Is CO2 Still Accelerating?

Not only is the amount of CO2 in the atmosphere on the rise, the rise itself has been getting faster — so CO2 concentration has been accelerating. A reader recently asked whether or not there’s any sign of its increase flattening out, or even stopping its acceleration.

Here’s the CO2 data from Mauna Loa:

I transformed this to anomaly, in fact I computed adaptive anomaly because the annual cycle itself has changed over time. The anomalies are clearly accelerating, so I fit a quadratic curve and plotted it (in red) along with the adapative anomalies (in black):

The CO2 growth follows the quadratic curve so closely, it’s a bit hard at times to tell them apart.

If this pattern has changed, we should see the change in the residuals from that quadratic fit. Here they are:

There’s lots of fluctuation, some of it related to known factors like the strong el Niño events of 1998 and 2016, but there’s no sign of a downturn recently.

I tested for any change in the acceleration in several ways. For instance, I computed the acceleration of each 10-year span and plotted the result: no sign that acceleration has stopped. I also tried 5-year time spans, which is too brief to show non-zero acceleration (the uncertainty is too big) but also shows no sign of any change in the acceleration.

What might be the clearest illustration comes from computing annual average CO2 concentration and using it to estimate the year-on-year change, which is the velocity of CO2 concentration. Acceleration will show as a trend in the velocity. Here are the estimates, together with a trend line which illustrates the overall rise in velocity (i.e. acceleration of CO2):

This makes it obvious just how much the “noise” in the system can make it harder to detect acceleration and its changes. But I’ve tested this time series for a change in its trend, and found no reliable evidence. Not even close.

Bottom line: CO2 is on the rise, the rise itself (velocity) has been getting faster (acceleration), and there’s no evidence at all that has changed recently.

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66 responses to “Is CO2 Still Accelerating?

  1. Susan Anderson

    Whoa! Woe! I thought we had at least slowed the rate of acceleration. But for your average layperson, they think we’ve reduced it. It’s like an obese person trying to diet.

    First they have to slow down the rate of gain, then stop gaining. Can’t do the second without the first. Then the hard work of beginning to reduce.

    Ain’t it stupid? I don’t think calling people idiots is useful, but this is beyond foolish, it’s dangerous.

  2. Reblogged this on Don't look now and commented:
    “In recent years, CO 2 emissions have been almost flat despite continued economic growth” GCP CarbonBudget 2017 HOWEVER …

  3. Everett F Sargent

    Adaptive anomalies? I.m interested in that method. Do you have any public domain references to this method?

    I’ve been using, more or less, the ESRL method, harmonic analysis then applying an IIR filter. I’m also using a combined SIO/ESRL (linear infilled, but later will just use the inverted harmonics for infilling) weekly dataset for my analysis. It is a work of mine, in continual progress. I’m also using the one year lagged rate of change (see, for example, the ESRL weekly 1974-2018 time series) combined with the IIR filter halfpoint set to one year (still working on padding the half year lost at start/end).

    My weekly updates are entirely consistent with what you have presented here (well there is a slight reduction in rate for 2017, ~2.2 ppmv/yr, but the long term rate of ~2.4 ppmv/yr currently, should continue it upwards rather linear trajectory AFAIK).

    Thanks for the post. Very timely and most welcomed.

  4. Reblogged this on Henrik Nordborg and commented:
    Unfortunately, if humanity made any progress in fighting climate change in recent years, we obviously forgot to inform the atmosphere.

  5. One thing to consider about CO2 accumulation in the atmosphere is that accumulation is not just calculating fossil fuel emissions, the accumulation in the atmosphere is affected by changes in natural carbon sinks and natural carbon sources. A warmed and warming planet means that we can’t be certain how the accumulation in atmosphere will proceed because we will have to watch and learn how the natural sources and sinks function in changed world. The bottom line: don’t get excited about headlines about falling emissions unless they fall so much that we start seeing significant changes in atmospheric accumulation. As Henrik alluded, our progress, or lack thereof, to slow global warming means should only be evaluated by atmospheric accumulation. This is the number that is driving the sixth great extinction.

  6. The question from the ‘reader’ asking if up-to-date CO2 data showed any signs of “its increase flattening out, or even stopping its acceleration.” This resulted from an interchange with me at RealClimate. My position is that obviously CO2 has been accelerating upward but the wobbles which the analysis has to negotiate (same as per wobbles in temperature analyses) make it impossible to support the assertion that CO2 is still accelerating. And estimates of global emissions suggest a flat level of emissions over recent years which would in turn suggest acceleration would be ended (while the flat level of emissions continues).
    This conforms with the take-away “CO2 is on the rise, the rise itself (velocity) has been getting faster (acceleration), and there’s no evidence at all that has changed recently” and answers his question. I do hope that remains so when it feeds back to RealClimate.

  7. Here is the big question:

    Why is CO2 still accelerating, if emissions had flattened in recent years (2013-2017), with, among other things, a tentative peak coal (demand) in China in 2013?
    How to solve this paradox?

    Maybe the CO2 emissions accounting is wrong? Didn’t the high resolution (both in space and time) NASA infrared satellites would have measured any deviation from the official numbers as bigger CO2 plumes in the main emission hotspots (China, India, Russia, USA, Europe, etc.)?
    [Any mistake should be a serious concern for foreign policy, and any country that did fraudulent accounting should receive sanctions…]

    Maybe the warming itself is extracting CO2 from soil & vegetation via increased organic matter decomposition and wildfires as the soil warms and dry up, and the droughts and wildfires become more common and severe?
    [This would be a serious concern also, as it would mean the “slow” feedbacks are really not so slow and have already begun and so even achieving zero emissions in the next decade might be not enough…]

    Maybe an increase in man-made land use change (i.e. mainly via farming and deforestation) in recent years?
    [Perhaps this is the least concerning possibility, as it can be reversed with forest & soil conservation policies as was done already in some regions]

    What do you think?

