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Comment by pier25 | Hacker News Reader

Doing a little math...

Considering 1100 Gtons in the atmosphere and $200 per ton would be roughly $220 trillions.

The current world's GDP is $78 trillions.

Even if the world invested $10 trillions every year it would still take 20 years to remove all the carbon emitted between 1850 and today.

Of course we would keep pumping about 37 Gtons per year (and growing).

https://www.carbonbrief.org/analysis-global-co2-emissions-se...

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This industrial approach to carbon dioxide removal is but one of several in our toolkit, and by no means the least expensive.

Project Drawdown ranks every approach in terms of tonnage of CO2 and cost. http://www.drawdown.org/solutions-summary-by-rank

These approaches get amplified by a price on carbon. If you are interested in convincing your Member of Congress to price carbon, take a look at the most effective organization doing this work: http://www.citizensclimatelobby.org

Thank you for spreading the word about Drawdown and CCL!

They are probably the two easiest ways regular folks can learn about and get involved in climate policy (and I mean real impacts, not just clicktivism).

Please get involved – it takes no money and very little time!

Thank you for introducing me to Project Drawdown. How eminently practical and sensible these recommendations are. I love the data-driven approach.

I was surprised to find that, of all things, "Refrigerant Management" is the single thing that holds the greatest potential to reduce carbon emissions [1]. It makes a lot of sense, but it would definitely not be what I would have guessed.

[1] http://www.drawdown.org/solutions/materials/refrigerant-mana...

that #1 single thing only makes up 89.74 of the total 1050.99 at the bottomm of that column! or about 8.5%

Sure... educating specifically only the girls is #6 on the list.

Why would they have to bring feminism into that? I mean sure, it's a good thing to educate everyone. But why mix it?

How can I trust all the other points on the list now? What if they are also just pushing some other political agenda?

I can't. They just compromised the list's integrity by that.

Did you read that section to see why they think it'll help? It doesn't sound like politics to me.

Yes I did. Because educated people have fewer kids... Might be true, but what kind of reason is that even!?

Why not also establish a one-child policy in western countries? Or start actively killing sick people? /s

All the other reasons were basically how it makes lifes better for those women. Which is surely a good thing, but doesn't matter in that context.

Women's education and empowerment is negatively correlated with the number of children they bear.

I’ve been sending the same math to people who’ve been getting excited about this. It’s premature. Even just trying to remove our annual emission would take 7% of our global GDP.

This needs to come down in cost 20x to be a viable solution to our problem. And that’s just going by cost, not looking at the logistical aspects. For example the plant pictured captures 1 million tonnes annually. So we would require 37,000 of those giant plants to capture our annual emissions. We haven’t explored how much energy would be required to do that and where we would get it from. The plant shown uses gas, a polluting power source oddly, and a very cheap energy cost figure in its calculations. Presumably we’d want to use solar. And thus half the efficiency of that plant. So double the number required to 74 thousand.

Everyone getting excited that this is a solutions has gotten ahead of the science and logistics. We’re far from being there.

Nuclear seems like a better option than solar. Assuming capital cost is a major factor, you'd want the carbon removal plant to run all the time, not shut down at night. Constant load is perfect for nuclear.

There are countless ways to store energy: hydrogen, artificial hydroeletric, batteries, etc. Solar energy is practically unlimited. Nuclear still requires fuel, and it's a very limited resource unless you start considering things like extracting fuel from the ocean where costs just skyrocket.

And it's likely that our global energy usage will skyrocket in the future for a variety of reasons. The first level is that many places are still undeveloped and have not yet hit their 'China' phase. But beyond that we can also just do some really cool sci-fi soundings things if we massively ramped up our energy production. Fossil fuels, and fuels in general, were never really fit for these sort of ideas - but solar certainly is.

This [1] article goes into detail on the remaining nuclear material. Keep in mind that this is at current consumption rates. Energy usage rates are going to increase in the future, and right now only 4% of global energy production is nuclear. In other words, you can shave orders of magnitudes off the numbers they give in that article to give a ballpark for how long nuclear would last. It's just not a great fit for the longterm future.

[1] - https://www.scientificamerican.com/article/how-long-will-glo...

Scientific American is flat out wrong, compare[1]. (Someone who states that "a breeder creates more fuel than it consumes" has to be wrong about many things.) Common rocks contain about 13ppm uranium and thorium, which gives them a 50x higher energy density than coal[2]. We will never run out of rocks. As a bonus, if we actually "burn the rocks", we end up with a lot of sand to be spread on fields, which counters soil erosion, serves as fertilizer, and captures CO2 through accelerated weathering. In other words, solar power uses land, nuclear power restores land.

