Sunday, April 04, 2021

Geoengineering the climate: The zombie idea that just won't die

Just when you think the last boomlet for geoengineering the climate has expended itself and we might be rid of any serious consideration of it as a strategy for addressing climate change, it rises zombie-like from the dead and starts roaming the Earth again.

The National Academy of Sciences (NAS) has recommended spending $100 to $200 million over the next five years to study the idea—its feasibility, possible unintended consequences, and an ethical framework for governing it.

The most important thing you need to know about geoengineering the climate is that we humans have probably been doing it since at least the dawn of agriculture. What we need now it seems is an intervention from TV talk show psychologist Dr. Phil to ask us his favorite question, "How's that working for you?"

We have certainly been doing geoengineering since the dawn of the industrial age which we know has stoked climate change through carbon emissions caused by the burning of fossil fuels; changes in land use (deforestation, primarily); modern agricultural practices (methane released by livestock fed on grains, for example); and industrial chemical releases, the most egregious of which is currently sulfur hexafluoride used in the utility industry as "a hugely effective insulating material for medium and high-voltage electrical installations." Sulfur hexafluoride is 16,300 times more potent than carbon dioxide over a 20-year time horizon and 23,900 times more potent over a 100-year horizon.

Now that's a feat of real geoengineering and the people who discovered sulfur hexafluoride in 1901 weren't even trying to affect the climate!

What I'm getting at is even more important than the unintended consequences mentioned in the NAS report above. "Unintended" in that case means we are actively looking for and evaluating such consequences. I'm more concerned about unanticipated consequences, that is, consequences we are completely blind to. That is, after all, what we are dealing with today, the massively negative unanticipated consequences of industrial society on the climate (and a lot of other natural systems).

What is it that makes us think we can anticipate the consequences of geoengineering the climate with enough precision that we won't make things worse than they already are? I am reminded of an observation often attributed to Albert Einstein: "The significant problems we face cannot be solved at the same level of thinking we were at when we created them." We have treated the building and governing of industrial society as engineering problems. We believe that if we just use the proper equations for building a skyscraper or managing the economy, we'll be all right.

If we treat climate change as simply an engineering problem, albeit on a large scale, we will be faced once again with the possibility of engineering failures on a planetary scale. Climate change is quintessentially a product of the way we think, the reductionist thinking we apply to practically everything we plan and execute in industrial society. We rarely, if ever, think about the consequences of our actions for the biosphere, the very envelope of life-sustaining processes that is our only home.

We generally act without reference to systemic effects which can amplify small changes radically. The small changes in the amount of carbon in the atmosphere cannot alone account for changes in the Earth's temperature. Instead, those small changes trap heat which warms water creating more water vapor which, as it turns out, is the biggest driver of climate change. The excess vapor wouldn't be in the atmosphere, however, were it not for the small additions to the carbon in the atmosphere brought on primarily through human activity.

Today, of course, we regard our carbon emissions as very large even though human-caused additions to the atmosphere are still counted in parts per million. We count those emissions as very large because their effects are very large.

If we set out on the path of geoengineering, we may face a host of unanticipated consequences that could be ruinous for some (and not others)—or ruinous for us all. I understand that the inability of our civilization to make any meaningful progress on addressing climate change is truly a crisis. But I do not believe we will address that crisis successfully by deploying strategies that use the same kind of thinking that got us here in the first place.

Kurt Cobb is a freelance writer and communications consultant who writes frequently about energy and environment. His work has appeared in The Christian Science Monitor, Resilience, Common Dreams, Naked Capitalism, Le Monde Diplomatique,, OilVoice, TalkMarkets,, Business Insider and many other places. He is the author of an oil-themed novel entitled Prelude and has a widely followed blog called Resource Insights. He is currently a fellow of the Arthur Morgan Institute for Community Solutions. He can be contacted at


Joe Clarkson said...

SF6 is a potent greenhouse gas, but the concentration in the atmosphere is only 10 parts per trillion. It has the same effect as 0.2 ppm of carbon dioxide, which is now roughly 415 ppm. I agree with your larger point that attempting geo-engineering of the climate is foolish, but pointing out that SF6 is about 20,000 times more potent as a greenhouse gas is just scaremongering. SF6 production is miniscule compared with CO2 and therefore has no chance of making a meaningful impact on climate.

ChemEng said...

The basic problem with geoengineering is that its use would be an admission of defeat with regards to programs such as ‘Net Zero by 2050’. Although the goals of such programs are probably unrealistic, at least let’s give them our best efforts before giving in.

