Comment by sulam
12 hours ago
FWIW my personal assessment is that this acceleration is both real and largely out of our control. Models in the past did not attempt to account for non-anthropogenic carbon emissions, but as we experience further warming, most especially in the Arctic, feedback loops and tipping points mean that this (carbon emissions caused by “natural” processes) are becoming more evident. This is especially sensitive because a large proportion of such emissions are methane, which is a much more powerful greenhouse gas vs CO2, albeit with a much shorter expected effect time once airborne (~12 years). Consider also that warming is not uniform and the polar regions are warming significantly faster (3x) than lower latitudes, making permafrost melting a very significant climate tipping point. The last point I’ll mention is not about non-anthropogenic emissions but rather absorption. The world’s oceans have been a significant absorber of CO2 however that process is sensitive to temperature and is less effective as the planet warms, not to mention acidic ocean waters prevent shell formation, which is a minor but meaningful carbon sink all by itself.
I’m of the opinion that direct air capture is the primary escape hatch we have for not hitting 3 or even 4C warming in the next 100-200 years, which mean major dieoffs in warm latitudes, even for humans, due to exceeding wet bulb limits. Oh and roughly 65M of sea level rise as the planet shifts to a snow/ice-free mode.
> Models in the past did not attempt to account for non-anthropogenic carbon emissions
They're literally mentioned by the first IPCC report already.
Early IPCC reports, all the way up to AR5 basically threw their hands up when it came to permafrost emissions. They admitted we didn't have the necessary data yet and for the most part didn't account for it at all in their models
Check out the 1.5C special report. Go to section 2.2.1.2, last paragraph says
> The reduced complexity climate models employed in this assessment do not take into account permafrost or non-CO2 Earth system feedbacks, although the MAGICC model has a permafrost module that can be enabled. Taking the current climate and Earth system feedbacks understanding together, there is a possibility that these models would underestimate the longer-term future temperature response to stringent emission pathways
https://www.ipcc.ch/sr15/chapter/chapter-2/#:~:text=Geophysi...
The claim being discussed is not that they didn’t account for it, but that they didn’t attempt to account for it. Reading that text, I think they did, but chose not to include it (I guess because they didn’t need to to make their point and, by not including it, avoided opponents from arguing about the validity of the result based on uncertainties in those models)
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> major dieoffs in warm latitudes, even for humans, due to exceeding wet bulb limits
my extremely pessimistic position is nothing will happen systemically even after the first few such events, and they'll take tens if not hundreds of thousands of lives.
I hope writing this out jinxes it.
You saw our reaction to covid. Millions. It will take millions of deaths in a nuclear armed country. See 'The ministry for the future'
I generally endorse that book but I am not sure we are quite so short-sighted. What's necessary is for the people who have power (not just billionaires and politicians, but even the middle class in democracies) to feel that they are in danger. A heat wave with a million casualties might do it, but I'm not sure it's the only way.
The ingredients for the Syrian conflict came about because of climate change (dried up farms - farmers moving to cities to find jobs - social tension). The last 10+ years has shown that the relatively well-off Europeans would rather watch the Syrians drown rather than "pollute" their luxury enclaves...
We'd rather kill everyone else rather than give up our luxuries...
Are you kidding? It will be Millions easily. It will just take 1 or two blackouts in wet bulb conditions to cause that
We are already far past the point of mere thousands of lives. Entire cities have been wiped off the map by floods.
It will take millions, if not close to a billion lives before we get serious
> Entire cities have been wiped off the map by floods.
Could you name some?
I wish it were different but I would not be surprised if it’s billions before anything changes. And even then there will be a major proportion of people that celebrate it as the second coming.
Billions? Sounds optimistic. Try trillions or quadrillions before anything really changes. Orders of magnitude are just a dime a dozen after all.
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Albedo modification (stratospheric aerosols) seems much cheaper than direct air capture, as a stopgap.
That unfortunately doesn’t help with ocean acidification.
