Audacity and Folly

"With great power comes great responsibility." We can't act responsibly if we refuse to acknowledge how powerful we are.

In this current moment—late 2024—I define audacity this way:

Audacity means admitting how powerful we really are. It means we’re willing to use proportional force to push back against the existential threats to our world.

And I define folly like this:

Folly means unleashing forces we can’t control because we don’t know, or refuse to admit, the power we have to make things better—but also to make them much, much worse.

With that in mind, let’s look at two projects we might use to save the world from the dire impacts of excess greenhouse gases in our atmosphere. Both projects are based on an understanding of just how much power the human species now commands. Is one of these folly and the other audacious? Or are both follies? Or audacious designs?

Accelerating Accelerated Weathering

This year we’re on track to pump an additional 37.4 billion tonnes of CO2 into Earth’s atmosphere. At the same time we are supposed to be decarbonizing; it’s true that renewables are eating fossil fuels’ lunch when it comes to price, and oil and coal’s days are numbered. But we still haven’t hit peak emissions, apparently, and though I expect that to happen very soon, our emissions have to be strongly negative for the next couple of decades for us to dodge the bullet of extreme climate catastrophe.

In practical terms, this means we should be removing 37.4 billion tonnes of carbon from the atmosphere this year. And next year. And the year after that…

Technology exists to do this. The umbrella term is Direct Air Capture (DAC). Generally, DAC systems are an industrial process run in reverse, using immense amounts of power and machinery to produce a tiny trickle of carbon dioxide. This is because while there are over a hundred gigatonnes of extra CO2 up there, it’s incredibly diffuse—measured in parts per million. Filtering this takes serious work; one estimate puts the energy cost at a megawatt per tonne.

A Carbon Air Capture plant. Photo: Climeworks/Dunlop

This will not scale.

A little math tells us that offsetting the world’s annual emissions this way would require 37 quadrillion watts of extra energy production. Per year.

This is why the scientific community is so insistent that we not put the stuff up there in the first place. It’s a hell of a lot cheaper to kick our oil addiction than to treat the symptoms.

Assuming that the vast Titanic of oil, coal, and gas production cannot be turned before hitting the metaphorical iceberg, what are we to do? Well, there are alternatives that use Earth’s natural systems to our advantage, notably ocean fertilization and enhanced weathering. Ocean fertilization has been tested, and even done (with controversial results). In the Haida experiment, 120 tonnes of iron dumped into the North Pacific resulted in a 35,000 square-kilometer plankton bloom that lasted months. The plankton, in turn, pulled CO2 out of the air to feed itself, then when it died much of it fell to the ocean floor as ‘marine snow’ taking the carbon with it. So this method might work.

A closely related method is accelerated weathering. It’s less controversial because in this case, we just give farmers some rock dust to scatter on their fields. The dust acts as a natural fertilizer and also absorbs CO2, so it’s a win-win. And there’s plenty of feedstock for such an industry, in the form of mine tailings. These are available nearly everywhere on the planet.

Still, the last estimate I’ve seen was that you’d need to scatter 50 tonnes of rock powder per hectare of farmland to make a difference. For a large farm, that’s a hell of a lot of rock. It’s still an attractive option because it doesn’t demand a huge new industrial infrastructure. It uses what we’ve already got.

But are either of these proposals audacious in the sense I’m using here? That is to say, are either of them truly ambitious? Are either of them plans that enable us to act at the scale of the problem? Remember, we need to not just eliminate the production of 37.4 billion tonnes of gas per year; we have to also draw down an equivalent amount.

Moving Mountains

The Mt. Pinatubo eruption of 1991 sent ten cubic kilometers of ash, dust, and gas into the upper atmosphere, causing the brief equivalent of a nuclear winter due to seventeen million tonnes of SO2 forming a temporary sunshield around the planet. Locally, the impact was cataclysmic. Globally, the volcanic ash served as a significant source of natural fertilization.

You can think of accelerated weathering using mine tailings as an extremely slow, labour, machine- and energy-intensive version of the same process. Granted the size of the problem and the timetable we’re on to fix it, ocean fertilization and accelerated weathering both still face a significant scaling problem. Basically, we have to build a whole new industrial infrastructure to offset the problems caused by the one we already have.

But what if there were an easier way? A much, much easier way? A way of mimicking the effects of a Mt. Pinatubo explosion every year or so, more or less for free?

Well, my friend, let me introduce you to Project Plowshare—the US’s investigation into the peaceful use of nuclear explosives.

Why employ thousands of workers and spend years tearing up a landscape with expensive earth-moving equipment to dig a canal, when you can just lay down a daisy-chain of buried nukes and excavate the entire thing in ten minutes? The PanAtomic Canal was planned for Nicaragua, but strangely, never made. Other proposals were actually tested; according to Wikipedia, the largest test was

“104 kilotons on July 6, 1962, at the north end of Yucca Flats, within the Atomic Energy Commission's Nevada Test Site (NTS) in southern Nevada. The shot, ‘Sedan’, displaced more than 12 million short tons (11,000 million kilograms) of soil and resulted in a radioactive cloud that rose to an altitude of 12,000 ft (3.7 km).”

