Cumulative and (probably) irreversible

This post may be written more in frustration than anything else, but I’ve had some recent discussions that have made me wonder if even those who spend their time thinking/writing/commenting about climate change fully appreciate that it’s a cumulative problem that is probably irreversible. Or, maybe, if they do, that they don’t fully appreciate what this really means.

It is now pretty clear that the overall level of global warming is going to mostly depend on how much CO2 is emitted in total; i.e., it depends on cumulative CO2 emissions. This leads to two basic conclusions; stopping global warming requires getting CO2 emissions to zero (i.e., net zero), and keeping global warming below some level would require doing so while also limiting total emissions (i.e., a remaining carbon budget).

It’s also been clear for quite some time that global warming is probably irreversible on human timescales. The changes that are induced will probably persist for many generations. If emissions don’t get to zero before the impacts become extremely severe, it will be too late to stop them from getting even worse. Yes, there are some possible technological fixes, but they carry their own risks and have never been implemented at a suitable scale.

So, if we decide to follow a pathway that will lead to higher total emissions than might otherwise be the case, we will be committing future generations to a level of warming that could have been avoided and to impacts that they might not have had to experience.

I realise that the above doesn’t immediately tells is that we should focus all our attention on emission reductions; there are many other important factors to consider. How do we do so in a way that is fair and that doesn’t do more harm than good? How do we do so in a way that also allows communities to improve their resilience and reduce their vulnerabity? Do we accept that there might be circumstances where it is still preferable to continue using fossil fuels? etc.

However, even though these other factors can be very important, it still seems crucial to be aware that, at the end of the day, the amount of global warming that people will experience will ultimately depend on how much CO2 is emitted in total, and that the resulting changes, and impacts, will probably persist for a very long time. I know this is clichéd, but there really isn’t a planet B and, if we’re not careful, we could end up substantially, and irreversibly, changing the climate of this one.

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30 Responses to Cumulative and (probably) irreversible

  1. Just in case anyone thinks the above applies to a discussion with them :-), I have also had a number of recent discussions where those involved do seem to get the various subtleties.

  2. RickA says:

    Is net zero based on the CO2 we emit.? Or is net zero based on our emissions – net natural sink amount?

    It is my understanding that 1/2 of what we emit is absorbed by the ocean, plants etc.

  3. Rick,
    Net zero is net zero our emissions. The reason that global warming roughly stops when we get to net zero is because the natural sinks continue to take up some of what we’ve emitted so that atmospheric CO2 concentrations drop enough that warming stabilises. If we got to the stage where the natural sinks were taking up as much as we were emitting, then atmospheric CO2 concentrations would stabilise and warming would continue.

  4. what happens if we get to net zero on CO2 but have paid no attention to controlling emissions of the other green house gases? CO2 is obviously the big dog, but should we worry at all about the little dogs?

  5. Small,
    That’s a fair question. However, most of the other anthropogenic emissions are short-lived and so don’t persist in the same way as a long-lived GHG (the dominant one of which is CO2). So, the long-term warming will pre-dominantly be due to CO2. However, it is true that if we sustain emissions of these short-lived GHGs then they can contributed a reasonably fraction of the warming. However, since they decay there isn’t an equivalent to a carbon budget and it’s less crucial that we start reducing their emissions as soon as possible.

    However, to meet some of our current targets (such as keeping warming below 1.5C) it does become important to deal with these other emissions. So, yes, we should worry about these other emissions, but CO2 is the key one when it comes to long-term warming.

  6. I like to use the term ghg when I talk about emission reduction and then specify that the big dog if CO2. If I was to talk about CO2 emission reductions, I would be inclined to mention the small dogs as well. You know, just to cover the bases and be a little more comprehensive. As you know, the short term heating impacts from the small dog heating gases might actually be significant if and when a person thinks about irreversible impacts of warming such as the collapse of the Thwaites glacier. If heating from the small dogs pushes us over the temp at which the Thwaites collapses, the impacts from a small dog, say methane, would be catastrophic and irreversible. I think a lot of people don’t fully appreciate the possibly irreversible changes that could be produced by the short acting greenhouse gases.

    I appreciate, but try not to share, your frustration with the folks who are having trouble getting their heads around the complex problems we face from our greenhouse gas emissions. I think I will continue to attempt to not be frustrated, but I have resolved a while back to occasionally mention my concerns and share my thoughts about them.

