Shrinking the economy won't save the planet
vox.com
vox.com
Of course setting "shrinking the economy" as a goal isn't going to do much good. But "shrinking parts of the economy" might be necessary for a safe and healthy future. And whether the parts that don't need to be shrunk will still provide enough growth to end up with overall economic growth is hard to say (i.e. a safe and healthy future might require some sacrifices compared to the status quo).
Oversimplifying, growth can come from increasing the resources you use or the efficiency with which you use them. The former might not be something that we can keep doing at the current rate (and we might need to reduce some resource usage). The latter is pretty much a pure win.
Similarly, aggregate growth can come from hypergrowth in a small part of an otherwise stagnant population. And aggregate degrowth can come from modest growth in part of the population and shrinkage in another part. So just setting "aggregate growth" as your target is just as naive as setting "shrinking the economy" as a goal as it might not have the results we collectively want.
I think it should be possible to radically simplify taxation and law, with the goal of maximizing productivity and minimizing parasitism. The economy would shrink in numbers, but quality of life should generally improve.
Bonus points if population growth is not encouraged, but is allowed to find a lower equilibrium. The global economy shouldn't work like a Ponzi scheme.
GDP grows even if someone profits while producing sewage, cause someone else profits from clean up. If you call both Growth naturally DeGrowth doesn't make sense.
Take the Attention Economy which is HN is a micro example off. People's finite Attention is being pulled and pushed here and there, traded, captured or stolen. But the only thing that get measured is Growth in views or ycombinators net worth.
The first economist says to the other “I’ll pay you $100 to eat that pile of shit.” The second economist takes the $100 and eats the pile of shit.
They continue walking until they come across a second pile of shit. The second economist turns to the first and says “I’ll pay you $100 to eat that pile of shit.” The first economist takes the $100 and eats a pile of shit.
Walking a little more, the first economist looks at the second and says, "You know, I gave you $100 to eat shit, then you gave me back the same $100 to eat shit. I can't help but feel like we both just ate shit for nothing."
"That's not true", responded the second economist. "We increased the GDP by $200!"
https://www.reddit.com/r/Jokes/comments/qp49wz/two_economist...
Especially today when our biggest problems are the result of flagrant consumption and pollution on mass scale I think it's time to get into the nuances of how we supply ourselves with the good life without dissipating so much energy.
In order to measure "progress" you have to determine what is good, which is an open-ended question that increases in difficulty as one's intelligence grows (so AI cannot help answer it no matter how powerful they are, and GAIs will be stuck in the same boat as we.)
In the wise words of the great philosopher Douglas Adams:
> The History of every major Galactic Civilization tends to pass through three distinct and recognizable phases, those of Survival, Inquiry and Sophistication, otherwise known as the How, Why, and Where phases. For instance, the first phase is characterized by the question 'How can we eat?' the second by the question 'Why do we eat?' and the third by the question 'Where shall we have lunch?'
The relationship is still positive, because of Jevons Paradox. No matter how you see it, even if there are bad diminishing returns to using additional energy, we can find additional useful things to do with it (new ways of recycling, terraforming, high-energy synthesis, etc.)
> In order to measure "progress" you have to determine what is good, which is an open-ended question that increases in difficulty as one's intelligence grows
Reducing suffering is probably the only universal good that I can think of, but we haven't even managed to come close to making it our priority. So until we focus on that, it's a good goal.
The best way to reduce suffering is through good healthcare and keeping a working social contract/order.
> we can find additional useful things to do with it
Useful for what purpose?
> Reducing suffering
Yes and no. Existence is suffering (you are already in the Torment Nexus), Gurdjieff spoke of the importance of "conscious suffering" but that's not something I want to get into here, today.
In any event, the best way to reduce suffering is to touch Ice Nine to your tongue, but where's the fun in that?
Once all the suffering is reduced what then?
(Sorry if I seem salty or sassy, I'm really just here for interesting and contrsuctive discussion, I swear.)
Replacing other processes. If something can be done for very cheap, we find new uses for it. Any economic activity can be done 100 different ways. If something becomes absurdly cheap, we start using that for a LOT of things it wasn't used for before.
For example, construction used to have great problems securing suitable building materials, but had great quantities of labor available. Hence, everything was custom. The name of the game was to use every piece of wood, every stone, every last bit of building material that was available in construction.
An extreme example is that in order to keep medieval staircases clean and maintained, they were taken apart twice yearly, the individual pieces of wood cleaned, and the stairs reassembled after cleaning. Labor was worthless, so why not?
