Time waits for no-one: mitigating climate change through solar geoengineering

  • 29 May 2020
  • Technology
  • Alana Cullen

Currently, Governments tackle each problem that climate change throws their way on an individual basis, but compartmentalising is not sustainable. We must deal with the root cause of devastating climate events - flooding, drought and wildfires - or one day will come an event too large that we cannot fight back.

We have seen countries take astonishing action to save lives with the Covid-19 pandemic. Some of that determination, and the hard choices, are needed again. Perhaps the answer lies in putting our efforts into the seemingly sci-fi technologies of geoengineering?

Geoengineering is the “the deliberate large-scale intervention in the Earth’s natural systems to counteract climate change”. Since its first proposal in the 1990s a range of techniques have been devised that could help mitigate global warming. One example of solar geoengineering techniques includes “marine cloud brightening”. The clouds’ reflectiveness is increased by spraying sea water up into them. Some of the salt particles then remain suspended, acting as reflectors so that more of the Sun’s heat is reflected into space.

Another solar engineering technology utilises stratospheric aerosols, designed to mimic the cooling effects of volcanic eruptions. When a volcano erupts, an ash cloud containing sulphur dioxide is released into the atmosphere. When combined with water, this makes sulphuric acid aerosols which reflect the sunlight. Therefore, by mimicking this natural phenomenon and releasing small reflective particles into the atmosphere, we can reflect some sunlight away from the Earth. Researchers forecast that these relatively inexpensive techniques which essentially dim the Sun and cool the planet, could prevent the temperature from rising above the dangerous 2°C mark as laid out in the 2015 Paris Agreement.

Have we had the solution to global warming all along, stored away for a not-so-rainy day when it was finally deemed necessary to intervene? Sadly, not quite. There is an array of issues with these solar radiation management techniques that mean they may never come to fruition.

A leading cause for concern is that these technologies focus on mitigation, not adaption. Changing the earth’s temperature through means other than cutting down on greenhouse gas emissions (in this case, through radiation) does not tackle the cause of climate change. If the world focuses on mitigation over adaption, which businesses will, as it economically more viable than changing their current systems, then the greenhouse gas emissions will keep on rising - resulting in a vicious cycle of mitigation technologies. Geoengineering is therefore a moral hazard. This moral tightrope we would navigate has led the Royal Society to state that solar geoengineering should only complement, not provide a substitute, for adapting our technologies to be evergreen. The fast acting nature of these technologies (effects could be seen in a matter of months) means they could be used as a short term mitigation to climate change to prevent reaching the 2°C limit, while the world catches up on its adaption technologies for cutting greenhouse gas emissions.

Although it seems that geoengineering would only be a short-term fix, as with all new technologies there are unknown long-term risks. Physical risks to the environment include ocean acidification, acid rain, and changing seasonal weather patterns which could lead to droughts and flooding. Scaling up these technologies will require deforestation, and massive changes in land use that will result in a loss of biodiversity.

There is also a climate justice angle that cannot go ignored. So far, most crises caused by climate change have affected those who have not caused it. Placing solar geoengineering technologies in the global south will likely displace many thousands of people from their homes and will affect livelihoods: a rather unjust solution. This raises countless ethical mazes of compensation and liability, that would require an international law to be enforced. Even where it is determined that people are eligible for compensation, multinational corporations often have loopholes to avoid giving people what they are owed - it is one thing to determine if people can have compensation, and quite another to ensure they are getting it.

Before we get too carried away in the ethical labyrinth, it is time for a reality check. Solar geoengineering research is modest at best. The technologies to date are rather hypothetical, and it is the assumption that they will work when scaled up that is a large driving factor behind research. Scaling up the technologies will need ever increasing amounts of land, just at the time when increasing populations will need to use that land for food and living. Having only been tested outdoors twice, it is impressive that these technologies have been branded as a cure-all to global warming. Certainly, there is not yet enough information to create an evidence-based policy.

In government, policy makers have taken a cautious approach to these novel technologies. There is widespread opinion that we must have ‘governance before deployment’, which indicates that solar geoengineering should not be implemented until we have the appropriate regulations in place. A task force would be required to assess public opinion and provide transparency on both the benefits and risks of solar engineering technologies. If this was to take place, careful planning would be needed to ensure that this was a dialogical engagement, where the public concerns were addressed, avoiding a repeat of the poorly designed and executed attempt of public engagement with GM Nation in 2003.

Such discussions would be the easiest part of implementing these technologies compared to the reality of getting Government to agree to them. Solar geoengineering techniques would be difficult to implement in practice due to their transboundary effects, and the need therefore to be shaped by international law makes the issue infinitely more complex. How will international relations be in 10, 20, or 30 years? Furthermore, there is a lack of incentive to engage, as politically it divides the Government between adaption and mitigation. This raises the complex question of on whose version of respect for ethics should the policy rely - government, scientists, or the public.

Solar geoengineering techniques are a catch-22 - too risky to rush, but too important to delay. When finally developed to a scale large enough to have a significant effect, these technologies must be consistently monitored, to ensure complacency doesn’t set in. Adaption must be our priority, but perhaps these innovative technologies could grant us the time we need to cut our carbon emissions.

Alana Cullen is a MSc student at Imperial College London studying Science Communication, and is the Social Media and Communication's Officer for the Foundation for Science and Technology.