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May 28, 2023·edited May 28, 2023Liked by Andrew Dessler

Thanks to both of you for this explanation. My problem is that I feel that these caveats are not highlighted enough in the paper. These should be stated very clearly upfront otherwise people that are not experts will become alarmed and draw the wrong conclusions, e.g. that Jim has found some missing physics that everyone else has missed and that we are doomed to 10C.

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I believe that Hansen is *also* saying that IPCC assumptions about warming/ZEC are wrong:

"Section 3 (Climate Response Time) explores the fast-feedback response time of Earth’s temperature and energy imbalance to an imposed forcing, concluding that cloud feedbacks buffer heat uptake by the ocean, thus increasing warming in the pipeline and making Earth’s energy imbalance an underestimate of the forcing reduction required to stabilize climate."

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Greetings from Auckland. I apologise for not being able to support you financially - I gave all my money to my children (the eldest 50) to buy houses to live in - but I did buy "Introduction to Modern Climate Change" prior!

My question is: If we stop emitting CO2, do the oceans start outgassing CO2? Since the oceans have been absorbing say a third of our CO2, one might think "yes". I guess it depends on how quickly the CO2 becomes sediment/how acidified they remain?

Yours is a great "hobby" - you CAN give up your day job ... hahaha :)

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No, the ocean is substantially undersaturated with respect to atmospheric CO2, so if emissions stop, the oceans will continue to take up CO2 for centuries.

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Its only in net-negative emissions scenarios that you get net-outgassing from the oceans (at least outside of implausibly extreme emissions/acidification scenarios).

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So if we reduced atmospheric CO2 level to say 350ppm what happens?

280ppm? (Okay, not going to happen any time soon.)

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At some point you'd switch from the oceans being a carbon sink to the oceans being a carbon source (generally around the point where you have net-negative global emissions). But this doesn't really change the behavior of the system all that much; you still get the same airborne fraction more or less applying to net-negative emissions as positive emissions (e.g. instead of the oceans/land taking up half our emissions, outgassing would counteract half our removals).

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That's what I thought. So we might need to remove about twice as much from the atmosphere as we have added to the atmosphere?

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Nope, same amount as we added. Carbon cycle is more or less symmetric, as Zickfeld et al point out.

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Please provide a source for your claim because according to this one the air-sea gas exchange equilibrates in under a year: https://www.pmel.noaa.gov/co2/story/Ocean+Carbon+Uptake

The deep ocean sink, which is what I assume you are referring to, happens on a much slower time-scale, often quoted in the range of centuries-to-millennia. This source also confirms what every other one I have read about this says: "It is difficult to determine the quantity of carbon stored by these mechanisms..." https://ocean-climate.org/en/awareness/the-ocean-a-carbon-sink/

So, while the oceans be may be largely unsaturated, they are also stratified and the surface layer that actually interacts with the atmosphere is saturated (or will be shortly after we are forced to stop our destructive ways). The mixing process is also believed to be slowing down, as mentioned in this article, increasing the stratification and weakening the sink: https://eos.org/features/the-future-of-the-carbon-cycle-in-a-changing-climate

"This freshening may result in less overturning of the layers of water in the oceans, thus slowing thermohaline circulation and carbon removal."

Yet when I read MacDougall et al. (2020) I find: "However, the three factors that drive ZEC, ocean heat uptake, ocean carbon uptake, and net land carbon flux correlate relatively well to their states before emissions cease."

Before emissions cease, the CO2 is being taken in as part of the physical process described by Henry's Law where the oceans are buffering against rising atmospheric concentrations. That equilibrates in under a year, so after emissions cease, oceanic carbon uptake will dramatically fall off as only the slow, deep-ocean mixing, process is left.

Henry's Law is also temperature dependent and warmer liquids are less capable of holding dissolved gases. With the really alarming ocean temperatures we have seen this year, one must wonder if they won't start outgassing instead.

MacDougall et al. (2020) also contains the following passage confirming that it is a purely academic exercise:

"4.3 Moving towards ZECMIP-II: For the first iteration of ZECMIP, the experimental protocol has focused solely on the response of the Earth system to zero emissions of CO2. However, many other non-CO2 greenhouse gases, aerosols, and land use changes affect global climate."

Because all of those things exist out here in the real world and by the way, Hansen et al., did attempt to account for those factors, so there really is no comparison between it and Zeke's "canonical" belief.

Some additional quotes from that EOS article regarding this very immature field of study:

"A Struggle for Consistency--Different methods of carbon flux observations do not always produce consistent results: There is an emerging chasm between constraints on carbon cycling derived from small-scale and large-scale observations: Not only do the physical processes differ at different scales, but different experimental methods and data sources produce different results."

"Looking forward, it's likely that potential nonlinear, time-dependent, and state-dependent feedbacks and responses in the carbon cycle will remain difficult to predict, particularly because many feedbacks interact with each other."

