In a previous post I looked at the effect of tree-planting to help counter climate change. This time I shall look at geoengineering. The United Nations Environmental Assembly considered a resolution on solar radiation modification, which called for the convening of an expert group to examine the benefits and risks. The resolution was withdrawn because the non-experts could not agree on whether to form the panel. Well, that was a huge achievement! It is claimed that research has identified potential risks, such as unpredictable effects on weather, biodiversity loss, undermining food security, and infringement of human rights across generations by passing on huge risks to generations that will follow us. In short, the risks that something will happen are the same as what we know will happen now. These changes are locked in, and are not risks. However, not all proposals are sensible.
Proposals include injecting millions of tonnes of aerosols into the stratosphere. The critics say this would alter global winds and rainfall patterns, leading to more drought and cyclones, exacerbate acid rainfall and slow ozone recovery. That would depend on what is done. It is not necessary to fire acidic material or ozone depleting material up there. The one criticism that is reasonable is that this expensive operation would have to be carried out continuously. Missing in action was a proposal to insert potential “dust” particles into aero-jet engines to make long-lasting contrails. A possibility would be something like diethyl zinc. Zinc oxide should remain volatile within the engine. There may be other problems, such as fuel storage but at least consider it.
An alternative is to make low-level clouds brighter by spraying microscopic seawater droplets into the air. This was rejected because there is no peer-reviewed evidence that it would work. Given nobody is trying, and looking at the attitude of potential reviewers, that rejection is ridiculous. As an example of “expert opinion”, one comment was, “Even if it worked, it is hardly environmentally benign.” That is a fairly good sign such a project would be rejected. On the other hand, not doing it makes sense: it would also be too expensive, so it would never happen.
One project was to spread tiny glass spheres over large areas of sea ice to brighten the surface. This failed – they sped up the loss of sea ice. A little thought on the physics would have indicated the spheres would refract the light and concentrate it in spots and enhance absorption when the sun was at an angle, which it usually is where there is sea ice. Another proposal was to spray the ocean with microbubbles or foam. If you cannot see what is wrong with that proposal, you are not thinking clearly.
So what do they think is the answer? Apparently 500 scientists signed an open letter calling for non-use of solar geoengineering, and argue that model studies suffer from uncertainties. Their answer to the problem is to cut greenhouse gas emissions. Apparently they have not noticed that we have made no progress on that at all, and we are accelerating in in the wrong direction.
Can geoengineering do any good? In my opinion, possibly. The best option I can think of is to fertilize the cooler oceans with dust, or better, a gel, containing iron oxide. The advantage of the gel is it does not sink. The result is a bloom of microalgae. This has been shown to work, but was rejected because the algae did not sink to the bottom. One could harvest them, for biofuels. In answer to the objection that we don’t know how to harvest them, then why not research the possibility? There must be some way. However, the important point is that the light absorbed by photosynthesis does not create heat – the energy is locked up as chemical energy. Further, if you seed the right microalgae you provide feed for animals and hence have more carbon locked up as life forms and more food for humans.
What seems to have happened here is that the concept started with activity and not thought. The obvious was proposed to get research funding, which probably shut out those proposals that came later and had more thought. As for the self-styled “experts”, the proposal to pass the buck to someone else is unfortunately only too familiar. And no, I do not think geoengineering is the answer. There is no single answer, although a massive expansion of nuclear generation in molten salt reactors comes the closest to one.
ianmillerblog 
Maybe the problem is everyone is looking for a single solution, rather than proceeding with multiple ones which collectively would be effective.
That wouldn’t be so bad if they actually did something. One answer won’t solve thee problem, but it could help.
Well said!
Geoengineering is already going on, at an unimaginable scale: we are ABOVE 600 parts per million of CO2 EQUIVALENT…. That the Antarctica metastable point! The paltry 420 ppm of CO2 usually rolled out considers only CO2 not all the man-made GreenHouse Gases such as CH4, NOx, Fluorocarbons, etc. which have a much stronger infrared retention factor.
So far all the geoengineering schemes proposed are silly as they wanted to mitigate the temperature rise. But CO2 per se is dangerous. The safe thing to do is to emit less CO2. And nuclear energy is the obvious way to do that. Potentially all electric production could be nuclear. All the objections to nuclear energy can be overruled by using more advanced technology: reactors can be made safe, non proliferating and eating their own waste.
The prominent greenhouse gas is water vapor. Man-made GHG and CO2 leverages the H2O. A recent paper pointed out that what matters is high altitude H2O. They claimed it’s injected only in few places equatorial (I think it’s more complicated than that). An idea would be to turn the vapor into rain before it could go stratospheric… If it really goes up only in a few spots.
Giant artificial near stratospheric mountains disposed strategically with nets in between may be a passive way to do that.
Yes, I ignored the other greenhouse gases simply because of the limits of space. Maybe something for another post some time. Water is interesting because it is self-regulating – it removes itself through rain, BUT it also has positive feedback – as the air warms through other greenhouse gasses, the air holds more water.
Yes, nonlinear feedback. Off top of my head about half of ther forcing is caused by H2O lifted by GHG. Counting other GHG augments the greenhouse by 50%. The IPCC is not paying attention… Deliberate, bcs if they did drastic decisons would have to be taken right away, like taxing carbon, planes, outlawing private jets, make sails madatory on vessels, mandating hybrid cars. Etc.