I'd be interested in seeing how these plots change over time if you take into account the weakening land and ocean carbon sinks (some of which are being transformed into sources), as well as the increasing contributions to atmospheric CO2 and CH4 concentrations from thawing permafrost.
Well, the difference between the two shouldn't change much at all, since its derived by calculating the difference between what actually happened and additional concentrations that would have occurred with higher emissions.
Does the determination of what would have happened to atmospheric concentrations if there were no plateau take into account the additional sink weakening and permafrost emissions that would have occurred with higher human emissions? (Probably extremely difficult to accurately account for those factors, and probably wouldn't change the result much for the short duration of the current plateau. But over time the impact on the counterfactual from those factors could be significant.)
Thank you for this. While I knew that emissions growth had slowed, I didn’t realize the extent to which emissions had plateaued, so that’s welcome news.
Thanks Zeke. A couple of comments. 1) The carbon cycle is quite vigorous. A lot of CO2 is taken up by vegetation and then re-emitted as the leaves and twigs etc fall and decay. This is manifested in the distinctive annual cycle in the concentrations as they rise. 2) The concentrations are measured at a number of spots, and because of its long lifetime, are known quite well. This is not the case for emissions. These rely on reporting and crude estimates and also many are underestimated for self-serving purposes. Traking the whole carbon budget is essential.
Zeke, this is clear to me and seems to contradict the arm-waving explanation by Michael Mann. I posed a rhetorical question to Claude AI and it affirms my understanding. Would you please opine on the Claude assessment of my query?
<<Today, Zeke Hausfather posted on his ‘Climate Brink’ Substack “Plateauing CO2 emissions have slowed atmospheric growth – CO2 concentrations have continued to increase - but more slowly than they otherwise would have” essay at the link below*
Does this align with or contradict Michael Mann’s and Al Gore’s (and others’) assertion that after reducing CO2 emissions to Net Zero around 2050, atmospheric CO2 concentration will begin to decline within 3-4 years and global temperature will begin to cool a few decades thereafter following achieving Net Zero,gradually plateauing at a peak temperature around 2°C-2.7°C.
Will Hausfather’s temperature trajectory follow Mann & Gore et al’s curve?
Thanks, Claude's response is intelligent! I recall asking ChatGPT last fall if it agreed with Prof. Dessler about the most embarrassing error in the DOE Climate Working Group Report (https://www.theclimatebrink.com/p/is-this-the-most-embarrassing-error/comment/162278086). It did, pretty unequivocally. The ability of an LLM to objectively evaluate competing claims on their factual and logical merits is pretty useful to us amateurs!
I see the term "doomer" as the elite equivalent of "alarmist" and they both annoy the hell out of me. Of course, I've only encountered them used by Americans living in comfort.
I would like to invite Michael Mann, Chris Hayes ("I'm not a doomer.") and Jeff Goodell ("I'm not either.") on a fully-funded trip to discuss the problems of "doomerism" to their choice of venue: the slums of Dhaka housing the Bangladeshi who lost their land to the sea, an audience of ground workers of the International Red Cross and Red Crescent, or the Global Coral Reef Monitoring Network.
Yes, I have had to explain to people that the human species is not going to go extinct, that natural selection will as always award the most "pre-adapted" life forms, or that facets of our current civilization will certainly survive, but that is at best technical pedantry. How will the "best plausible scenario" impact the food supply and quality of life for 8.3 billion people?
Or maybe I should embrace the attitude of General Buck Turgidson, as he certainly wasn't the dreaded "doomer":
"I'm not saying we wouldn't get our hair mussed. But I do say... no more than ten to twenty million killed, tops. Uh... depending on the breaks."
Well said, and props for the cinematic allusion. One of the most brilliant satires ever produced. But as Prof. Dessler said last week, "nobody knows the future of energy", which largely determines emissions, which largely determines atmospheric CO2 concentration, which largely determines GMST. The excess atmospheric concentration over the multi-millennial average is wholly anthropogenic, and so is its future trajectory until anthropogenic emissions effectively cease, and poorly-understood natural drawdown takes over.
We acknowledge the future's contingency on past events and the stochasticity of what happens next within that constraint, "depending on the breaks". Climate science can project future GMST under specified scenarios, but the range of probable scenarios depends on *future individual and collective human behavior*. There is as yet no science of Psychohistory with which to predict more than a few years ahead. IOW, the cone of credible futures expands, even as we natter away on the Internet. Hey, it passes the time in retirement.