    • Even if the slow down is not offset by feedback, it hasn’t been long enough to really expect any slowdown to show up in the statistics.

      [Response: Hammer: meet head of the nail.]

    • My guess is, that you missed one main thing: Human CO2 emissions are nearly double the amount of CO2 increase in the atmosphere. This means, that nearly half our emissions are absorbed by carbon sinks like the oceans, forests, etc.
      But there is no guarantee, that those sinks will be able to absorb our carbon with the same pace indefinitely. In case I think e.g. the ocean’s ability to absorb carbon decreases with higher ocean temperature. And as the ocean are warming, it will only be a matter of time, that our main carbon sink will get weaker. So even if we would reduce our emissions e.g. by 1% it could still be possible, that CO2 levels increase faster, if e.g. the ocean absorb 2% less, and thus offsetting our reductions.

      I don’t know if there are good estimates for how the carbon sinks will evolve with time and how much uncertainty there is doing those estimates. Maybe someone other knows that?

      • Prof Glen Peters suggested to me some time ago that The Global Carbon Project is seeing some evidence of such deterioration in sink capacity, so I would pay attention to their reports for details of it.

  8. US emissions have flattened out the past few years, worldwide CO2 has continued to increase. The US still puts a huge amount into the atmosphere, it has just not grown percentage wise the past couple of years.

  9. Kudos to @smallbluemike for hitting the sinks issue on the head: There is evidence from the Global Carbon Project that sinks are slowing down in their uptake. Hasn’t been run to ground causally, but there is evidence, for example, that phytoplankton have decreased in oceans over time, so, since this is a major sink, take-up of CO2 would be expected to slow.

    As far as methods go, I’ve had success fitting smoothing p-splines to such data and then estimating, like, first and second derivatives from the p-spline. The spline judges what are good intervals, rather than relying upon arbitrary fixed-width time bins. In one dimension, this is similar to variably-sized grid methods for PDE solvers in multiple dimensions. R has a pspline package that serves.

  10. Producing, following and analyzing reports of carbon emissions is a fine thing. It’s a better us of time than golf or nascar racing, but it’s pretty meaningless unless the reports of falling emissions could be verified by a clearly related reduction of CO2 accumulation in the atmosphere. Until that happens, the emission reports should be printed out and used to fan oneself to stay cool. Also useful to wrap fish or to line the bottom of birdcages.

    Alberto asks several good questions that deserve some thought. LouMayTrees demonstrates the best function of the emission reports: they are useful propaganda for allowing nation states to use in global political struggle which distracts us and reduces our ability to act as a global community facing an existential threat.

  11. The accelarating of CO2 is to be expected. I did some work on antropogenetic CO2 myself and the data i had(CO2-emissions Worldbank) shows that de yearly emissions of CO2 is increasing. So the amount of CO2 in the atmosphere has to accelarate. It is basic mathemeatics.

  12. Is CO2e not more important than CO2? Is crime of self censorship becoming fashionable? This URL advises were up to 489ppm already. How long before screaming panic protest?

    [Response: Yes, total GHG forcing (CO2eq) is what really matters. But the URL you link to makes too much of the dramatic rise in CO2 during 2016; it was mainly due to the strong el Nino so it didn’t last.

    When you mention self-censorship, I have no idea what you’re talking about.

    My advice: protest definitely, screaming maybe, but panic, definitely not. If you can keep your head when all around you are losing theirs …]

  13. Steve Milesworthy

    Last year’s Met Office CO2 forecast had a brief mention of some of the inputs to the forecast, and it has links to other people’s attempts to relate rates of rise to other aspects of the ecosystem.

  14. It is clear that CO2-equiv is not getting enough coverage. However, the best place to get it is here:

    The only good news is that CH4 and N2O don’t have long atmospheric residence times.

  15. Is there an ENSO pattern here? CO2 increase greater in El Nino and less in La Nina? Can these be addressed – in order to open a discussion about the sinks “slowing down”?

    • The presumptive answer is ‘yes’–in commenting on the CO2 residuals graph, Tamino said this:

      “There’s lots of fluctuation, some of it related to known factors like the strong el Niño events of 1998 and 2016, but there’s no sign of a downturn recently.”

      And the spikes in CO2 rates around those ENs are indeed quite visible.

      One logical line of thought on this is the obvious relation to temperature: warmer waters don’t hold as much dissolved CO2. But probably more important is the fact that upwelling off the South American coast is suppressed during El Nino episodes. In ENSO-neutral conditions, there’s a lot of deep water upwelling which is not only cooler, but presumably also less carbonized (if I may speak so), since it last interacted with the atmosphere a millennium or more back, when we were at maybe 280 ppm.

      Or at least that’s how I understand it now–perhaps others will have more detailed or up-to-date knowledge.

  16. An ideal Carbon Atmosphere, would be at 350 parts per million

    1700s to 1800s ppm Carbon 260ppm – 280ppm

    1980 ppm carbon 350

    2015 ppm of Carbon 405

    2017 ppm of Carbon 407.35 and Rising

    “I will show you the rise in CO2 levels every 5 years from 1958 to Dec. 2017. I will also show the CO2 difference beside it from the previous reading. Each reading is taken in the March of the respective year.
    Year…………………….CO2 Levels……………Growth
    The last entry is early since it is not yet March 2018.
    This shows the ever increasing growth of CO2 levels in our atmosphere.