We simply drop a giant tub of baking soda into the ocean every now and then.
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So what? You still save millions of lives.
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Re carbon capture -- we can cut trees and dump them in "carbon storage" places like the bottom of some water bodies where due to lack of oxygen no rotting happens, like peats and e.g. Black Sea.
And grow new trees in their place of course.
Considering the scale that we are burning oil and gas, our sequestration efforts would have to be comparable. Continuing to burn oil and gas and trying to recapture it is madness, like realizing you are driving way too fast and instead of taking your foot off the gas, you keep flooring it but start applying the brakes.
If we could actually grow trees to capture carbon equivalent to 250M+ barrel of oil per day, it would be better to just grow trees and burn them for energy.
If we just could stop burning that oil, that would be great.
It’s difficult to scale this to the levels we would need to make a difference.
Yes, agree. But I'm not sure direct air capture is more scalable than trees. Yes trees need to be moved, but at least they grow by themselves.
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Depending on the tree, freshly cut wood can have anywhere from 1:3 to 2:1 ratio of water to actual wood fiber.
So, unless we want to remove a massive amount of fresh water from the ecosystem, we also need to invest energy in drying out the wood well below natural humidity levels (transport to a desert maybe?) on top of electrifying what is currently a diesel and gas heavy industry (cutting and transporting logs with heavy machinery).
There's definitely lower hanging fruit for getting C02 out of the cycle.
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The more likely candidate is mineral based, because yes trees are hard to scale this way.
Excellent comment. I would only add two points.
I think it's important to mention the effects we're seeing today are caused by the emissions from decades ago.
Second, not sure if the paper in the OP touches this but we've reduced aerosols in the atmosphere. These previously were masking the effects of climate change by cooling the temperature.
The paper states it adjusts for "ENSO, volcanic eruptions, and solar variations" and not (afaict) the changes in shipping bunker fuel that reduced atmospheric SO2 (if that is what you mean by "reduced aerosols"). Below is a summary of the topic for those who are unaware. I withhold any opinion of validity of mechanism or effect.
> Oh and roughly 65M of sea level rise as the planet shifts to a snow/ice-free mode.
Current rates of sea level rise are still in single digit millimetres per year (https://en.wikipedia.org/wiki/Sea_level_rise), so that would take millennia. If there's even enough ice in the caps to get that far. Pre-historically, vast ice sheets covered broad swaths of regions now considered "temperate" (per the famous XKCD, "Boston [was] buried under almost a mile of ice"); what remains is a tiny portion and it's simply hard to imagine that it could fill the seas to such an extent.
If you have detailed calculations, please feel free to cite them. But my back-of-the-envelope reasoning: NOAA gives an average sea depth (https://oceanservice.noaa.gov/facts/oceandepth.html) of 3,682 meters. You propose that this could increase by nearly 2%. But the density of water only exceeds that of ice by about 9% (via https://en.wikipedia.org/wiki/Ice); the thickness of the https://en.wikipedia.org/wiki/Antarctic_ice_sheet is only about half that average sea depth; and it covers only about 4% of the water-covered area of the planet (14 million km^2 vs. 361 million km^2, per https://en.wikipedia.org/wiki/Earth) which is not even all oceanic.
This is a very common figure you can find much support for. Here’s one legitimate source: Ice Melt | Global Sea Level – NASA Sea Level Change Portal — https://sealevel.nasa.gov/understanding-sea-level/global-sea...
Okay, so they say it, but they don't appear to show their work.
What about solar shades? Seems like a relatively quick and easy way to regulate solar input. It's nice too because you can quickly remove it if necessary.
How long would a single cargo-load of shades have to be operational just to offset the amount of CO2 emitted by its launch?
What percentage of the 128-million-square-km cross-sectional area of the earth are you proposing to shade?
kinda obvious, the wealthy parts?
Only becomes viable if you have things like Starship online and fully operational, with launch rates at the level of Falcon 9 today. At the minimum.
