#4 Have we reached the geoengineered future?

In the last weeks, we did the math – and realized: To prevent global warming of more than 2°C (aka a climate catastrophe) we need to rapidly reduce carbon in the atmosphere.
Divestment might be a way to accelerate a clean-energy transition and level the playing field for large-scale renewable projects, as briefly introduced in the last post. However, even though the divestment-campaign might be quite successful in terms of political and social impact (more on that in my blog post on divestment) scientifically spoken, we are currently moving away from the “well-below” 2°- Goal: Just a few weeks ago, a group of scientists released a report stating: After three consecutive years of almost no growth in emissions (with an average of 34.4 GtCO2 CO2 emissions) this year, global emissions from fossil fuels and industry are projected to rise by 2% -  a new record (Global Carbon Project, 2017)
Under counterfactual conditions, the rise in emissions could have been even higher without mitigation efforts on various levels. However, in the words of climate scientist Alan Robock - global warming is society’s failure.

Thus, in the next two blog posts, I want to talk about a highly technical approach on the other end of the mitigation scale: Geoengineering, one of our seminar topics. You are shivering by the sound of that word?

Geoengineering might sound quite "spacy", yet it is not much of a new idea. As early as 1977 the term "geoengineering" was first introduced and has since increasingly gained attention (Marchetti, 1997). Certainly, geoengineering is more commonly associated with earth-scale chemical-technical experimenting than with a tangible and feasible solution for global warming. However, geoengineering is a much broader term than many would expect - it is not just about capturing liquid carbon deep in the ground or releasing sulphur in the stratosphere.

Solar Radiation Management: A plan B for the planet? Source www.thefluidlens.com

So, what is geoengineering?

Broadly speaking, it’s large-scale efforts to combat climate change through altering planetary-scale processes (Caldeira et al., 2013). By artificially intervening natural biochemical and geophysical processes one attempts to slow down climate change. The focus lies primarily (but not exclusively) on carbon-induced climate change (Keith, 2000). There are two different approaches, one of which I want to discuss today:

Solar Radiation Management (SRM) is the attempt to disturb the link between emissions and climate change by offsetting their warming influence through reducing the amount of sunlight absorbed by the earth. One aims to increase the planetary albedo through satellites in space, dispersing aerosols in the stratosphere or brightening marine clouds.

A prominent approach is the proposal to use stratospheric sulphate aerosols to increase the amount of sunlight reflected from the clouds. An early advocate for this method was Budyko who compared the climatic effect of injecting SO2 in the stratosphere to the cooling effect of large volcanic eruptions such as after the Mount Pinatubo eruption in 1991(Budyko, 1982). Practically, one sprays sulphate aerosols (a mix of water vapour and sulphur acids) in the lower stratosphere (e.g. in 20 km height over the tropics). Natural wind patterns then disperse the sulphate aerosols. Ideally, the albedo of the stratosphere then rises and prevents solar radiation to reach the atmosphere when reflecting the radiation. In a (controversial) editorial in 2006, climate scientist and Nobel Prize Laureate Paul J. Crutzen prominently argued in favour of a serious consideration of sulphur aerosols injections. Another SRM method is space-based sun shields (which could look like giant mirrors) placed in the orbit which, again ideally, reflect sunlight which otherwise would be absorbed.

Overall, SRM is highly controversial: Some scientists fear that their cooling effect on the Stratosphere could aggravate changes to stratospheric chemistry and cause ozone depletion. Further consequences could be an increase of magnitude of precipitation changes due to disturbed hydrological cycles. Further oceans play a crucial role: Since SMR does not alter the current level of atmospheric CO2 it does not mitigate CO2 induced ocean acidification. Hence oceans will continue to function as sinks – the 30% rise in ocean acidity compared to pre-industrial times has already a severe impact on marine ecosystems and thus humans. Here, SRM does not provide a solution. In the worst case scenario, say a failure of either of those techniques, the planet would experience enormous positive climate forcing hence a rapid rise in temperature for several decades. Politically, SRM could negatively impact global climate discourse by providing an excuse to slow down on other, desperately needed, mitigation efforts. Adding to these technical and scientific concerns, there are underlying financial and moral considerations: Which entity could coordinate and take responsibility when altering the biophysical foundation of life (solar radiation)? And, who would and could pay?

Source: www.theguardian.com

Taking these points into account one could dismiss SRM as an interesting thought worth a critical discourse (such as promoted by The Solar Radiation Management Governance Initiative) but ultimately a Dystopia. However, in the face the world’s struggle to combat rising CO2 emissions it appears as every loophole out of our warming spiral has to be taken into consideration. In March 2017  the Harvard University launched the largest and most comprehensive solar geoengineering study of all times in order to gain a better understanding of the potential of the SRM.
In 2022, the $ 20m project plans to disperse calcium carbonate particles while also looking at other aspects for instance how to prevent the destruction of the ozone layer. After all, it is happening – we might be stumbling towards geoengineered future. Unless we prove that we can cope without.

I inserted the promotion video of the Harvard Project. Even though it serves a promotional purpose, it might give you a vague idea of their objectives. Source: youtube.

Finally, check out the blog by Fay from my class, she wrote exclusively on Geoengineering.