    Can society even exist in it's current form at 600ppm CO2 concentration ?

    I know the planet has been at that level before, but it took tens of thousands of years to get there and back again, not 250 years.

    Add in the CH4 levels at 1857ppb, and you have an equivalence of ~580ppm already. Mark Bevis

    We Our Already Baked in to 10C. – ? Tempurature Rise, Even if We Stopped Emitting Carbon and Methane Right Now.

    There is a 10 year Lag time with Methane,

    And a 30 to 50 year Lag Time with Carbon,

    Until we Fill the Full Effects of the Warming (Heating) and Holding More Water Vapor in Their Molecules.

    Methane is 72 – 86 Times more Potent Than Carbon in Its First 10 years.

    Then Reduces Down to and Stays at Around 34 Times More Potent Than Carbon !

    For every 72 pounds of Carbon Being Emitted, Equals One Pound Of Methane.

    Methane + Carbon + Water Vapor is Abrupt Hot and Cold, Rain and Snow ( Until Greenland is Half Melted Away), Sea Level Rising way Faster Than they are Telling US

    We are Filling the Full Potency of Methane From 2007 Fracking Emissions, Methane Hydrates Emissions, and Mantle Methane Emissions Today.

    We are Filling The Full Potency of Carbon emitted From 1967 to 1987 ! Right Now.

  17. The Keeling Schadenfreude Game. Guess what the peak CO2 concentration in the air will be this year.

  18. Jeffrey Davis

    I’ve seen conflicting stories about the increase in atmospheric CO2 in 2017. One is that the increase came despite a decline in human-sourced contributions. (Carbon sinks have become saturated and are either not accepting new CO2 or have actively become sources.) The other is that human-sourced contributions increased unexpectedly in 2017.

    Can anyone confirm either scenario?

    • It was human-sourced. CarbonBrief did a story on it following the prelimenary findings for 2017 from GCB back in mid-November. The story – ‘Global CO2 emissions set to rise 2% in 2017 after three-year ‘plateau’’ – is HERE (Note that the actual 2017 emissions figures are yet to be published.)

    • Dr Pete Sudbury

      From what I understand, both are happening. Recall that human contributions include the attractively-acronymed “LULUCF” = land use, land use change, forestry. Cutting down forest carbon sinks doesn’t work well. Modern intensive agriculture causes soils to sweat out carbon as they progressively lose their humus content. Human CO2 emissions flattened out in the last couple of years.

  19. A question that arises in my mind when looking at the Mauna Loa CO2 concentration data relates to the quality of the fit of the curve to the data. As Tamino has done, I have also derived a second order polynomial to fit the data (using annual averages of CO2 concentration for 1960 through 2017). The fit is remarkable — I get an R-square value of 0.9994. I have done a fair amount of statistical analysis of biomedical data during my career, and I don’t recall ever seeing a fit that good of anything to anything else with this much data. There is very little scatter around the regression line. Given that the atmospheric concentration of CO2 is the net result of a number of different processes, I can’t help but wonder how this works so well.

    Another way of looking at acceleration, perhaps too simple minded, is to divide up the data into segments, perform linear regression on each segment, and compare the slopes. I did that by dividing the range into 15 year segments (with a 1 year overlap between segments). The result was as follows:
    Segment Slope
    1960-1974 0.98
    1974-1988 1.56
    1988-2002 1.62
    2002-2017 2.27
    Not sure what to say about this other than it appears to support the idea that the rate of CO2 rise is accelerating.

  20. I think Al Rodgers is committed to making everyone back away from that statement that the “rate of CO2 increase IS accelerating.” I believe his position is that we can only state that CO2 rise HAS been accelerating. Do I have that right, AR? It makes me think back to Bill Clinton’s need for definition of the word is. I think it is hard to argue that we know the rate of CO2 increase is rising today. It seems to me that these questions can only be answered definitively by a look in the rear view mirror.

    This post asks the question “Is CO2 still accelerating?” and the response from Tamino is framed in the past tense, it has been rising, there is nothing to suggest the trend has changed. I believe the answer is yes, rate of CO2 increase continues to accelerate, but there are a lot of wobbles, smoothing that have to be done to confirm the trend at any point in time and that all has to be done in retrospect.

    I think a lot of folks read emission reports that claim falling emissions and believe the reports of falling emissions are coupled to changes in the rate of increase of CO2 in the atmosphere. I think the coupling there is pretty loose for a number of reasons which I don’t think we need to spend time on, like are the national reports accurate or are the numbers being spun by nation states for global political advantage?

    And, yes, CO2e is actually the better measure of how we are doing and it looks pretty bad as well. I just track CO2 because the fixes for CO2 accumulation will also address CO2e, so I choose CO2 to keep it simple. I like CO2 accumulation because it is a hard number to distort, it’s just measured in the atmosphere at several points. There it is. We don’t get a bunch of nations jumping in with their own measurements. CO2 and CO2e levels are the hard facts that are cooking the planet and increasing ocean acidification. Emission reports are fluff as long as CO2 and CO2e continue to rise. And remember, we don’t have to just slow the rate of increase, we have to live in a manner that makes the CO2 and CO2e needle go down instead of up.

    But, hey, what do I know?

