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Climate Confusion

Posted on 27 June 2022 by Evan

Climate Confusion

I periodically see the phrase, "when we reach net-zero emissions," as though it's a foregone conclusion. It is not. What if the best we can do over the next 100 years is no better than stabilizing CO2 concentration. What then?

Current climate models indicate that future warming is a function only of future emissions, and not current atmospheric CO2 concentration (read here). However, if CO2 stabilization is the best we can do, then the minimum warming we will experience is defined by current CO2 concentrations. These two views are compatible, because to stabilize CO2 concentration at current levels and hold it there over the next 100 year requires some level of continuing emissions. CO2 stabilization therefore implies some level of future emissions that would be unavoidable. A world where the best we do is to stabilize CO2 has, for all intents and purposes, "warming in the pipeline", something that does not occur if and when we reach net-zero emissions.

Some people seem so confident that we will achieve net-zero emissions that they no longer consider current CO2 concentrations to represent a minimum commitment temperature. This is dangerous. Considering that as of 2022 CO2 is still accelerating upwards, it is prudent to consider what happens if the best we can do is CO2 stabilization.

Here is the specific event that prompted me to write this piece.

I recently used Fig. 1 in one of my posts. The top curve shows the expected warming corresponding to measured atmospheric CO2 concentrations for an Equilibrium Climate Sensitivity (ECS) = 3ºC/doubling CO2. The bottom curve shows measured temperature anomalies. The dotted line labeled "Ocean Time Lag" indicates that the oceans delay the warming because of the time required to heat up the top layers of the oceans. This plot shows measured data only: there are no modeling results, other than showing expected warming based on ECS = 3ºC/doubling CO2

Graphs of expected warming for ECS = 3 and another graph showing measured warming up to 2021

Figure 1. Top curve (solid orange points) shows expected warming corresponding to atmospheric CO2 concentration (shown by the open circles) and an ECS of 3ºC/doubling CO2. The bottom curve shows the GISS measured Land-Ocean temperature anomalies (read here).

In response, a reader commented

No... although the ocean lag is plausible and is still often cited, it was questioned a decade ago and is now much in doubt...

I believe the commenter was well intentioned, because they cited a credible source by Zeke Hausfather (read here), but drew the wrong conclusion about what it says about climate science. There are three important physical principles that I would like to emphasize. No modeling study I'm aware of has modified the efficacy of the following.

Principle 1: For given CO2 concentration, there is a corresponding equilibrium temperature that indicates when the Earth is in energy balance.

Principle 2: If the current temperature is lower than the equilibrium temperature, Earth will warm until the two temperatures are equal.

Principle 3: The oceans delay the time to achieve energy balance due to the time required to warm the oceans.

Principle 3 is often embodied as the concept of "warming in the pipeline" associated with the time to warm the oceans. For ECS = 3ºC/doubling CO2, the relationship between atmospheric CO2 concentration and equilibrium temperature, ΔTeq, is ΔTeq=3log(CO2/280)/log(2). Table 1 summarizes some typical values of ΔTeq vs CO2.

Table 1. ΔTeq vs CO2 concentration, rounded to the nearest 0.1ºC.

CO2 [ppm] ΔTeq [ºC]
350 1.0
400 1.5
445 2.0
500 2.5
560 3.0

Figure 2 shows one way to visualize these three physical principles. According to recent climate models (read here), if and when we achieve, and indefinitely maintain, net-zero emissions, the situation is straightforward: atmospheric temperatures stabilize at that point and there is no significant change in temperatures for centuries. The more complicated situation occurs if we do not achieve net-zero emissions, but that the best we do is to stabilize CO2 at some level. Even though stabilizing CO2 at current levels is "easier" than achieving net-zero emissions, stabilizing CO2 is itself very difficult. By writing about these two pathways, I am not implying anything about the likelihood that either will be achieved.

Figure 2 shows the hypothetical situation where CO2 is stabilized at 2022 levels for about 100 years. To stabilize CO2 concentrations, Hausfather indicates that GHG emissions must initially drop about 70%. To maintain stable CO2 concentrations, GHG emissions must decrease to 0 over about 100 years and then remain at net-zero thereafter. Indefinitely. The exact profile by which emissions must decrease to maintain stable CO2 concentrations is complicated and not important for this discussion. What matters is that if our emissions over the next 100 years result in stable CO2 concentrations, then for all intents and purposes, there is "warming in the pipeline" of a magnitude represented by the difference between the equilibrium and current temperatures. Think of this temperature difference as a spring, pulling the current temperature up to the equilibrium temperature.

Warming in the pipeline due to difference between equilibrium and committed temperature anomalies

Figure 2. Temperature trajectory assuming atmospheric CO2 stabilization near 2022. To achieve this trajectory, CO2 emissions must first drop about 70% and then continually decrease until they reach net-zero emissions about 100 years later. About 100 years are required for the temperature to stabilize because of the time required to warm the oceans.

Dangerous Confusion

The problem is that many people, including, I believe, the commenter to my post, believe so strongly that we will achieve net-zero emissions, that any talk about levels of "warming in the pipeline" due to current atmospheric CO2 levels is old science and incorrect. The path where future emissions allow us to cap warming at current temperatures is very difficult. Although we can talk boldly about what future we will "choose", this is not like choosing what clothes to wear or what to have for dinner. A much more likely emissions pathway is one where current equilibrium temperature anomalies represent minimum, committed temperatures.

The pragmatic point is this. As long as CO2 concentrations are increasing, by any amount, for all intents and purposes, there is warming in the pipeline. Even if we manage to stabilize CO2 at some level, there will still be warming in the pipeline for at least 100 years. And to maintain that level of CO2 indefinitely, we will have to reach net-zero emissions at the end of that 100-year period.

If we do not achieve net-zero emissions, there will always effectively be "warming in the pipeline", delayed by the time required to warm the oceans.

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Comments 1 to 50 out of 54:

  1. Confusion over "warming in the pipeline" reminds me a bit of the general  confusion over the so-called "hiatus" observed in certain temperature records during whenever-to-whenever (1998-...?) any particular study showed a deceleration or halt of temperature rise.

    There was never and could never be a "hiatus" in overall planetary warming short of a vast and mysterious disappearance of various GHG species, or some other impossibility. What appeared to be a slowdown or stall in warming to the extent this showed up in our metrics was (had to be) simply lack of perception on our part, incomplete instrumentation. There was no implausible change in radiative balance, sudden (and oddly unobserved) global albedo change or any other physical means of actually reducing the amount of energy accumulating on the planet. The energy was simply going where certain means of measurement couldn't see it. 

    But "hiatus" means a specific thing in the minds of most people, an actual pause in action. 

    "Warming in the pipeline" and "hiatus" are both examples of hastily conceived, poor terminology, sharing the feature of being mental pitfalls for information consumers of the normal, average variety. 

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  2. Doug, do you have a suggestion for better terminology that reflects the warming delay due to the difference between the current and equilibrium temperature anomalies?

    I like the mental concept of "warming in the pipeline" from a pragmatic viewpoint. If atmospheric CO2 concentrtions are increasing, then there is additional warming to come. If CO2 concentrations are stable or decreasing, but there is a difference between the upper and lower curves in Fig. 2, then there is also "warming in the pipeline.: This is consistent with the statement that future warming is due to future emissions, because if CO2 concentrations are increasing it implies continued emissions. But whereas the average person cannot easily get a handle on global GHG emissions, they can readily follow what the Keeling Curve is doing. So even if the phrase "warming in the pipeline" is flawed from a purely scientific viewpoint that says that all future warming is due to future GHG emissions, I find the concept of "warming in the pipeline" appealing from a purely pragmatic viewpoint.

    From Fig. 2, if and when we manage to achieve net-zero emissions, then the upper curve will come down towards the lower curve, the springs will relax, and the amount of "warming in the pipeline" will also decrease. But as long as these two curves are separated, there is effectively "warming in the pipeline".