    Cheers

  7. This is perhaps a technical point, but one that is similarly frustrating to me.

    It’s when people say something along the lines of “we need to eliminate (or sharply reduce) our CO₂ emissions *first* and then deploy NET’s to deal residual emissions and/or overshoot”.

    If you are dealing with emissions that are cumulative, and temperature and other damages that are largely irreversible, *and* you anticipate an eventual requirement for multi-GtCO₂/yr CDR, it makes no sense to delay or hold back deployment in reserve.

    I keep making this👇 point for both for illustrative effect and genuine concern reasons, but consider the case of nitrous oxide.

    N₂O is also has a century+-scale lifetime, and represents ~6-7% of both our current incremental and historical cumulative radiative forcing. The *best*cases in the IPCC AR6 WGI SSP’s have us reducing emissions by perhaps 30% by 2100, and I am not even aware of drawing board ideas how to get it much lower.

    So just offsetting the additional annual radiative forcing would require either ~2.5 GtCO₂/yr of (~permanent!) CDR or some other equivalent radiative forcing offset (but what? SRM? N₂O-removal?).

    My point being, if you are going to need, conservatively, 2.5 GtCO₂/yr by 2050 or 2100, how can waiting to bring this online be optimal or even justifiable/ethical?

    If you could wave a magic wand and scale up immediately, you would be ahead almost 200 GtCO₂ of avoided cumulative emissions versus delaying its introduction and scale-up until later.

    Even if the argument is moral hazard about not otherwise cutting emissions sufficiently if such technologies could have been used, how do you justify to future generations that, well, we *could* have used these technologies at scale earlier, but we chose to delay rolling them out until after irreversible ice-loss had occurred. There are certain things – like ice – where it really matters whether we approach our stabilized temperatures after overshoot on cumulative emissions or not.

    Maybe I am sensitized on this, but I see a lot of opposition to, say, CDR that makes a perfunctory nod to “needing some, someday…” but then suggesting it should be discouraged as much as possible. That may make sense politically or strategically, but it doesn’t make sense from the p.o.v. of science of cumulative emissions.

    Even if it were to turn out that we were to find out that we can’t scale CDR past, say, 3 GtCO₂/yr for some unforeseen technical reason, we are *still* better off knowing that sooner and having it deployed earlier than waiting for some sort of moral or strategic reason.

    It’s like withholding insulin or blood pressure medications from an already compromised patient until they get a certified A+ on their diet and exercise report card.

  8. Rust,
    That’s an interesting point. I hadn’t thought of it like that. I agree, though, that given that the problem is cumulative, anything we could do to reduce emissions as soon as possible would ultimately reduce total emissions, and any delay will probably increase total emissions. Hence, the sooner it it implemented, the better (from a cumulative emissions perspective).

  9. There are a lot of people who describe the situation as a crisis and mouth the words about the need for an all-hands-on-deck, all-of-the-above approach…

    … but in the next tweet or wherever start insisting on purity tests or other conditions/exclusions as if we had all the time in the world, and certain emissions or reductions count against our cumulative budget and others seem not to.

    “Do we need steel for the energy transition?” “Yes!” “Do we need steel?” “No, we should pause steel production until it can be produced without emissions! And no CCS – it a scam!”

    (real👆)

  10. russellseitz says:

    How do we do so in a way that is fair and that doesn’t do more harm than good?

    Run the global numbers on limiting CO2 increase to a part per million a year, and divide by world population , and 365 , and the result is a per diem fossil fuel ration that wouldn’t fill a Christmas stocking with lumps of coal.

    Will 2022 be the year in which ignoring climate mitigation flanks carbon mitigation in the calculus of moral hazards ?

  11. Willard says:

    Speaking of moral hazards:

    If there’s anyone who should be willing to cover the cost of climate mitigation on a new arena, it ought to be Edwards. In addition to building CNRL into a major global player, he also co-founded FirstEnergy Capital, one of the oil and gas sector’s biggest financiers, in the early 1990s alongside Brett Wilson, Jim Davidson and Rick Grafton.

    But even if you set that aside, there’s the fact that climate mitigation isn’t a theoretical risk for the Calgary Flames or its fans, who watched the Saddledome get flooded up to the cheap seats back in 2013. For him to balk at the modest costs of preparing a new arena for potential climate risks isn’t just a bad look — it’s an epically bad read of the room.

