[#8]Geo-Engineering 1: Cause vs Effect, or Hubris vs Necessity

[Excerpt from upcoming book — It’s Getting Hot in Here: Reflections of a climate hawk grappling with the inevitable]

Geo-engineering is hard to accept. It reeks of failure, panic, hubris. But we did fail — accepting that is the point of this book. And panic is a natural reaction to Bad Warming as the public demands solutions. Perhaps it’s the hubris that really irks here. To think we can safely engineer our planet when we failed to take care of it in the first place feels a bit like doubling down to make rent money at a crooked casino.

There are two ways to engineer the heat content of our biosphere: directly control global temperatures (target the effect) or reset carbon dioxide levels (hit the root cause). I predict we’ll try the former to give us time for the latter. Neither is a magic bullet.

Controlling global temperatures directly is the stuff of distopian science fiction: rogue governments put aerosols in the upper atmosphere to reflect sunlight; NASA puts mirrors in space that do the same; fleets of robot boats cruise the oceans to boil water and make clouds to reflect more sunlight — these ideas felt (and feel) absurd. Some have proposed an array of massive heat pumps to push atmospheric heat down into the oceans.

Once we’ve committed to controlling atmospheric temperatures there’s no turning back. I once compared it to putting a lid on a boiling pot of water. The lid initially keeps hot water from slopping over the edge, but as pressure builds it takes more and more force to keep it on. You can never stop or the thing explodes. It’s literally a pressure-cooker: that’s the first sort of geo-engineering to me — a risky, never-ending planet-wide effort to keep the lid on a boiling pot. I hate all these ideas, but absurd as they sound it’s inevitable we try at least one.

The easiest is aerosols in the upper atmosphere. It’s simple: we inject sulphur in commercial jet fuel. It’s cheap: any rogue billionaire, government or even airline could do it on their own. We know it works: in a way, we’re already doing it. When sulphur was regulated out of shipping fuel recently there was an immediate uptick in local heat variance over oceans. Alarmingly, there’s about a half degree C of global cooling due to particulates from coal. When we stop burning the stuff we’re due for a serious bump in warming (that’s partly why the 1.5C target is a pipe-dream).

So it’s easy, cheap and we know it works. What’s the problem? Unintended consequences. We’ve no idea how that cooling shift will manifest as local weather. When a massive monsoon hits Pakistan or Africa suffers an extra-fierce drought, who’s to say the aerosols aren’t at fault? How could we know otherwise? Who sues whom over what? The science needs to be refined so issues like governance, liability, regulatory frameworks — which feel hypothetical today — get resolved.

We’ll go this route when we panic — especially if Uncontrolled Warming starts to rear its head. As we approach tipping points to truly catastrophic outcomes, turning down the heat to give us some breathing room is the smart play whatever the unintended consequences. When everything is at stake, what’s looks crazy today seems reasonable. But regulating temperature — dealing with Bad Warming’s effects — is a stopgap to buy time to go after the root cause.

We need to reset atmospheric carbon levels, ideally to pre-industrial levels. This is NOT the same as reducing emissions, or getting to net zero, but implies massive negative emissions. Removing atmospheric carbon is accretive to achieving net zero. The right image is a bathtub. It’s full of historic emissions. They come from our emissions tap. Partly closing the tap is reducing emissions. Turning it off is net zero. Draining the bathtub is negative emissions — that’s geo-engineering.

This sort of geo-engineering feels (slightly) less hubristic. It’s more like a humble admission of error, an honest attempt to make amends to the earth. The industry term for sucking carbon out of the atmosphere is CDR: carbon dioxide removal. There are two ways to do it: hard and soft. Hard is brute force. We build a gargantuan system of industrial machinery to grab dilute carbon dioxide out of the air via a chemical reaction[1], compress it to a liquid, and stuff it down pipes underground. That’s DAC: direct air capture[2]. A softer, more subtle way leverages nature’s own machinery to get the same result. (I’ll cover nature-based capture in the next edition — spoiler alert: it comes out way on top).

How much do we need to capture? As much excess as we put up there! Assuming ghg levels rise to ~525 ppm by the end of the century, we’ll need to suck about half that back, or about 3 trillion tonnes (3000 GT) or about 30 GT/year for a century. How much will it cost? Optimistic estimates of $50–200/tonne[3] implies a total bill of ~$150–600 trillion. That’s 1–4% of global GDP — for a century. An awful lot of money. But we spend that much on wars, so it’s theoretically doable if climate risk is prioritized as a top global security threat.

But … it’s still absurd. Going brute force means building the single largest industry on earth, with zero economic upside. Demand for its output is entirely artificial — voluntary donations or government diktat and taxpayer money. It must be powered entirely by clean energy that could otherwise be used to de-carbon productive industries. Capturing each of those 3 trillion tonnes takes enough energy to run a North American home for a month. We are talking about building thousands upon thousands of huge carbon-sucking factories, that produce zero accretive or useful[4] economic output and use the energy equivalent of many multiples of existing global nuclear[5] capacity!

Crazy as it sounds, this is where we’re headed. We need to fix our mess, and once it’s clear civilization itself hangs in the balance we’ll be willing to pay anything. Not all of us have accepted it yet, and until we do, there’ll be limited economic support for an unproductive industrial project of this scale. It starts with expensive voluntary carbon reduction, bought as carbon credits by companies who justify the spend as marketing. It ends with a regulated economic system that produces the cash flow required to embark on such an ambitious project.

I want to yell from the rooftops: it’s so much cheaper not to pollute in the first place! It’s like eating fast food in the car, throwing all the garbage out the window, then paying people to walk down the highway and pick it up. You’d save a lot of money waiting to put that crap in the next garbage bin. Once dispersed, carbon dioxide is very expensive to gather. Fighting entropy is hard. Clean energy advocates have been arguing for years paying to accelerate clean energy deployment past market norms saves money. The cost of global DAC puts some context to those claims.

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[1]Typically via a solvent like aqueous alkaline solutions (NaOH, KOH), amines, amino acids or peptides. These chemicals grab the CO2, then it’s released by regenerating the solvent using high temperatures or some electrochemical push. It takes a lot of energy to push large volumes of air (to get at the low-concentration CO2) and to energize the regenerative step.

[2] This is not the same as CCS — carbon capture and storage. CCS (when it works) prevents carbon pollution from going up the stack. At best, it keeps atmospheric levels the same. CDR removes stuff already emitted.

[3]The lower end is the soft (natural systems) approach, the upper brute force.

[4] It takes about 1200 kwh to capture one tonne CO2 [MIT, Howard Herzog]. A barrel of oil releases 426 kg CO2, so it takes ~500 kwh to recapture its emissions. But that barrel’s energy, if used in combustion at 30% efficiency, is only 510 kwh. So it’s energy breakeven just to make that oil carbon neutral! Even if we assume a 2x decrease in energy consumption of DAC, it’s only 50% efficient … This does not include transport or sequestration.

[5] To capture 30 GT per year requires 30B*1200 kwh = 36 trillion kwh per year (w 2x efficiency call it 15T kwh/year). A nuke plant produces 8 B kwh/year. Hence we need 2000 nuclear plants to power this industry.