"Finally, a large spread in future carbon uptake is predicted by terrestrial biosphere models, suggesting that they do not yet have sufficient skill to offer precise predictions of future uptake at fine scales and into the far future."

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Yes. In fact, the sinusoidal Keeling curve demonstrates that, on a seasonal basis, CO2 uptake by the natural sinks routinely exceeds anthropogenic CO2 emissions. Annually, the CO2 uptake by the natural carbon sinks, being directly proportional to atmospheric CO2 levels; is currently more than 20 GT/year CO2 (above preindustrial periods). We should therefore expect hysteresis in the system as we reduce anthropogenic emissions. For example, if we succeed in achieving roughly 50% over the next few decades, uptake rates by the natural sinks should more than balance emissions, and we should see reductions atmospheric levels as well. At about 70-80% reduction in emissions, the new "equilibrium" could be near 350 ppm in the atmosphere, which is conveniently the target suggested several years ago by James Hansen.

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First to say I appreciate Zeke Hausfather thoughtful comments. Jim Hansen has a track record of very good work without ever trying to get it published in top journals (which due to space limitations would not never publish such analysis.)

Regarding some comments here on the question, raised by the author of this article, whether GHG levels will necessarily decline at some point in the future - i.e. at the latest once we run out of fossil fuels and CO2 emissions will stop: there is another one of Hansen's papers published 10 years ago that estimated the implications of burning all available fossil fuels, using a similar method based on paleo-climate analogues and minimal modeling:

Hansen J, Sato M, Russell G, Kharecha P. 2013 Climate sensitivity, sea level and atmospheric carbon dioxide. Phil Trans R Soc A 371: 20120294. http://dx.doi.org/10.1098/rsta.2012.0294

He estimated a resulting forcing of 9 W/m^2 and an (actual) warming of 16C, 30C at the poles and 20C over land areas. That would make much of the planet uninhabitable:

"Such temperatures would eliminate grain production in almost all agricultural regions in the world. Increased stratospheric water vapour would diminish the stratospheric ozone layer. [...] A warming of [only] 10–12C would put most of today’s world population in regions with wet a [deadly] bulb temperature above 35C. [...] there are more than enough fossil fuels to cause a forcing of 9W/m2 sustained over centuries."

My additions and omissions in [].

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9 W/m^2 is basically quadrupled CO2. While I don’t think anyone says we can’t do that, it seems unlikely on our present emissions trajectory. If we did it, though, it would indeed be bad.

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I think the point here is that we still have no evidence that "we" on a collective global level are capable of stopping the increase in greenhouse gas levels. We get confused by the fact that CO2 emissions have started to flatten. But as long as they are larger than the land and ocean sink combined, CO2 levels continue to increase. We still have a very long way to go until we reach this point.

What if the current drop in the price of renewables (and climate policy) will have a big effect, but due to continued economic growth it will simply lead to substantial but not complete displacement of fossil fuels. This could then end up in a situation where CO2 (and other GHG) levels stabilise rather than drop. A situation that could in principle continue for centuries. Especially likely given the increase in conflict, the global decline in democracy and rise in sectarianism and authoritarianism. Do not forget that the military needs fossil fuels, and may continue to need them very far into the future. So FF infrastructure will likely never be abandoned completely.

So we could still exhaust a very substantial part of FF reserves in the long-term. Don't get confused by RCP scenarios, they tend to stop in 2100. It's not that long in the future. My daughter, hopefully, will turn 85 that year. What about her children or grand-children?

Also worrying is the fact that in the IAM scenarios, e.g. the 1.5C scenario by the IEA the price of fossil fuels drops to very low levels. To assume that there will be no major national sized free riders and circumvention of carbon price regimes is just as characteristic of how detached from reality the IAM community, compared to how detached the IPCC is from the level or danger posed by the fact that we are - as GHG levels go - in a very dangerous climate regime right now (Hansen's point).

(see also https://braveneweurope.com/wolfgang-knorr-what-lies-beneath-on-the-latest-net-zero-scenario-by-the-international-energy-agency)

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What about the accelerated warming the preprint talks about - is this a new suggestion? I understand that sulfate aerosols mask warming, so a reduction of aerosols alone would increase temperature - but are they suggesting the effect is greater than previously believed?

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You write, "We will definitely stop burning fossil fuels in somewhere between a few decades to a few centuries."

What makes you think that? Do you think that as a species, we will forget how to build internal combustion engines? Perhaps you're assuming some political miracle? What would drive that massive reversal?

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at some point, we're going to run out of the stuff. it can't last forever.