Still a more viable option than bringing greenhouse gas emissions into the negatives globally, by the way. But that's a low bar. Nuking the ocean floor is probably a better call.
I'm confident that pushing everyone involved with Starship into the ocean would be a better and faster and more ethical green transition.
Reducing sunlight to the surface means we lose solar power effectiveness and we need to use more power for artificial lighting to grow plants.
Not to a significant degree.
Preventing 1% of sunlight from hitting Earth is more than enough to offset climate change heating. It's not enough to make agriculture or photovoltaics uneconomical. In many regions, it might make agriculture more viable on the net, not less - by reducing climate risks.
Most of the surface of the earth is covered with water...
What if we cover the ice caps, and cover parts of the ocean instead of messing with grow cycles of plants on land...
No reduction in solar power, no artificial lights to grow plants. What effects might that have on ocean life? (below a certain depth - probably nothing, so surface ocean life is what we need to look at).
Just my two cents... we got plenty of surface area we can cover and potentially not affect much at all for day to day for animals, plants, and humans.
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Regarding carbon capture, it will take more energy to capture the carbon than we burned putting it up there in the first place. Alan Kay, who actually did some systems work on the environment, explained it to me that the climate system is like an upside down coke bottle. It doesn't take much energy to tip it over, but it takes a lot more to put it back up.
In other words, we shouldn't have tipped it over in the first place. We may not have the energy to put things back to a habitable place.
Physically that’s not the case.
Scaled up nuclear power could be had for $3-4B a gigawatt/h. We waste say $1T a year on basic things, like not having universal healthcare. So a simple policy change would let us build about 300 reactors a years, after some scaling period. The excess energy can be used to turn C02 back into oil.
It’s not technically that difficult, we just chose to waste money on stupid things and rich people toys instead.
Energy abundance is simply the choose to build nuclear power plants at scale
Since the industrial revolution we've emitted about 1.5 trillion tonnes of CO2. Direct air capture requires roughly 1,500 kWh per tonne, so recapturing all of it would take around 2,250,000 TWh. Current global electricity production is about 30,000 TWh/year. That's 75 years of the entire world's electricity output just for capture, before you even convert it back to fuel, which costs even more energy. And thermodynamically you can never break even: we only extracted maybe 30-40% of fossil fuel energy as useful work, but reversing the dispersal of CO2 from 420ppm in the atmosphere fights entropy all the way back. It will always cost more energy to put back than we got taking it out. As for the nuclear numbers: Vogtle, the only recent US build, came in at ~$16B/GW, not $3-4B. The world started construction on 9 reactors total in 2024. The all time peak was ~30/year in the 1980s. 300/year has never been close to reality. Average build time is about 9 years per reactor. I'm not anti-nuclear but you can't hand-wave your way past thermodynamics and industrial scaling with "it's just a policy choice."
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What if global warming is beneficial to keep the next ice age at bay?
Can't wait until the arctic unwinds and releases massive amounts of methane into the air, then in the hot hell that earth becomes, all the fucking idiots saying "See I told those stupid liberals that the warming process was natural and not from my truck!!!1!1"
> Oh and roughly 65M of sea level rise as the planet shifts to a snow/ice-free mode
65M seems a lot bigger than the 3.6mm/year rise we are seeing today (with +1.5C in warming already happening). Where did you read that we will get 65M of sea level rise with 1.5-2.5C more warming?
> Oh and roughly 65M of sea level rise as the planet shifts to a snow/ice-free mode.
Where is this new figure coming from? It seems about 60X what's being published elsewhere.
If all glaciers and ice sheets on Earth melted, sea levels would rise roughly 65–70 meters (about 210–230 feet). It’s worth noting that a full melt of Antarctica alone would take many thousands of years even under extreme warming scenarios, so this is more of a thought experiment than a near-term risk. Current projections for this century focus on partial contributions, with estimates ranging from roughly 0.3 to over 1 meter of rise by 2100 depending on emissions pathways.
