Can geoengineering be eco-friendly?

At the 250th National Meeting of the American Chemical Society in August, a research team from George Washington University presented a new carbon nanofiber production process that uses the atmosphere as the source of carbon to make the nanofibers. Used on a large enough scale, they say, this could potentially reduce atmospheric carbon dioxide to pre-industrial levels in just a decade. In August a team at Lawrence Berkeley Laboratory also reported progress in capturing carbon dioxide using a catalytic molecular lattice, but they are being more modest about its potential. It was perhaps inevitable that sooner or later there would be a technology that could pull carbon dioxide out of the atmosphere on an industrial scale. At first sight this appears to be a miraculous solution to the problem of global warming. What could possibly go wrong?

Take the announcement at face value. Within ten years, the George Washington team suggest, this technology could bring down atmospheric carbon dioxide to pre-industrial levels. 

As a geoengineering initiative this would be a far more potent environmental intervention than the fossil fuel industry, since it would take it only ten years to reverse what it has taken well over 100 years of fossil fuel use to achieve. It sounds too good to be true, because surely it’s an overriding objective to bring down today's high carbon dioxide levels? 

The question that perhaps ought to be asked is what will happen, after only ten years, when the targeted low pre-industrial level is reached? If the production process carries on the carbon dioxide level will continue to drop, which as far as we know would risk turning global warming into global cooling (more on this below). As this point nears the inventors would ideally either stop further use of the technology, or bring it into balance with other sources and sinks of carbon dioxide. How easy is this likely to be?

Any company exploiting this production technology will presumably hope to fund itself by selling the carbon nanofibers. Indeed, this is the virtuous thing to do in a business civilisation – turn business into a force for good. So in ten years the owners of this technology will have an excellent money-making business, not to mention considerable environmental acclaim, and their investors may be reluctant to turn off the tap. They might even become climate-change-reversal-deniers, lobbying government to ignore the dangerously dropping levels of carbon dioxide. 

On the other hand, suppose the original stockholders are in fact remarkably enlightened, and decide to close down the business. What about copycat producers in, say, China? Will they show the same restraint? In short, what will happen when this technology is out of Pandora’s Box, and there is runaway carbon dioxide drawdown from the atmosphere? 

If too much carbon dioxide is going to make the climate hot, having too little will mean it’s going to get cold. We know about the long-run history of the world’s climate from deep polar ice cores. They warn us that the only thing stopping the planet from entering a new ice age is the raised emission of carbon dioxide and methane since the beginning of agriculture 8000 years ago. Drop below this level, and the next ice age will begin. 

We are currently at the top of the long-run climate cycle, in an interglacial or warm period. These periods are relatively short, lasting only ten to twenty thousand years, alternating with much longer glacial periods lasting around 100 thousand years. Most of the cycle is spent in ice-age conditions. The whole of recorded history, the rise of civilisation, has happened during the present warm period, the Holocene. By now, if we had not been inadvertently pumping up the levels of carbon dioxide, the average temperature would be heading down and a new ice age would be underway. 

In other words, the risk of any rapid carbon dioxide drawdown technology is that if it is too successful and has no braking mechanism, it will trigger a new ice age. At present, anyone who invents a geoengineering technology is free to deploy it if they can find the money. It is probably pointless to ask if this should be the case, since no one government has the global authority to regulate such things. Yet the following thought experiment is worthwhile: if this authority did exist, suppose it was used not to ban such technology but rather to build in safeguards. What would they be?

From an ecosystemic perspective the challenge is clear. The proposed technology is a one-way street. Assuming it’s possible to reach an appropriate level of carbon dioxide and bring the climate to a set point – an assumption that needs to be carefully examined – some additional mechanism would be needed to hold it there without overshooting. This calls for a homeostatic feedback circuit, like the one that keeps our body temperature at a steady level. The technology should respond to signals from the environment, and only draw in air from the atmosphere when the carbon dioxide concentration is above a certain level. This means it should be designed from the outset to accept an alternative source of carbon. What could that be?

One obvious answer is to use recycled carbon nanofibers. After ten years enough would have been produced to provide adequate volume for recycling. The existing nanofibers would create a reservoir of carbon that could be converted into new fibres at times when the atmospheric carbon dioxide was at a low enough level. In other words the technology should be designed at the outset with two modes – drawing carbon dioxide out of the atmosphere or operating as a closed loop and making use of the carbon previously extracted from the air in the form of recycled nanofibers.

The inventors of this technology are obviously concerned about the environment. But it takes more than pushing on a single ecological variable to make a technology that can qualify as ecologically benign and ‘ecosystemic’. Intervening safely and effectively in the global ecosystem requires a systemic approach, involving feedback pathways and balancing loops to regulate the technology. Ideally these would be baked into the engineering design and the business model rather than relying on the vagaries of government regulation.  

Why then do many geoengineering proposals have an overly narrow focus? Part of the explanation is the way environmental problems are communicated. Global warming is blamed on an excess of carbon dioxide without any reference to other systemic complexities. This leads inventors to focus exclusively on that one factor, often using the same industrial mass-production logic that caused the original problem. 

It is easy to communicate that carbon dioxide is a bad thing, and less easy to communicate that it is a complex systemic thing. To some extent, systemic logic can be simplified as being about loops. This is why the ecologically benign circular economy concept is based on closed loop material flows. Similarly, solutions to global warming could be imagined and designed as systemic loops. Global warming itself could be communicated as a breakdown of circularity. If this idea was taken on board, inventors would naturally focus on inventing inherently systemic solutions. 

The problem would-be geoengineers are trying to solve is an exponentially growing one-way flow of pollution or waste into a complex living system. Yet the proposed solutions often simply mirror the logic of the problem, involving a linear or one-way flow running in the opposite direction. This risks simply substituting one problem for another. 

A simple comparison would be between fairground carousels and seesaws. Geoengineering that uses industrial logic is like a seesaw on which counterbalance weights are being piled with no ability to take them off. Put on too many and the whole thing will tip over the other way. Closed loop design is like a carousel that can move endlessly without going too far in any direction. The ability to stay level is built in and as it rotates everything is continuously returned to its starting point. 

So, going back to the team at George Washington University, how might they reframe the design of their technology to make it ecosystemic? Their environmental objective at the moment appears to be to reduce atmospheric carbon dioxide as fast as possible. A reframed challenge might be: to produce carbon nanofibers as part of a closed loop of carbon, with the stock of atmospheric carbon forming part of the loop (the pump-priming part) and with the nanofibers acting as a balancing carbon storage reservoir, to be drawn on when the atmospheric carbon dioxide level is low.  

Something along these lines could be a template for geoengineering proposals in general, if geoengineering is going to be compatible with a future circular economy and not just be a risky extension of industrial era linear thinking.