    But I am open to a better way to phrase this. Comments?

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  3. I don't know the graphs above are meant to be or if I am reading them right. But..

    The ocean time lag is 30 yrs?

    The current temperature anomaly is 1.2C?

    The current CO2 concentration is 420ppm?

    30 yrs ago the CO2 concentration was 350ppm?

    pre industrial CO2 concentration was 280ppm?

    So 350-280 is a 70ppm rise has resulted in a 1.2C increase in temperature?

    420-350 is also a 70ppm rise so what temperature anomaly are we expecting in 2050?

    Is the ECS of 3C for 280ppm rise overly optimistic?

    I know I am being extremely simplistic here, but?

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  4. From the article, "EMISSIONS 29 April 2021 15:00
    Explainer: Will global warming 'stop' as soon as net-zero emissions are reached?.   
    "To stop these impacts may require reducing global temperatures through net-negative global emissions, not just stopping temperature from rising by reaching net-zero."
    Negative net-zero seems intuitive to me and necessary as a goal to promote, rather than "net zero." It's a wicked problem and negative net-zero may sprout its own wicked problems; we'll never know.
    I'm stumped.

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  5. wayne@3, thanks for your comments.

    The ocean time lag is a complicated function of the difference between the Equilibrium and Current temperature anomalies. Currently it is about 30 years for the current, specific CO2 profile, but this could change in the future. Currently temperature is increasing about 0.2C/decade, but hopefully this will decrease if and when we begin to aggressively cut GHG emissions.

    An ECS of 3C is a reasonable estimate, and is about midway between the range of low and high estimates used by the IPCC.

    EddieEvans@4, it's easy to write about the need for net-zero or net-negative emissions. Realizing them is quite another matter. The reason I focus on showing the CO2-stabilization scenario depicted in Fig. 2 is that by definition, we must achieve this much "easier" goal before we can ever hope to achieve the more ambitious net-zero or net-negative goals. So think of Fig. 2 as kind of a necessary first goal, first step. Just doing what Fig. 2 depicts would already be a huge success and would be a necessary precursor to more ambitious action.

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  6. There is the idea that a sudden end to CO2 emissions will result in the reduced forcing from continued CO2 draw-down balancing the pipe-line warming such that there is no extra warming beyond the end of emissions. As a theoretical exercise it is roughly correct but there is more to AGW than CO2 and a worldwide end to CO2 emissions (tomorrow morning, 0930 hrs GMT - set your watches) is but theoretical. But there it is, and folk do check it is a valid interpretation of what would happen (as per the lt blue trace below - graphic from this CarbonBrief item).

    CarbonBrief warming after zero CO2 graph

    But realistic zero-CO2 scenarios will not react like this. The IPCC AR6 SPM shows temperature peaking under SSP1-1.9 before zero CO2 is reached in 2050. And note its Fig10 which attempts to set AGW ΔT as a function of cumulative CO2 emissions. If you scale that graph, you'll find +1.5ºC equals to 2,960Gt(CO2). Note this is Gt(CO2) not Gt(C). And as of today June 2022 we have managed 2,510Gt(CO2).

    IPCC AR6 SPM fig 10

    But what is less well known is that post-2050 the SSP1-1.9 scenario expects negative emissions which according to the graphs in Meinshausen et al (2020) total 1,100Gt(CO2). That means we maintain the +1.5ºC (or a statistical chance of maintaining it) by extracting and storing out of harms way all our emissions from now to zero-CO2 as well as all the emissions back to 2008.

    That's quite a task to prevent pipeline warming from messing up the +1.5ºC limit. And the SSP1-1.9 scenario also shows (as does any logical analysis of what the 2,960Gt(CO2) budget implies) global CO2 emissions halving by 2030. And 2030 is not now very far away.

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  7. Love the balance acknowledgements. I dont hear this much yet it covers all of nature. By nature I extend to include the universe. Balance to me is like gravity. It is everywhere and will drop the apple on your head for lunch or speed you to demise when you step off the ledge. Orbits, plantlife, rivers and mineral cycles; even the milky way is in a 350M year orbit around our galaxy group. Balance. Co2 is a close brother of oxygen, and even though we draw up old reserves of that goo, Ox too is captured in the limestone and will require storms and erosion to bring it back up. Ox is in a steady decline for a M years in another cycle. I am watching for Co2 to balance with the 20% increase in foliage (Nasa) since 2000, 5% each last couple years, and the evaporation and cooling and added clouds and albedo this brings. Until once again there is balance, as this author references. There are millions of cycles interacting and the only constant is change and a desire to balance, without regard to one species or intent (see apple and falling above). Earth balanced after the big one (which sequestered the co2 and ox in the calcium and carbon slew), back from 4k ppm co2. If we consider balance, then warmer and erosion and trusting gravity and balance could mean the bigger picture just has us hubristically interjecting ourselves in to something, well, that might be needed later. Involving ourselves in something, not past our understanding, but past our paygrade. Interjections we are too important to get understanding just from an apple or acknowledging we know truly little, and that we can and will fall when we go past the edge.

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  8. Regarding the ideas of getting to 'net zero' and going beyond this perhaps getting back to pre industrial levels of CO2. There is a school of thought and some science that says atmospheric concentrations of CO2 are already high enough to stop or limit another ice age, so would it actually make sense to suck too much CO2 out of the atmosphere?

    That said, obviously we need to cut emissions fast and at least reach net zero.

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  9. Nigelj,

    The last time CO2 was this high the sea level was over 20 meters higher.  Most major cities are located at sea ports.  If the level of CO2 was reduced the final sea level will be lower.  

    I am skeptical that large amounts of CO2 can be removed from the atmosphere.  Who will pay for it?

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  10. nigelj@8, interesting thoughts.

    From what I understand, the ice anchors ocean and atmospheric currents. We might avoid the next ice age, and completely mess up the currents that sustain life by thinning the ice too much.

    Could humans ever hope to "adjust" the level of CO2 for a particular purpose, such as preventing the next ice age? Although I have no data nor science to back me up, I am sure that the best we can do to stabilize the atmosphere will leave us without any looming ice ages, but will leave us with whacky weather.

    The reason I wrote this piece is that I continually here this kind of talk about "how far we should go with NET technology," as though we will have the ability to deploy it at any arbitrary scale. I don't mean this in response to what you're writing Nigel, but to me this represents just one thing.


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  11. It may be possible to scale carbon capture and storage up enough to reverse the trend of GMST, but it will surely require a lot of energy. It would hardly make sense to power CCS with fossil fuels, nor to build dedicated renewable or nuclear energy capacity for CCS when fossil carbon is still being burned elsewhere.  At best, CCS must wait until the global carbon-neutral economy is built out.

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  12. nigelj,

    You have brought up a great example of "discourse of climate delay or denial" (refer to "Skeptical Science tackles 'discourses of climate delay' and 'solutions denial'")

    The focus on a small part of the big picture can look appealing as a justification for delaying doing, or deny the need to do, what is understandably required to limit the harm done to future generations of humanity. And limiting the harm done is the first step in 'developing sustainable mprovements' (harmful developments can appear to be helpful, as long as the focus is only on the 'good looking bits').

    The following Carbon Brief item from 2016, "Human emissions will delay next ice age by 50,000 years, study says", indicates that without the damaging human climate change impacts the next ice age would have been expected in about 50,000 years. It indicates that the current rapid increase of CO2 has created a long lasting condition that would 'delay' the ice age onset by an additional 50,000 years. Note that the ice age still happens. And this more recent Carbon Brief item, "Explainer: How the rise and fall of CO2 levels influenced the ice ages" provides more details regarding CO2's role in ice ages.

    The current high levels that would delay the ice age by 50,000 more years were not needed to offset the ice ace until 50,000 years from now. Wouldn't it be great to have well known reserves of fossil fuels that are kept buried and accessible until they were really needed? Maybe the entire next ice age could be offset by timely thoughtful use of those fossil fuels.

