Even if we stopped emissions today, Earth will keep warming up for a couple of decades. We’re not at equilibrium temperature for the current CO2 levels.
There’s been a few over the last few hundred years. If there’s dust and haze it might be a respite, apart from famines due to poor harvests.
I guess we’ll find out should it happen.
We’re in a more precarious state, and these random natural events could be very tricky.
When the Canada haze hit here the temp dropped from "forecasted 90s" to "pleasant 70s" and not only were the temps lower but there was no direct sun beating down. Me and the boys were expecting some outdoor work we had planned to suck and take a long time. We ran through it in no time flat.
https://en.wikipedia.org/wiki/2022_Hunga_Tonga-Hunga_Ha'apai...
Aug 02, 2022: https://www.nasa.gov/earth/tonga-eruption-blasted-unpreceden...
December 20, 2023: https://research.noaa.gov/hunga-tonga-2022-eruption/
20 May 2025: https://www.nature.com/articles/s41612-025-01056-2
I'd say ongoing...
They way I think/hope we can fix this is two parts:
1. The only way I think you can get rid of the excess CO₂ at scale is to permanently sequester it underground. The oil/gas industry can cheaply deposit huge amounts of gas there. The unsolved problem is extracting enough CO₂ from the atmosphere at reasonable cost. People are working on that, but it will probably be decades before it's is approaching practicality.
Which is why we need to do this in the meantime:
2. Spray the stratosphere with SO₂. This reflects some some sunlight and cools the planet. It sounds scary, but is actually safe: https://makesunsets.com/pages/new-faq
The emission reductions in our simulations correspond closely to the emissions reductions realized in East Asia over the period 2010–2023, in magnitude and geographical location. This allows us to put our results in the context of the recent uptick in the observed rate of global mean surface warming. Here, we find that emissions reductions in East Asia have contributed up to 0.05 °C/decade since 2010, explaining a large fraction of the observed increase of 0.06 °C/decade over the same period, after filtering out the effects of interannual variability. (from https://www.nature.com/articles/s43247-025-02527-3)
While it remained, northern hemisphere temperatures lowered by ~0.5°C.
USGS report: https://pubs.usgs.gov/pinatubo/self/
Since the stratosphere is far above the rain cycle, it's very hard to imagine a mechanism whereby this could produce acid rain, and even if it did, acid rain is a much smaller problem than global warming.
In fact it used to be a common occurence during the heavy industrial pollution in the 20th century. So much that after the pollution stopped, farmers had to start applying sulphur to their fields as nutrients for some crops (I learned about this after unsuccessfully trying to grow tomatoes in alkaline soil).
I remember watching news reports about acid rain in the 90s and being terrified that any ominous rain cloud might be full of acid rain which would melt away my town and family.
> acid rain is a much smaller problem than global warming
Possibly, but acid rain can devastate marine ecosystems and cause issues with soil quality, so I'm not convinced that we can just hand-wave it away.
I can foresee greedy capitalists rubbing their hands together over being paid to seed SO2 into the stratosphere and then being paid to clean it up too. There's probably a lot of money to be made selling clean air if we can pollute the atmosphere enough to cause health problems for people.
Humanity has a track record of making assumptions about complex systems and treating them like a simple engine.
The Pina2bo strategy!
https://www.goodreads.com/book/show/57094295-termination-sho...
We already cannot stop burning oil today because the economy would implode. I don't think that it is reasonable to think that not only we could stop burning oil entirely, AND at the same time produce more energy than we got from oil just for extracting the CO2 from the atmosphere... And the reality is even worse than that, because on top of all that* we would need more energy to... live.
It's important people understand that we cannot extract the CO2 once it's out there. It's practically impossible, period.
Posted by the account, BurningFrog. You can't make this shit up.
Forgive me if I do not take "making sunsets" as a credible source of information.
There's a body of research that covers existential risks associated with sai and srm:
- https://www.sciencedirect.com/science/article/abs/pii/S00163...
- https://www.frontiersin.org/journals/climate/articles/10.338...
- https://agupubs.onlinelibrary.wiley.com/doi/10.1002/2017EF00...
Further from an actual credible source:
https://www.unep.org/resources/report/Solar-Radiation-Modifi...
> While there is a growing body of literature and advanced modelling on the topic, which has been developing for many years, there is very little evidence or research on the risks and impacts of SRM. The report outlines these limitations in the evidence base. UNEP is concerned that while the scientific literature shows that SRM, and stratospheric aerosol injection specifically, can cool the globe, there is a dearth of data on the risks and impacts. For technologies that can alter the chemistry of the stratosphere, the world needs much more information to support decision-making.
No, it is not "safe" by any measure.
https://www.science-gate.com/IJAAS/Articles/2025/2025-12-01/...