That's been known for a long time - it just hasn't been considered a likely scenario. It's the rise we'd expect if all the ice on Greenland and Antarctica were to melt:
https://sealevel.nasa.gov/understanding-sea-level/global-sea...
> direct air capture is the primary escape hatch
We MUST MUST MUST stop burning things. Stop it.
- We are still mining and burning coal. This is incomprehensible. US, AU, etc Eg: https://www.nacoal.com/our-operations
- We are still subsidizing oil to around $1T/year, not counting oil wars.
Yes it will take some grid and storage upgrades (US) and continue to embrace renewables. It would be cheaper than the oil subsidy.
Otherwise it doesn't make sense to put CO2 into the air with one hand and take it out with another.
This is why it's clear we will never do anything to slow the progression of climate change.
By far the most effective an immediate solution to limiting the damage of climate change is to simply to keep fossil fuels in the ground.
People talk about the economic pain of doing this, but that economic pain is nothing compared to the impact of unmitigated climate change.
Even though this would be painful, it is also by far the easiest and fastest to implement solution. It would take fantastically more time and resources to scale up direct air capture (even if it existed in a scalable format today) to come anywhere near addressing this problem.
> Yes it will take some grid and storage upgrades (US) and continue to embrace renewables
This is not exactly true, we would have to experience global economic collapse in order to reduce our fossil fuel use. 80% of energy is not spent on electricity globally and this is non-electricity usage is where most of the fossil fuels are consumed and this drives most of the global economy. There's a good reason there are multiple wars being fought over for oil.
The economic pain is current. The impact of unmitigated climate change will happen in the future. Thus, the ingrained short-term thinking of the markets and politicians makes this sort of planning ahead difficult.
It seems like the whole economic system runs on a quarterly time scale - just look at all the times negligent maintenance to improve profits in the short term have caused disasters in the long term.
Not sure what the solution is though, so I won't complain too much.
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Genuinely not being snide, I really do not know.
Is it possible to produce steel on industrial scales without coal?
I know early ironmaking (I live fairly close to Coalbrookdale!) used charcoal, but is that possible at a large scale?
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> We MUST MUST stop burning things.
Yes, we must. It is so rare to see someone saying this in public. Thank you for this simple clarity.
Stop burning everything! Fossil fuel, wood, plastic, garbage, paper. Stop making methane.
We only need solar energy at 1 dollarcent or eurocent (it will get much cheaper still!!) and a little batteries for the convenience of using electricity when the sun does not shine.
In the north and south you need more solar panels in the winter than in the summer by a factor of 50. But that pays it back in summer when you have a squanderable abundance of free and clean energy. We can store that surplus energy in purifying drinking water, melting iron ore or aluminum [5], melting reusable plastics or purifying silicon ingots.
Storing surplus heat or cold in the ground is another luxury, because it is more expensive than 1 dollarcent or eurocent solar running a heatpump.
Wind and hydro are also more costly than solar so they are another luxury with worse environmental costs than pure solar cells.
We need to build Enernet, a peer to peer electricity net and internet between all buildings with power routers. for around 100 dollar per building. You buy and sell your house surplus solar electricity to the neighborhood where it can be stored in car batteries. See my Fiberhood white paper [2].
[1] Enernet: Squanderable abundance of free and clean energy - Bob Metcalfe https://youtu.be/axfsqdpHVFU?t=1565
[2] https://www.researchgate.net/profile/Merik-Voswinkel/publica...
[3] Amory Lovins https://www.youtube.com/watch?v=v02BNSUxxEA
[4] Saul Griffith on the one billion machines that will electrify America https://www.youtube.com/watch?v=iEOPx2X-EtE
[5] 101 million machines away from a zero emission Australia https://www.youtube.com/watch?v=FQ8-uAhG-zs
> Stop burning everything! Fossil fuel, wood, plastic, garbage.