[1] - http://www.nuclearfaq.ca/cnf_sectionG.htm#uranium_supply

[2] - http://energyfromthorium.com/cubic-meter/

It's a misleading, but technically accurate marketing point for breeders. More specifically it's fissile material, which is converted from larger amounts of fertile material used in the reactor. There's no violation of conservation principles, just some fast talk. Read your own links - as at least the first mentions this.

The second link is junk. The average distribution of elements in the Earth's crust does not mean each every and every chunk of earth contains exactly that distribution. And while many types of rocks do contain trace amounts of uranium, it's nowhere near 13 ppm. Though so far as I can see even that site didn't state that.

> It's a misleading, but technically accurate marketing point for breeders

That's the point, it's not technically accurate. A breeder makes more fissile material than it consumes. Fissile material is the fuel in light water reactors, but breeders use a different, more abundant fuel. I know that, you know that, and we both know that we both know that. But inaccuracies like this lead to the likes of Helen Caldicott dismissing the whole technology with a sneer such as "a breeder that magically makes more fuel than it consumes".

> trace amounts of uranium, it's nowhere near 13 ppm

It's about 13ppm uranium and thorium, in fact about 10ppm thorium and 2-4ppm uranium. And while energyfromthorium doesn't state these numbers explicitly, it clearly uses them in the energy density calculations.

> does not mean each every and every chunk of earth contains exactly that distribution

So "burning the rocks" will never work, because there are a few rocks that don't burn? It works even better, because some rocks burn better, e.g. Conway Granites at 56ppm thorium.

I'd expect we'd need either fast reactors or thorium reactors to cover that much usage. Either would be about 100x more fuel-efficient. There are two fast reactors operating commercially in Russia.

Extracting uranium from the oceans is about 5x more expensive than mining it. Since fuel is a small component of nuclear cost, that's not a big deal; we don't do it right now because mining covers our needs. With fast reactors, it wouldn't be a problem at all, and would cover our needs for many millions of years, even at much higher consumption rates.

Storage adds quite a bit of cost to solar (other than hydro, which is geographically limited). If we get storage technology that makes storage+solar cheaper than nuclear, then sure, that might be better.

However, we're already nearing a planetary limit on land usage, after which we seriously impact biodiversity. The vast solar arrays this would require wouldn't exactly help.

Fuel, at least according to Wiki [1], runs about 28% the cost of a nuclear plant's operating expenses. And our current nuclear tech was chosen largely because it was cheap. You're also looking at much greater expenses in running breeder plants. Those are already pretty substantial costs. And now on top of the cost extracting/refining/enriching fuel from saltwater would cost, you also have to keep basic economics in mind as well. Right now there's little demand for nuclear material, and so this is reflect in its cost. However, should this change you'd expect to see the cost change in turn, and likely quite sharply. That's a lot of stuff piling up pretty fast!

I'm not sure where you're getting he millions of years for breeders. The article mentions the value I've seen pretty much everywhere which saltwater extraction could theoretically provide enough material for about 60k years of nuclear operation. And breeders could ideally reduce consumption to a bit less than 1% of current usage. So that'd be 6 million years, but that's at current consumption rates. If we replaced our energy with nuclear that'd be a 25 fold increase in usage so we're down to 240k years at current rates. And that's in the scenario where we're extracting all the material we can from ocean water, using every single resource we have on the planet, and doing it all with perfectly functioning breeder reactors.

Just seems we should be targeting something that isn't a numbers game, though granted you can probably make some argument that cobalt will be a limiter on solar but solar also comes with many other perks - decentralization, minimal danger from failure, much cheaper, practically infinite energy availability, and so on. The only issue is storing energy, but this can be done affordably in numerous ways even with present day tech - and decentralization can also remove lots of the burden here.

[1] - https://en.wikipedia.org/wiki/Economics_of_nuclear_power_pla...

So only, say 100K years before we have to figure out fusion or something? I'm thinking we could live with that.

However, uranium in seawater is actually in an equilibrium, so the more we extract, the more gets dissolved from rocks. Effectively it's a renewable resource:

https://www.forbes.com/sites/jamesconca/2016/07/01/uranium-s...

https://cna.ca/news/theres-uranium-seawater-renewable/

Whether breeders would be more expensive depends on their design. One that looks quite economical, according to independent engineers who evaluated it, is Moltex:

http://www.moltexenergy.com/

Or to take it a step further, massively build up Nuclear to match daytime peak (give or take some renewables) and then use carbon sequestration as the load on the grid at night time instead of batteries (or other sorts of storage).

20 years is an incredibly quick timespan in which to do this. If we can become carbon neutral by 2040 and carbon negative after, we can stave off many of the worst parts of climate change.

I'm with you. I have to believe a joint country climate accord where member nations pledge to suck X gigatonnes of carbon from the atmosphere (or finance those that do) is a much easier political sell than 1) taxing fossil fuel companies/cartels or 2) enforcing emissions restrictions on various industries.

