Geoengineering: now, with asteroids!

It’s very likely that stratospheric sulfate aerosols will be used for climate engineering within the next few decades. But why wouldn’t we use asteroid capture and mining for that? Also: Dyson Spheres!

Let’s being with a book recommendation: The Planet Remade: How Geoengineering Could Change The World by Oliver Morton. (Note: Part of this article is based on an earlier post on my weblog)

I would change the title of this book to “The Planet Remade: How Geoengineering Has Changed The World And Will Continue To Change It As Long As Humans Are Monkeying On It, In It, and Around It.” But I understand that might be a less catchy title.

Morton makes a distinction between ‘willful change’ and not: he needs to establish some boundaries for the discussion. It’s a reasonable distinction to make. But everything’s willful to a degree or another, is it not?

It’s pretty clear we’ve already created massive changes in the planet’s systems. We have altered its features, most obviously by redirecting rivers, creating dams, digging giant tunnels into mountains, covering hundreds of thousands of square miles with concrete, cement, asphalt and all kinds of other crazy stuff (like, say… putting golf courses in the middle of deserts), and (mostly for bad reasons) blowing up lots and lots of different places. We have pumped and continue to pump trillions of tons of gases and chemicals into the biosphere. Mining has gone from digging into the earth to simply blowing the top off mountains (literally) to get at the stuff inside.

Geoengineering is already happening, so how about we do it for something other than manufacturing complicated barbeque grills, phone cases and christmas tree decorations?

The book’s discussion on the transformation of the nitrogen cycle is particularly interesting and important, since this was a key factor in making Norman Borlaug’s high-yield dwarf “superwheat” a feasible crop at large scale (dwarf wheat consumes more nitrogen). Much is frequently said of Borlaug’s work and the Nobel prize he got for it (and with good reason) but less is known about the massive geoengineering activity that started before that work and made it possible.

Geoengineering will be a key element in reversing some of the effects of climate change, since it is pretty clear that “just” reducing emissions won’t cut it.

“Just sulfate it.”

If I had to bet on what will be one of the first methods for climate engineering that’s going to be used in the next few decades, I’d go for stratospheric sulfate aerosols — which the book covers well. Why? As The Dark Knight’s Joker in said of gasoline and dynamite: “They’re cheap!”

If none of the world powers is going to do it, any one of a number of other countries will eventually decide that it’s time to stop the ocean from erasing their coast sooner rather than later. The consequences of this could lead to (surprise!) war, perhaps even nuclear war, which Morton discusses as well. Nothing like some optimism about saving the planet sprinkled with apocalyptic thinking. Nuclear winter is also discussed in terms of its climate impact.

Near the end the book spends a good amount of time talking about asteroids, but not in the way I thought would be … kind of obvious. It focuses on asteroids as an Extinction Level Event. Dino-killer, etc. The point he makes is that the various ideas discussed around how to stop an asteroid from crashing to earth are in a way similar to the idea of using geoengineering to save us from a different kind of cataclysm.

This is an interesting argument but…


Asteroid Mining + Stratospheric Aerosols = Profit!

Fine… maybe not profit, just saving the world. My point is: what the book doesn’t discuss is the use of asteroids for geoengineering, and not as an argument for action.

One of my personal obsessions is the topic of asteroid mining.

Yes, within the next few decades we will begin mining asteroids, there’s no doubt in my mind about that.

And it seems inevitable to me that we’ll also be using some of the results of that for climate engineering via the stratosphere (and later to create massive structures in orbit around the planet).

Why? because the biggest cost in seeding the stratosphere is energy, specifically, the kinetic energy you need to spend to move millions of tons of what essentially is dust from the ground (where it is manufactured cheaply) to its stratospheric destination over 8–10 kilometers above the surface of the earth, depending on latitude.

I’d argue this cost is more of a logistical cost rather than a pure/absolute energy cost. How so? Let’s look at the first option for distribution: airplanes.


(Not the movie). Let’s say we are going to seed a million tons of sulfate aerosols into the stratosphere.

The energy required to lift a mass of a million tons of material to a height of 10,000 meters would be ~98.1 terajoules (give or take a Joule, E = m g h) = ~27 GWh (gigawatt-hour) = 27,000,000 kWh.

In the US, with average energy cost of 12c/kWh, just lifting the dust would cost at minimum 2.7 million dollars. Add to that the necessary costs for stamps, copy paper, printing receipts and office parties, copies of Microsoft Windows, safety goggles, and such, and the cost would rise by several million more. So round it up to 10.

