Geo-engineering is increasingly looking like the only politically viable way of averting temperature rises above 2 degrees in the coming century. This is for three interlocking reasons: i) Any mayor country can try geo-engineering on its own without permission from anyone else, meaning one does not need a world coalition sustained for centuries to have an effect; ii) It holds the promise of immediate relief because ‘natural Solar Radiation Management’, ie volcanic eruptions that add lots of light-reflecting particles into the atmosphere, were found to cause immediate worldwide temperature drops, which compares favourably with the lags of decades and centuries that hold for CO2 emission reduction plans; and iii) It might be exceedingly cheap compared to any policy involving emission markets. For instance, according to a 2012 piece by McClellan and co-authors, we could keep the planet at current temperature levels at a cost of merely 10 billion dollars a year by having a fleet of planes deliver reflective particles high in the earth’s atmosphere.
Given that continued global warming is predicted to happen in the next century no matter what emission policies are adopted, geo-engineering by some impatient large country is starting to look nigh inevitable. I reported in 2012 on the research efforts funded by the Royal Society, the Gates Foundation, and others. You now have dedicated institutes on this issue (eg. http://iagp.ac.uk ), and lots of new proposed experiments. With a large glut of published studies in recent years, it is time for an update: how far are we now in the world of geo-engineering?
The honest answer is that the scientific community is pussyfooting around when it comes to geo-engineering. Field experiments are largely stalled as scientists are awaiting regulatory frameworks that will protect them from criticisms of other scientists and environmental groups. Proposed regulatory frameworks designed to deliver this, such as by Nordhaus and colleagues, find it hard to get much political traction because politicians seen to support regulatory frameworks themselves become targets for criticism, both by those who pretend there is no climate change and by those who insist there is climate change but who also insist on emission reductions as the only way to return to our current climate some 300 years from now. Voters who agree the world is getting too hot and who would like it cooled down in their own lifetime rather than that of their great-great-great-great-grandchildren are still too rare to bother with for politicians.
This does not mean there is a lack of bright ideas. The engineers looking into this really are a very creative bunch, talking about whitening clouds, aerosol sprays, reflective shields, and artificial trees. One new idea that I hadn’t heard before is to genetically alter our crops so that they reflect sunlight better than the current crops. I don’t know whether this has any chance of getting serious traction, but one has to admire the ingenuity of the idea. Still, ominously, almost no field tests or large scale long-term testing is underway as scientists are waiting for societal approval to go ahead.
A good example of the ‘adverse climate for studies into geo-engineering’ is the reaction to the experiment with iron fertilisation off the coast of Canada in 2012: two businessmen/scientists dumped 100 tonnes of iron into the oceans in the hope of stimulating huge algae blooms that would capture a lot of carbon. The algae blooms failed to materialise, showing that iron fertilisation on its own was not as effective as once hoped for. Yet, these scientists were denounced as ‘rogue’ and there were widespread calls for legal action. This reaction was absurd once you think of the puny scale of the experiment: they only dumped 100 tonnes of iron ore into the oceans. Given a yearly world iron ore production by humans of around 3 billion tons per year, the experiment was insignificant compared to the amount of human-processed iron that flows to the oceans on a daily basis in terms of rust! You don’t hear equal amounts of complaints whenever an old ship is deliberately sunk to form an artificial reef, even though that is a similar amount of iron being ‘dumped’! The reactions hence were silly, vindictive, and essentially irresponsible. No wonder that the scientists looking at geo-engineering are waiting for official societal permission in the form of regulation that could sanctify their experiments and thus insulate them from the moral crusaders.
So at the moment, the scientific debates about feasibility and costs are mainly fought by means of computer simulation studies, with the usual claims and counter-claims that one gets when there is no real data. Typically, published reviews of this literature are critical of any form of geo-engineering that would have the potential to have immediate effects, usually saying the unknown risks are unacceptable. A good example is a recent paper by Cussack and others in 2014 that grudgingly admitted that Solar Radiation Management is indeed likely to be cost-effective at cooling the planet down quickly for relatively little money, but nevertheless says would entail unacceptable (but unknown) high risks, leading the authors to advocate broad-scale application of carbon-sequestration.
Carbon-sequestration is an oft-quoted darling in the literature critical of Solar Radiation Management, but is really a pretty hopeless technology as soon as you realise that coal is a beautifully compact form of sequestered carbon. To go from digging it up and burning it, which is what we do now in greater amounts than ever before, to re-creating it and then burying it seems rather costly, doesn’t it?
Re-sequestration would thus need to be done on a huge scale to have any effect, essentially undoing 2 centuries of digging up coal, oil, and gas, by putting similar substances back into the ground, preferably just as deep. The volumes involved would be such that we’d be talking decades of enormous industrial efforts to do it, which raises the question who would pay for it. Apart from the cost question though, the time-frame is off as it would not reduce the temperatures quickly but, once again, would only see its ‘benefits’ felt decades later. You might hence say that the world is still ‘unsequestering’ as fast as it can and ‘resequestering’ would only seem likely to happen if current populations were willing to expend huge efforts to aid their great-great-great-great-grandchildren. Not very likely, is it? This is typical of the studies critical of geo-engineering: they have little appreciation for the role of impatience and opportunism that are pervasive aspects of voters and their politicians.
We are thus a bit in scientific limbo-land at the moment, with moral crusaders preventing real progress: on the basis that the planet is hurtling towards disaster, we are asked to change our way life dramatically now, yet we should also accept that the damage takes centuries to undo and that we should just live with the climate change caused by our past sins. Solutions with immediate effect are seen as a form of cheating on our just deserts, and are said to involve unacceptable risks, with research designed to find out about those risks seen as unethical and already too risky. Why it is apparently more ethical to rejoice in the US-China announcement that they will keep increasing emissions for decades to come, is somewhat of a mystery: how can anyone truly fearing irreversible climate disaster see such non-binding agreements of sustained high emissions as real hope? It’s bizarre.
The stalemate that we see now in the science of geo-engineering would not seem sustainable though. Research funds keep being poured into this and the scientists involved will find ways to have real experiments in order to give the funders a real return. Also, at some point large groups of concerned voters will wake up to the absurd level of patience and altruism that the IPCC is currently asking of them, at which point they are going to force their politicians to cut through the fog of political correctness and experiment on a wide scale, moralising crusaders be damned. How far are we away from this? Hard to know, but I would be surprised if we need to wait more than 5 years for big experiments to see the light of day.
 Justin McClellan, David W Keith, and Jay Apt, “Cost Analysis of Stratospheric Albedo Modification Delivery Systems,” Environmental Research Letters 7 (2012).