Cleaning up 150 years of emissions in 20 or 40 or even 60 years seems like a miracle on par with the moon landing or eradicating smallpox.

Just stopping things from getting worse would be an achievement on those scales.

I love your real-world examples of "miracles"!

In front of me right now I have the June issue of the IEEE Spectrum special report, titled "Blueprints for a Miracle: 10 Technologies for a More Livable Planet". Its highlights include carbon-eating fuel cells; turbines driven by super-critical CO2 (nearly "free" carbon capture, courtesy the Allam cycle); a plant in Iceland producing methanol fuel from renewable (geothermal) energy and waste CO2; a pure-electric airplane; plant-based and in-vitro meats; and a sodium-cooled travelling-wave nuclear reactor with decent performance.... It seems to me like we're coming to the fight awfully late, but we may also have more weapons than we'd realized.

An economic loss of $10 trillions per year during 20 years would be catastrophic for the economy. It's simply not sustainable economically.

Also, let's not forget that our emissions are still significant (and growing) and that feedbacks will keep on warming the planet regardless of what we do.

We're not talking about an economic loss, we are talking about a potential subsidy to a sector of the economy to build massive numbers of carbon capture facilities. I'd prefer a $1 trillion carbon-mitigation subsidy over a $1 trillion tax cut to be sure...

This debate feels a bit like people talking about how much money is 'wasted' on a Mars rover, ignoring the difference between "the value of materials shot into space" and "the total cost of building something, including salaries and capital expenditures that aren't destroyed".

The cost of doing something is not the same as an economic loss from doing it.

Would doing so in such a short timespan have a big effect on the weather during the transition?

Maybe the first goal could just be removing the current year's production? That would still be a vast improvement over every other proposed solution.

By his numbers that's still ~ $7.4 trillion, or about 10% of the world's GDP. And it doesn't include storing the captured CO2 anywhere permanent.

I think it's a lot more practical to reduce our emissions to close to zero, hard as that is.

Anything we do is going to be expensive. "Stopping all use of fossil fuels" like you suggest would also be very expensive, even if we ignore obvious costs like disposing of all the corpses created by such an endeavor.

Presumably, Zeno's Paradox will be hard at work. We don't have to remove it all in one go. We just have to remove it faster and faster and faster, as we get closer to the limit (whatever that limit is).

This isn't my field, but so many human endeavors go like that. Just buy a little time so we can figure out how to do better, which then buys time to figure out how to do even better.

By many accounts we have already passed the limit.

If we're totally screwed then it doesn't matter what we do; so frankly it isn't really worth thinking about. Better to assume we can save ourselves and try, than assume we are doomed and give up.

There are many tons of emissions that can be avoided for far less that $200/ton. These are the things like stopping the burning of fossil fuels, increasing energy efficiency, planting trees, capturing from industrial point sources, etc. DAC is the high cost alternative, that means it will be used last as a strategy for dealing with CO2 emissions.

Seeing as that the entire world economy for the last century, responsible for the greatest reduction in poverty in the history of the world, is driven heavily by fossil fuels, it does not seem that unreasonable.

You don't need to capture anywhere near the total amount emitted into in the atmosphere. Just enough to offset warming.

That "just enough" is probably half of what is presently in the atmosphere. The oceans have absorbed huge amounts of what we've emitted, and would disgorge it accordingly. The CO2 level in 1900 was about 300 ppm; now its 400. To make a substantial reversal in climate change by only removing CO2 from the atmosphere, we'd have to make a massive stride by 2050.

The oceans may also end up being a higher priority at least at first because there is already evidence that acidification caused by absorption of excess atmospheric carbon us causing ocean ecosystems to break down while disruption on land is still relatively minor.

I'm not sure you can target oceanic CO2 over CO2 in the atmosphere. Ocean acidification is an equilibrium process driven by the partial pressure of CO2 in the atmosphere increasing.

If you start reversing acidification, the ocean is just going to start pulling in more CO2 from the atmosphere.

Sounds like you should "just" target whichever one is easier (cheaper) to pull CO2 out of, then.

In most cases it is easier and more practical to accelerate reactions in liquid media as opposed to gases. This is chemistry not magic.

There are a couple of problems here.

1) Nobody really knows how much is that. 350ppm? 300ppm? 250ppm?

2) Don't forget about feedbacks which have already been triggered and will keep adding warming regardless of what humans do.

Your math is not wrong but your assumptions are. We only need to remove enough to produce fuel so that we can stop dumping c02 in the atmosphere by consuming oil and replace that with what we produce from co2. Once we do that, nature will do the rest. Slowly of course but it will trend the right way. So, there is no need whatsoever to actively remove that many tons of CO2.

My thing is that we should be charging/taxing the companies producing these sorts of emissions. But of course capitalism is about socializing the costs (fixing these emissions) and privatizing the profits.