I don't understand the wood argument. Isn't it widely accepted we need to do burns to manage forests? Wood is a short-term cycle of carbon. It releases when it burns but frees up space to capture it right after. When people live on rural plots and trees fall, should they burn for heat (and lessen needing other energy sources) or let it decompose and cause the same thing? It's not the same as extracting deeply embedded carbon sources that won't make it to the atmosphere if untouched (fossil fuels)
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US, AU?
https://ourworldindata.org/grapher/coal-consumption-by-count...
Yeah true. I was just giving western examples.
To be fair, CN is known for exploring all avenues and are deploying a ton of solar and nuclear. http://large.stanford.edu/courses/2022/ph241/patel2/images/f...
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> Otherwise it doesn't make sense to put CO2 into the air with one hand and take it out with another.
I agree that it doesn't make sense, but I also want to challenge the engineering assumption that an extremely relatively inefficient solution should be ruled out.
If direct air capture worked and simply required absurd amounts of carbon-free power, say from nuclear, it would mean that we no longer have to fight political battles against the entrenched incumbents. They could simply emit whatever our elected politicians let them get away with, and DAC would soak it up.
I completely acknowledge that it seems somehow egregious to do it this way. I am an efficiency-minded person and would hope that we could do it the efficient way. But given all the ugly constraints and lack of progress so far, should we really expect this to be solved the way an efficency-minded engineer might prefer?
If we get to that level of desperation though, I would hope that we could simply pay the emitters to install carbon capture.
What I don't think will work is a politics of rage, righteous or otherwise. I don't recall any incidents in history where a politics of rage led to cool-headed, efficient technocratic solutions. The perennial problem is that the same politics of rage is equally accessible to your opponents, and it spirals down from there towards disorder and violence.
Stopping burning fuel now will return us centuries in the past, I suppose to about 1700. Twenty years ago it would return us to 1500. Then a handful of people had heating in their homes and a horse to travel. This will happen again if we stop burning now.
Such claims are ridiculous. Nobody needs burning fuel. Everybody just needs energy and it does not matter which is its source.
If enough energy is produced by other means than burning fossil fuel, nobody will return to the past.
I happen to be one of those who does not use directly any kind of energy, except electrical. Despite the fact that I am still connected to methane gas distribution, I have never burned it for already around a decade. (And unlike most, I cook myself from raw ingredients everything that I eat, but I stopped using flames for that many years ago.)
If burning fossil fuel would stop completely right now, that would not affect me at all, much less would return me centuries in the past, as long as the electrical energy supplier has enough sources in its hydroelectric, solar, wind and nuclear plants, all of which are abundant where I live.
For aircraft and spacecraft, hydrocarbon fuel will remain the best solution, but synthesizing hydrocarbons was already possible at large scale before WWII and it could solve easily this problem in a CO2-neutral manner, if a fraction of the money wasted for various useless or harmful things would be invested in improving the efficiency of such critical technologies.
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Bro what are you talking about. Nuclear power exists. You simply scale one we have now by 10x and buy BYDs EV capacity for 5 years and you’re done.
It’s not even particularly expensive relative to GDP.
No offense, but internet opinions are a dime a dozen -- do you have some special experience / credentials in this area? The arguments you provide are all just the sort of thing that PhD students would study, and incorporate into their models. I'm inclined to believe the experts, but if you _are_ one, and are saying with authority that these effects are missed, that is a much more interesting story.
The question is not if the commenter is an expert, but if they are correct.
The claim that some models didn't take larger systems into account is also because an expert in the arctic wasn't an expert in oceans. And the expert in biodiversity isn't an expert in food supply chains. Expertise isn't the question. Instead it is - do all of us who are non experts (all of us) have enough expert data to have a systemic understanding of an accelerating trend?
Ya, I agree, but I am not familiar with the intimate details of present climate models, nor am I planning to be. I can't/won't directly evaluate whether the argument they present is correct. But if _they_ are familiar with the intimate details of present climate models (ie, if they are an expert), I will tend to trust them more.
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On the internet the default pisition is not true/untrue; its, why should I acknowledge you?