    In addition to finding and keeping the fossil fuels for that important future use (and 50,000 years is a reasonable amount of time for future humans to figure out how to effectively use the fossil fuels to do that), it is important for current day humans to reverse (clean-up, undo) the current massively harmful excess CO2. Expecting the next generation of humans to figure out how to live with the harm done (or correct things) is callous and irresponsible. There are many harmful results of keeping CO2 levels higher, not just sea level rise mentioned by michael sweet @9 (btw, michael I agree that if the systems of profitability and profit continue to be the governing systems more damage will continue to be done, and not just climate impact harm).

    The following CBC News item "Analysis reveals how climate change is influencing extreme weather" and BBC News item "Japan swelters in worst heatwave ever recorded" are added examples. But there are even more harmful consequences of the current excessive CO2 levels, harms that are irreversible, harms that will not be undone by reducing the current CO2 levels. And those harms are made worse as the CO2 is pushed higher -— even if pushing it higher today could be claimed to delay the next ice age by even longer.

    The best way to deal with high heat conditions is not the actions described in the most recent SkS repost of the Yale Climate Connections item "How to stay cool in hot weather". What would be best is leadership actions that rapidly limit the peak CO2 levels and rapidly bring them down (done in ways that still improve the lives of all those who are not yet living basic decent lives - but not caring if the higher-status harmful living ways get chopped down a few notches). The Joy Riding Party Bus humans who denied the undeniable understanding of how harmful they were being through the past 30 years and want to push CO2 even higher because they don't want their Good Time Harmful Fun ways of living to be limited or scaled back deserve to be severely disappointed (no matter how angry that makes them - like I, as a professional engineer, have had to tell clients they could not get what they wanted, no matter how angry it made them. And my MBA education helps me understand their anger and know what they want and why they want it. But I have maintained my engineering responsibility to Do No Harm rather than be tempted to personally benefit by letting them have what they want and reward me for allowing - and make me to blame if it turns out bad).

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  13. In my comment @12, the following wording probably makes more sense.

    (btw, michael I agree that if the systems of popularity and profit continue to be the governing systems more damage will continue to be done, and not just climate impact harm)

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  14. M Sweet @9

    Thank's for the info. That 20 metres of sea level rise at current CO2 concentrations / warming  is deadly serious although my understanding is it will be gradual over millenia. An ice age will also be serious and gradually emerge over millenia from what I've read. I'm not sure which is worse. Its a bit mind bending. But by then global population might be a lot smaller due to the trend towards smaller families,  and this will help with adaptation to either eventuality.

    I tend to agree sucking huge volumes of CO2 out of the atmosphere will be expensive or impractical. The best shot we have is reducing emissions. I think the whole sequestering carbon idea is just delaying reducing emissions, unfortunately.


    OPOF @12

    "Wouldn't it be great to have well known reserves of fossil fuels that are kept buried and accessible until they were really needed?"

    Yes this would be prudent. Lubricants, plastics, fertilisers, medicines etc.

    "Maybe the entire next ice age could be offset by timely thoughtful use of those fossil fuels."

    I've contemplated that idea myself. Might be a useful idea, but its geoengineering, and would acidify the oceans and would have other downsides and other challenges.

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  15. nigelj,

    I will clarify my point regarding the next ice age being offset. 49,000 years from now humans start using fossil fuels to keep CO2 levels nominally higher to stop the northern hemisphere ice growth.

    Right now humans have to focus on ending the increase of CO2 and focus on rapidly bringing CO2 levels down.

    And ending the production of unnecessary plastic from the fossil fuel resource would leave more for that valuable ice age offsetting.

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  16. This comment was prompted by:

    • michael sweet’s comment @9 “I am skeptical that large amounts of CO2 can be removed from the atmosphere. (because) Who will pay for it?”
    • Mal Adapted’s @11 “At best, CCS must wait until the global carbon-neutral economy is built out.”

    Those are both examples of ‘discourses of climate (action) delay’.

    And examples of the diversity of degree of leadership being harmfully compromised by the popularity and profitability of ‘discourses of climate (action) delay’ include the following two recent reports related to leadership actions to effectively limit the harm of climate change impacts:

    My responses to michael’s and Mal Adapted points include:

    • Who should pay for it? Obviously the people who benefited most from causing the harmful result should “pay the most to clean up the mess and repair the damage done”. This is why I used the analogy of Harmful Party People. Who should clean up and repair the damage done by a Harmful Party Crowd? Similarly, who should clean up litter? Those questions raise the more relevant questions “Why is harmful activity tolerated?” and “Why do people who are aware of the harm being done, the people who have to put up with or try to clear up or repair the damage done, not stop the harmful activity before it is gets too bad?” If the harmful people are the party crowd and they have the power, or ability to threaten and intimidate, to keep others for limiting the Fun They Are Having, then everyone else suffers the consequences and has to try to limit the harm done and try to clean up the mess made and repair the damage done - while the Party Crowd fight for the Freedom to be more harmful.
    • Why is technological development considered to be the only possible way to reduce Carbon levels? Indeed, in addition to significant reduction of energy consumption by humans, the remaining essential energy consumption needs to rapidly become net-zero. But many corrections of what has developed, and new developments that will reduce carbon, do not require any new technology to be developed. Check out Project Drawdown for many examples of non-technical human actions that would significantly drawdown carbon. Many of the ‘solutions’ are changes of regional food production to pre-industrial ways that are more sustainable regional ways of growing food. What needs to happen is ‘un-learning of the belief that technological developments are improvements by default’.
    • Why do people believe in and excuse systems developed by pursuits of Popularity and Profit that are undeniably harmfully compromised by persistent misunderstanding that excuses understandably harmful actions? Many harmful unsustainable systems have develop due to the collective of humanity inadequately limiting pursuits of power and personal benefit. Harmful winners can be expected to create harm through Authoritarian Rule, Dictatorship, Free Market Democracy or any other system that fails to effectively limit their Freedoms of Belief and Action. Any system can be less harmful and more helpful. It just depends on how harmfully compromised the people with the most power in the system become.

    Looking that the BBC and NPR news items with that understanding, the leadership of some of the 27 nations in the EU are more harmfully compromised. But, collectively, they were able to advance the development of helpful policy. The EU appear to be making advances in reducing harmful leadership influence. However, in the USA, the Supreme Court is now harmfully compromised in a potentially long lasting way. The USA leadership of global sustainable development efforts has always been questionable (The belief that Americans did not have to change how they lived, and the related leadership refusal to accept the understanding at the root of the Kyoto Accord that those who benefited most from the harm done so far must lead the rapid correction, even if it reduces their status – and competitive advantage - relative to Others). The USA being able to provide a helpful leadership example appears to be more questionable today than it was a decade ago.

    My closing point relates to Evan’s statement “Although we can talk boldly about what future we will "choose", ...”. That is also a tragically common misleading way of stating what is happening. The current day people are allowing the harmful among them to do more harm to the future generations of humanity. Current leadership is allowing harmful party crowd to make a bigger mess and do more irreparable damage to the ‘only known to be viable home for everyone now and in the future’. Another way to say that is “Although we can talk boldly about how much we will benefit from the harm our actions and inaction will impose on Others and the Future Generations of Humanity ...” (note that saying it that way makes it harder to continue saying anything).

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  17. Evan @ 5

    If we stabilize at 420ppm. At .2C per decade and a 3 decade lag we end up with 1.2 + 0.6 = 1.8C but the change from 280 to 350 resulted in 1.2C so there is still another 0.6C to consider which would bring it to 2.4C. I know its not a linear relationship but I doubt its going to break in our favour. The numbers just dont seem to match up in my mind. Land use is obviously a big factor but that doesnt seem likely to go our way in the near future either

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  18. wayne@17

    Let's separate the time lag from the equilibrium temperature. If we stabilize at a particular CO2 concentration and hold there for a sufficiently long time, the temperature will rise to a level that corresponds to the radiative forcing associated with that particular CO2 concentration. The relationship is something like this.