On top of the fact that this probably doesn’t scale up to geo-engineering scales linearly even if you assume the article is correct in the costs it gives.

Reminder: If CO2 levels fall below 150 ppm there will be a mass extinction of land-based plants.

It is a grave mistake to believe that CO2 as such is bad and must be removed from the atmosphere. It is an essential fertilizer for both phytoplankton and land-based plants (at current levels these plants are in effect starved for CO2, because they evolved during geological time periods with much higher CO2 levels).

> these plants are in effect starved for CO2, because they evolved during time periods with much higher CO2 levels

Oh, the old argument trotted out again. What do you mean, plants "evolved" in the past and then what? Stopped evolving? If plants were starved of CO2 now they would go extinct, which they aren't. To prove my point, I present exhibit A: The Amazon rainforest.

Starvation is not equivalent to death, it means that plants are not growing as fast nor as well as they would with higher levels of CO2.

This is a proven fact and has been amply demonstrated in scientific experiments; it is related to well-understood biological processes in photosynthesis. It is the reason greenhouses deliberately increase CO2 ppm. [1] And yes, the plant kingdom has evolved just a few pathways for photosynthesis that worked well at much higher CO2 levels (10-15x current) when they originated; and these pathways are not magically "evolving" to function with diminishing CO2 levels, they've merely become suboptimal given the atmospheric conditions in the last million years, and would stop working below specific levels.

Your ignorant dismissals are moronic denials of facts and science. Surely you don't pretend that there is no lower limit to the viable amount of CO2 in the air for Earth vegetation to survive?

[1] http://www.omafra.gov.on.ca/english/crops/facts/00-077.htm#s...

this is why I have been trying to promote CO2 production to a target level of 1200PPM. With enough solar, biofuels and wind -- which are all net negative entry input vs energy output (which promotes CO2 production) I was hoping we could do this.

1100 GTons is what humans have added on top of the natural CO2. Nobody is saying we should remove all CO2.

Your asserted number (1,100 GtC) seems to be a wild exaggeration: "In the period 1751 to 1900, about 12 GtC were released as CO2 to the atmosphere from burning of fossil fuels, whereas from 1901 to 2013 the figure was about 380 GtC." [1]

"From 1870 to 2014, cumulative carbon emissions totaled about 545 GtC. Emissions were partitioned among the atmosphere (approx. 230 GtC or 42%), ocean (approx. 155 GtC or 28%) and the land (approx. 160 GtC or 29%)." [2] (And 230 GtC is 843 GtCO2, so that doesn't match either.)

Your asserted number appears closer to an estimate of total GtC in the atmosphere, not merely the modern addition via human CO2 emissions. Where did that 1,100 number come from?

[1] https://en.wikipedia.org/wiki/Carbon_dioxide_in_Earth%27s_at...

[2] https://www.co2.earth/global-co2-emissions

I tracked down one scientific paper that mentions "1,100 Gt CO2" but the context is completely different from what was being claimed (total human emissions so far): it's an estimate of the remaining global carbon budget from 2011 onwards for the political goal of limiting global temperature rise to 2 ̊C.

"A temperature rise of 2 ̊C is consistent with combustion and release of around 1 trillion tonnes of carbon (1000 Gt C). The 2013 IPCC Working Group 1 report calculates the remaining global carbon budget from 2011 onwards consistent with the political goal of limiting global temperature rise to less than 2 ̊C to be 300 Gt C, equivalent to emission of 1100 Gt CO2. Current known and exploitable fossil fuel reserves are equivalent to 3100 Gt CO2, three times greater than this cumulative emissions budget. A conservative estimate of the additional fossil carbon resource that could be extracted is 30-50 times greater (~45000 Gt CO2)." [1]

Their reference for that amount is "IPCC. Fifth Assessment Report Summary for Policymakers, Working Group 1: the physical science basis (2013)". [2] However when I read and search that document that particular number is absent. A search of the full 1,552 page report [3] also comes up empty.

[1] Scott. V., Haszeldine, R.S.H., Tett, S.F.B., Oschlies, A., Fossil fuels in a trillion tonne world, Nature Climate Change 5, 419–423, 2015. (https://www.nature.com/articles/nclimate2578)

The author ‘post-print’ PDF version is available through Edinburgh Research Explorer: https://www.research.ed.ac.uk/portal/files/19407404/Fossil_f...

[2] https://www.ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_SPM...

[3] http://www.ipcc.ch/report/ar5/wg1/

That's like saying that not eating for a month will kill you, in response to an article about the obesity epidemic.

I hope this is not your usual standard of thinking or argument.

At what CO2 level in the atmosphere would land-based vegetation go extinct? should one take this into account when designing or advocating massive mechanisms to remove CO2 from the atmosphere? once you've admitted that some CO2 level is good for the planet, why and how do you determine an ideal/target level?

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