You answered it yourself: it's not possible to get rid of the excess CO2. Think about conservation of energy: we extracted energy by burning stuff and producing CO2. We cannot revert that with less energy than we extracted from doing it in the first place.
> It sounds scary, but is actually safe
Famous last words.
We're talking about using more energy than the one we got from the fossil fuels we burned, right? So that means that on top of replacing fossil fuels with renewables, we would need to more than double it in order to remove CO2 from the atmosphere.
This, in itself, is impossible. Already we won't be able to replace fossil fuels entirely, we will just end up with less energy in total. We most certainly won't end up with twice as much.
And that's assuming that we could extract the CO2 from the atmosphere with close to the amount of energy we got by burning it in the first place. Which is wrong. CO2 in the atmosphere is actually very costly to extract in terms of energy.
It's not that it's not easy. It's practically impossible.
The total annual CO2 budget of the earth is tremendous; less than 5% of CO2 emissions each year into the atmosphere are from humans. Volcanism, photosynthesis, and other natural sources outweigh humans by far. In numbers, ballpark 730gigatons from natural sources and about 30gt from humans.
If you look at the amount the CO2 levels increase each year in the atmosphere, you'll find that they net increase by 16gt per year or so.
Implying that if we ceased all human CO2 emissions, the atmospheric levels would start recovering at around half the rate they're currently increasing.
Imagine every year a company makes $730,000 in revenue but spends $730,000 on various expenses. Its bank balance doesnt change because the income and expenses cancel out.
Now suppose the company starts receiving an additional $30,000 every year while its expenses stay the same. At the end of each year, its bank balance increases by $30,000.
By your logic, someone could argue: "That extra $30,000 can't be responsible for the growing bank balance because it's less than 5% of the company's total annual cash flow of $760,000."
That's obviously nonsense. The bank balance grows *entirely because of the net imbalance*, not because the extra income is a large fraction of the gross cash flowing through the account.
The carbon cycle works the same way. Natural emissions and natural uptake are both enormous and are approximately in balance. That 730 gigatons of CO2 released by natural sources has a corresponding 730 gigatons of CO2 capture from natural sinks. Its human emissions of CO2 that are the extra deposit that creates an ongoing imbalance, and that's why atmospheric CO2 continues to rise.
Also photosynthesis is not a source of CO2, on the contrary it's one of, if not the biggest carbon sink, reclaiming a significant portion of that 730 gigatons of CO2 released by volcanos and other sources.
Yes, this is my whole point. You wrote a long condescending comment accusing me of being a climate denier that fully agrees with me.
My point is that the actual amount of atmospheric increase per year is less than the amount humans put into the atmosphere per year, so 1) obviously humans are responsible for CC, and 2) could stop it at any time by dropping emissions below the amount the atmospheric increase amount.
The net CO2 impact of natural processes is -19Gt/yr. Humans add +37G/yr for a net +18Gt. If we stopped everything, you'd expect -19Gt/yr; however, natural sinks like the ocean will start off-gassing, cutting the improvement to about half.
Because of how long this switch will take, most IPCC options need 100 to 1000 Gt of net CO2 removal by the end of the century to limit the temperature increase to 1.5 degrees.
That is the message I am.trying to convey.
Then goes ahead explaining something completely different.
I say that's not so. We need only to sufficiently reduce emissions.
Well I agree on that. And even if we cut them to zero, the temperatures will not go down. So the very best we can hope is to keep the temperatures at the current level, and that's assuming that we cut all our emissions.
And the fact remains that we would need unreasonable amounts of energy to extract CO2 from the atmosphere (it was suggested with solar panels and stuff).
I didn't know that if we completely cut emissions, then CO2 would go down (and temperature would not during our lifetime, but they would at least stop rising). But "humans extracting CO2 from the atmosphere to compensate for their emissions" is impossible for the reasons I mentioned.
So to cover double the energy consumption of fossil fuels with solar we need to cover 0.2% of the surface in solar. Compare to around 10% covered in farmland.
Again, very back of the envelope math, but in my opinion this does not seem impossible.
But that doesn't matter while we're still emitting.
You can use pyrolysis to reduce usage of energy. Instead of building ethanol using corn etc, some fast growing crop can be converted to biochar using pyrolysis. And stored indefinitely underground or somewhere. Of course this isn't profitable and probably will run in to climate activists roadblocks.
The stratospheric injections of SO₂ can bring temperatures down to healthy levels. This fixes most of the negative effects of high CO₂, and can go on for centuries if need be...
... but I'd prefer to get that CO₂ out once and for all. Solar powered machines that extracts it from the air and pumps it down to eternal underground cavities should be able to do that once we have much better tech. If it takes decades or centuries doesn't matter too much.
The bigger unsolved problem is how to get this paid for.
> Spray the stratosphere with SO₂
Raining salt over terrestrial ecosystems is not the way, but over the ocean, may work.
You have my applause teravor.