    • And remember, we don’t have to just slow the rate of increase, we have to live in a manner that makes the CO2 and CO2e needle go down instead of up.

      Yes, indeed. The disconnect between the public concern, at least in some quarters, and the urgency of heading towards zero quickly is in itself alarming.

      I’m giving a Lyceum talk in Needham (not yet posted) on the 11th of February 2018 addressing emissions and the collective lack of progress. (Even the EU.) And the talk also breaches, for the first time in my talks, a serious consideration negative emissions engineering, what it takes, and what it might cost. To work a cost estimate I arbitrarily start from 750 ppm CO2 and want to get to 350 ppm. Based on just an extrapolation from recent emissions trends, with all the usual qualifications about doing such a thing, I argue that we could be there by 2040. (Fit exponential to emissions from 1940 to 2010, etc.)

    • smallbluemike appears to want to bring into this thread the exchange at RealClimate that led to this OP. In putting in my ten pen’orth, I should say that I am conscious of the situation back in the 1980s when there were those saying Global Temperature remained flat and that there was no statistical argument that any recent high temperatures had changed the ‘No Warming’ conclusion. I am uncomfortable seeing an analogous argument being used with the atmospheric CO2-rise.
      Today, if CO2 emissions have flattened, there is every reason to expect a leveling out of the rate of atmospheric CO2-rise; that is a reduced/zeroed acceleration. But the wobbles in the CO2-rise are perhaps three-times bigger than the SAT wobbles (when measured relative to their rates of increase). So we will have to wait longer than the wait back in the 1980s to achieve a resolution for CO2.
      The graph I produced to demonstrate the wobbliness is HERE. Do note that these are decadal figures. A positive trend in CO2-rise is ‘over the last decade’ and not ‘now’.
      I suppose the battle-lines here are drawn between on the one-hand those who believe in either significant natural feedbacks impacting the carbon cycle as-we-speak or who believe today’s mitigation measures are useless, and on the other-hand those who would welcome some signs of a weakening of the accelerating CO2-rise as this would encourage more mitigation actions (and less hand-wringing) and who consider CO2 emissions reporting is more than “fluff”.

  21. thanks. I like it when different methods agree.

  22. Meteorologist Nick Humphrey

    Reblogged this on Weather and Climate News.

  23. Dr Pete Sudbury

    Lovely piece of analysis. Must work harder to start bending that curve!

  24. I’m a mathematician, not a climatologist. But I can tell you that there is an extremely simple piece of math that explains many kinds of accelerations in the world today. And it’s NOT quadratic.

    The QUADRATIC curve is what you’d get if something is falling off a cliff. That’s a good familiar metaphor for the suddenness and abruptness of climate change, but I think that is NOT what is going on here. Gravity is not the main force driving the climate change.

    There are plenty of FEEDBACK LOOPS in the climate system, and in the various forces driving the climate system. Technically speaking, it’s self-reinforcing feedback, not self-inhibiting feedback. It’s called “positive feedback,” but that’s “positive” in the sense of “it’s getting bigger,” not in the sense of “I have happy news for you.” Feedback means that some of the CONSEQUENCES ARE ALSO CAUSES, and so the bigger the system gets, the faster it grows. I taught calculus for 30 years, and the course includes these formulas:

    p'(t) = kp(t) implies p(t) = p(0)exp(kt).

    So we’re looking at EXPONENTIAL growth. That starts off much slower than quadratic growth, but after a while it’s much faster. After a while the curve goes off the page — but it goes out the top, not the right side of the page. Unlike the quadratic curve, the exponential curve has ALL of its derivatives positive.

    I’m sure that the phenomena we’re seeing are not EXACTLY exponential growth. Nothing in the real world is ever that simple. But I think we’re seeing phenomena that are approximately p'(t) = kp(t), and therefore approximately p(t) = p(0)exp(kt). The approximation is not close enough that I’d have any idea what the values of p(0) or k are, but I do expect acceleration to continue.

    We need to make drastic changes in a big hurry, or we’re screwed. And I don’t think those drastic changes will happen under capitalism, where the oil company lobbies have more influence than the environmentalists.

    • “We need to make drastic changes in a big hurry, or we’re screwed. ” Exactly the way it looks to me. Are we handwringers?

      • Smalllbluemike, I don’t think I’m a handwringer. I believe the only hope of making those drastic changes is by spreading ideas quickly. Good ideas rarely spread quickly, but there is no law like gravity that says it can’t happen, and I’m doing all I can to make it happen. I jump frequently into conversations on Facebook, being as polite but radical as I can be. And I write leaflets, and hand them out at crowds that seem receptive — for instance, I managed to distribute 100 copies at the local Martin Luther King march. You can see my leaflets at . … I haven’t stopped trying, but I’ll admit that I’m not feeling optimistic.

      • Backstopping the harsh realities of the moment, I think it is important to begin to point out to the public that there are strong limits on what Science and Engineering are capable of doing, particularly when there is no viable mechanism for strong, global cooperation. There is a certain religion in the belief in technological progress and in the power of entrepreneurship and “the markets”, but these are not unbounded.

        I am beginning to attempt to carefully explain the magnitude of the task of Putting the Genie Back in the Bottle, that is, clear air capture of CO2, and, of course, in consequence, the cost. The most notable thing about that is that any serious involvement in that project assumes, first things first, that Carbon emissions are zeroed, as much as possible. Yes, it won’t be possible to zero the incidental emissions associated with agriculture, even assuming planting, tending, harvesting, transport, and processing are all done with zero emissions. But it is nearly impossible to create a global deployment of clear air capture which keeps up with emissions at the rate they are now, let alone succeeds in drawdown.