Today, building materials are very cheap compared to labor. So we have extremes like prefab homes, but generally we use large amounts of building materials just to avoid even small amounts of labor.
Today, we replace stairs entirely to avoid maintaining the wood they're made of. Especially if it doesn't have to look good. Just buy a premade stair and throw the old one out.
Science and capitalism have delivered technology and wealth, not evenly distributed, yes, but considered as a species we have won history.
The goal is not to rearrange atoms until the Earth glows like a lightbulb from our waste heat. Take the long view (and "long" here means a handful of centuries[1]) and lift your sights.
[1] https://dothemath.ucsd.edu/2012/04/economist-meets-physicist...
But in practice, it's never the case. Having energy available to consume always increases your quality of life, because it opens doors to make things better. Energy gives you freedom. Freedom not only to simply consume more things that are good (e.g., turning the AC on for longer to be comfortable for longer), but also freedom to improve the baseline (e.g. being able to focus and invent a more efficient heat pump, because you're at a comfortable temperature).
To bring this freedom into existence you must have more energy. You cannot make something from nothing.
I'm not so sure about that. Let's say humanity finds a way to build a sophisticated torment nexus and the infrastructure to power it. Then, one day a way is found to make it 5 times more energy efficient. As a result, we will have 5 torment nexuses (nexi?), not less energy consumption.
No. I decline to say that at this time. Thank you.
(I keep a little pickled Roko's basilisk in a jar on my bookshelf. I sometimes take it down and shake it at errant logicians to tease them. I know I shouldn't but it's just so funny.)
They say that degrowth ideas would do "approximately nothing," but then their own article they link to states that "a shift toward plant-rich diets would do more than any other single change" to reduce emissions. They bash on eating local, but the academic paper they cite concludes "eating locally grown fruits and vegetables may be an effective strategy to meaningfully reduce food system GHGEs from transportation."
That's a great question. In my mind the great question. I have not encountered much degrowth sentiment online, it seems largely to be anti-growth-at-all-costs sentiment (the former of the two questions). The article appears to assume and argue against the latter.
See this podcast: https://techwontsave.us/episode/226_how_degrowth_will_reshap...
Here are two that I'm aware of: https://techwontsave.us/episode/198_how_effective_accelerati... https://techwontsave.us/episode/138_dont_fall_for_the_longte...
Most importantly degrowth is a loosing position in the popularity contest, that is democracy.
Selling carbon net neutral to negative ways of hedonism are the only way out.
I don’t follow the logic of the comment you’re replying to that degrowth would be a hard sell to a democracy, but reducing comfort and pleasure wouldn’t.
I don’t get how the degrowth movement can seriously argue that blocking that sort of progress would help the planet.
Instead, we should price in environmental externalities whenever possible.
E.g., want to manufacture plastic? Great. Recycle at least as much post consumer waste into feedstock equivalent to what you shipped, and also use atmospheric carbon capture to bring your net co2 emissions to zero, pay to clean up the air pollution, etc.
Of course, doing that would create GDP growth, and also require a growth in our energy supply.
This is in fact very commonly not the case, to the point that its a standalone concept in Economics called Jevons Paradox
It's funny to think of applying degrowth to past environmental problems. Let's imagine it's 1900 and we are concerned about the sustainability of whale hunting, would degrowing the world's economy be the right approach then? Maybe that is too extreme, what about ozone depletion 50 years ago? Would strangling economic development & technological innovation back then lead to a desirable future?
b) Look at a country like Norway. One of the wealthiest countries in the world (due to oil!) and they invest heavily in renewable energy and have the highest percentage of electric new car sales in the world.
b) At 12.6 tCO2eq/cap/year [0] I would not call this a success.
[0] https://edgar.jrc.ec.europa.eu/report_2023?vis=ghgpop#emissi...
0: https://fair.org/home/comcast-owned-vox-explains-the-great-d...
1: https://www.google.com/search?q=citations+needed+vox+site%3A...
A lot of people seem confused about "degrowth". (In quotes because it's a terrible neologism.)
Look, people, degrowth is going to happen.
It's not optional.
We overshot basic physical realities and a "correction" is coming.
The question is not whether we drastically change our economic and industrial systems, because that's going to happen no matter what, the question is how to soften the disasters so that billions of people don't die in the next century or so.
Just to hammer this home: things will change, because Nature will change them for us. We can try to mitigate the worst of it, but we will have to scramble.