I note that it isn't the political initiatives that are explicitly directed at saving the planet which are reducing emissions, but complete self-interest on the part of China and those parts of the world that are sick of spending their national treasure on fuel from a few large petro-states.
I also expect further reduction in emissions soon from economic slowdowns (already started in much of Southeast Asia) rather than policy efforts.
Silence of the lambs. We, in comfort, are much more comfortable putting blinders on to the poor in the tropics as Earth 🔥. There is no doom if they don't exist in our minds.
I think your undertandings are correct but to me that is only a part of the picture as others commentators have already underlined. first, other chg’s, second, tipping points, third it considers that sink will continue unabated despite the huge impact we are doing on the environment. for example the 2024 el nino moderate event had a huge effect on the co2 released net in the atmosphere due to immense wildfires in southern america. So good that we are plateauing co2 but the message shall be that we have not to relax as we all known that net zero is an hoax and DAC’s are simply a dream.
Interesting - but odd that you note the carbon sinks but apparently don’t include them in the model. They must be very significant since they equilibrated natural CO2 emissions until we began burning ancient carbon.
If we’re at equilibrium combustion and probably going to decline (given solar and battery massive uptake), why not include the sinks?
Great explanation Zeke! The one unknown is the weakening capabilities of the carbon sinks from heat stress as you implied. To me, seems prudent to help cool Earth now.
Zeke, thank you for spelling out the relationship between emissions-concentrations so clearly: the recent flattening of CO2 emission => a straightening of the Keeling 'curve'. Since the data you present shows visible impacts beginning to emerge over the past decade (+/-12 yrs), perhaps you could take the next step and relate the emissions-concentrations relationship to the doubling in the earth energy imbalance that has been observed over (more-or-less) this same time period (multiple papers using top-down/down-up measures).
Zeke .. I'd like to address the 'elephant in the room'. Yes wholeheartedly agree reductions in emissions are to be celebrated. But. There is a massive increase in the build up of built in the Earth's energy imbalance.. the EEI and the sheer rate of increase in CO2 over the the last 20 years .. plus methane..
In the meantime we are starting to experience in real time the impacts. Temperatures NOW.. this week.. across Europe and the UK are reaching 10+ degrees where they should be against the seasonal norm.
Surely your post seems to 'imbalance' idealism against reality?
As always, if you haveca conscience you have to respect the science 🌏🙏❤️
As someone wittier than myself put it (thanks Mr Snarky Gerkin on Substack), a half built bridge isn't considered a failure because people are still using ferries in the meantime.
Economic alarmist fears are the most potent memes in the Doubt, Deny and Delay playbook and nothing is more potent an antidote to it than renewable energy. I think that even more than the actual emissions avoided the undercutting of those fears may be the most significant benefit the RE and Electrotech advances are giving.
There was a time, not so long ago that few world leaders would even dare to say they support a zero emissions target. There is a long gap between rhetoric and actions of course and maybe a lot of the credit taking is for RE being taken up for commercial reasons, that was going to happen anyway but we are better placed than ever. And not impeding it is better than nothing.
That Doubt, Deny, Delay politicking has lowered the bar and increasingly depends on corrupt influence to overwhelm our institutions of law and governance and democratic principles might be better seen as evidence of desperation; they don't fear zero emissions targets, they fear renewable energy - and because of that they fear democratic processes. Underneath it all there is the expectation that global warming won't go away, with a return of support for zero emissions commitments that isn't ever going away.
Useful to know, but CMIP7 projections were greenhouse gases (CO2e). Global CO2e emissions (2024) and atmospheric CO2e (2024) were increasing, about as fast as ever- driving accelerated global warming. Just posted.
Since the price of oil has started to rise, Ukraine has focused on the destruction of Russian oil export infrastructure to reduce the invaders' income, resulting in massive, multi-day columns of smoke at many of the targets.
Especially since the whole project will probably result in quicker reduction of emissions from other human sources overall. Suddenly the budgeting incentives have changed: How many individuals will convert to EVs (or PHEVs) sooner than they expected? How many municipalities and school systems will switch to electric buses faster? How many countries will follow Ethiopia's commitment to a green economy?
