To what extent should we engineer the climate?

Ibrahim (Year 9)

Climate engineering – or geoengineering – is the purposeful intervention into the climate system to reduce and slow down the effects of climate change. There are two types of engineering: greenhouse gas removal (GGR) and solar radiation managemen (or SRM). GGR focuses on removing gases, emitted from human activity, from the atmosphere, directly reducing the greenhouse effect. SRM, meanwhile, is the label given to a diverse mix of large-scale technology ideas for reflecting sunlight away from the Earth, thereby cooling it.

It is increasingly looking like we may have to rely on a combination of such technologies in facing climate change. The authors of the recent IPCC report concluded that it is possible to limit global warming to no more than 1.5°C, but every single one of the pathways they envisaged require the use of greenhouse gas removal, often on a vast scale. However, these technologies are not ready to be developed yet and so if efforts to reduce greenhouse gas emissions by transitioning away from fossil fuels fail, or greenhouse gas removal technologies are not researched and deployed quickly enough, faster-acting SRM ideas may be needed to combat the effects of climate change.

One of the main geoengineering methods being discussed involves sulphate particles or other aerosols being injected into the stratosphere from planes or high-altitude balloons, otherwise known as “stratospheric aerosol injection” or SAI and used to reflect sunlight into space in order to cool the planet. Stratospheric aerosols are the only solar geoengineering techniques “we know work today”, says McMartin of Cornell University. “We see what happens after a large volcanic eruption like Mount Pinatubo: put sulphate aerosols into the stratosphere and the planet cooled by about a half a degree”. SAI will help to cool the planet drastically, in a time where no other established solutions are being provided and will reverse and reduce the effects of climate change, such as melting ice caps and rising sea levels. SAI will also be cheaper than other methods of combating climate change, making it more accessible for even developing countries. Despite that, a range of potential problems are already causing concern. Injected sulphate aerosols could deplete the ozone layer and sulphates would also eventually come down as acid rain, says McMartin, a particular worry for the relatively pristine parts of the planet which have not previously experienced this. It could also pose a risk to geopolitical systems. If a country decides to deploy solar geoengineering unilaterally, that could completely disrupt weather systems for another country, which would then disrupt its agricultural systems, and its GDP, resulting in massive tensions.

Another potential big risk of widespread deployment of SRM is something called termination shock, where the technology is abruptly stopped, for example, by war or

https://www.sciencedirect.com/science/article/pii/S1750583615002650

natural disaster. This would cause temperatures to rise very quickly to reflect the atmospheric concentration of greenhouse gases. If societies are locked into the technology, these speedy rises could be truly catastrophic. Even if SRM were to be used only temporarily, the long atmospheric life of CO2 means that abrupt termination would still lead to a massive, swift warming effect.

In terms of GGR, the UK has invested £30 million into numerous innovative methods of large-scale greenhouse gas removal from the atmosphere,

aiming to help the UK reach its legislated net-zero climate target by 2050. One of these methods involve using biomass for energy, capturing the CO2 emissions, and storing them to provide lifecycle GGR, in other words: bioenergy with carbon capture and storage (BECCS).

A primary benefit of BECCS is that it provides energy whereas other carbon removal pathways like direct air capture, use energy. The value of the energy provided by BECCS reduces its net cost of carbon removal compared with other technological options. However, lots of land is needed to carry out the process, resulting in displacement of communities for land conversion affecting people’s livelihood and social identity. The land conversion will also have an impact on natural habitats, threatening the biodiversity of the area and may cause some animals to become endangered. The question also arises about where to store the CO2, raising concerns about geological storage; transporting and injecting CO2 into geological reservoirs raises concerns about pipelines, CO2 leakage, seismic activity, and water pollution, even affecting certain animal’s habitats, making the environment a place no longer safe to live. Yet many of these issues would arise only from very largescale adoption of BECCS. Smaller scale applications using agricultural residues or marginal agricultural land generally pose fewer risks. But for the method to have a meaningful impact, small scale projects will not be enough.

A second method the UK has invested in is afforestation. Growing new trees and improving the management of existing forests. As forests grow, they absorb CO2 from the atmosphere and store it in living biomass, dead organic matter and soils. As well as helping to resolve the problem of climate change, afforestation helps to provide new wildlife habitats for animals, and in some cases endangered animals, improving biodiversity in the area. The process also prevents soil erosion. The roots of the trees help to bind the soil together, stopping regions from becoming dry wastelands which can no longer be used for things like agriculture. Despite this, afforestation comes with serious opportunity costs. The transformed lands can no longer be used for such as residential developments and agriculture that are highly beneficial to the society through more supply of food and housing for those who need them, having an effect on the economy and health of the people as food is not only useful to feed people but also to trade with other countries.

In conclusion, I believe that geoengineering will be a key component in the journey to combating climate change, but, at this moment of time, more research is needed to be put into the technology and the methods need to be developed further so that they can be used safely, with no negative effects. If countries do decide to use geoengineering against climate change, it should not be the only solution they rely on, as they may become too dependent on it, and they should like for other ways to stop climate change at the same time.