The good news is that we know what to do and how to do it. We could fix things overnight (well, within a year or three) if we really put our minds to it, because we already have all the solutions (most of them were worked out in the 1970's!)
The debate about degrowth is not whether or not to do it, the debate is whether to cushion the blow or just run off the cliff.
Interesting choice of headline for the article. Maybe a better one would be "Metatudy notes degrowth studies' methodologies lacking."
Simply making people poor to cut down on 5% of emissions is just like banning plastic straws but allowing plastic cups.
Realizing as well that constant economic growth is impossible in the long term is required so we start figuring out a more sustainable system.
I'm pretty sure quality of life can be improved even if the GDP shrinks, but it needs to be put as a primary target. At the same time, as an EU citized, the fact that shipping a product from the Netherlands is twice as expensive as a product with free shipping from Temu means that we've got low hanging fruits that can be instantly tackled, but nobody is interested in cost/benefit analysis but only in optics of elections.
I've come to the same conclusion as the Vox article. I haven't found any compelling argument for how or why degrowth specifically would work.
Sure, I think it's toxic that individuals and corporations pursue growth at all costs, but currency is fundamentally a tool created to resolve debts and for that to work effectively must come with some incentives for allocation and payback.
Capitalism has brought the entire world out of poverty and enabled massive innovation at a global scale before most modern technology as we know it. It's the most efficient way to allocate needed resources as far as I can tell.
What I do think is urgently needed are 2 things:
1. Some way to incentivize local spending over global spending, and it's probably not tariffs due to easy loopholes and negative externalities. People have started to do this of their own accord because we can sense it is right and more just.
2. Find better, more general ways to encourage competition and prevent anticompetitive behavior in markets. Everyone here knows how much more efficient small groups of people can be relative to large organizations. How can we make anticompetitive behavior and market dominance harder in the general sense?
There aren't easy answers to these two problems, but it sure as hell isn't total deregulation with laissez-faire capitalism and it sure as hell isn't centralized planned economies and communism. It's obviously somewhere in between.
You can almost certainly solve climate change with degrowth, the plantet can probably handle ten billion people living stone age lifestyles, it is just a question of how much we have to give up. But the not really part is the important one, you are not going to convince people to reduce their living standards significantly. If the required amount of degrowth means going back to the living standard from a couple of decades ago or more, that is not going to happen before the surface of the Earth is a deserted wasteland and people really feel the need.
I guess the best you can do is maintaining the current living standard and put future growth into making that living standard less environmental impactful instead of further raising the living standard.
The proof of this is North Korea, which is broadly in the middle of major ecological collapse because it's farming doesn't work and the people have essentially stripped the land bear trying to gather enough food to survive.
From a different angle, Wikipedia says there are about 1.4 billion hectares of arable land and the best number I could quickly find is that one needs one to two hectares per person without modern fertilizers, that would imply a limit of only about a billion people.
[1] https://en.wikipedia.org/wiki/Lists_of_mammals_by_population
>Livestock make up 62% of the world’s mammal biomass; humans account for 34%; and wild mammals are just 4%.
Not sure if that’s true. The claim is that wealth inequality and standards of living are not distributed evenly. A very small percentage of people on Earth emit much more carbon than the rest. Enough of a difference, perhaps, that the argument that we’d all be living in stone huts is a bit ridiculous if we were to focus on degrowth.
What I find hard to digest about all of this is that the foundations of economics is based on a lot of shady hand-waving and pontificating. How we base our society and planning for our future on such a weak discipline is tiring.
One would really have to carefully analyze what you can fit into the available footprint with current technology. Maybe you only get two plane trips during your lifetime, that is one of the first things that comes to mind that people did a lot less in the past, travelling. But the would of course cause ripple effects and it could be really hard to predict the effects.
But the vast gulf of consumption between a typical upper class North American family outputs vastly more carbon than a typical family in Pakistan or Nairobi that there is probably a lot of wiggle room to plan a more even distribution of wealth. And such redistribution may not make the 0.01% much richer but doesn’t it seem possible that it could also have the effect of slowing down our carbon emissions as well as keeping up the positive trends of reducing global poverty?
Next I guess you have to assume that everyone in the world raises its living standard to the highest living standard in the world, people will not accept to permanently have a lower living standard than others. Essentially divide the available resources by the number of all humans, that is what you have to work with, people currently below that will eventually demand their fair share.