    • 350 ppm CO2 leads to 1C warming
    • 400 ppm CO2 leads to 1.5C warming
    • 450 ppm CO2 leads to 2C warming
    • 500 ppm CO2 leads to 2.5C warming

    And so on. So if we stabilize CO2 at 420 ppm and hold it there for 100 years, we will eventually warm to about 1.7C. The time lag to get to that temperature depends on a lot of complicated interactions in the biosphere. Under current GHG emissions, there is about a 30 year delay, but that delay could increase or decrease depending on how our emissions change. But in any case, the final warming is linked to the CO2 concentration.

    The reason we would lock in the current temperature anomaly if we were able to achieve net-0 emissions today, is that under net-0 emissions the atmospheric CO2 concentration would slowly decrease to a level that corresponds to the current warming. Considering we are at about 1.2C today, if we achieved net-0 emissions today, and stayed at net-0 emissions for a sufficiently long time, then presumably CO2 concentration would eventually drop to something like 370 ppm, a concentration that corresponds to 1.2C warming.

    Hope that helps, and hope the real climate scientists in the room don't find too much wrong with my description.

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  19. I'm still not sold on the idea that zero or net-zero emissions implies no future warming, as Evan says "A world where the best we do is to stabilize CO2 has, for all intents and purposes, "warming in the pipeline", something that does not occur if and when we reach net-zero emissions."

    First of all, it is not ultimately GHGs that determine warming, it is the EEI that does that. In other words, as I understand it, if the EEI is positive, but GHG emissions are zero, Earth still warms. 

    I also find it problematic that the idea of "zero emissions" or "net-zero" seems to imply to most people that all we are talking about are human emissions, when the possibility of an end to human emissions could exist while (significant) non-human emissions (for example permafrost melt) could still create warming, so that we are actually not at zero or even net-zero emissions regardless of source.

    I have long searched for a really solid scientific explanation of the concept of baked-in or committed warming that carefully tries to help people understand why some scientists say it exists and some say it doesn't. But the Zeke piece (and I don't trust for-profit scientists on this) is not convincing and neither is the Scientific American piece.

    Neither is the MacDougall 2022 ZECMIP study paper which clearly states "The most policy relevant question related to this research is: will global temperatures continue to increase following complete cessation of greenhouse gas and aerosol emissions? The present iteration of the study aims to answer part of this question by examining the temperature response in idealized CO2-only climate model experiments. To answer the question in full, the behaviour of non-CO2 greenhouse gases, aerosols, and land-use-change must be accounted for in a consistent way," which is another way of admitting that ZECMIP at this point is still "garbage in, garbage out."

    In fact, the pieces I have found seem to rely purely on models which are always incomplete, as is ZECMIP.

    And neither is this piece by Evan able to clarify this for me. Evan simply says it does not happen, as if that's been settled. He does not mention the warming, for example, that would come from the (potentially sudden? would it even matter?) end of reflective fossil fuel aerosols.

    The amazing lack of clarity on this subject, which is absolutely crucial to the discussion of any need to lower emissions, is astonishing, and leads cynical people like me to assume that it is a result of the IPCC-induced obfuscation and the complete ineptitude on the part of scientists to recognize that this issue is important and to do something about providing clarity. 

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    Moderator Response:

    [DB] Sloganeering and accusations of deceptions snipped.  Please conform future comments to adhere to this site's Comments Policy to avoid such behaviors in the future.  Thanks!

  20. Markp @19 , your final paragraph is, in itself, showing lack of clarity.

    Cynical people (like you and I ) as well as non-cynical people, should surely wish to take practical action to achieve nett-zero carbon emissions in a reasonably quick manner  ~  even though those scientists (with various levels of "ept" )  fail to give perfect precision of projection of the probable prospective developments  [futurists refer to this as the problem of pppppd  scenario ].

    More seriously, Markp . . . what alternatives are you suggesting?

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  21. Markp @ 19:

    In your first paragraph, you appear to be confusing two different scenarios:

    • net zero implies that anthropogenic net additions to atmospheric CO2 are zero (which means emissions are zero, or we have found ways to remove CO2 as well as add it).
    • Stabilize CO2 means that atmospheric concentrations are not changing - which can happen when anthropogenic net contributions are still positive, but are balanced because natural removals exceed natural additions by the same amount.

    In the first case (net zero), natural removals (which currently exceed natural additions) will cause a reduction in atmospheric CO2 over the next decades, and we expect to see temperatures stabilize. The decreasing CO2 will not lead immediately to cooling, because the current CO2 levels still have "warming in the pipeline" that will offset the immediate direct cooling effect of less CO2.

    In the second case (CO2 stable), there is still "warming in the pipeline", so we expect to see temperatures continue to rise for a while.

    Once you understand this difference, I expect that much of your confusion will dissipate.

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  22. MarkP... Zeke Hausfather has a very good explainer on this topic that may assist in your understanding of this topic.

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  23. Not sure how to respond to comments to my comment... There is no "reply" etc., featured in those comments, so I'll just say to Eclectic that I'm sorry you find my last paragraph unclear, and to Bob Loblaw and Rob Honeycutt: I'm clear on the difference between different types of "zero" CO2 scenarios, whether they imply constant concentrations or not. And Zeke's "explainer" is nice but is only a case in point: too many people simply assert that under a complete end to human emissions scenario, whereby natural uptake through oceans and trees continue drawing down CO2, heating will stop. Almost immediately. And they seem to base that belief purely on what has been modelled. And as everyone should know about models: garbage in, garbage out. The models don't reflect reality, though they try. Their inputs aren't complete, but merely partial. For example, ZECMIP is only CO2. The fact is, when we talk about hypothetically achieving no more human emissions, we're talking about a time in the future that is not tomorrow or next year or next decade, but at the very least, several decades, at least going by the extremely lazy response by humanity thus far. Correct? So by that time in the distant future, as emissions have continued, and tipping points have tipped, many things will have likely changed that our current thinking (or modeling) does not account for. So it is a bit silly to claim that temperatures will just stop IF/WHEN/? we ever manage to end human emissions, or "net" end them through the net zero concept. We place far too much reliance on models here, or rather I should say, those who are cheerleaders for net zero do. 

    So to Eclectic, I'm not proposing an alternative to reducing emissions. We need to reduce emissions. But that won't be enough. We also need to try the best form of SRM we can manage, which in my view is land-based mirrors, because the tech is here now, it's low tech, non-toxic, completely scalable, does not block sunlight from reaching our flora and fauna, and has an immediate effect on warming, unlike all the downstream GHG management methods.  

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  24. Markp @ 23:

    Ah, I see. You simply dismiss models. It must be really difficult for you to do any science with no models of any sort. Since science is based pretty much entirely on models (descriptive, statistical, mathematical, etc.), dismissing models is pretty much saying you dismiss science writ large.

    ...but then, the people doing the science (with models) and presenting results, you dismiss as making "assertions".

    I'm glad you "asserted" this viewpoint.

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  25. Markp @23 , to respond is simple.  Name the person you are addressing, and preferably add in the # post number, for greater precision. Occasionally that # goes "wrong" if the Moderator has altered some post numbers ~ but usually posts go onto the thread in the chronological order they were received.

    Again, I am not sure why you are bothered by "models and scenarios".   As you say, the social/political/technological response to CO2-derived global warming is rather tardier than ideal, in slowing and eventually halting the current rapid warming.   Yes, decades.

    Simply apply common sense, and remember the first step needed is the reducing of human-caused CO2 emissions.   Eventually, the CO2 level stops rising (and if you are curious, you can observe how much more warming occurs after that . . . so no actual need for "models").   Then you can observe the speed of subsequent CO2 level fall . . . and take further high-tech action if that seems warranted, in order to accelerate the CO2 decline.  If not going the high-tech route immediately to begin with!