Two months later, I would be born, a few hundred miles Northeast of the area. I wonder what tales the isotopes in my bones could tell?

Interesting that a single detonation moved eleven million tonnes of material. If they’d set off the blast in the middle of a basalt rock formation, they would have unwittingly accomplished accelerated weathering. Shame about the fallout, of course...

Kinda makes one daydream, though. What if you could set off carefully tuned blasts in remote areas that didn’t release any fallout at all, while pumping millions of tonnes of SO2 into the stratosphere? Or if you blew the same mass of rock dust across a continent or ocean? Widely dispersed, of course, and mimicking natural processes that have gone on since before life existed?

You could in fact move a lot of basalt dust into the upper atmosphere while releasing little or no radiation. Key to this process is that the explosion happens deep underground and the cavity so created collapses in on itself, trapping the radioactivity inside. There are hundreds of these scattered across the United States and central Asia. So far, there is no evidence that any have resulted in groundwater or other pollution.

Numerous experiments to achieve a variety of effects were done in the 1950s and 60s. Project Plumbbob, for example, consisted of 29 nuclear explosions on American soil. One underground shot, Pascal-A, accidentally released 50,000 times more energy than expected, resulting in a giant column of radioactive fire. Not ideal, so for Pascal-B the scientific team welded a one-ton metal plate over the borehole. As Wikipedia puts it, “When Pascal-B was detonated, the blast went straight up the test shaft, launching the cap into the atmosphere. The plate was never found.” Scientists believe compression heating caused it to vaporize as it sped through the atmosphere at six times orbital escape velocity.

That metal plate is important because it shows that we can use nuclear explosives as a launch system. You could put much more than a manhole cover into orbit this way; the largest system contemplated to date would use a ten-megatonne bomb buried deep in a subterranean salt formation to orbit 280,000 tonnes of cargo, intact and fallout-free. Said cargo could not include human beings because the acceleration would be about 8,000 gees, but military equipment is regularly built to withstand such forces.

I used this idea in one of my Gennady Malianov stories, “Laika’s Ghost,” which is set in near-future Kazakhstan.

We know a lot about tuning the effects of nuclear explosions and have a lot of experience with keeping the radiation underground. We could launch a complete orbital sunshade with four or five such detonations (I call this use of the tech the Verne Gun). But, instead of putting a quarter-million tonnes of intact cargo into orbit, we could loft several million tonnes of pulverized basalt and SO2 aerosols into the stratosphere. Basically, Pinatubo in a can. The best part is, we already have the nukes. They’re arguably more dangerous if kept in our arsenals, so we could remove them from play while positively impacting the biosphere. A blast or two a year, carried out over several decades, might be sufficient to remove all the excess carbon, and decisively reverse climate change.

This is thinking at the scale of the problem.

But is it audacity, or folly? (Or simple insanity?) Nuking the world to save it is definitely a blunt-instrument kind of approach. Each shot would have regional effects at least, and probably global ones. Even with our prior experience from Pinatubo and similar blasts such as Mount St. Helens, it would be impossible to anticipate all the knock-on effects of this scale of geoengineering. As I’ve argued elsewhere, the best we could probably do is base our moral calculus on whether this program would add more energy to the climate system, or remove it. (It would be designed to do the latter.)

Since we already have the nukes, it would essentially cost nothing. Compare that price with the vast industrial system needed to remove the CO2 using DAC machines, or the $3 trillion price (in early 2000s US launch-cost dollars) of an orbital sunshade using conventional rockets. Nuclear Acclerated Weathering (NAW) could also be undertaken by a single state actor—any member of the Nuclear Club could do it without asking permission from the others.

Here, of course, the violation of non-proliferation treaties (including the test-ban treaty) and the whole issue of already being within a hair’s distance of a nuclear war… well, they complicate matters. Maybe we have to admit that while NAW might give us the power to make the world better, if something goes wrong it could make things much, much worse.

Rethinking Wind Power

Above I said that conventional DAC will not scale. This assumes it is built as a consumer of power, metals and other materials, land, and human resources. The NAW approach dispenses with essentially all of these but at the cost of being, well, terrifying. As Harry Potter’s wand-maker said of Voldemort, “terrible… but great.” Or in this case, great but terrible.

What if there were less extreme ways to scale DAC? Ideally, the industrial system that supports CAC should itself be carbon-negative and not add significantly to our industrial, mining, and transportation costs. If you think about DAC in terms of how it integrates with our planetary (not just industrial/economic) systems, the whole equation becomes about negatives. It should be material-negative, power-negative, ecologically neutral, or regenerative, etc. Ocean fertilization does a great job on nearly all these counts, but it’s tricky to get it right. It’s basically a way of gaming oceanic ecologies, with all the potential hazards that implies.

Sticking with what we know how to do—building machines on land—are there other ways to scale DAC?

