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Comment by Lonestar1440 | Hacker News Reader

I'm continually surprised that this idea gets so much traction. While possible to build, it's also strictly Temporary and just leaves us with a worse problem later on. We'll just need a bigger one, 20 years down the line, when CO2 levels keep going up! At some point, it's pretty obviously a non-solution.

Let's put this energy into Nuclear Power and CO2 recapture; and actually fix things.

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> Spraying a form of sulfur from a plane is incredibly cheap. A full programme would cost less than $20b per year. That’s much cheaper than carbon removal ($600b per year, to remove just 10% of annual emissions @ $100 / tCO2).

It is 30x higher both in time and cost to capture carbon. At $20B/yr geoengineering the atmosphere can be done for 50+ yrs. In 50yrs, carbon capture would need $30T vs only $1T for spraying sulfur. Carbon capture as a long-term solution doesn't make sense. Also, how much carbon you can capture in 50yrs? At 10% of annual emissions, you can probably reach 30% by the end of 50yrs. Carbon capture is still leaving 70% carbon in the environment. It's a make believe solution build to give us false sense of action for saving climate.

Among other downsides, spraying sulphur in the atmosphere doesn't remove any Carbon at all. It just tries to balance one pollutant out with another. I'd rather have the sunshade, honestly.

I'm not a physical scientist, but I'd imagine that the amount of Carbon you can capture is fundamentally proportional to the energy you can use on Carbon Capture. That's why I believe a large expansion of Nuclear Energy would be needed.

Alongside a continued reduction in emissions, this is a practical path forward. Throwing new curveballs at the earth, while not addressing the present level of Carbon, is not.

That's not the point the author is trying to make. What he's saying is, whether you like it or not, it's cheap enough that somebody will do it, either a desperate government or an individual American technocrat.

If I did my back of the envelope math right, direct air capture (DAC) at the currently commercially feasible efficiency, powered by nuclear power could capture annually about as much CO2 as we emit annually if powered by around 2300 large nuclear plants.

It could also be done with roughly a million km^2 worth of solar panels.

I'm curious...do we have the resources to build either that many large nuclear power plants or that many solar panels?

What do sulfur damages to crops cost?

And can we breathe that? At some point it's gonna be noticeable, right?

sulfur is one of those things people can detect in ppm... so yeah maybe

we screwed up the earth so much the only way to keep it livable to is to make it smell like farts

In the United States I strongly suspect that at least one major political party's reaction to sulfur spraying would be to try to increase the production and use of coal and oil.

I suspect that this reaction would not be confined to the US.

We could end up in a situation where greenhouse gas levels in 50-100 years are massively higher than they are now, with heating being held in check by continual sulphur spraying.

It would then only take for something to disrupt the sulphur spraying for a year to have sudden massive warming.

It would make more sense to save sulphur spraying for after we are firmly on the road to zero emissions and have reached the point where it is not economically feasible to revive coal and oil. Then sulphur spraying as a temporary measure to lower temperature until our falling emissions make it unnecessary might be safe.

That won't be easy for them to justify when solar, wind and battery prices are cheaper.

You know that famous (around here) article: "Reality Has A Surprising Amount of Detail" ?

Sadly for all of its popularity the essential message seems to have missed people. I listen to people talk about Mars colonies in their lifetime, because they refuse to acknowledge the complexity beyond "big rocket go fast". This topic is very similar, it requires a staggering amount of engineering, economic, environmental and other disciplines to really understand why it's such a terrible idea. The expense, the known and unknown unknowns, the politics and the reality that it's a band-aid over a sucking chest wound.

People just don't get it, and only engage with these topics as a sort of sport, not something they need to grasp the complexity of.

The article makes the point that it's the kind of thing an arrogant billionaire will probably do on their own because they feel it's necessary. I'd say that your point probably reinforces that idea.

Excellent comment.

I hear that argument lot, but the perspective that seems missing to me are the secondary effects - right now, we have a lot of self-reinforcing loops from rising temperatures, like melting permafrost emitting even more greenhouse gases. At least those should stop if the earth is artificially cooled down, no? If so, then it could be considered a form of preemptive removal - stop it from getting into the atmosphere in the first place. Not sufficient on its own, but a bandaid that would buy some time (which has its own risks, given our record of dealing with problems too late).

