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> We know that the continued exponential growth of solar means that fossil fuels won’t be absolutely necessary for the economy in 10-15 years.

Where did you get that from ?

Renewable are stacked on top of fossil, we use as much (more even) fossil fuel than ever before, it never went down: https://ourworldindata.org/energy-mix

Germany is the prime example of this green washing: https://www.cleanenergywire.org/sites/default/files/styles/g...

If you accept that PV will continue to grow exponentially, the historical trend is ~1000x growth over the last 21 years, or 10x every 7 years.

PV is about 10% of global electricity demand and about 1% of all-forms global energy demand today; 7 years (even without wind) and its going to be dominant over electrical generation, 14 and there's enough electricity to electrify everything else we do, too.

If you accept that the exponential growth will continue. It's not guaranteed.

France is 70% nuclear and the average co2 per capita still is ~10 tonnes per year... to get it to a sustainable level I think the target is under 3 tonnes according to the Paris agreement.

I think a lot of posters in the thread run a very simplified version of the world in their mind

3 tons per capita per year, globally, is 24 gigatons — that would only be a 30% or so reduction from the status quo.

We need a 99.9% reduction to be long-term sustainable; that's 4375 grams of CO2 per person per year. If there was no carbon capture, it would be at the level of "everything everywhere except for North Korea" or "everything in every country except for land-use changes to grasslands"

Thinking of simplification, France is ~70% nuclear electricity, which I emphasise because I'd already noted a roughly 10x gap between worldwide electrical and worldwide all-forms power.

Great ref, from Germany’s energy mix!

Here’s an S-curve model I made based on two maximum carrying capacities for solar; the lower bound is the current amount of farmland devoted to ethanol while the upper bound is 1% of the earth’s surface. Data models based on historical growth in solar [1].

I show the current total electricity usage and the total energy usage. These are growing slowly worldwide, around 2%.

https://claude.site/artifacts/eb3c4763-3b70-458b-8e70-6b8370...

We are deep into the massive exponential growth of solar. Can we keep it up?

[1] https://ourworldindata.org/grapher/installed-solar-pv-capaci...

I might be misreading the cleanenergywire.org diagram but it shows that oil consumption went down, coal as well.

Or did you mean that this diagram _is_ the greenwashing? If so, why?

The funniest part is probably that this rapid recent rise is partially due to attempts to switch to cleaner fuels in maritime transport. Ships burning sulfur rich bunker fuel have been helping quite a lot by already doing lite geoengineering and we've abruptly cut that stopgap like absolute idiots.

You mean stories like this?

https://www.msn.com/en-us/science/environmental-science/ship...

Fuel additives for ships to increase clouds and fuel additives for planes to reduce clouds could reduce their warming impact by roughly 30%. (High clouds trap heat and low clouds reflect it)

The problem with geo-engineering is that it only treats the symptoms, not the root cause. Treating the symptoms has a side-effect: it lowers the incentive to treat the cause by making it less pressing.

What we want to avoid is not a 1.5 degrees warming, it's a 3 or 4 degrees one. By doing geo-engineering, you could fix the issue in the short time but you would also increase the probability of a bigger problem in the longer term.

What is the non-geo-engineered solution?

Emit less CO2.

Does sequestering what has been emitted count as geoengineering? If not, that too; if so, then surely the status quo of emitting it is already geoengineering?

I would assume that anything done by people is geo-engineering.

Check out the big red band "China"

https://ourworldindata.org/co2-emissions

But, as I noted in another comment, it's misleading since China has absorbed so much manufacturing for other countries, a lot of those products end up in your hands after you get it from Amazon Prime.

Note that China emits a lot less than the US or Canada calculated per capita (from that same page).

Yes, China's 1.4 billion citizens divided by their number 1 status as a carbon emitter, means that they produce less co2 than the USAs 345 million divided by it's (relatively) lower total emissions.

But as I pointed out, there is likely misleading: the US (and other nations) buy lots of goods from China effectively shifting coal emissions from the US to China by having them made there.

If the US were purchasing 100% US made goods, per capita co2 in the US might be much much higher

No need to hypothesise, it's been calculated:

https://ourworldindata.org/consumption-based-co2

https://ourworldindata.org/grapher/imported-or-exported-co-e...

China is essentially importing ~1 GT of emissions, and the USA is essentially exporting 0.56 GT of emissions.

The USA would emit about 10% more and China about 10% less if all manufacturing was local; but that would mean the USA per capita emissions would go up to 16.5 tons per capita from 14.9, while the Chinese per capita emissions would go down to about 7.2 from about 8 tons per capita. (Assuming I read the charts correctly).

I aver that none of this matters either, because all of us need to get down to "approximately none" and this kind of thing is just playing a nationalist version of the "no you" game.

Cool beans.

I guess it's time for the US to kick it's Chinese import addiction, in which it shifts it's addiction to cheap foreign (Chinese) labor fueled by 'clean' coal, and then works to whittle it's own emissions problems down to zero by whatever means necessary.

Solar might help with carbon emissions even at apex deployment, but there's a lot of carbon emissions otherwise.