But, more acidic oceans mean that fewer carbonates are precipitating out right? And warming temperatures release more CO2 (not anthropogenic, but the result of human use of fossil carbon) as well as methane, correct?
I didn’t express myself clearly: I was wondering what our “warming path” looks like when considering all the greenhouse gasses. Plateauing CO2 corresponds to a certain warming curve or trend; do the other contributors bend the curve upward (worse future)?
Why the focus solely on emissions? Emissions (additions) are one part of the equation resulting in concentrations. The other is absorptions (subtractions). Three years ago Canada was reported to have lost over 50,000 square miles of boreal forest to fires (and more before and since of course, and that’s just Canada). The consequence was not just one-off emissions but a long-term reduction in subtractions. And every time a new airport or Manhattan-sized data centre is built on a greenfield site, subtractions are permanently lost. They are difficult to measure so calculations are (highly) approximate, but perhaps the continuing reductions in absorptive capacity - man-made, resulting from feedbacks, or otherwise - is an important factor in the continuing rise in concentrations? And one hopes that neglect of it is not down to a reluctance to accept that the “American way of life” may need to be “open to negotiation” (cf. George HW Bush at the Rio Earth Summit).
I'd be interested in seeing how these plots change over time if you take into account the weakening land and ocean carbon sinks (some of which are being transformed into sources), as well as the increasing contributions to atmospheric CO2 and CH4 concentrations from thawing permafrost.
Well, the difference between the two shouldn't change much at all, since its derived by calculating the difference between what actually happened and additional concentrations that would have occurred with higher emissions.
But more broadly, the carbon budget more or less balances today, despite some evidence of weakening sinks (which we expect in a warming world!): https://www.carbonbrief.org/analysis-fossil-fuel-co2-emissions-to-set-new-record-in-2025-as-land-sink-recovers/
Does the determination of what would have happened to atmospheric concentrations if there were no plateau take into account the additional sink weakening and permafrost emissions that would have occurred with higher human emissions? (Probably extremely difficult to accurately account for those factors, and probably wouldn't change the result much for the short duration of the current plateau. But over time the impact on the counterfactual from those factors could be significant.)
Thank you for this. While I knew that emissions growth had slowed, I didn’t realize the extent to which emissions had plateaued, so that’s welcome news.
Thanks Zeke. A couple of comments. 1) The carbon cycle is quite vigorous. A lot of CO2 is taken up by vegetation and then re-emitted as the leaves and twigs etc fall and decay. This is manifested in the distinctive annual cycle in the concentrations as they rise. 2) The concentrations are measured at a number of spots, and because of its long lifetime, are known quite well. This is not the case for emissions. These rely on reporting and crude estimates and also many are underestimated for self-serving purposes. Traking the whole carbon budget is essential.
Kevin
Zeke, this is clear to me and seems to contradict the arm-waving explanation by Michael Mann. I posed a rhetorical question to Claude AI and it affirms my understanding. Would you please opine on the Claude assessment of my query?
<<Today, Zeke Hausfather posted on his ‘Climate Brink’ Substack “Plateauing CO2 emissions have slowed atmospheric growth – CO2 concentrations have continued to increase - but more slowly than they otherwise would have” essay at the link below*
Does this align with or contradict Michael Mann’s and Al Gore’s (and others’) assertion that after reducing CO2 emissions to Net Zero around 2050, atmospheric CO2 concentration will begin to decline within 3-4 years and global temperature will begin to cool a few decades thereafter following achieving Net Zero,gradually plateauing at a peak temperature around 2°C-2.7°C.
Will Hausfather’s temperature trajectory follow Mann & Gore et al’s curve?
• https://theclimatebrink.substack.com/p/plateauing-co2-emissions-have-slowed>>
CLAUDE RESPONDED: https://claude.ai/share/71c77f2a-e109-4da1-afd8-da0e7272879f
Concentrations do start to decline before zero emissions, but warming does not. I explained it here: https://bsky.app/profile/hausfath.bsky.social/post/3mmz3qxujt52l
You hit the jackpot in substack posting ideas! What if every post had a Claude reply to the posters question? It gives additional context at least.
Thanks, Claude's response is intelligent! I recall asking ChatGPT last fall if it agreed with Prof. Dessler about the most embarrassing error in the DOE Climate Working Group Report (https://www.theclimatebrink.com/p/is-this-the-most-embarrassing-error/comment/162278086). It did, pretty unequivocally. The ability of an LLM to objectively evaluate competing claims on their factual and logical merits is pretty useful to us amateurs!
