Solar Geo-engineering: research needed

As you may be aware by now, I am fairly sceptical about solar geoengineering techniques on the whole. Having focused heavily on carbon dioxide removal techniques thus far, I felt it would be fair to consider some of the solar geoengineering methods despite my negative opinions towards them. The Youtube video in this post is a Ted Talk on the need for a proper research programme for solar geoengineering techniques. It puts across a lot of the pros and cons of solar geoengineering methods so is well worth a watch if you have 15 minutes spare.

The key message I got from listening to this talk, which was also the objective of the talk, was not that solar geoengineering is necessarily a good (or bad) idea but the fact that there is a desperate need for a serious research programme into the effects of these different schemes. At the moment, there is simply not enough information on the potential benefits and risks. The need for a proper research programme is key to avoiding making ill-informed decisions that could be disastrous.   

Solar geoengineering has been proposed as a way to avoid climate tipping points. This is achieved through reducing the amount of solar radiation reaching Earth, leading to a lowering of global temperatures. There are a number of different methods to achieve this which are described in detail in the Caldeira et al. (2013) paper. The problem with all solar geo-engineering methods is that they do not alter the levels of carbon dioxide in the atmosphere despite decreasing global temperatures. This is potentially risky as if a solar geo-engineering technique were to fail, temperatures would rise at an even faster rate than we see presently.

Another major drawback of solar forms of geo-engineering is the costs of implementation. Injecting sulfate aerosols into the stratosphere is no different to other forms in this regard with high financial costs. In addition to the actual pumping of the sulfur dioxide into the atmosphere, there are high costs associated with the production and transport of this gas. One suggestion is to only use stratospheric aerosols over the Arctic to reduce sea ice melting. This would help to reduce the costs whilst still seeing significant benefits. All forms of geo-engineering are costly, both financially and in terms of climate risk which means humans must be certain of their impacts before attempting to implement them.

The biggest reason to avoid solar geo-engineering is the high risks associated with many of the methods. One method I do see as feasible in the short term is roof whitening. A paper by VanCuren (2012) highlighted the radiative forcing benefits of roof whitening in California, USA. The paper concluded that there could be significant benefits of this form of geo-engineering in California but these benefits are spatially variable depending on climate.

As it is clear to see, I feel that the drawbacks of many solar geo-engineering methods far outweigh the benefits and this is why in this blog I have chosen to focus on the more feasible and cheaper carbon dioxide removal techniques. They may not be as effective at reducing climate change in the short term but at least they are not as risky as many of the solar geo-engineering methods proposed.