The objection to geoengineering is because those either involve large scale impacts to an already threatened biosphere (I do not accept than even 1% of biosphere threat due to solar energy reflection is understood), it often is pushed by the petroleum industry and they are the living embodiment of not caring about environmental impacts, and the cost of geoengineering is usually so high it begs the question why we don't invest in practical sustainablity.

Ultimately, geoengineering is a delay. And what the petroleum industry in general economic powers that be due is delay cost as long as possible, while imposing costs upon other people. It is the essence of externality economics, which is to say industrial economics, which is to say economics.

We are an economic world built on the religion of economics. That religion has no conception on a practical basis of environmentalism and sustainability.

The fundamental problem externality economics, is that we cannot price the externalities on a practical basis. If you cannot price things, they do not exist to economics.

The problem with geo engineering is that in the proposed shape it doesn't solve two major problems: ocean acidification and impact of CO2 levels on animals (including humans).

Even if we get back to lofting sulphur, it won't stop aquatic life from dying. And our cognitive function won't be better if it's 1000ppm CO2 at 1.5°C degree increase rather than 1000ppm CO2 at 3°C degree increase.

Geoengineering is insufficient.

Cognitive impairment isn’t an issue. High temp already impairs cognition—air conditioning can fix excess co2 and excess heat — indoors.

The ocean ph is currently 8.08. At 1000ppm (worst case scenario) the ph drops to 8.03. Disruptive to ecosystems, but not as bad as people think. Changes in heat will be worse.

The other piece— we can do geoengineering with calcium carbonate! That is alkaline.

Geo-engineering, or carbon capture?

The former has two problems:

1) You can't stop, ever, if that's all you do. Worse, if we're still emitting, cost rise, because the cost depends on how much CO2 is in the air, not much was emitted last year.

2) CO2 has many environmental effects, not just temperature.

Carbon capture is fine for the last 10% or so, IMO.

> You can't stop, ever

I'm not really worried about "ever"; mostly just till I'm through with this planet.

Zero empathy for younger humans?

I think the opposite; I have so much empathy for them that I never created any in the first place. I can't imagine the despair of being young today. I'm not quite old yet myself and am terrified of what we will do to this planet.

> mostly just till I'm through with this planet.

That kind of thinking is how we got into this mess in the first place.

The long-term impact of climate change was evident 20 years ago, well before we reached this point; back then we didn't have cheap renewables, but there was enough time to have done a big nuclear roll-out.

> CO2 has many environmental effects, not just temperature.

Like the oceans acidifying [1].

[1] https://www.noaa.gov/education/resource-collections/ocean-co...

Indeed. Or CO2 causing cognitive impairment in humans.

You can stop once you’ve stabilized co2. It buys time for building out a solar power base and develop carbon removal tech.

We need to buy time.

> You can stop once you’ve stabilized co2. It buys time for building out a solar power base and develop carbon removal tech.

That presupposes that we're going to build out the PV and develop carbon removal.

I hope we will, but it does presuppose it: if this were false, then the costs go up each year because the CO2 only gets stabilised when all the fossil fuels get burned.

> We need to buy time.

Agreed.

I assume other people have put thought into this but just as your standard braindead engineer I see some problems with dimming the sun. Some big ones:

1: it would make solar less effective so we'll have a harder time reducing our fossil fuel usage

2: fossil fuels will actually run out at a certain point, and we'd still be stuck with a dim sun but without the warming effects of fossil fuels

3: engineering is a process of trial and error, and we can't afford to try this and fuck it up

1. SRM will reduce efficiency of equatorial solar but minimally effect solar in northern climes. Like, less than 5% reduction. Pretty good trade off for stabilizing temperatures.

SRM from lofting sulfur or calcium only lasts about a year. It has to be done yearly. So, no long term effects, for better or worse.

2: We will fry the planet long before running out of fossil fuels. There is a lot left.

3: we absolutely can and must try geoengineering at small scales before scaling up. It isn’t a binary phenomenon. Every time there is a volcanic event, we get a natural experiment.

> But, geoengineering seems to be the only plausible mechanism for preventing global warming at this point.

I'd rather geoengineering being beta-bested on other planets first than in the only place we can live.

Besides, global warming might not be so bad, if we consider that we are currently in one of the coldest periods in human history.

Temperatures have been going up and down for millions of years, with or without humans.

https://en.wikipedia.org/wiki/Milankovitch_cycles

Well I must sadly inform you that we're officially unable to go to Mars until we "fix all of our problems here on Earth" as people put it. /s

> Besides, global warming might not be so bad, if we consider that we are currently in one of the coldest periods in human history.

I don't know where you got this idea from, it's not supported by your link.

We were already in an interglacial warm period, and the warming since the preindustrial average is of the same scale as the difference between the preindustrial average and when the ice sheets withdrew from Chicago.

maybe check out the book "termination shock"? getting humanity into sulfur-addiction is running hard towards danger don't you think? Also who decides, and who gets the blame and anger when anything climate related has a big visible impact?