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May 22, 2023·edited May 22, 2023

Wow, you're extremely ignorant about oil supply! You know a lot about climate change, but apparently not about the thing that causes climate change. That is entirely forgivable, because there are big investments in keeping this knowledge out of the public sphere. Indeed, it is very motivating for me in a positive way for me to continue my writing on oil, coal, and gas. I encourage you to go dig in to my petro-histories, where you will find that there is a perpetual over-supply of oil relative to the market. At almost every juncture -- even the junctures of apparent scarcity, like the oil shock in 1973 -- there are ample known reserves in the ground, and the main problem that oilmen face is to open up markets for it. To have demand. Literally, to market oil. If there is a momentary supply issue, then that creates an excuse to raise the oil price -- which is the goal of all petropolitics: to support high (or at least attractive) rates of return for a product of which there is a massive global oversupply. When prices ARE raised, that's then used as an excuse to build not only new production sites, but also new infrastructure. The contemporary example of that is the boom in LNG in Europe, which is not providing a single molecule of product to the European market--since the new infrastructure won't come online at least until 2026. The contracts that have been signed to support that infrastructure are 10 and 15 year terms of guaranteed purchases. Of METHANE, not Co2, but the incredibly potent warming gas that is very likely leaking out of the entire production chain, we'll never know because we're not able to measure how much is leaking out. No, my friend, we will be cooked long before we run out of supply. Peak Oil was completely disproven by the Fracking and Shale boom. Your optimistic tone in this is based on false assumptions -- the worst will happen.

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Factually speaking, the supply of fossil fuels on earth is finite, so if we keep burning it, sooner or later we will run out. How long that would take is anyone's guess, but retrospectively there will be a date of "peak oil". The notion is not wrong, just the prediction of its date. My prediction is that one or more factors will lead to a cessation of fossil fuel extraction before all of it is depleated. These include, in no particular order 1] Price pressure from renewables; 2] Extraction becomes impractical; 3] Law suits against producers and distributors gain traction; 4] Political reality converges with facts; 5] FF and bank execs, FF supported politicians start having unexpected health problems, a la Ministry for the Future.

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May 23, 2023·edited May 23, 2023

Factually speaking, the quantity of fossil fuels that are within that finite amount matters much more than whether it's technically finite -- there's so much of it in the ground that the surface of the earth will be indistinguishable from the surface of venus before we meaningfully start running low.

1] We've already seen that cheaper renewables don't result in a decrease in emissions. This free-market based idea assumes that the oilmen will graciously give up the power that they have carefully cultivated through decades of covert action and complicity with warcrimes, just because their product is being outcompeted. We may use more renewables in future, but that will not be accompanied with a substantial decrease in FF useage.

2] Extraction only becomes impractical at a given price point. As supplies begin to threaten to dry up, the price of oil goes up which allows for more inefficient methods of FF production to come online. Your hope here is that at some high price of oil, we stop being able to afford it -- that it becomes too expensive. But that will never happen, because the price of oil determines the price of everything else. The horizon of affordability expands as the price of oil goes up. As individuals we may not be able to afford to feed our family, but as a society we will always be able to afford oil, because the price of oil defines the floor of the economy.

3] Ask Stephen Donzinger how that's going. The fight will continue but when the FF companies literally buy the judge and the prosecutor both, it's going to be an uphill battle. Forever.

4] what political reality have you been living in? The one I'm living in gets more and more insane and detached from the facts every year. Did you not live through the trump administration? And then witness that the extreme insanity of Trump didn't result in any leftwing backlash, but rather just a resumption of center-right technocratic governance?

5] I fully support a campaign to assassinate executives. I am personally incapable of doing so, given that I lack the violent tendencies, resources, and abilities (I'm a writer not a fighter). I don't see ANYONE else stepping up to the plate to do that, except for far right-wingers who love fossil fuels.

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The supply of oil executives and ability for them to build armies of bodyguards is inexhaustible.

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It is not only a matter of price. It is also a matter of how much energy input is necessary to get a given oil energy output. What the literature calls EROEI. It has fallen by a factor 10 since the beginning of industrial oil extraction. For derived products like gasoline, it could already be as low as 6:1. [1] It will continue to fall, for sure. The question is how fast compared to alternative energies, and that I don't know. But the trend is not in the favour of the argument that it can outdo the competition for centuries.

[1] https://www.sciencedirect.com/science/article/abs/pii/S0360544204002890

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The assumption that it will be outcompeted rests on some fantasy of a free and fair market that doesn't exist. In reality, oil companies act as a government above the government, a source of power that permeates and corrupts democratic power. The source of its power is and has always been the American War Machine which has given oil an excuse to supersede human interests. They will use that power to make sure that if oil gets more expensive, they will simply get better subsidies, using 'national security' as cover. They will allow other types of power to compete only as far as it doesn't impact their own demand. It is as if they and we are being controlled by an ancient malevolent lovecraftean being from within the earth, we and our economies have lost our free will to this tellurian Force. To defeat it, we cannot wait passively for oil to become unaffordable because the horizon of affordability expands as oil price goes up. Instead we must focus on destroying the military-industrial complex that is the source of oil's power.

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