        And, as far as technological whizbang improvements go, I bring those down to cost. The most optimistic cost estimate at present is like US$100 per tonne free CO2 captured. If you want to bring down 400 ppm, that’s 3100 GtCO2 from atmosphere. But, given equilibrium in soils and oceans, acknowledging they’ve taken 55% of emissions, in reality, you need to drawdown something like 6900 GtCO2, probably over a couple of centuries, because of lags. There are some astronomical cost numbers there. Technological efficiencies can be in terms of 100x improvements to that, so it costs $1 per tonne CO2. Of course, this has to be magically done with little or no Carbon-based energy generation, and at global scale. Obvious, right? Easy, right? Nope.

        The conventional economic analysis will say that it isn’t worth doing any of that unless harm is of similar magnitude. Thinking about this for a while, I’ve concluded that conventional economic analysis is bupkis, incapable of dealing with things at this scale. So you aren’t doing to incur a cost of $X now because sometime iif you don’t, with probability p, it might cost you down the road $X + $Y + $Z, where Y >> X, and XZ << Y? Y denotes the cost of clear air capture, just sketched. Z denotes the cost of climate harm. So the activation probability p ends up being like 0.001 or less of big climatic impacts. (Tersely, for what range of values p is X > p[X + Y + Z]?) Given what we know, failing to choose to spend $X now makes no sense at all, given that to stop spending $Z down the road, you need to spend $X + $Y.

        [Response: It’s obvious to me. It’s obvious to you. We’re “numerate” (the math equivalent of “literate”). How do we get “Joe the plumber” (or “Jane the plumber”) to understand this?

        They’re not idiots, but as soon as you write x, y, and z their mathophobia just might kick in. As for members of the U.S. congress …]

      • Hypergeometric, I agree that conventional economics is terrible. If you look in conventional economics textbooks, they’re all asking the wrong questions, and so there’s no way they can get the right answers. They ask the question, “how can I acquire more money for myself, my friends, my company, in the short term?” They do not ask about long-term consequences. They use a lot of math, but if you start with false axioms, you’re only going to reach true conclusions by a remarkable accident, not by reliable reasoning.

        But our ignorance is actually one of the things that gives me hope. Our species still has at least a year or two left, maybe even a decade or two left, if present trends continue. WE DON’T KNOW, and we cannot know, what we might discover if we try — i.e., if we take money out of wars and other forms of stupidity, and put it instead into research about how to stop climate change. I’m optimistic about biochar, and about recent results in selective breeding of phytoplankton. But we do know what we will discover if we DON’T try: Nothing. So we need a revolution. No, that’s too mild a word; really we need an awakening.

      • With respect, we can discover a lot, but there is a big difference, gap, and lag between a discovery and deploying a global-scale solution. The energetics of CO2 with its covalent bonds and its rarity in atmosphere (1 part in 2000 at the time anything can be deployed).

        This energetics challenge makes perfect sense from a Physics perspective. We’ve mined a series of transitions of a system with a series local potential energy wells which are successively lower, and end up with a byproduct which is in the well having the least potential energy. To get it captured and into the ground more-or-less means climbing back up the mountain of wells, applying energy. From where?

      • “Applying energy from where?” I don’t know. How about self-replicating, flying, solar-powered nanobots? … The Manhattan Project took 6 years to design an atomic bomb from scratch. Admittedly, an atomic bomb is much simpler than a self-replicating, flying, solar-powered nanobot, but our technologies today (especially our information technologies) are far, far more sophisticated than they were in 1939. Some research and development still needs to be done, but the biggest thing missing is the political will.

        (I was being partly facetious in suggesting “self-replicating, flying, solar-powered nanobots.” I can think of a dozen other schemes, most of them sounding just as preposterous; but I think half of them would be feasible within a few years if we spent on them a small fraction of the money that we are currently spending on wars. By the way, solar-powered aircraft do already exist, not mass produced, but in working prototypes; one of them circumnavigated the globe a few years ago.)

      • Let’s reconsider this statement:

        Yes, it won’t be possible to zero the incidental emissions associated with agriculture, even assuming planting, tending, harvesting, transport, and processing are all done with zero emissions.

        There are those arguing that, in fact, it is possible not only to zero out agricultural emissions, but it is possible to make agriculture a sufficiently large sink that it can solve a very large chunk of the carbon drawdown problem.

        The basic concept is that you rebuild soil humus by restoring grasslands to their natural function. (You can also apply this methodology to croplands, at least to some degree.) The claim is that the sink is much larger than the atmosphere, and that natural microorganisms will, given proper land management, serve the role of the ‘solar-powered nanobots’ imagined above. Supposedly productivity and profitability can be maintained, sometimes improved.

        (The generic term is “regenerative agriculture”, and I’m pulling what I know about it–very little!–from Scott Strough, who has discussed this at some length over at RC.)

        Now, if all this sounds too good to be true, then know that you are not the first to have this thought. I do not myself claim all this is true, I merely note that it is claimed, and that there is some literature supporting at least some of the claims made. However, given the difficulties and dangers that we face, I think we’d be remiss not to at least do some due diligence on the possibilities. I’ve been collecting references on this for a while, with a view to looking into them, but have had other items on my plate.