Anonymous said...

Kurt - long time since we've differed to this extent.

1st, the widely adopted definition of geoengineering (by UK's equiv to 'Academy of Science) refers to "intentional large-scale intervention in the atmosphere" for human benefit. In this light, beside the three main proposals for the Planetary Albedo Restoration [PAR] mode of Geo-E (aka SRM), there are various proposals for the Carbon Recovery mode (aka CDR).

So does your opposition to Geo-E extend to getting CO2 back out of the atmosphere, or is that acceptable if carefully researched ? (One particularly bad method could in theory result in anoxic zones spreading across the oceans to cause the death of all marine life).

2nd, as we slide towards:
- the global dieback of productive forestry (on which our Carbon Recovery effort will largely depend);
- the onset of Serial Global Crop Failures (and their ruinous geopolitical consequences);
- and the eight Major Interactive Feedbacks accelerating their outputs to the extent of offsetting our efforts at GHG emissions control;
we drift directly towards the emergency use of the Geo-E option of Stratospheric Aerosols that mimics the global cooling achieved by Mt Pinatubo, which is the nearest we have to a well researched reliably benign and effective option. Its proponents hope to mitigate the disruption of the hydrocycle that it has been shown to risk.

So if we continued without proper stringent scientific research of better PAR options, is there a number of millions of deaths by famine that should be tolerated in your view before we deploy Stratospheric Aerosols ?

All the best,
Lewis Cleverdon

Teresa from Hershey said...

It would be easier, safer, cheaper, and probably more effective to plant millions of trees.

Anonymous said...

Teresa, the right form of sylviculture on a commensurate scale looks essential in my view, but, that's about 6 orders of magnitude more than 'millions' of trees, since it takes a million saplings to plant 400 hectares, which is only 1.54sq mls.

There is also the time factor to consider, since globally trees on average take in only ~5.0tC /ha /yr during their best growth-years, so even a billion hectares (of Native Coppice Forestry) would only take in ~5.0GtC/yr. To sequester that around 67% of the harvested carbon can be made into charcoal for plowing into farm soils as a permanent fertilizer called "Biochar" (which stays put at least for millennia).

The outcome is thus of ~3.3GtC/yr sequestered, but society is currently adding GHGs equivalent to about 14.5GtC/yr. This and perhaps some other Carbon Recovery techniques are very worthwhile, but I've yet to see how they could be more than a valuable contribution to a strategy that includes rapid global Emissions Control as well as eventual cooling via Planetary Albedo Restoration.


G Wang said...

QUOTE: ***But I do not believe we will address that crisis successfully by deploying strategies that use the same kind of thinking that got us here in the first place.***

The BEST way to address that crisis? Leave industrial civ behind.

Not that I expect it will happen. Through our conscious choice anyway.

Kurt Cobb said...

Thanks for all the thoughtful comments. I'll address two in detail:

Joe Clarkson is right to say that the contribution of sulfur hexafluoride to climate change is small. I use it as an egregious example of one of many industrial chemicals that together do have a discernible impact. We must count nitrous oxide among them as it comes chiefly from the application of nitrogen fertilizers as part of our industrial agriculture. Methane has both natural and man-made sources, but one can only count natural gas extraction as an industrial process, so I would include fugitive methane releases as an industrial contaminate of the atmosphere. My point was to ask this question: "What is this chemical doing in the atmosphere? Certainly, we didn't intend for it to be there." The answer, of course, is that we just didn't think about it. We kept to our reductionist ways without any systems thinking.

Lewis Cleverdon has noticed that I do not speak to specific climate geoengineering proposals. I suppose it might be possible to say that anything humans do that affects the climate is a type of geoengineering including agriculture and deforestation (as I indicated in my piece) as well as the reduction of carbon emissions and the deployment of wind and solar power to reduce or mitigate our contribution to climate change. My critique is, of course, focused on the conscious, planned intervention in the climate system with the specific intent to alter it in ways entirely apart from curtailing human activity which has altered it inadvertently in the past.

Lewis does mention one form of carbon sequestration--biochar--which I believe (if carefully regulated) could have a profound effect on reducing carbon levels while enriching our depleted soils (from which the carbon is being released by industrial agriculture techniques). If this is geoengineering, then I am fine with this type of geoengineering since it mimics age-old techniques used by pre-Columbian Amazonian civilization. (Yes, we now know the Amazon was home to large cities and advanced agriculture before Columbus arrived.)

Likewise, planting trees seems like a good idea though I believe Lewis is right in pointing out that it is unlikely to solve the problem by itself.

