which we do not need a geo-intervention, I have been in favour of that for decades, but we are in the situation we are in now.