        So, since it came up, here are a few references, if others want to check them out:

        Grasslands and their soils can be considered sinks for atmospheric CO2, CH4, and water vapor, and their
        Cenozoic evolution a contribution to long-term global climatic cooling. Cenozoic Expansion of Grasslands and Climatic Cooling”
        “The subsurface location of methanotrophs means that energy
        requirements for maintenance and growth are obtained from
        CH4 concentrations that are lower than atmospheric. Soil Microorganisms as Controllers of Atmospheric Trace Gases
        (H2, CO, CH4, OCS, N2O, and NO)

        Upland (i.e., well-drained, oxic) soils are a net sink for atmospheric methane; as methane diffuses from the atmosphere into these soils, methane consuming (i.e., methanotrophic) bacteria oxidize it. IMPACT OF METHANOTROPH ECOLOGY ON UPLAND METHANE BIOGEOCHEMISTRY IN GRASSLAND SOILS

        Nevertheless, no CH4 was released when soil surface CH4 fluxes were measured simultaneously. The results thus demonstrate the high CH4 oxidation potential of the thin aerobic topsoil horizon in a non-aquatic ecosystem. Methane fluxes from differentially managed grassland study plots: the important role of CH4 oxidation in grassland with a high potential for CH4 production.

        Of all the CH4 sources and sinks, the biotic sink strength is the most responsive to variation in human activities. Environmental impacts on the diversity of methane-cycling microbes and their resultant function…

        The CH4 uptake rate was only 20% of that in the woodland in an adjacent area that had been uncultivated for the same period but kept as rough grassland by the annual removal of trees and shrubs and, since 1960, grazed during the summer by sheep. It is suggested that the continuous input of urea through animal excreta was mainly responsible for this difference. Another undisturbed woodland area with an acidic soil reaction (pH 4.1) did not oxidize any CH4. Methane oxidation in soil as affected by land use, soil pH and N fertilization…

        (Hopefully, I haven’t dropped any HTML tags. We’ll see…)

      • Well, I’m addressing this in part in my talk to come:

        I won’t belabor this matter, but there are slides in the ralk which address it. These will be pubicly available afterwards, alongvwith hopefully an audio record of the talk. And I have done the scholarship to back these up.

        From what i know, the estimates of sequestration for these is widely optimistic. If given free reign and if the negative contingencies don’t materialize, they might get to 30% of where we need to be. But there are temperature dependencies and land use constraints, and some full fledged experiments under controlled conditions haven’t yielded the promisef returns. There is also the question of how long the soils can hang onto the Carbon and under what conditions. They need to do it for a couple of thousand years at least, and in an atmosphere which has less CO2 if drawn down by other means.

      • I should have given references with my previous post, but I was away from my references before and, worse, using a smartphone to post rather than something real. So here they are. These are not details …. There are many more of those, and I have not curated or grouped them into a category specifically dealing with these issues. There is a term, climate smart agriculture which, while I applaud, isn’t going to get us where we need to be, despite the claims of people like Allan Savory. That does not mean these techniques and approaches should be disregarded. And there is recognition this is an important plank to set down. But where it gets tricky is that more than one of my friends have seen this stuff, and concluded that there isn’t the urgency to reducing emissions that they once thought, and if the Powers don’t see climate smart agriculture or building of humus as a priority — although how you introduce biochar into a rice paddy is beyond me — then it isn’t their fault.

        Anyway, these are links to broad and serious overviews of the issues.

        S. Fuss, et al, “Research priorities for negative emissions”, Environmental Research Letters 11 (2016) 115007.
        P. Smith, et al, “Biophysical and economic limits to negative CO2 emissions”, Nature Climate Change, 7 December 2015.
        K. B. Tokarska, K. Zickfeld, “The effectiveness of net negative carbon dioxide emissions in reversing anthropogenic climate change”, Environmental Research Letters, 10 (2015) 094013.
        S. Kartha, K. Dooley, “The risky promise of `negative emissions’: Why we should not assume that land-based measures will save the climate”, Stockholm Environment Institute. See also the full report.

        There are many problems with stepping into this world. People forget, but this has nipped at the heels of the environmental movement from the very beginning. Remember the Last Whole Earth Catalog?

        We are as gods and might as well get good at it.

        Stewart Brand, the creator of Catalog, credits the phrase to Edmund Leach‘s A Runaway World?. It is an idea with which environmentalists have great difficulty. The religious and those with native American or indigenous roots feel it is blasphemous. (It may be.) Embracing it means embracing the full complexity (which demands the full understanding of Science) of running a wholesome environment. Maybe Thorium nuclear reactors really aren’t that bad? Where, then, goes the revulsion the environmental movement has for anything nuclear? Maybe the tradeoffs of ecological engineering, which professional ecologists and ecosystem managers do all the time, are necessary. What does that mean about personal choices to eat vegan? Are the moral bases for these choices vacuous? What if a billion personal choices in individual living (recycling, choice of food) really don’t matter?

        Then, perhaps, there’s an environmental maturity needed here. Who among us, with kids flung to the four winds on different continents, will pass up a trip by plane to visit them because of the extraordinary emissions of such aircraft and their particular impact upon climate? What about people who are just trying to keep their families warm at a reasonable price?

        To the degree use of fossil fuels is structurally intertwingled with modern life, maybe those of us who known it’s a really bad thing should cut those who don’t know, or don’t believe they can choose otherwise a little slack? And, therefore, maybe we ought to look at these negative emissions technologies and pathways more closely. After all, if there’s any moral hazard in doing do, it’s already been embraced.