If you are still trying to gauge truth before this, you are poisoning your mental heuristics. Thats why propaganda are ao effecfive: you can be told something is either, and it can still be effective.
Humans and LLMs are similar: the separation between input and commands is not a hard barrier.
So, back to GP: CLIMATE CHANGE is reversible. It just depends on whether we are talking about socipecnomics or physical processes.
2 years ago this was hard won knowledge, searching for papers and then putting it all together in survey form for analysis. Today I can tell you: feel free to ask Deep Research or another LLM you trust to do that work for you, generating citations along the way. You can convince yourself vs me having to convince you. It will take about 15 minutes.
I do not trust any LLM. But I am with the other person, the intention is not to discredit you or make you convince us - you are doing exactly what a comment section is designed for. Your comment is so good, in fact, that we want to trust it more than a comment in general deserves to be trusted.
while i agree its better to go off and prove it to ourselves, there is merit in having a conversation here
For better or worse, I don't trust an LLM to give me a correct answer in this space. But you've kindof dodged the question by recommending LLM's -- do you have special experience / credentials in this area?
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The people who say the Earth is flat have been "searching for papers" too.
No offense, but you sound like an oil shill.
Surely the children churning out papers in a memey field, with no real special insight into computational modeling, are the real ones to trust! Their papers are in Nature!
Ridiculous take, and you’d know that the OP was correct if you cared enough to know what researchers were actually saying.
Climate arguments devolve into appeals to impact claimed by authorities rather than any examination of what they’ve said.
Would a PhD student incorporate something into their model that flipped their results from agreeing to disagreeing with the premise that has not only practically become a religion, but forms the foundation for more and more funding flowing into their field each year?
Would they really want to risk being basically excommunicated from their area of research for daring to provide ammo to “climate change deniers”?
This is rather disingenuous. It can be hard to overcome momentum in research, but most researchers would be giddy with excitement if they could show our (extremely disturbing) forecasts regarding climate change are wrong and that things are much rosier than expected.
I also suspect you would find easy funding from existing climate change deniers. There is no shortage of well-heeled folk in that space.
Do you have a chip on your shoulder regarding research? You're begging the question by stating it is conducted in a "practically religious" way. Ask whether that's true before you question the effect it would have on somebody's behaviour.
> I’m of the opinion that direct air capture is the primary escape hatch
Great! That means we dont need to reduce emissions, cuz the magic bullet will just take care of everything. No need to change anything.
Relying on DAC is putting our fate in the hands of a technology we've never deployed beyond some pitifully small pilot projects, and expecting that we're going to be able to deploy that at a larger scale than we've deployed any technology since electricity itself.
We're going to have to resort to geoengineering alright, but it's gonna likely be stratospheric sulfate injection given how cheaply that can be done. Is it ideal? Nope. Better than global warming itself? Time will tell.
It's going to have to be a mixture of approaches. Stratospheric injection buys time for more holistic solutions.
The prospect that the future we're headed for will be one where the survival of civilization (and much of humanity) depends on a massive, ongoing industrial process of upper atmosphere pollution, in order to counteract the massive, ongoing industrial process of CO2 pollution we can't be arsed to rein in, leaves me feeling relieved to be mortal.
I don't disagree. At this point, I'm thankful I never wanted kids.
> I’m of the opinion that direct air capture is the primary escape hatch we have for not hitting 3 or even 4C warming in the next 100-200 years
Why is it always never 'burn less fossil fuels'.
Anything but the oil company bottom line huh?
We could cease burning all fossil fuels tomorrow and we'd still have to resort to geoengineering. Read the IPCC projections. All of the ones that keep us below 3c require 'negative emissions'. That's code for DAC, a technology that we've only ever deployed to small pilot projects, deployed more widely, more quickly, than we've deployed any technology ever.
TLDR: We're gonna have to use sulfate injection until we can transition our economy
Yes. And if we don't also stop burning fossil fuels then we'll never even break even.
nobody will champion degrowth because it means less profits