    Probably best to ensure the CO2 does not drop below about 350ppm  (since eventually the natural Milankovitch-cycle cooling will start to show).   That "natural cooling" has been estimated to become problematic in roughly 15,000 years . . . so not an urgent problem!   Plus humans will then have the option of warming the planet by burning small amounts of coal (assuming we have been wise enough to keep a goodly amount of coal available for such future need . . . although by that stage presumably we will have the option of heating limestone per fusion-powered electricity).

    Markp, your idea of mirrors (ground-based, not space-based) seems reasonable in theory . . . but what about the practicalities?  Please go ahead and "show your workings" for areas needed / desirable locations / dollar cost per sq. meter / CO2-cost of building & installing mirrors / and so on.

    Remember the old axiom : Politics is the art of the possible.

    Stop worrying yourself about models ~ leave the models to the scientists.  Your personal responsibility (to yourself and others) means taking practical action with what you can do now .

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  26. Markp @23...

    "The fact is, when we talk about hypothetically achieving no more human emissions, we're talking about a time in the future that is not tomorrow or next year or next decade, but at the very least, several decades, at least going by the extremely lazy response by humanity thus far. Correct?"

    I'd say this is a faulty assumption. It is most certainly a Herculean task that is required, made even more difficult by the need to pull ever more humans out of poverty. But when you look at the changes that are occurring, particularly in how quickly renewables are now getting deployed, I think there's a decent chance we'll get to net zero around 2050 and full zero in the decades following that. 

    It must be disheartening for all the scientists and engineers who have been working on renewable energy for decades, and for them to have now created methods that generate electricity that beat the cost of FF's, only to constantly hear people make statements like "the extremely lazy response by humanity thus far."

    But perhaps they're too busy to take notice or even care what others say.

    It's worth noting, we are definitely going to see huge global challenges in the coming decades as the planet likely warms another degree celcius. So, perhaps it's important to put yourself in the mind of someone living in 2050 with far worse climate impacts each and every year. I think all of humanity is going to be laser focused on getting the last vestigages of carbon emissions eliminated.

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  27. I am not a scientist, but I've been working in climate science for a couple of years now.

    I wouldn't say I dismiss models, I'm just careful with them. Perhaps "garbage in, garbage out" is more common an expression to describe models in the financial world than in the natural sciences, but even so, when it comes to climate modelers I'm merely echoing sentiments from those like James Hansen, who clearly value models but prefer using real data, real-world, whenever possible. I've spoken to established research scientists who laugh off the climate modelers who so cheerfully say "temperatures will just stop rising" if net zero is achieved. These are people I trust. They've had long careers doing real science, not short ones playing with computers.

    And Rob, believe me, I do live a low-carbon life myself but I know very few others know or care about the need for that. The problem is, the accepted wisdom for many years now has been to not alarm people with GW talk, and churn out messages with hope and optimism, so what has happened is that people pretty much think "the experts" are taking care of things and there's nothing to really worry about. The person on the street has no clue how bad things are or how soon things will get very bad. No wonder they don't change their lifestyles further than maybe switching to a new sexy Tesla and eating vegan once a week.

    I'm also involved in the renewable energy business and that's definitely been an excellent development but again, people are being misled into thinking that's all we need to do, but it's not going to happen. Have a look at Simon Michaux's work.

    We've had the IPCC for 35 years and not much to show for it, and anyone who doesn't believe that is either simply ignorant or is fooling themselves. The IPCC plays politics with science. We need to take their estimates and double or triple them to achieve results close to reality.  

    All I can say regarding decarbonizing is that the money and the power is dead set against it because they're only concerned about today's profits, but as more and more of the world burns up, as food insecurity gets worse and water scarcity as well, their hands will be forced. The question is: will there be enough time then? Will the "laser focus" that might (might) be squeezed out of people when their backs are against the wall be too late? What is required, at the very least since people aren't acting like adults, are laws limiting waste in all industries, in all areas of government, and in our private lives, but is that coming? Are laws restricting unnecessary consumption coming? Laws banning the worst of the world's luxury goods would put a big dent in the fattest carbon emitters and send a message to all those people idolizing such frivolous living but is that coming? We could put tight curbs on new car sales and enforce drastic changes to allowable car specifications (reduction of size/weight/horsepower). We need governments to enforce "work at home" for all industries and jobs where that's feasible.  We need public service messages telling people to stop trying to "live large," we need celebrities to publically downsize their lifestyles, television shows to stop glamorizing the selfish life... the list is very long. So much needs to be done and could be done, but is it? Scientists gluing themselves to bridges is what we need, it's just about the only sensible thing to do this late in the game to make people wake up, but instead of getting the message people scorn them and governments lock them up. We cannot blame these protesting scientists. They've been asked to do something they were never trained to do, and for which no infrastructure exists, and to make matters worse, they're being pushed into solving this emergency by adopting a profit-making model that flies in the face of the spirit of science.

    The way I see it, we've got about one decade of "somewhat normal" life left before the food insecurity hits the privileged classes hard, and at that point, the societal collapse that has already begin is going to be much more life-threatening than heat. Net zero goals for 2050 may no longer matter when everything begins to fall apart.   

    As for the mirror concept, all the details are being researched but we're not talking about traditional glass mirrors but rather "specular reflectors" such as what you get combining PET with aluminum for a cheap, thin, durable, flexible mirror-like tool. These are already in use for local heat adaptation, but going from adaptation to global heat mitigation is just a matter of scaling up, and there are plenty of resources for it, unlike so much of the other ideas floating around. Plastics with no metal at all are also being developed that could be used. The whole concept is a simple evolution of white paint, which is not feasible for many reasons including the fact that it gets moldy and needs regular attention and re-surfacing. 

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  28. Markp... It sounds to me like you're seeing this as a problem that is solved through an individual's choices in lifestyle, and I think that's misdirecting where the problem is solved. 

    Most climate solutions are a supply side issue. The supply of energy, the supply of low carbon emitting building materials, etc. Individuals readily embrace low carbon solutions when they are available in the marketplace. But when low carbon alternatives aren't available individuals generally have no choice but to use carbon emitting products and services.

    Laying any blame at the feet of individual choice is essentially letting the fossil fuels industry off the hook for their responsibilities to humanity and a sustainable environment.

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  29. Markp... "We've had the IPCC for 35 years and not much to show for it..."

    Again here, you're seemingly making the claim that nothing has happened when the opposite is true. A great deal has been accomplished. A great deal more must be accomplished. You can certainly make the claim that the changes aren't happening fast enough, but you can't rationally claim nothing has happened.

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  30. Markp @ 27:

    Bluntly, when you dismiss information you don't like with statements such as this one:

    I've spoken to established research scientists who laugh off the climate modelers who so cheerfully say "temperatures will just stop rising" if net zero is achieved. These are people I trust. They've had long careers doing real science, not short ones playing with computers.

    ...then it is hard to take you seriously.

    If you want me to actually believe that such "established research scientists" exist, then you will have to point to a credible source of the statements they make and their arguments against the "established research scientists" that have studied and modelled carbon cycles for many years.

    And I'll see your "working in climate science for a couple of years now" and raise you "studying and working in climate science for 45 years now". Only five of those years were spent dealing with forest carbon cycles and their relationships with climate, though. And I've only been "playing with computers" for 45 years, too.

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  31. Hello

    No, I'm not at all advocating that individuals adjusting their lifestyles are the answer, far from it (I'm surprised to hear this from you!), but it is something that must be done. Average people pushing the politicians and business leaders to act is necessary as well, because as we can see, without that they'll continue making targets and holding discussions that don't get us anywhere.

