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Comment by passwordoops | Hacker News Reader

Emissions budgets are calculated using accounting best practice, which are not designed for full transparency (ref: the creative accounting used to obscure every financial scandal and economic bubble). THIS is the curve that matters:

https://gml.noaa.gov/ccgg/trends/global.html

The Iran blip is clearly seen, but it's just that - a blip. Levels continue to steadily rise.

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These two views are not necessarily in conflict: atmospheric CO2 concentration is (vagely/roughly) the integral of emissions. So if emissions are basically flat (-0.4%) you'd still see atmospheric levels rise.

Because flat is still very much an issue, we need a big reduction in output before we start to see the absolute value level off :/

Of course. But this isn't a process that can be made fast and "flattening" increase of emissions is a cool milestone.

There’s too much for abstinence to fix it now. We are going to have to intervene in land management practices to draw down the CO2 we already released. They’ve been trying to figure out how to decarbonize concrete and some of those techniques might eventually lead to net negative or at least closer to neutral.

It doesn't matter that abstinence couldn't fix everything anymore, because additional emissions still make the problems worse!

That's wishful thinking:

https://www.futuretimeline.net/blog/2025/09/27-underground-c...

Whatever we release now, we should expect to be permanent.

I'm not talking about putting gas into holes in the ground and then expecting it to not bubble back out and/or kill us. I'm talking about recarbonizing farm land, which we will need anyway to deal with climate change, aforestation, and probably accelerated rock weathering.

It took us 200 years to break it, we'll probably be 300 years fixing it, at which point the ocean will have likely absorbed all it can and started giving it back to us.

That’s like an alcoholic saying it took 60 years to destroy his liver but it’ll just take 90 years to fix it. It doesn’t work like that.

I'm sure you're trying to be clever but you've succeeded in communicating nothing.

We don't have 300 years to fix this.

Realistically it's easier to stop producing more than sequestering carbon. That's what the only target should be to stop releasing more carbon into the atmosphere as carbon capture etc requires energy which releases more carbon till we reach carbon free energy all form of carbon sequestration is mostly a con to get government contract or by oil and gas companies/countries to keep burning more.

If we reach net 0 carbon, which we won't, we still have the extra carbon we already added. That doesn't just go away. We will have to get to net negative to fix most of this.

Particularly because all the CO2 we dump into the ocean will return to the surface in ocean upwellings once the currents have run a full cycle.

if we get to 0 carbon that would mean we have reached carbon free energy so then using it capture and store carbon would be okay till then any carbon capture apart from growing more tree is pointless

We can think about capturing AFTER we stop emissions. Emissions can be significantly reduced. All vehicles can be electric, they add storage to the system and can supply power back, which means we can wean off of oil (transportation), coal and natural gas (electricity, heating).

If people stop buying gas cars, and every vehicle bought is EV, it will take 20 years for all vehicles to be EVs. Thats enough to build massive storage just using EVs: https://news.ycombinator.com/item?id=50257308

Western countries have high wealth and disposable incomes, they can ban all ICE cars and bring down costs significantly (already cheaper CapEx and cheaper OpEx), accelerating everything else. Ethiopia banned new gas cars in 2024, western countries can do it too.

This is doable in 20 years. All road transport, electricity from fossil fuels. In these 20 years, we can focus on other things and have R&D breakthroughs (maybe zero/low carbon concrete).

I am not too worried about it in the long term.

Electric Cars are the future, and that is speaking as someone who still prefers to drive a petrol / gasoline car. It will be a long 10-20 year replacement cycle. And China is rapidly reducing its CO2 emissions. To the point I won't be surprised if in the future they could advertise to the west about their product being cleanly produced.

Solar and Batteries are advancing fast. To the point it isn't even about being green, it makes zero economic sense not to use it. We aren't that far away from it.

It is going to be a bit of a bumpy road. But we are advancing in the right direction.

Transport is only 25% of emissions. If we converted all planes, trucks, ships etc to electricity tomorrow then emissions would go back to what they were in... 2005.

China emits ~33% of global CO2, they could get 50% of their electricity to be renewable in next 5 - 10 years. When Solar and Batteries ( Semi Solid State Sodium Battery ) catches up for grid, and Electric cars, we are talking about a global reduction of ~20%+ say by 2035.

It is not perfect, but I dont think that is too bad. We should be able to cut 50% globally by 2050 if not earlier. As I believe both the technology and production scale will accelerate in typical Chinese fashion.

And all of that is without any incentives. Just pure economical play.

Levels as in emission levels or total levels? Emission levels may have blipped (and the Iran war is a pretty clear inflection point especially in the developing world) but obviously until we're net negative total levels will not decline because it's cumulative

How would we get to negative emission levels?

Carbon capture presumably. Something we've only just started experimenting with.

If we stopped emitting carbon, cutting down forests, and got lucky with forest fires, natural processes would automatically begin to bring down total atmospheric carbon.

How long would it take to go down, and how sure are we?

I'm sure natural processes have some capacity to absorb additional carbon, but I feel like we're way past that point. Given how much we've already increased CO2, it will likely take centuries for any noticeable drop.

I didn't make any promises about the rate of decrease.

Going meaningfully faster will require massive reforestation and maybe some geo-engineering.

I didn't say you made any promises. But I've noticed that in the context of discussions like the one around climate change, this kind of ambiguity has a high chance to poison the debate - IMO because it unnecessarily leaves room for wildly unrealistic interpretations, which then become the assumptions on which subsequent arguments build. Once there are enough opposing assumptions it becomes impossible to bridge the gap, because you can't even tell anymore which faulty assumptions are at the root vs. which ones sprouted from those.

So I'm asking you in the hopes that your argument will be understood correctly, instead of being misleading due to distorted interpretations.

No matter what happens after it, getting to net zero carbon and net zero deforestation is step 1. That does not change - ambiguity or not.

Millenia. If it gets bad enough, human intervention will be necessary. And it's almost certainly going to be bad enough over the next 100 years.

I like the idea of fertilizing the dead parts of the ocean with iron oxide.

Recarbonizing the soil will also help make us more resilient to drought.

It will be interesting to see if the security implications of unreliable fossil fuel supply brings forward the date of peak co2 emissions. Adoption of EVs and solar PV is really spiking, particularly in the developing world.

Its also entirely possible things go back to "normal", like happened after the ME oil shocks of the 70s.

From 1980 -> 1990 the CO2 mole fraction (ppm) rose 20pts. from ~340 to ~360.

From 2022 -> 2025 the CO2 mole fraction (ppm) rose 10pts. from ~416 to ~426.

It seems we'll have the ppm rise 10pts. in 6 years, which is 40% faster than 40 years ago, which seems like an insane increase to me; almost like things are getting MUCH worse not better.

why did you use 2 different time scales? why not 10 or 3 years for both? What is the 10 year increase 2015 to 2025?

edit: I looked up the answer to my question. NOAA reported 25 ppm increase 2015 to 2025, from 400 parts per million (ppm) to over 425 ppm. (A 25% increase from 1980s)

NOAA has nice charts of ppm growth rate by year and decade https://gml.noaa.gov/ccgg/trends/gr.html

The difference between those curves isn't "accounting", it's that the emission rate is essentially[1] the time derivative of the CO2 concentration. They have different shapes because they're different (but related) quantities.

It's entirely consistent with precise and good faith emissions measurements for CO2 to be still increasing.

[1] Modulo the seasonal variation, absorption in the ocean, emission from other sources like permafrost thawing, yada yada.

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