      • HG says: ” There is a term, climate smart agriculture which, while I applaud, isn’t going to get us where we need to be, despite the claims of people like Allan Savory. That does not mean these techniques and approaches should be disregarded. And there is recognition this is an important plank to set down. But where it gets tricky is that more than one of my friends have seen this stuff, and concluded that there isn’t the urgency to reducing emissions…”

        A couple of things. Enthusiasts for one CO2 management approach or another tend to get tunnel vision and possibly overstate the potential of their approach. Or possibly readers don’t understand the presentation and the takeaway is flawed. I think that any one approach, smart ag or solar powered flying nanobots or falling emissions, is not going to solve the problem of CO2 accumulation. The solution, if it exists for our species’ way of life and its propensity for spewing carbon into the atmosphere is going to be employing every approach that we can think up. It’s not an “either or” solution, it’s going to require “both and” thinking.

        It is discouraging to think that some rather intelligent folks can review our situation and start feeling optimistic when there is currently no evidence to suggest that our collective actions have slowed the accumulation of CO2 in the atmosphere. This is an urgent problem and our actions to date have not scaled up or developed in a manner that reduces the urgency of the problem. This isn’t handwringing and it’s too bad that the rhetorical trick of using a term like handwringing scores so well in debate points since it is so toxic to the reasoned discussion that is taking place.

        The mitigation efforts that have been employed are great, but they appear to be inadequate to date, they have not been scaled up to a level that addresses the problem, they have not produced the change we need to see in atmospheric CO2 accumulation.
        When AL Rodger says, “Today, if CO2 emissions have flattened, there is every reason to expect a leveling out of the rate of atmospheric CO2-rise; that is a reduced/zeroed acceleration.” many folks will breathe a sigh of relief and think “Zeroed acceleration! Wow! We have done it.” and the sense of urgency is gone. But the target is not zero acceleration, the target is zero increase.

        If we don’t convey the target correctly, many innumerate folks just won’t understand the challenge at all. I like the “train over the cliff” analogy. If we zero acceleration, we are like the train the goes over the cliff at 20 mph or 2 ppm instead of 30 mph or 3 ppm. It’s a difference that does not a difference in this situation because it’s not the forward velocity we have when we go off the cliff that is going to hurt us, the it’s the downward velocity we are going to attain once we are over the cliff.

        On the up side, I think the technology and change required to create zero increase will translate somewhat easily into a slow reduction of atmospheric CO2. I will relax quite a bit when I see the CO2 ppm needle start to show reduced acceleration, not zero acceleration. A decade with an increase number under 2.0 ppm. That would be encouraging, but still disastrous since it means an environment with CO2 at 425 ppm. Dr. Mann said in 2014 that we should keep it under 405. I like his number, let’s go with that one, shall we?

        A footnote: when I use the term atmospheric CO2, it is shorthand for CO2 and CO2e. It is also shorthand for atmospheric CO2 and ocean acidification because I think these are all quite closely coupled. I use this shorthand because I think we have to keep it simple for many other earthlings or they get confused about the problem we are facing.

        Great discussion, I appreciate this post and discussion very much.



      • “We are as gods and might as well get good at it.” I agree with Stewart Brand. But so far we have not been good at it. In fact, so far we have been absolutely awful at it.

        In this perhaps I differ from most environmentalists in our society. There is a “back to nature” theme in our current culture, which says let’s interfere with nature and intervene in nature as little as possible — even when things go bad. It is a position of privilege which ignores the problems of people who are too hot, too cold, or too hungry (and by “too” I mean not just a little bit, but dying). It also ignores our history, where we came from, what we really are, how we survived when we lived in trees and caves. We are tool-making animals, par excellence. No wings, no sharp claws, no huge teeth, nothing else to keep us alive except our tool-making. Our walking on hind legs evolved to keep our hands free for tools. Our gift for poetry and philosophy evolved as an offshoot of our ability to tell our tribe about a new tool. Etc. Drop a nature-lover alone in the middle of an immense forest and ask whether he’ll survive, and he’ll say sure. Drop him with no tools, and he’ll say probably he’ll survive, because he’s planning to make his own tools. But drop him with no tools, no clothes, NO KNOWLEDGE of how past generations have made tools, and on top of that forbid him from “interfering with nature,” and he’ll be dead in less than a day.

        And in what way have we been absolutely awful at being gods? The biggest flaw in it is our economic and political system (which environmentalists and climatologists rarely mention). A large part of it is usually called “capitalism,” though I think “hierarchy and property” is more accurate. It is a system that actively discourages us, and sometimes even forbids us, from cooperating and planning together on a wide scale, and it justifies that by an accompanying erroneous belief that we are not CAPABLE of cooperating and planning together on a wide scale. Up until a few centuries ago, when we humans were few in number and our artifacts were biodegradable, it didn’t much matter that we didn’t cooperate and plan — we still weren’t capable of fucking up the planet very much. But now all that’s changed, and we’d better change our attitude in a hurry, or we’re screwed.

      • Thanks for the substantial response, hg. Excellent questions… we are hedged with uncertainties, not least in discerning which ‘pathways’ really lead through the thicket and which are dead ends.

        And thanks for the references, especially. I’m not letting myself off the hook in doing some of that ‘discernment.’

    • thank you for your efforts, lefty! I am feeling punched out since the 2016 election cycle. Hoping to feel revived by 2018, but not sure it can happen. I have watched my generation fail the generations to come. It ain’t over, but it’s getting late.