    That might be because Edwards doesn’t spend much time in the room anymore. As CNRL’s 2020 filings revealed, he now lives in St. Moritz, Switzerland — a move some have speculated is for tax purposes. He first left Canada in 2016, just as federal and provincial income taxes were set to rise, although he insisted that wasn’t the driving force behind his initial relocation to London. But wherever Mr. Edwards cares to hang his hat these days, it should be abundantly clear by now it won’t be Calgary.

    https://www.nationalobserver.com/2021/12/23/opinion/calgarys-billionaire-nhl-owners-just-played-themselves

  12. angech says:

    The strong message is that if the science is right it is already to late.
    A point made by SBM and some others here.
    Human nature is, well, human nature.
    Two ways to do things and humans en masse go for self interest and the wrong way.

    In that context the urge to do something is itself problematical and paradoxical.

    Practically the best solutions are.
    Pretend nothing is happening, relieves stress.
    Acknowledge it is happening and party anyway, avoids stress.
    Adopt a different mindset, admit the world is an illusion and reduce one’s own needs to the minimum

  13. angech,
    I think if the science is right, then it’s not too late. In fact, it will probably never really be too late, but it could get much later than we might eventually like (or, maybe, it may eventually become clear that things were probably left much later than they probably should have been.)

  14. Joshua says:

    angech –

    > Two ways to do things and humans en masse go for self interest and the wrong way.

    I always love it when ideologues reduce complex phenomena, where there’s much conflicting evidence, to a simple conclusion that fits their beliefs.

  15. dikranmarsupial says:

    You are in a car heading at high speed towards a brick wall. Physics tells you you are not going to be able to brake in time and you are going to hit the wall no matter what.

    “Practically the best solutions are.
    Pretend nothing is happening, relieves stress.
    Acknowledge it is happening and party anyway, avoids stress.
    Adopt a different mindset, admit the world is an illusion and reduce one’s own needs to the minimum”

    Or perhaps take your foot off the gas and apply the brake to minimise the speed at which you hit the wall so that your injuries (and those of your unwilling passengers) will be minimised.

    Sadly angech has a point about human nature. I suspect too few will take action and injuries will be far from minimised. But that does not justify actively encouraging that attitude because *you* can’t face taking action and significantly damaging your own standard of living. I can have no “sharing of values” with those who suggest that, only discussion of the science.

  16. I sometimes think of the “car headed towards a brick wall” when I encounter “doomist” arguments on twitter, etc.

    It’s like we’ve realized that the wall is 70m away and we’re travelling at 100 km/hr. We know we have to get our foot off the accelerator, slam on the brakes as hard as we can, and we also know that we are going to hit the wall pretty hard regardless. (if my distance and speed aren’t righr, just go with the analogy)

    Doomists be like telling the driver “Hey! Because CMIP6, ECS, methane bomb and Thwaites, we’re actually 65m from the wal, travelling 105 km/hr, it’s foggy and the road is wet! You need to know this! Are you even listening to me?”

    Like, the driver’s job #1 is unchanged here, and the new information not going to change what the driver already realizes he needs and intends to do. It’s also not helping the driver – likely quite the opposite.

    Yes, analogies always break down… we’d like to know exactly how hard we’re going to hit so we can radio ahead for enough ambulances… But one thing that I find infuriating is the enormous amount of effort put into “warning” everyone that the impact might be rougher than expected… but not having anything to say about how that changes what we need to do. What are we supposed to do at this point? Aim for a *maximum* of 1.0°C warming? Build time machines?

    Even if they are speaking code for geoengineering, it still doesn’t change what the driver needs to do at this point.

  17. By the way, I probably left something out of (most) doomism helpful dialogues with the driver:

    “I don’t think the brakes are going to work!”

    🙄

  18. “Pull over and let someone else drive!”

  19. “And Bill Nordhaus =b>sucks! Hello? Are you even listening to me?”

  20. “This would never have happened if you had followed my directions! I’ve been studying this in detail since 2018!”

  21. that’s right. Keep it simple. I have been saying “hit the brakes” since at least 2018. Hit the brakes. Hit the brakes. Hit the brakes!

    Enjoy the holidays all! and Hit the brakes.

    Mike

  22. your comprehension skills and learning curve appear to have flatlined or achieved a negative slope in 2021. Fail better in the new year, A.

  23. angech says:

    Happy Xmas all.
    I know ATTP has this up on the next post but I will stay out of the way here.
    Have a great New Year as well.
    “Pull over and let someone else drive!”
    RNS you would have to know my driving just to start appreciating how apt this comment is.
    Sorry to be so gloomy.
    Hopefully we will be able to find a fossil less safe way forward that I just cannot see at the moment.