And thinking about it some more, do we even have any footprint to divide up? There are, as far as I know, no fast natural carbon sinks, so we can not emit any carbon dioxide at all without raising atmospheric carbon levels.
We all know what the solution to that has to be. What does a world without fossil fuel use look like? How do we maintain healthy economic indicators in the current modern understanding without them?
The amount of economic advantage fossil-fuel consumption gives people over people who don't seems quite large.
I'm not certain degrowth is the answer but I don't think it's complete non-sense either. We're not dealing with a zero-sum game here but it doesn't seem likely that our current course will achieve our goals.
It can't. And evidence of it is that the population only really grew once people changed their lifestyles.
But if you make extracting fossil fuel impossible, you will only have to be concerned about local pollution and ecosystem destruction. Those two will almost completely wipe out non-domestic life in a few years, but some parts of the world will probably survive until nearly all of those 10B people die.
Can we keep growing by a few percentage points a year for the next few centuries? Yeah, probably. Can we do that until the heat death of the universe and beyond? Probably not.
Stuff gets weird when you include "infinity".
2 percent a year for 200 years (the minimum rate and years that could count as a few) is a multiplier or around 52.
For population that would give about 400 billion.
> Can we do that until the heat death of the universe and beyond? Probably not.
For population and energy we hit severe physical limits long before that.
At 1% annual growth in population in 12000 years we run out room. What I mean by "run out of room" is that assuming no FTL travel then since every human right now is on Earth or in low Earth orbit no human 12000 years from now can be more than 12000 light years from Earth. The volume of a sphere 12000 light years in radius, divided by the population after 12000 years of 1% growth, is less than the volume of a human.
How about energy? 9300 years of 1% annual energy growth starting now reaches a level where our annual consumption equals the energy of the entire Milky Way galaxy. By "energy of the entire Milky Way" mean everything...electromagnetic radiation, gravitational potential energy, the E=mc^2 energy of everything that has mass.
If we can somehow actually do that, 2700 more years of 1% annual energy growth and we are annually consuming the entire energy of the observable universe.
Its similar when you look at the mass to make human bodies. Here's what 1% annual population growth looks like in terms of mass needed: 3400 years to where the mass of human bodies equals the total mass of Earth and Moon. 600 more years and we also need Jupiter's mass. 700 more and we need the mass of the whole solar system.
Then it is another 2000 before we need the mass of the entire Milky way. 100 more years and we need the Andromeda galaxy's mass too. That's 6800 years from now. Then it is 5500 years until all mass in the observable universe is needed for human bodies.
Unless we get FTL travel it seems pretty clear than sometime in the next 12000 years either growth must slow or we have to change humans to require a lot less space, mass, and energy.
That constitutes as growth. The degrowth ideas don't differentiate what kind of growth they are fighting, neither does targeting neutral growth. You can't target a single number that accurately, we need a details-based intervention.
What we are observing being anything other than noise is highly unlikely.
I think it's incredible that people have been told for 2 decades that the number of humans that exist is too many, that people should not have kids (it's so hard!, and expensive, treat yourself!), and so forth.
But on the other hand, our society is designed in a way that: if it's not growing; it's disasterous.
Which meant that our societies, thinking short-term as they do: turned to migration. Which can be quite unpopular and lead to civil unrest.
IF having children is bad for the environment, why don't we just plan to shrink our economies? I know I sound naive but it's absurd to me that we don't make plans to have a shrinking population if obstensibly that's what we have to do as humanity to survive.
Importing people is the worst kind of band-aid, it's totally unsustainable! And we still tell people not to have kids.
Why? We could all just forever keep doing what we are doing today, nothing bad would happen. With a few caveats. We are depleting non-renewable resources and the population size is changing, that would eventually cause problems if not addressed. Also living standards are very unequal, in reality you could not convince the poorer people to not try to become richer.
But yeah, "this thing is wrong, so we must do that other wrong thing instead" is a great talking point.