    This is going to come down to us agreeing to disagree, I guess, for example regarding the IPCC and all the supposed "progress" we've made. I know that most people in climate science (scientists and others) think like you, that a lot has been done, etc. I just don't buy it. We've certainly managed to elevate the overall knowledge of GW among everyone - people from all walks of life (not with the honesty and clarity that is needed in my opinion, but...). But that has not translated into the kind of action we need by a LONG shot. It's politics and it's scientific reticence (i.e. David Spratt) and many other reasons, but it's there, staring us all in the face. Maybe I'm just speaking here to the optimists, 45-years of experience or not. I don't know. But if you think you shouldn't take me seriously because of my attitude towards models re "the end of temp rise" I'll just reiterate that it's not just me but people like James Hansen who have expressed those opinions. Just look at his latest tidbit: "Equilibrium Warming = Committed Warming?" where he writes in the 4th paragraph: "...climate science should be focused on data. That's the way science is supposed to work. However [the] IPCC is focused on models. Not just global climate models, but models that feed the models, eg. Integrated Assessment Models that provide scenarios for future GHG levels...sometimes the models contain hocus-pocus. As we mention in our current paper, they can assume, in effect, that 'a miracle will occur.'" And as you know, he's not the only one to criticise the overreliance on models. I'm assuming you are all familiar with Spratt and Dunlop's "What Lies Beneath."?

    At the end of the day, scientists are no different from anyone else in this world where we all have to struggle for survival and protect our jobs and reputations and do things we have to do but may not believe in. Research isn't done for fun or for pure curiosity unless one bankrolls one's own laboratory, which few do. It's done to support the money, make a product, build a name for oneself, etc. 

    So people like (unnamed) set up for-profit companies as sidelines in addition to their responsibilities with their universities and, look what he just did: sold Carbon Engineering for over $1B. Nice. Ka-ching. You can't sell simple solutions for that kind of money, can you? And Climeworks, when are they going to have an IPO and cash-out, for worthless DAC? And this is all because the IPCC said "We MUST do this!"

    An extremely important statement from the foreward of "What Lies Beneath" is from Hans Joachim Schellnhuber, professor of theoretical physics, etc., long list of credentials, when he said we are running out of time and so " is all the more important to listen to non-mainstream voices who do understand the issues and are less hesitant to cry wolf [than for example those scientists working with the IPCC]".

    I work with those non-mainstream scientists because they are the ones who seem to be cutting through the BS towards real solutions that give us more than hopium.

    Let me just ask you, and I am trying to be fair to the scientists in climate, generally speaking, because I imagine the vast majority are really doing their best. They aren't free to do what they might if they weren't trapped in the system we all are trapped in. (I know one who is a physicist but works with the IPCC on policy and he told me once "You have to trust your institutions, Mark"!!! Really. I trust the post office to deliver a letter. I don't trust politicians to solve global disasters that require those in power taking home less money.) But let me ask: if scientists really have been trying as hard as they could for decades now to come up with ways to stop rising heat and protect life on Earth as fast as possible, why has nobody else but a man who left his academic career at Harvard behind in order to found a nonprofit been able to come up with the solution staring us each in the face every morning when we brush our teeth, involving mirrors? Could it maybe have anything to do with the fact that it is just not very sexy? Honestly, I cannot understand or explain it any other way. And I've seen big-wig scientists in the climate sphere hear of this and say "where's your peer-reviewed research?" instead of just turning their brains on and thinking about the idea first. "Hey, makes sense, pretty obvious, actually...could be some complications, but overall, interesting idea..." (Kudos to Eclectic on this one) No, instead they just wanted research to back up the idea that ice will melt in a hot frying pan. 

    Well...would have been more fun over a beer. Take care.

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  32. Markp... 

    It's a little difficult to cut through your tone to get to a substantive discussion. I read a lot of frantic hand-waving but not much in the way of data or linked citations needed to evaluate the position you're putting forth.

    All I'm left with is restating what I've already said. 

    • A lot is happening toward decarbonization
    • Decarbonization needs to happen faster
    • We know a hell of a lot more about the climate than we did decades ago
    • We have a good chance of getting to net zero by ~2050
    • Once we get to net zero, warming is expected stop
    • There are going to be increasing impacts in the coming decades
    • The sooner we get to net zero the better off we are
    • There is going to be a longer, more difficult task of getting fully to zero emissions which will take some decades more

    We could rant all day long about what actions should have been taken and when they should have happened, but that changes nothing. We are where we are. People are working hard on the problem.

    I would add here, the basic premise of the 2°C limit is, we know with a reasonable degree of certainty that the last interglacial reached about 2°C over the modern Holocene preindustrial temperature without setting off any spiraling amplification effects. And 1.5°C has been set forth as a modern safe limit to try to stay under.

    We are almost certainly going to break 1.5°C. As I understand it, we'll probably also breach 2°C by ~2050 but global temperature will settle back down below that. I think the question becomes, how resilient is human civilization going to be, and how resilient are natural systems going to be. 

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  33. Rob Honeycutt @32 :

       Well stated.


    Markp @31 (and prior) :

       There is a danger zone, in posting, when an increasing word-count tends to cause a loss of focus.   Just as a 10-minute sermon does better than a 45-minute sermon.

    Worse ~ as verbiage increases, some cracks may start to appear in the messaging.   And the naive reader (such as me)  begins to identify contradictions :-   This  part looks Extinction-Rebellion-ish . . . That  part looks Denial-ish . . . Here  is some disingenuous arguing . . . There  is a practical impossibility . . . and so on.

    It all leaves a feeling that one is looking at a mask ~ with another mask beneath that ~ and perhaps a third mask underneath that.   It erodes confidence in the candor of the commenter ~ and the naive reader starts to look under bridges for those mythical inhabitants.

    Overall, it is best to avoid anything suggestive of smoke & mirrors.  Practicality should be King.   And speaking of mirrors, Markp, you have not yet provided a practical outline of your "mirror solution" ; an outline which is at least back-of-envelope  in quantification.

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  34. For Rob: I know I have not provided much data to back what I've been saying, but that's mainly because I was going on the assumption that you may already be aware of the data that could support me. In other words, I don't think what I've said is uncontroversial from a data point of view, but I do accept that it might be controversial from the point of view of making those holding a mainstream view (and I know that's vague) uncomfortable.

    I disagree with little of what you say about climate in this last post. From your list of 8 items, only 1,4 and 5 are problematic in my view. Unfortunately, those few items are weighty:

    "A lot is happening towards decarbonization" is vague enough to require examples to qualify the statement. There has definitely been a lot of talk about decarbonization, but as 2022 saw global emissions hit a new high of 36.8 Gt, according to the IEA's report "CO2 Emissions in 2022" one has to ask what decarbonization achievements, what action, in place of mere talk, can we point to. Renewable energy production plus use of EVs, heat pumps and who knows what else saved about 550 Mt. Fine. But this growth rate (growth of renewable contribution) won't hold up. So when you say "a lot" is happening, what's that really mean? And could you give just a few bullets on how you think we'll achieve net zero by 2050? 

    I'm also curious to know how much your vision of "net" zero relies on offsetting schemes, because I don't trust them and fear that they are being relied on too much for comfort.

    As for what happens to the rising temperatures in a net zero 2050, we'll have to wait and see.  

    I'm certainly with you on breaching 2C by 2050, but since I've got little hope we'll be anything close to net zero by then (for whatever net zero is actually worth as long as we've got all the offestting nonsense thrown in there) it looks worse to me than to you.

    Finally, and to change the subject a bit, I think the talk about models went too far. I'm not saying models are bad, just that they're being relied on too heavily in certain important cases. And as my primary experience (nearly 30 years now) has been in the financial arena for many "quant" strategies where, in that industry it is painfully common to see wonderful quant investment funds with great backtested results finally have some real money thrown at them and start a live track record, only to see the live returns look nothing like the lovely return characteristics of those backtests, I confess a lot of my skepticism comes from just that type of environment. Still, when we continually see news reports with headlines running "Researchers present shocking new data that climate change is happening much faster than expected" and the previous expectation was based on models, I don't feel at all surprised. I've just had a look at the "myths" section of Skeptical Science specifically at the models myth and I also see there that most of the argument seems to be toward trying to convince climate deniers who say models are all wrong that GW is real. That's clearly not me.