Let’s design one.

First, it has to be able to operate on immense quantities of air. It has to equal ocean fertilization’s thousands of square kilometers of surface area in contact with the atmosphere. Getting this air in contact with whatever sorbent we use to remove the CO2 can’t require any extra energy. With ocean fertilization, that part of the process is free. Can we do one better, and actually produce energy while removing the carbon?

This brings us to the idea of building carbon-negative power plants. Imagine our renewable energy system involving solar power, hydroelectricity, and something like wind power, but wind power where all that moving air is captured momentarily, and the CO2 sucked out of it. The idea of bolting a giant DAC device onto every windmill in the world is ridiculous, but there’s another wind technology that might do the trick. It’s called the solar updraft tower.

A solar updraft tower, viewed through the plexiglass collector roof. Image courtesy of Wikipedia.

A large tower is surrounded by an area of land roofed over with plexiglass to capture heat. Air flows in and up the stack due to convection. If you place wind turbines in apertures at the bottom of the stack, they will generate power from the incoming air.

The attraction of updraft towers as power plants is that they harvest the difference between the air temperature above and under the collector, not the absolute temperature. That means that such a stack will continue to operate on a -30C day in Siberia. Their downside is the size of the greenhouse roofing that surrounds the tower; a 100 MW plant would require a kilometer-high tower and a greenhouse of 20 square kilometres. I think the size of the greenhouse could be significantly reduced or even eliminated by using geothermal energy to heat the air inside the tower. Something like an Eavor loop could be used.

For our purposes, the size and low relative efficiency of the system are less important than the fact that is concentrates the incoming air. This gives us an opportunity to pass all of that air through sorbent filters. The latest breakthrough in CO2 absorbing materials, a substance called COF-999, still works after thousands of cycles, absorbs CO2 directly from the air at moderate temperatures, and releases it again when heated to 60C.

Imagine, therefore, a 100 MW solar updraft power plant with a COF-999 powder shower inside the stack. The powder absorbs CO2 as it falls, and when it reaches the bottom it’s conveyed to a regenerator that warms it slightly and captures the carbon dioxide. Then it’s reused. For a stack with a height of a kilometer or more and a diameter of 100 meters, you’d get a very large, constant, predictable and reliable flow of air that’s also contained; if the COF-999 grains are the right size and mass, few if any will be carried up the stack. If you configure the parameters right, none of it should be lost.

Using this design, we’re producing electricity while capturing carbon. The lingering question is, what to do with that carbon?

The solution I proposed in my short story, “Kheldyu,” is fracking. —More specifically, that we build many of these towers atop or near major basalt formations such as Siberia’s Putorana Plateau or the Deccan Traps in India. Fracking is used to create deep, extensive cracks in the basalt. When you pump carbonated water through those cracks, it turns into limestone.

We’d still need to build hundreds or thousands of such collectors and frack an unbelievable amount of subterranean rock to permanently requestor the CO2 this way. There are other subsurface sinks available; the basalt is merely the most permanent solution. In any case, the idea is simple: transition the current wind-power sector of the renewables industry to the combined power-generation and carbon-capture cycle possible with updraft towers. Not carbon-neutral, but carbon-negative power production on a global scale. Who knows? Maybe it’ll be able to scale to gigatonnes of drawdown.

So, what do you think? Is this idea audacious, or folly? It would involve roofing over a ridiculous amount of land if we go with the original design. That and the material costs are bound to have an environmental impact, as will pushing warm air from the ground into the upper atmosphere. But will that be greater, or less than alternative proposals?

The Audacious and the Batshit-Crazy

I’m not an engineer, so I have no idea whether either of these approaches would work. All I’m doing is indicating the scale at which we will have to work in the coming years—and I want to point out that humanity has the ability to operate at that scale.

Global temperature increases past 1.5C are only locked in if we assume that our response will not be equal to the problem. In other words, they assume a business-as-usual world, or one that eschews perfectly possible solutions simply because they are too audacious. Audacity always looks like folly from the outside; just remember that only a few weeks ago, SpaceX plucked a descending rocket the size of a twenty-story building out of the air, on their first attempt. It’s safe to say that most of the world thought that idea was batshit-crazy.

Bearing in mind that folly as I’ve defined it means not thinking about possible unanticipated consequences, what could we do if we were willing to embrace responsible audacity as a principle? Daring, but calculated daring where we act on the scale of the planet’s whole geophysical system, but if we fail, we don’t do any damage to it?

Is such action even possible? The two proposals here are deliberately extreme and are intended to exhibit both audacity and folly. But there are other approaches that could work on the scale we need, without the danger.

Think about the possibilities. And, so you don’t think I’m batshit-crazy myself, I won’t mention the little thought I had the other day, about using lunar mass-drivers to send a constant stream of basalt pebbles from the moon to Earth, where they’d heat up on reentry and absorb CO2 before dispersing as dust onto the land as fertilizer, and the ocean to rebalance its PH…

Naw. You’d never buy it, so we won’t even go there.

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