"Shared by doomers and skeptics alike...."
----
I see the term "doomer" as the elite equivalent of "alarmist" and they both annoy the hell out of me. Of course, I've only encountered them used by Americans living in comfort.
I would like to invite Michael Mann, Chris Hayes ("I'm not a doomer.") and Jeff Goodell ("I'm not either.") on a fully-funded trip to discuss the problems of "doomerism" to their choice of venue: the slums of Dhaka housing the Bangladeshi who lost their land to the sea, an audience of ground workers of the International Red Cross and Red Crescent, or the Global Coral Reef Monitoring Network.
Yes, I have had to explain to people that the human species is not going to go extinct, that natural selection will as always award the most "pre-adapted" life forms, or that facets of our current civilization will certainly survive, but that is at best technical pedantry. How will the "best plausible scenario" impact the food supply and quality of life for 8.3 billion people?
Or maybe I should embrace the attitude of General Buck Turgidson, as he certainly wasn't the dreaded "doomer":
"I'm not saying we wouldn't get our hair mussed. But I do say... no more than ten to twenty million killed, tops. Uh... depending on the breaks."
Well said, and props for the cinematic allusion. One of the most brilliant satires ever produced. But as Prof. Dessler said last week, "nobody knows the future of energy", which largely determines emissions, which largely determines atmospheric CO2 concentration, which largely determines GMST. The excess atmospheric concentration over the multi-millennial average is wholly anthropogenic, and so is its future trajectory until anthropogenic emissions effectively cease, and poorly-understood natural drawdown takes over.
We acknowledge the future's contingency on past events and the stochasticity of what happens next within that constraint, "depending on the breaks". Climate science can project future GMST under specified scenarios, but the range of probable scenarios depends on *future individual and collective human behavior*. There is as yet no science of Psychohistory with which to predict more than a few years ahead. IOW, the cone of credible futures expands, even as we natter away on the Internet. Hey, it passes the time in retirement.
I note that it isn't the political initiatives that are explicitly directed at saving the planet which are reducing emissions, but complete self-interest on the part of China and those parts of the world that are sick of spending their national treasure on fuel from a few large petro-states.
I also expect further reduction in emissions soon from economic slowdowns (already started in much of Southeast Asia) rather than policy efforts.
I wonder what The Oracle says about the fate of this climate fiasco.
Silence of the lambs. We, in comfort, are much more comfortable putting blinders on to the poor in the tropics as Earth 🔥. There is no doom if they don't exist in our minds.
Relativity bites.
♫♪ Always look on the bright side of life....
LOB! Also, we know the answer is 42.
Yep. Catastrophe is in the eyes of the victims!
I think your undertandings are correct but to me that is only a part of the picture as others commentators have already underlined. first, other chg’s, second, tipping points, third it considers that sink will continue unabated despite the huge impact we are doing on the environment. for example the 2024 el nino moderate event had a huge effect on the co2 released net in the atmosphere due to immense wildfires in southern america. So good that we are plateauing co2 but the message shall be that we have not to relax as we all known that net zero is an hoax and DAC’s are simply a dream.
Thanks a lot for this, honestly. Hope is seldom seen in this environment but works like this one let me have a bit of it.
Interesting - but odd that you note the carbon sinks but apparently don’t include them in the model. They must be very significant since they equilibrated natural CO2 emissions until we began burning ancient carbon.
If we’re at equilibrium combustion and probably going to decline (given solar and battery massive uptake), why not include the sinks?
Carbon cycle models include sinks, though the simple one I'm using here doesn't include climate-mediated variations in those sinks.
Great explanation Zeke! The one unknown is the weakening capabilities of the carbon sinks from heat stress as you implied. To me, seems prudent to help cool Earth now.
Zeke, thank you for spelling out the relationship between emissions-concentrations so clearly: the recent flattening of CO2 emission => a straightening of the Keeling 'curve'. Since the data you present shows visible impacts beginning to emerge over the past decade (+/-12 yrs), perhaps you could take the next step and relate the emissions-concentrations relationship to the doubling in the earth energy imbalance that has been observed over (more-or-less) this same time period (multiple papers using top-down/down-up measures).