But perhaps the planet isn't actually what we want to save, contrary to the headline?
as i understand it, the degrowth position is not, as she says, either 'the uncontroversial claim that what really matters is people leading good lives, or (...) the wildly controversial claim that people would lead equally good lives even if we were to systematically shrink GDP in rich countries to focus on sustainability'. rather, the degrowth position is that people are inevitably going to lead worse lives than at present, but that we can choose between things getting kind of bad, by systematically pursuing degrowth, and things getting apocalyptically bad, which is what will happen if we continue pursuing growth
i think this position is wrong, but that's my understanding of what degrowth advocates are promoting
specifically they argue that continued economic growth, or even continued economic activity at current levels, will unavoidably destroy the natural environment, and that that destruction will diminish the human standard of living in ways that no economic prosperity can replace; you can't compensate for widespread desertification and pervasive environmental endocrine disruptors with products you can buy. going for a walk in the park without needing a respirator cannot be replaced with visits to disneyland; the opportunity to have children of your own cannot be replaced with tasty vat meat
however, i have to admit that wikipedia's summary of degrowth https://en.wikipedia.org/wiki/Degrowth is closer to theunitofcaring's in this article. and check out this abstract of the opening keynote at last year's degrowth conference in zagreb, by diana ürge-vorsatz, who is apparently the vice-chair of ipcc working group iii (mitigation):
> It was in 2022 when the IPCC first mentioned Degrowth and sufficiency in its reports. It is a significant move considering that most IPCC member states still struggle from meeting basic human needs. However, there are many sections in IPCC products that indicate that growth imperatives make meeting ambitious climate goals extremely challenging or risky. An important risk is that pathways towards ambitious climate goals within the growth paradigm, may in the end shift the problems to biodiversity, resource depletion of rare earth minerals and others, microplastics, man-made material exceeding living material, PFAS increase and the like. At the same time, it is questionable how much economic growth has managed to increase our well-being in developed economies in recent decades. With increasingly elaborate planned obsolescence, ever faster and more obscure fashion forcing consumption on us, and with marketing employing more psychologists to rewire our brains and make us addicted to health-damaging consumptions than we have to cure these ailments, it is a question if it is worth it. On the other hand, there are shocking inequalities in emissions, and it is a serious question if we can solve the climate crisis without reducing this inequality. Moving away from our addiction to growth could improve the quality of life for many in the overconsuming North, and can leave more carbon space for the global South to flourish. Degrowth scholarship also needs to consider that the proposed measures for redistribution do not reproduce the mistakes of our communist past as ample evidence shows that some egalitarian measures in the past resulted in even worse resource use and pollution, while others economized resource use.
https://zagreb.degrowth.net/en/9_int_dg_conf/public/events/4...
although much of this is clearly correct, it certainly sounds a lot more like 'the wildly controversial claim that people would lead equally good lives even if we were to systematically shrink GDP in rich countries to focus on sustainability' than my more rational reconstruction above of what degrowth advocates ought to believe. worse, it includes the red flag that the speaker, despite being a professor of environmental sciences and a vice-chair of the ipcc, believes in 'resource depletion of rare earth minerals', which is not a thing
unfortunately i dare not quote the person who comes to mind as a more rational degrowth advocate
ürge-vorsatz's keynote does not seem to have been leaked to youtube, and liveleak is dead now, so we'd probably have to guess what she actually said, but recent interviews with her include https://www.youtube.com/watch?v=dyNYrAOOrdA, in which she sticks to a mostly highly defensible but still very alarming overview of global warming. like kelsey's 'wildly controversial' position, though, she's advocating "to reach the same services or to supply even better services" despite lower energy consumption, rather than accepting a reduction in quality of living. so i am forced to admit that this is not a strawman kelsey made up, but the actual position of the first prominent, powerful degrowthist i looked up
still, i don't think you can reduce the whole spectrum of degrowthism to kelsey's two extremes, and i think the more plausible position i outlined above also falls within it. https://ehne.fr/en/encyclopedia/themes/material-civilization... outlines a wider spectrum of positions
my disagreement with that rational reconstruction of degrowth is severalfold. first, there are vastly more resources available than are merely on earth. second, especially with respect to energy, the accessible resources even on earth are mostly unexploited; terrestrial solar energy input is about three orders of magnitude larger than world marketed energy consumption, or two orders of magnitude larger if we include food (the iea doesn't), and, depending over what time period you propose to extract it over, geothermal energy is another three orders of magnitude larger than that. third, economic value is not measured by the resources consumed, but by the utility provided to the consumer, so there is in principle no limit to economic growth even on a fixed resource base. fourth, the most urgent environmental problem for human quality of life is global warming, and atmospheric carbon capture is necessary to solve it, a measure which will almost certainly require vast expansion of human energy exploitation and therefore economic growth (because you can have growth without increased resource exploitation, but probably not vastly increased resource exploitation without growth)
I can't speak for others who advocate for degrowth, but that seems about right to me, with the caveat that I believe ecologically harmonious lifestyles would be more fun and fulfilling than what we have now.
