Putting out fire with gasoline

Proposals to 'fix' climate change with geoengineering are unhinged, but risk becoming inevitable

Geoengineering: the deliberate interference in the climate system in order to try to reduce the impacts of human-caused climate change. It’s not a new idea. Back in 1991 the eruption of Mount Pinatoba blasted nearly 20 million tons of sulphur dioxide up into the stratosphere. This formed highly reflective clouds that produced a global cooling effect of about 0.5°C for a couple of years. Scientists took note and recalled that back in the early 1970s pioneering climatologist Mikhail Budyko speculated that humans could deliberately undertake sulphate injection as a method of solar radiation management in an attempt to offset some of the global warming that humans were production from burning fossil fuels.

Budyko’s reasoning then was that if humanity did not stop burning fossil fuels (perish the thought), and/or the climate system proved to be more sensitive to the trillions of tons of carbon dioxide that all that fossil fuel burning was producing, then we may be able to artificially cool the planet by emulating a massive volcanic eruption. Sulphate Aerosol Injection (SAI) is an example of Solar Radiation Management (SRM). There are various ways this may be achieved. For example, a fleet of several hundred wide body passenger jets could be retrofitted as high altitude tankers. These would spray sulphuric acid into the higher troposphere. The highly reflective droplets would block some of the energy from the Sun reaching the Earth’s surface.

This idea bubbled along largely under the radar. When it did break the surface there was typically quite a strong reaction against it. Putting out fire with gasoline (specifically Jet-A1) doesn’t seem like a tremendously wise thing to do. It’s also the case that the other major environmental crises of ozone depletion and acid rain were solved by stopping the pollution doing the damage. The Earth system then recovered (or healed itself if you prefer). Trying to stop dangerous interference in the climate systems with more interference threatens to open up a whole new world of hurt. Perhaps more importantly, how could the international community ever agree how to deploy geoengineering? It can’t even fairly allocate the remaining carbon budget to limit warming to below 2°C which is a relatively much easier challenge.

About 15 years ago I attended a session of the European Geosciences Union annual meeting in Vienna that was billed as a town hall about geoengineering. I cannot remember who was on the panel but I do remember pretty much everyone in the hall raised their hand in response to being asked if they agreed that geoengineering should not be pursued.

Well time has marched on, and along with it cumulative emissions. We are in the process of not just passing but crashing through 1.5°C of warming. Not only that, there are increasing indications that the rate of global warming is accelerating and that climate impacts are towards the higher range of expectations. Oh, and massive ice sheets in Greenland and Western Antarctica may be in the process of disintegrating, which along with other tipping points in the Earth system represent irreversible and potentially catastrophic climate change impacts (be sure to register for the 2025 Global Tipping Points Conference in Exeter to hear more about these and other exciting developments in Earth system science).

Geoengineering research has also come a long way and it’s fair to say there is a much better understanding of how SAI could be done and what it could do. It’s also had something of a rebrand with the label Responsible Climate Intervention. Obviously ‘responsible’ is doing a lot of lifting here. One argument is that if the climate really does look like it is going to spiral out of control then intervention may simply be the least-worst option. It may not be pretty, it may make some things worse, but it may be necessary to save civilisation. After all, a surgeon will harm a person in order to avoid greater harm, perhaps even death. Think of an emergency leg amputation as an example of Responsible Limb Removal.

So while there will be some risks involved in sulphate injection (for example, it may significantly destabilise the Indian monsoon, or wreak havoc with other regional weather patterns and so threaten the livelihoods, perhaps lives of hundreds of millions of people), the risks of unabated climate change may be much much larger.

This risk:risk approach is not just wrong, it’s unhinged.

Let’s just remember that if you were really motivated to reduce the risks of climate change, then you would be doing everything you can to reduce emissions now. That’s not happening because the actual risks policy makers are trying to minimise are the economic impacts resulting from climate change.

More greenhouse gasses in the atmosphere are trapping more heat. That means there is more energy in the climate systems to drive winds and to move water. What we experience is increasingly devastating storms, droughts, floods and fires (I wrote a book about this, to be honest it’s a bit of grim read at times so bear that in mind if you want to get a copy). As climate change gets worse, more damage will be done to societies. We can measure that damage in economic terms. For example, 2°C of warming may result in a 2% decrease in economic activity as measured by global GDP. This is likely a vast underestimation. Moreover, the way economic damage is assessed may be fundamentally flawed (to put it politely).

But at least there is an easy to understand economic rationale for limiting climate change. You would do that by phasing out fossil fuels and so reduce emissions and future warming. However, if you do that quickly you risk slowing down economic growth because fossil fuels still supply around 80% of total energy. Also, think of all that fossil fuel infrastructure and other assets that risk being stranded if we really do kick the hydrocarbons habit and transition to low-carbon societies.

Policy makers attempt to balance the physical risks of climate change with the transition risks that emerge from rapidly getting off of fossil fuels. The net result is the current dog’s dinner of net zero in which emissions continue to rise and we face catastrophe while politicians blithely witter on about end of century temperatures targets. This current approach also means that geoengineering is almost inevitable. Because when, finally, the leaders of governments and corporations get it into their orthodox-economics-addled heads that we are facing not just a few points shaved off of GDP but actual near-term real-world disaster, then risk assessments will swing very quickly to deployment of SRM.

Before that moment, some of the world’s richest people will be staring at alarming asset deflation as a result of escalating climate impacts. Middle class people’s pensions will be evaporating. Politicians must do something! And so they may pull the geoengineering lever even sooner. They will do so with ‘a heavy heart’. Perhaps they will send some token disaster relief along with thoughts and prayers when some hapless community gets washed off the map as the result of a geoengineering-induced flash flood.

This will be the result of a continual series of decisions that prioritises the interests of a tiny fraction of humanity. It’s not inevitable. But if it is to be averted then those interests need to be challenged now.