    For Eclectic: I don't think I've written too much, do you? I know people these days don't like to read anything longer than a twitter post, but I don't think your assessment here is fair. I've tried to keep it short, in fact. Like I said, I assumed, and maybe wrongly(?), that you folks had a decent understanding of the data already, and could follow commentary like mine that took a broader look at things rather than fussing over citations and decimal points because I'm not claiming anything that boils down to a disagreement over small measurements but has been more about one's basic orientation: some of you seem to be wearing rose-colored glasses in my view, like too many people are.

    As for the mirror concept, if the goal were to limit global temperature rise to 2C by 2100 we would need about twice the surface area of the contiguous USA. Although these reflectors would be useful in many instances, like on rooftops, parks, outdoor markets, reservoirs, etc., the main idea is for them to be used in agricultural settings because there's a lot of agricultural land, and because the reflectors would bring both local benefits to the crops by cooling, saving water and increasing yield, and contribute to global cooling. How to do that on a large scale is a problem that needs to be worked out. Any cropland managed by tractors and other large machines would either need to involve reflectors that would be removed from time to time for those machines to do their work, which wouldn't be easy, or they'd need to be placed so as not to interfere with those machines, perhaps by having them suspended vertically alongside crops rather than horizontally over them. And of cource, horizontal coverage would not involve blocking all available sunlight as to choke off photosynthesis, but as most crops can thrive with up to 30% shading, it would be placed intermittently. Anyway, this is the rough idea. Reflectors made from PET and aluminum cans from landfill provide more than enough for this level of scale, but other reflector constructions/materials could pop up as well. If you feel this isn't the type of detail you'd like to see, I'm not allowed to offer more. Not to protect technology or profits, because this comes from a nonprofit, but simply because I'm not authorized. As some of you know, the science takes time. We're working on it.

    If that surface area seems "too big" as in "nobody will go for that" I can certainly feel that, but what choice have we got? The Earth is big. We can do it. We've got 4 million miles of roads in the USA. When cars first got started, nobody would have thought that possible. All of our climate "solutions" are by nature on a grand scale. Nothing to do about that as far as I know. And why people might balk at lots of mirrors/reflectors when they seem to think DAC (or your solution of choice) can clean (enough of) the entire atmosphere, I'm stumped. 

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  35. Markp... The conversation gets unweildy when you do such long posts. Can you please try to engage in a bit more editing to get your comments better focused? I think it would improve the value of this exchange.

    I'm only going to address your first observation here: "'A lot is happening towards decarbonization' is vague enough to require examples to qualify the statement."

    I'm sure there is a better thread for this but, if the mods will allow, I'll just post a response here for now.

    First is the mere fact that onshore wind and solar are now cheaper than FF sources. This is relatively recent yet is already starting to show benefits in the energy marketplace.

    The result of this is now renewable energy is scaling exponentially.

    Bear in mind, this is still the early phase of exponential growth, so the true effects of that growth are going to be realized out past 2030-2050.

    In the latest EIA LCOE (levelized cost of energy) reports they're now including battery storage technologies because those costs are now falling in line with peaker plants.

    So, to try to somewhat tether this to the topic at hand, these technologies are the product of decades of very hard, complex work done by a lot of very smart people. These are the fruits of those efforts. This is why I say, while there are still many large and looming challenges, there is a lot of positive change afoot that should not be ignored.

    These advances are very likely a product of the sorts of communications and political engagement done over the years by the IPCC and various resulting international agreements. It would have been unlikely any of these advancements would have occurred with out the IPCC's work.

    These are the kinds of advancements that have to occur in order to get to net zero and then eventually zero carbon emissions by 2050 and after.

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  36. Markp... I'll also add this report from the IEA on the chances for net zero by 2050:

    Net Zero Emissions by 2050 Scenario (NZE)

    "There are many possible paths to achieve net zero CO2 emissions globally by 2050 and many uncertainties that could affect any of them; the NZE Scenario is therefore a path, not the path to net zero emissions."

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  37. Markp:

    I am also not going t try to wade through a long post, either. I will respond to one small portion. You state, with respect to models:

    And as my primary experience (nearly 30 years now) has been in the financial arena for many "quant" strategies where, in that industry it is painfully common to see wonderful quant investment funds with great backtested results finally have some real money thrown at them and start a live track record, only to see the live returns look nothing like the lovely return characteristics of those backtests, I confess a lot of my skepticism comes from just that type of environment.

    All I will say is that climate models likely bear very little resemblance to the sort of models you run into in financial topics. For one, climate models have an awful lot of physics in them. They are not pure statistical models (although statistical models do get used in climatology). The laws of physics put some pretty strong constraints on how  climate models behave.



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  38. Markp , thank you for a tad more detail on your "suspended mirrors" in post 34 paragraph 9  (please consider numbering your paragraphs & subsections, as per Congressional law-makers ).

    Perhaps SkepticalScience has a suitable thread for such discussion?

    Overall, mirrors wil be a hard sell to farmers, and to aircraft pilots who will have their own professional objections.

    Also a hard sell to the general public (such as me)  who might grumble at the "visual pollution" of fields of wind-turbines and fields of solar panels  ~ but who recognize the immediate benefit of cheap low-pollution electricity on top of the long-term environmental benefits.   A field of raised & suspended mirrors . . . not so much.

    Markp , as a financier of sorts, you will have considered not only the per-square-kilometer levelized costing of mirrors, but also the opportunity cost.   Opportunity cost analysis would be interesting, indeed.

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  39. Rob, thanks for the chart, but merely looking at a cost comparison between FF and renewables overlooks a lot. Have you seen Michaux's paper on this? You can find it here. It's a large report but worth looking at.

    The report is called "Assessment of the Extra Capacity Required of Alternative Energy Electrical Power Systems to Completely Replace Fossil Fuels." One of his conclusions is that the amount of metals required far outstrips current reserves to build the needed infrastructure for the first generation of such a "transition" only (1st generation needs to be mined because until it's been built there is little to recycle). He writes: "Current expectations are that global industrial businesses will replace a complex industrial energy ecosystem that took more than a century to build. The current system was built with the support of the highest calorifically dense source of energy the world has ever known (oil), in cheap abundant quantities, with easily available credit, and seemingly unlimited mineral resources. The replacement needs to be done at a time when there is comparatively very expensive energy, a fragile finance system saturated in debt, not enough minerals, and an unprecedented world population, embedded in a deteriorating natural environment. Most challenging of all, this has to be done within a few decades. It is the author’s opinion, based on the new calculations presented here, that this will likely not go fully to as planned."

    So even if wind and solar energy is cheaper than FF, we may not be able to replace FF with them, even if the IPCC says "we MUST."

    Thanks also for the IEA link to "Net Zero Emissions by 2050" but this is a big paper. When I asked you how you thought this could be done, I asked for a few bullets. I will have a look at the paper, but my fear is that, as Simon Michaux's has pointed out, a lot of the "plans" for a better climate future have, amazingly, been made without consideration for the reality of time, energy, resources, etc. So they contain bold statements about what MUST be done, as if saying it is all that's needed. Like I said, I'll look at it but I'm not going to be surprised if I don't find a realistic assessment.

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  40. Eclectic, thanks. I always find it odd that people will say that such -and-such a solution will be "a hard sell" when we've arguably got no alternative other than extinction. This is not a "sale" the way one buys a new car and wants it a Honda to be perfect or they'll buy a Mercedes (or whatever). There are no perfect solutions here. 

    I think people who grumble at windmills but accept that they produce energy, will just as easily accept mirrors (which a tiny percentage of the public would ever see as they may indeed occuppy mainly relatively lonely parts of the world) knowing that they are keeping life on Earth possible.

    Farmers will be happy to be able to increase their yields and actually grow and water their crops, which the way things are going, is getting really difficult. The cost will likely be born by the governments, as they will probably be tied to "offsetting" schemes (tax write-offs or direct subsidies). 