The challenge is to return to harmony with Nature while still enjoying the benefits of science and technology.
- - - -
> fourth, the most urgent environmental problem for human quality of life is global warming, and atmospheric carbon capture is necessary to solve it, a measure which will almost certainly require vast expansion of human energy exploitation and therefore economic growth (because you can have growth without increased resource exploitation, but probably not vastly increased resource exploitation without growth)
Václav Smil has me convinced that atmospheric carbon capture on a scale great enough to counter-act our continued fossil fuel use is a pipe dream, pretty much for the reason you say: it takes too much energy to sequester the carbon.
Here he is at Driva Climate Investment Meeting in 2019. It's a great lecture IMO, and he starts bagging on carbon capture around minute 39: https://www.youtube.com/watch?v=gkj_91IJVBk&t=2343s
vaclav's 10% goal is obviously not enough. we need to be able to capture more like 150% of current co₂ emissions, not 10%. his argument is very weak, though, so weak that he can't possibly be expecting to convince anyone who doesn't already agree with him; his argument is that the mass of co₂ you'd have to handle is 4 billion tonnes a year (because the total is 41.2 billion tonnes a year https://en.wikipedia.org/wiki/Greenhouse_gas_emissions#Data_... if we only count co₂), and that's an implausibly large amount of mass for a new global industry to handle, because it's comparable to the amount of mass handled by the oil industry (82.8 million bbl/day according to https://en.wikipedia.org/wiki/List_of_countries_by_oil_produ..., which does indeed work out to about 4 or 5 billion tonnes a year)
this is a very weak argument because there are several industries that handle more mass than that. https://en.wikipedia.org/wiki/Concrete#Construction_with_con... says about 7.5 billion cubic meters of concrete were being produced per year in 02006, which works out to about 20 billion tonnes; more recently, https://en.wikipedia.org/wiki/Sand#Resources_and_environment... says 9.55 billion tonnes of sand were consumed in 02007, and in 020222, 50 billion tonnes of sand and gravel, mostly for concrete. water withdrawals from freshwater sources, mostly for irrigation, are about 4 trillion tonnes per year: https://www.statista.com/statistics/1258433/water-withdrawal... of which 13% are municipal. (https://en.wikipedia.org/wiki/List_of_sovereign_states_by_fr... agreees that it's about 3.90 trillion tonnes per year.) we can roughly estimate that those 500 billion tonnes of municipal-use freshwater produce 500 billion tonnes of sewage; https://en.wikipedia.org/wiki/Sewage#Flowrates says the average is 35–90 liters of sewage per person per day, which works out to 100 to 250 billion tonnes per year, which is a dismaying discrepancy from statista's unsourced figure, but still close enough to establish that we're not talking about a mere four billion tonnes of sewage per year
so establishing a new industry that handles 60 billion tonnes a year of carbon dioxide (150% of current emissions) is a completely plausible thing to do, even at the current level of economic development. currently it's too big a job for any single country
smil also implicitly expresses some skepticism about the idea that you can keep the co₂ in the ground once you pump it there. that's just because he's completely unfamiliar with the field; gas in natural gas deposits has kept its co₂ (a useless diluent) underground for tens of millions of years, and some of those gas fields are being used today for co₂ storage, but also it turns out in the recent experiments with mineral carbon sequestration that olivine-rich rocks deep underground serpentinize extremely readily when you pump concentrated co₂ though them, after which they are known to be able to retain it for billions of years. those rocks are available everywhere on earth
now, keep in mind that these numbers are all at our current level of economic development. with ten or a hundred times as much energy, we'll be able to handle much larger volumes of material
which brings us to your argument, which is a much stronger one than smil's: getting those 60 billion tonnes a year out of the atmosphere will require much more energy than getting the same amount of sand out of ancient seabeds, water out of rivers, gravel out of quarries, or sewage out of people's butts. i can't find my calculations at the moment, but plausibly it would require about 10% of world marketed energy consumption, a couple of terawatts. there are various high-tech scrubbing materials like synthetic zeolites and triethanolamine, but soda-lime would work fine and is much cheaper; it just has to be heated to a higher temperature to regenerate it
i'm not sure why smil doesn't mention this, because it's a much better argument than his actual argument and he must have heard of it, but at least in the segment you pointed to, he doesn't. it's possible that he's too unqualified to understand why it's a better argument
so that's why i think a lot of economic growth is needed in order to put atmospheric carbon capture into action