Zeke .. I'd like to address the 'elephant in the room'. Yes wholeheartedly agree reductions in emissions are to be celebrated. But. There is a massive increase in the build up of built in the Earth's energy imbalance.. the EEI and the sheer rate of increase in CO2 over the the last 20 years .. plus methane..
In the meantime we are starting to experience in real time the impacts. Temperatures NOW.. this week.. across Europe and the UK are reaching 10+ degrees where they should be against the seasonal norm.
Surely your post seems to 'imbalance' idealism against reality?
As always, if you haveca conscience you have to respect the science 🌏🙏❤️
As someone wittier than myself put it (thanks Mr Snarky Gerkin on Substack), a half built bridge isn't considered a failure because people are still using ferries in the meantime.
Economic alarmist fears are the most potent memes in the Doubt, Deny and Delay playbook and nothing is more potent an antidote to it than renewable energy. I think that even more than the actual emissions avoided the undercutting of those fears may be the most significant benefit the RE and Electrotech advances are giving.
There was a time, not so long ago that few world leaders would even dare to say they support a zero emissions target. There is a long gap between rhetoric and actions of course and maybe a lot of the credit taking is for RE being taken up for commercial reasons, that was going to happen anyway but we are better placed than ever. And not impeding it is better than nothing.
That Doubt, Deny, Delay politicking has lowered the bar and increasingly depends on corrupt influence to overwhelm our institutions of law and governance and democratic principles might be better seen as evidence of desperation; they don't fear zero emissions targets, they fear renewable energy - and because of that they fear democratic processes. Underneath it all there is the expectation that global warming won't go away, with a return of support for zero emissions commitments that isn't ever going away.
Useful to know, but CMIP7 projections were greenhouse gases (CO2e). Global CO2e emissions (2024) and atmospheric CO2e (2024) were increasing, about as fast as ever- driving accelerated global warming. Just posted.
Estimate from →first two weeks← of Iran war is more than 5 million tonnes of CO₂e generated:
https://www.qmul.ac.uk/news/latest-news/2026/humanities-and-social-sciences/hss/war-in-iran-has-already-produced-emissions-equivalent-to-a-year-of-icelands-carbon-output.html
================
Since the price of oil has started to rise, Ukraine has focused on the destruction of Russian oil export infrastructure to reduce the invaders' income, resulting in massive, multi-day columns of smoke at many of the targets.
Russian refinery bingo: https://x.com/KHoholenko/status/2063667173327880532
ETA: Better image of June 7 status https://pbs.twimg.com/media/HKOeTGAXIAA2yu4?format=jpg
5 million tons of CO2 emitted is bad, but doesn't move the needle much globally given annual emissions of 40,000 million tons.
Especially since the whole project will probably result in quicker reduction of emissions from other human sources overall. Suddenly the budgeting incentives have changed: How many individuals will convert to EVs (or PHEVs) sooner than they expected? How many municipalities and school systems will switch to electric buses faster? How many countries will follow Ethiopia's commitment to a green economy?
But, more acidic oceans mean that fewer carbonates are precipitating out right? And warming temperatures release more CO2 (not anthropogenic, but the result of human use of fossil carbon) as well as methane, correct?
How do things look if we add in all the non-CO2 gasses such as methane?
Methane emissions continue to increase (as atmospheric concentrations are more or less a function of the rate of emissions, unlike for CO2).
I didn’t express myself clearly: I was wondering what our “warming path” looks like when considering all the greenhouse gasses. Plateauing CO2 corresponds to a certain warming curve or trend; do the other contributors bend the curve upward (worse future)?
Why the focus solely on emissions? Emissions (additions) are one part of the equation resulting in concentrations. The other is absorptions (subtractions). Three years ago Canada was reported to have lost over 50,000 square miles of boreal forest to fires (and more before and since of course, and that’s just Canada). The consequence was not just one-off emissions but a long-term reduction in subtractions. And every time a new airport or Manhattan-sized data centre is built on a greenfield site, subtractions are permanently lost. They are difficult to measure so calculations are (highly) approximate, but perhaps the continuing reductions in absorptive capacity - man-made, resulting from feedbacks, or otherwise - is an important factor in the continuing rise in concentrations? And one hopes that neglect of it is not down to a reluctance to accept that the “American way of life” may need to be “open to negotiation” (cf. George HW Bush at the Rio Earth Summit).