    Mirrors do not bother pilots or birds (the first thoughts of many). In fact, one of our first mirror test sites was either on or adjacent to a local airport's land and their permission was required, and it was given. There are some physics needed to explain why a mirror field does not affect pilots but I'm not prepared to offer them. 

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  41. Markp... "When I asked you how you thought this could be done, I asked for a few bullets."

    And when I gave you bullet points you challenged me to provide sources. Which I did.

    I'll read the Michaux's paper but I think this is an old discussion point about necessary resources for the technologies, whether it be lithium or cobalt or whatever. The good thing is, there is a near constant stream of new technologies coming to market all the time now. People have understood resource constraints and view it as both necessary areas for development and potential market opportunities.

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  42. Rob, I missed your bullets on how we can achieve net zero by 2050. Are you talking about these?

    >A lot is happening toward decarbonization
    >Decarbonization needs to happen faster
    >We know a hell of a lot more about the climate than we did decades ago
    >We have a good chance of getting to net zero by ~2050
    >Once we get to net zero, warming is expected stop
    >There are going to be increasing impacts in the coming decades
    >The sooner we get to net zero the better off we are
    >There is going to be a longer, more difficult task of getting fully to zero emissions which will take some decades more

    Because if you are, I fail to see how there explain how might be able to reach net zero by 2050!

    As for the real problem of materials, I'm trying not to fall off my chair at your comment about new tech. We are talking about replacing FF. What new tech is on the market, or coming, that will replace FF and fill the huge gaps expected from wind and solar? 

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  43. Markp... When I say "new tech" what I'm alluding to is new materials. Replacements for cobalt. Potential for, say, solid state batteries. New methods and materials for the production of solar panels. 

    You can fall off your chair all day long, but people are continually working on better ways to generate energy. There is no lack of ingenuity being applied to these problems.

    I think this illustrates the potential problem with your evaluation of the issue. If you look at any of this as steady state and extrapolated forward from there, you're inevitably going to end up with a doomsday scenario. But, as I've stated from the start, things are happening. Smart people have been working hard on these issues for decades and it's bearing fruit. The IPCC's work has been instrumental in keeping that ball moving forward though international agreements.

    The task remains nothing less than Herculean, but it is wholly inaccurate to suggest that nothing has happened. 

    I tend to harp on this issue quite a lot because I believe rhetoric suggesting nothing has happened leads people to give up, right when we need people to understand that real progress is being made.

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  44. Markp,

    Your comment @40 contains the following helpful point: "In fact, one of our first mirror test sites was either on or adjacent to a local airport's land and their permission was required, and it was given."

    This is helpful because it appears to establish that, along with your earlier mention of being very familiar with 'climate related finance', you appear to be 'invested' in a 'mirroring enterprise'.

    Mirrors may be a helpful measure, along with other actions that increase the reflection of sunlight, to reduce the current degree of human impacts on global warming. They could be a part of the broad diversity of helpful actions. But they are unlikely to be 'the primary solution'.

    Project Drawdown (at developed by Paul Hawkin (author of The Ecology of Commerce) is an informative resource. It lists and evaluates climate impact reduction solutions. In their words "Project Drawdown’s world-class network of scientists, researchers, and fellows has characterized a set of 93 technologies and practices that together can dramatically reduce concentrations of greenhouse gases in the atmosphere." But their list of solutions includes helpful actions that do not reduce ghgs like the one they evaluated that seems close to your 'mirror' application - Green and Cool Roofs (Linked to Project Drawdown).

    Maybe you should get in touch with Project Drawdown to get your idea added to their list of evaluated solutions.

    However, I am pretty sure about what the primary solution is. And it is not covered by Project Drawdown. It is not a 'new idea'. It requires nothing new to be built. And it requires no alteration of any developed activities. It is:

    Reduced Consumption - especially by the people who have over-developed levels of consumption (who consume 'beyond necessary consumption') - especially the reduction of types of consumption that are ultimately undeniably unsustainable like fossil fuel use (which cannot be continued to be 'enjoyed by everyone' centuries into the future even if there were no harmful impacts).

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  45. Markp @42 and prior :

    Simon Michaux is an intelligent guy, but is a "paralysis alarmist" who promotes inaction as the response to future difficulties which he sees as insuperable.   Rather similar to those  ( literally gloomy )  Malthusians who thought that an increasing world population would inevitably be condemned to nocturnal gloom and darkness ~ because there could never be enough whale oil for our lamps.

    OnePlanetOF  points out how AGW can be tackled not by a single silver bullet  [or even an aluminium-film-coated bullet ]  ~  but by a multiplicity of methods . . . though it's likely that "Reduced Consumption"  by the general public would be a very hard sell.

    Markp , what is the mirror coverage that you require?   My back-of-envelope  [Direct Normal Insolation 1000 W/m2 ; mirror efficiency 80% ; and 80% efficiency of shortwave transmission to space ]  points to around 400,000 square kilometers of mirroring needed, to produce a 1 W/m2 of reduction in global warming.  And presumably you would be aiming for at least 2 W/m2 reduction during 50 or 100 years?   Might need to supplement that with some CO2 emissions reduction, as well.

    For 400,000 or 800,000 square kilometers, the Sahara Desert would do nicely  (being conveniently away from airports )  if the local inhabitants were suitably bribed . . . or bribed to move to an immigrant-welcoming locality such as Texas.

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  46. Eclectic @45,

    I agree with the understanding "...though it's likely that "Reduced Consumption" by the general public would be a very hard sell".

    But I maintain the importance of understanding the need to limit the over-consumption of those who have developed a liking for consumption that is beyond what is necessary. I would also argue that there is plentiful evidence that 'lower cost' is a crude, and potentially very damaging, measure of merit, advancement or improvement. 'Less harmful' is almost always more difficult and more expensive.

    The 'best future for humanity', including the least climate impact harm done, can be understood to be achieved by the most significant reduction of unnecessary consumerism, including the ending of harmful activity that developed popularity and profitability. Reduced consumption reduces the harm done during the transition period where harmful unsustainable activity is ended.

    Correcting any harmful unsustainable ways of 'enjoying life more' that have become popular or profitable is 'a hard sell'. That sentiment applies to every identified necessary climate impact change, including the need to get people to accept that significant harm is being done by continued fossil fuel use. Many people incorrectly perceive that more consumerism beyond what is necessary indicates 'advancement to higher status'.

    The focus needs to be on the harm done by the development of perceptions of status based on harmful inequitable and ultimately unsustainable actions. There have been many presentations throughout history of the unsustainable harmful development of an 'unjust ruling class' excused, supported and admired by an 'unjust noble class' - all excused, supported and admired by portions of the divided 'lower class'.

    The root problem is the powerful forces developed by increased inequality. A very good recent presentation of this understanding was made by Matthew Stewart in "The 9.9 Percent" (about how the most powerful 0.1% win with support of the 9.9% - all excused by a portion of the remaining 90% due to their divisive fighting to become 'higher-status' like the top 10%).

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  47. Rob

    Yes, real progress is being made. But if we don't pay attention to all the greenwashing, pure money-chasing and ill-informed "solutions" like tree planting, the real progress won't have as much room to breathe in and expand. I'm all for progress on climate change, but I'm not into the hype and the BS, and there's a lot of it.

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  48. One Planet...

    I'm not involved in mirrors for money. It's nonprofit. We want to show people a method that can work and hope they run with it. That's all. And we certainly don't see it as a "primary solution" but it's probably the best SRM idea in town. Because drawdown just isn't going to happen fast enough. 

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  49. Eclectic

    Simon Michaux does not promote inaction. That is not fair at all. Where do you come out with crap like that? He's concerned father and is trying to help people not be led down a dead end. 

    I'm done.

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  50. Simon Michaux does not explicitly promote inaction.

    But to put it another way: like the Old Irishman giving directions :-

    "You can't get there from here."

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