10 MM USD = 1 million tons of material at stratospheric height.

Now, the Mount Pinatubo eruption in 1991 is estimated to have injected 20 million tons of sulfates and resulted in an estimated 0.5 C cooldown across the planet within a year. This cooldown dissipated as quickly as it arrived (at least in geological terms) so a long term geoengineering operation would require adding sulfates for several years, perhaps decades.

With this we could derive a “baseline cost” of 200 million dollars to make global temperatures drop half a degree centigrade within a year. Sounds cheap! We could have a 2x1 offer and make it an even degree cooler.

The energy transfer, sadly, is not “pure”, and so, therefore, neither is the cost. If you are spreading the material from, say, a plane, the weight of the plane, the fuel, transport to airfield form the factory and so forth also comes into play. The logistics chain and equipment required becomes really complicated, really fast. Not impossible by any means, just complicated and much more costly, running into billions. For a more precise and systematic (but way longer) analysis, please see Geoengineering Cost Analysis and Costs and economics of geoengineering.

Here’s where asteroids come into play. Because Earth is not the only source of material.


(Not the videogame). Using asteroids for this purpose seems to me like a perfect match. Any nasty by-products of the mining and manufacture remain in space, where hazardous chemical waste is not a problem since a lot of the stuff out there is already hazardous chemicals, plus no one can hear you scream.

Asteroids contain enough material to either obtain what you need directly or by synthesizing what you need using micro factories landed on the asteroid, or built (by other micro-factories landed on the asteroid!) for that purpose.

Fuel and Braking, Courtesy of Sir Isaac Newton

The energy required for the deployment of the material will be far lower (you’ll always need some amount of energy expenditure in the form of thrusters and the dispersion device), but you would be able to rely on gravity to do most of the work.

If the asteroid in question has been captured and placed in orbit around the earth, even better: instead of fighting gravity, we’d be using it to our advantage.

Most of the maneuvers involved in transferring material would rely on gravity assist rather than rockets (plus aerobraking for atmospheric reentry when needed) which makes them cheaper, and, something that is hardly ever mentioned, less prone to failure simply because there are fewer components in the system, particularly components of the very large, very explosive kind, like the Saturn V’s S-IC of the Space Shuttle’s SRBs.

Now that Dyson Spheres are a more widely discussed topic after we have found a candidate in our own neighborhood (KIC 8462852 FTW — only 1,480 light years away!) talking about these types of projects could sound to people more like science and less than science fiction. As a bonus, this gets us closer to a Type II civilization. In the Kardashev Scale this is “a stellar civilization — can harness the total energy of its planet’s parent star (the most popular hypothetical concept being the Dyson sphere — a device which would encompass the entire star and transfer its energy to the planet(s)). We’ll definitely need to throw a party when that happens.

Asteroid Mining is probably a required step in the evolution towards a Type II civilization, and it seems fitting that part of that could be healing the planet that was our early home as we venture towards others.

Can We Do It?

Our political process seems broken, and it seems we can’t agree on so many basic things, how could we possibly get any of this done?

Yes, this is one of those types of endeavors that we don’t seem to quite do so many of anymore: huge, ambitious, daring, world-changing. Not self-centered, on the pressing needs of today, but rather focused on creating more options for a better tomorrow.

Focusing on the needs of today is important. Focusing only on the needs of today is a catastrophic, civilization-ending miscalculation.

There’s reasons for optimism, though. First, there’s actually good progress being made: there’s Planetary Resources, Space X, Blue Origin, and others as well as all the people in university labs and government agencies.

Second, a more general observation: as a group, humans do get better at things. (Shocking, no?)

Humans evolved in an environment of food scarcity, and that meant that when there was food, you ate it. You ate all of it. If an two hours later you found more food, you’d eat that too, but that rarely happened if ever. This is stuff that is deeply wired into our most fundamental survival systems. My grandmother grew up in poverty, and often would have to choose between feeding herself or her brothers and sisters. When she was older, there was plenty of food, but there was no way you were getting up from her table if you hadn’t finished your portion.

So it was perhaps inevitable that when food became abundant many of us got fat. We are now going through the difficult process of jumping across eons of evolution and willing change — working at adjusting our habits.

Similarly, the information age has given us the gift of instant, universal communication and knowledge sharing, but it has also temporarily drowned us in a seemingly endless sea of irrelevant bullshit, paranoia, and fear.

But we are learning how to navigate it. We are! As the balance shifts we start looking further. It’s in our nature. We look for it, that something.

Something that literally makes you stand, look up at the sky, and wonder where we’re going next.