Many of the other ideas for extracting carbon from the atmosphere at scale require enormous amounts of energy. From where will that energy come? Fossil fuels still supply the lion's share of energy for everything we do. Building out new energy systems takes time and uses those same fuels to accomplish the build-out.

I do not think Lewis is being hyperbolic in his fears about the future. I share them. So, his concern about what we will do if those fears are realized is a legitimate question. But I would pose another question to Lewis: How many people must die from a geoengineering intervention, say, as a result of changing rain patterns, a failure of a monsoon, or its opposite, overwhelming flooding, which can just as easily spell doom for millions--before we discontinue that intervention? And, how will we even judge whether our intervention is the cause? Will those who are profiting from the intervention--either by providing the infrastructure and inputs for it or by getting the benefits of extra but not excessive rainfall in areas previously marginal for farming--will they be willing to admit such failures? Or will they insist that those failures have nothing to do with the intervention?

And, I certain I don't need to remind Lewis, that simply lowering the Earth's average temperature by blocking out some of the sunlight will do absolutely nothing to address the problem of ocean acidification, which threatens much of the food chain.

I acknowledge that we are in a tough situation. I am still convinced that engaging in giant geoengineering projects is likely enough to create catastrophic consequences that are not foreseen that we should look elsewhere for ways to address climate change.

Anonymous said...

Kurt –

I'm intrigued to see that the question you chose to put to me has a ‘best answer’ that is the same as for mine to you :
- that we should urgently undertake all commensurate action to avoid ever being faced with such an appalling choice.

To this end, it is worth noting that the Stratospheric Aerosols [SA] option of cooling by Planetary Albedo Restoration [PAR] has been promoted among US scientists as the leading choice for research, while other options have more support elsewhere.

This matters because, as you say, we should look elsewhere than giant projects that are likely to cause unforeseen catastrophic consequences. One of Britain's climate scientists, Prof. Piers Forster of Leeds University, wrote an article in "The Bulletin" about the need of any PAR option having 10yrs of stringent scientific research and field trials before its utility could be assessed. Given that only one option can sensibly be trialled at a time, the present focus should thus be on agreeing criteria that will identify the most promising candidate for a 10yr international research program.

An option known as "Marine Cloud Brightening" is worth considering in this regard for its exemplary characteristics. It entails the lofting of a seawater-mist to about 3,000ft from around 1,200 dispersed wind-powered ocean catamarans, where its evaporation leaves miniscule sea-salt crystals to act as nuclei for unusually small cloud droplets, which in turn form unusually bright white clouds that reflect solar heat back out to space.

With clouds’ average lifespan being nine days before raining out or dissipating, their effect can mostly be halted within nine days should eventual sea-trials show some untoward impact; (the control period for the SA option is of two years before it rains out). The locations of the mist-lofting vessels can be selected to avoid any mal-effects on land while also, at best, focussing the cooling effects where they are most needed (e.g. halting the Artic sea-ice Albedo-Loss Feedback). By contrast, the Stratospheric Aerosols simply spread around the planet as a veil that is maintained by a fleet of large tanker aircraft routinely resupplying them.

Global Emissions Control by technical and behavioural change is the leading priority, but even with the temporary Covid cut of emissions, the US output is only a few percent below the 1990 baseline level (that Bush reneged on). What faith people have in achieving a global cut of around 50% by 2030 - which is required to have a 2-in-3 chance of staying below 1.5C - is their own affair. However, given the stakes in terms of potential suffering "just hoping for the best" is not an ethical option.

It was seen in the Paris Accord that Carbon Recovery will be needed on a large scale to meet the Net Zero emissions by 2050, but it is quite clear that significantly reducing airborne CO2 from its future peak back towards 280ppmv will be a slow process over many decades, followed by yet more decades of time-lag on the cooling effect being manifest.

With both Emissions Control and Carbon Recovery thus being "necessary but not sufficient" the requisite complement is of global cooling by a reliably benign and effective means of Planetary Albedo Restoration. Having studied the options for over 25 years I've not found any choices outside of these three strategies. Deficient action on any one of them undermines a successful outcome, and it should be understood that time is very short.

There is a steadily closing window of opportunity for research and deployments of all three strategies before ruinous impacts accelerate the decline of society's ability to respond - or even to understand the ongoing societal fragmentation. We cannot afford to fail to research crucial options simply for fear of scientists getting them wrong: the only sustainable choice is to try to ensure the effectiveness of that scientific research of reliable mitigation techniques.

All the best,