  24. dikranmarsupial says:

    Angech “Hopefully we will be able to find a fossil less safe way forward that I just cannot see at the moment.”

    “when faced with a problem you do not understand, do any part of it you do understand, then look at it again.” – Robert Heinlein

    There are plenty of small things we can do to reduce our dependence on fossil fuels, e.g. drive less, turn the thermostat down a bit in your house, avoid empty consumerism… None of these things will get us to net zero, but none of them are exactly rocket science and they will make more incremental progress than doing nothing out of despair. Above all, don’t vote for politicians that don’t care about the environment.

    Happy Christmas to all, I’ve just used up my quota of hope and good cheer for 2021, normal service will be resumed in the new year! ;o)

  25. I love the Heinlein quote, DM. I use that approach all the time in various projects where I can’t clearly see the whole process and it works for me.

  26. “I think if the science is right, then it’s not too late.” Even if the science indicated it is too late, I would say, hey, let’s do the right thing. Let’s do the best thing we can. If we can’t figure out the whole picture, then we follow the Heinlein proposal and do the steps that we can do. And, even if we are going into an extinction event or civilization collapse, let’s live our lives with as much joy, generosity and loving kindness as we can muster. To the extent that anyone thinks I need a label like “doomist,” then that label has to accommodate the joyous and generous living commitment as a first principle.

    Another quote that I find instructive:
    The first principle is that you must not fool yourself and you are the easiest person to fool.
    Richard P. Feynman

    I think that one is like the Heinlein suggestion. Keep reviewing and questioning your assumptions on a regular basis. I think it’s pretty easy to fool ourselves, so a little energy committed to unfooling ourselves is probably a good idea.

    Cheers
    Mike

  27. Look! It’s a brick wall and the brakes are out!!! Turn left!

  28. JMurphy says:

    “There are plenty of small things we can do to reduce our dependence on fossil fuels, e.g. drive less, turn the thermostat down a bit in your house, avoid empty consumerism… None of these things will get us to net zero, but none of them are exactly rocket science and they will make more incremental progress than doing nothing out of despair. Above all, don’t vote for politicians that don’t care about the environment.” dikranmarsupial

    I’m not sure that that sort of thinking is the way forward anymore. I do that and whatever else I can but it seems that just allows the majority to say “If I don’t have to do anything because others are, maybe everything will be alright anyway and I haven’t had to do anything different. If not, it’s not my fault and I don’t see why I have to do anything if most other people don’t either.”
    I think selfishness, looking after number one/your own, laziness and apathy are rife. What we need now are pressures on governments and politicians, to make sure that they all accept the seriousness of the situation and won’t hesitate to make tough decisions (like fuel duty increases and taxes on plastics, etc.) while also spending money on helping those less able to absorb those increases (rather than on nuclear weapons, for example). Politics has got to change and the role of politicians has got to change but we also need to change collectively not just individually. Unfortunately we get the politicians we deserve .

    It also means that companies need to stop using plastic. I’m fed up with doing my best to put out as little plastic for recycling as possible (and I still can’t buy many food items without that plastic, unless I want to spend all my extra money on more expensive plastic-free products) while watching my neighbours haul out huge bags full of the stuff. Plastic has to be made more expensive, restricted in use, and non-plastic coverings must be subsidised so no-one has suffer unduly.

    I don’t see where this change is going to come from, or when, but I’m lucky that I don’t worry unduly about it because I do what I can and am insulated enough from financial and social shocks that I can only marvel at the shortsightedness of the majority.
    I don’t hold out much hope but I also don’t despair! Che sarà, sarà..

  29. russellseitz says:

    Willard : climate mitigation isn’t a theoretical risk for the Calgary Flames or its fans, who watched the Saddledome get flooded up to the cheap seats back in 2013

    Thanks for the Canadian Gothic update !
    https://vvattsupwiththat.blogspot.com/2018/04/canadian-gothic.html

    Was The Friends Of Science billboard washed away ?
    https://friendsofscience.org

  30. dikranmarsupial says:

    “I’m not sure that that sort of thinking is the way forward anymore.”

    I disagree. As I said it is not sufficient (“None of these things will get us to net zero”), but it reduces the problem for the real solutions.

    “that just allows the majority to say “If I don’t have to do anything because others are”

    The flip side of which is, of course, if we don’t it allows the majority to say “If others aren’t doing anything, why should I?”.

    This isn’t about “messaging”, it is about what we do to minimise the problem. I we want to change society, we can’t expect to do that while not making that change ourselves.

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