While possible to build, it's also strictly Temporary

And may, as per the author says, save our asses while we get our shit together.

Now, granted, this is one of the craziest things Ive ever read in my life. And Im being proportionate here.

It's just an insanely large and dangerous and global version of setting up a sprinkler or mister to use to cool off when it gets too hot outside.

The magnitudes of the vectors are much much larger, but it's the same dimensions of environmental modification for our own comfort.

What's funny is I think it's one of the most rational takes on the current situation that I've ever read. What's crazy is the status quo wherein we are destroying the only ecosystem that can support our civilization. We are already engineering the climate, just not purposefully.

We are already not doing much against climate change now, so "get our shit together" is wishful thinking.

This is just another distraction from the list:

- "there is no climate change, let's continue business as usual"

- "there is climate change, but not human-made, let's continue business as usual"

- "there is human-made climate change but it is too late, let's continue business as usual"

- "environmental activists are to blame, let's continue business as usual"

- "maybe we will find magic-technology, let's continue business as usual"

- "geoengineering will buy some time, let's continue business as usual"

I think there are certain actions that are only insufficient because the trend line isn't steep. Electric car sales go up every year, solar/wind both go up as a % of our energy mix in the west every year. Some amount of geoengineering might allow the current pace of those trends to be 'fast enough'

exactly. we need more time for the trends to mature.

I disagree; I think we are doing a lot. We're on track so that renewable sources will provide 1/3 of all electricity generation by 2025. That's quite a massive change, considering how much electricity infrastructure needs to change for that to happen.

The issue is that CO2 emission is so massive that even big changes are a drop in the bucket.

Dude you're discounting things like the fact that solar and wind account for like 44 percent of europe and even in the united states I go driving around and see solar panels everywhere. Like, it's all growing like a weed and going gang busters but still it needs to go even fater sure but buy us time and solar and wind would get even cheaper along with batteries and anyone who tried to advocate for more coal or natural gas would be met with resistance in corporate america as there are cheaper alternatives.

The history of industrialization, as well as most people’s consumer choices, should explain why it has so much traction. When faced with an expensive solution that permanently solves a problem vs a cheap one that kicks the can down the road a few years, people invariably choose the cheap one. That’s how we got in this mess in the first place.

Remember that people are mortal. Rather than invest in permanent solutions that grant us eternal life, evolution favors solutions that keep us alive just long enough to reproduce, then making a half-copy and throwing out the old body.

>While possible to build, it's also strictly Temporary and just leaves us with a worse problem later on.

Sounds like how humans have been operating since eons.

A nuclear power plant generating 5gwh/year could capture around 4 million tons of CO2 per year at 1,200 kwh per ton. Emissions are in the billions of tons per year.

> just leaves us with a worse problem later on

That's the beautiful part. When wintertime rolls around, the gorillas simply freeze to death.

The growth of renewables, particularly solar, is on pace to replace a pretty large proportion of fossil fuels "for free" by being more economically viable. Transitioning most people and industry from ICE to electric and things like heating to more electric is going to happen naturally, but it'll take a few decades. Likewise it's reasonable to believe the biosphere is going to ramp up carbon sinking as time goes by. A stopgap of dimming the sun with sulfur for... eh... 20 years might just be the ticket.

> is on pace to replace a pretty large proportion of fossil fuels

Is it? According to ourwoldindata[0], fossil fuel usage is growing worldwide. ie more fossil fuels are being burned now than ever before.

[0] https://ourworldindata.org/grapher/global-fossil-fuel-consum...

Yes. Solar is growing at an exponential rate, fossil fuel growth rates have been slowing.

Solar and wind growth rates should be expected to continue increasing, fossil fuel growth should reach zero in the next decade and start a long term decline.

https://en.m.wikipedia.org/wiki/Growth_of_photovoltaics

I’m talking about the second derivative of usage not the first.

Nuclear power is not affordable, wind and solar are far more cost effective. Carbon capture is a great application for a variable supply grid as it can easily be load shed.

The affordability of nuclear power is purely political (and emotional).

In the real world nuclear costs in the $80 per MWh range, nearly twice that of offshore wind

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