      • Smallbluemike, I think you are making a mistake if you concentrate too much on elections. Elections are a measurement we make every 2 or 4 years, when we measure how much progress we have made in changing people’s minds during the time between elections. And they’re not a very accurate measurement anyway, since the plutocracy won’t permit us to run candidates that really represent the people. If we’re to save the ecosystem, we’re going to have to end plutocracy, and we won’t accomplish that by electing better plutocrats. The very notion of “representative democracy” is an oxymoron, because concentrated power corrupts. Here is one of my recent leaflets; feel free to hand copies of it to people.

    • You make the situation sound worse than it is. Don’t forget the Stefan–Boltzmann feedback of T^4 on what the Earth radiates back into space. That means that only part of the Earth should become uninhabitable, rather than all of it. That’s assuming we don’t trigger a hydrogen sulfide belch into the atmosphere, or something else catastrophic.

    • I presume that you can fully specify an exponential by 3 points. So choose 3 dates ending at (say) 2000. Then compare the extrapolation with what has actually happened. I fear that may be the only way to get good news out of the CO2 data.

      • John, yes, you could specify an exponential curve from three data points — or even two data points — if it actually were an exponential curve. But it’s not. Perhaps I should have emphasized that more. I’m merely saying that it’s approximately an exponential curve. I think it may be more like an exponential than a quadratic, but the reality is surely more complicated than either of those. It’s not even just an exponential curve plus random noise. It’s a mixture of several different kinds of processes, one of which is exponential, plus random noise. I’ll let someone else stake his or her reputation on more precise predictions. All I’m predicting is that it’s going to continue accelerating for a good many years to come. Until the feedback loops are no longer in effect.

  25. My negative reaction to your optimism and certainty relate to this kind of statement:

    “Today, if CO2 emissions have flattened, there is every reason to expect a leveling out of the rate of atmospheric CO2-rise…”

    First, that’s a big IF for second word. Remember, we have to be talking about emissions from all sources. And, it’s not as simple as controlling emissions, there is also the question of how we do at making the most of carbon sinks.

    I would rewrite your sentence to read: If CO2 emissions have flattened, there is reason to hope for a leveling out of the rate of atmospheric CO2 rise.

    I do not believe there is “every reason to expect” a leveling.

    I think/hope it makes more sense to have this discussion here rather than at RC where there is a large amount of noise in the UV thread comments.

    Do you understand my concerns with your presentation about falling emissions, AR?

    Cheers, buddy


  26. smallbluemike,
    You go too far. Where have I a “presentation about falling emissions”? And if the account of CO2 emissions includes FF+LUC, how would “making the most of carbon sinks” be in any way relevant to the issue of what to expect from atmospheric CO2 under flat emissions?

    • “You go too far!” Apparently beyond earshot as I am without a response. Does that “make more sense” than the previous RC exchange?

      • I am sorry, I don’t understand your question, but will attempt an answer since you seem to want one. As per your presentation on falling emissions:
        at 142 at RC you say “CO2 emissions are encouragingly looking flat-ish over recent years. If this continues, we can expect the wobbly increase in the rate of rise of CO2 to show signs of dropping back towards zero.”

        to my ear and in my shorthand, you are talking falling rate of CO2 emission. I understand your belief in falling rates of CO2 emission are based on global CO2 emission reports which you believe are real and reflect real reductions in CO2 (and maybe CO2e) emissions and that these reports of CO2 emissions falling to flat-ish numbers will cause the rate of rise of CO2 to drop back toward zero. Richard Martin at MIT Tech Review and others share my sense that the emission reports are notoriously unreliable and that calls your premise into rather serious question. Additionally, you appear to believe that CO2 emissions and the accumulation of CO2 in the atmosphere are more closely coupled than I am inclined to believe. Time will tell on all this. I can wait. If you want a tickler in your calendar to revisit the question, please do so. I do not believe we will see any meaningful flat-ish reduction in the rate of CO2 accumulation in the atmosphere that will match the flat-ish reduction of CO2 emissions that you believe has happened for several years. I am going to assume that you are talking possibly 2013 or 2014 to 2016 for flat-ish emissions because I believe the data suggests a 2% increase in CO2 emissions for 2017.

        Lastly, I think you make too much of the EN events and their ability to skew the decadal numbers. For one thing, I think most decades have one or more EN and LN events, so my sense is that these begin to smooth out when you look at decadal increase numbers. But in any case, it is possible to track each year on a graph and do the accepted smoothing and the result shows that the rate of increase has been accelerating. There is no evidence of a change in that trend. Not even close per Tamino.

        Cheers buddy.


      • Yes, much of the reported Massachusetts emissions or, for that matter, U.S. EPA before Trump-Pruitt are based upon self-reported emissions from companies. Yeah they are supposed to be accountably correct but there is no independent auditing except in the large by aircraft overflights, satellites, and, in California, the CalAir tunable LIDAR spectrometer network.

        In the case of CH4 these self-reports proved to be horribly understated, even accounting for the recent finding if excess CH4 sources from forest fires.

      • tinybluemike,
        It is a little worrying that you are unable to ”understand” questions which simply throw your own statements back at you.
        I asked you to explain ‘Where have I a “presentation about falling emissions”?’ You point to a comment on a thread at a different website but even there I do not countenance ”falling emissions.” I did talk of a future where ”we cut our emissions by more than a half. That will not happen for at least a couple of decades.” And I did set out that under continued flat emmissions ”we can expect the wobbly increase in the rate of rise of CO2 to show signs of dropping back towards zero. “ But of ”falling emissions.” in the here and now (which is your meaning) – not a mention.

        Your second paragraph (bar the evidence of ”your ears” which must be wonky) sets things out reasonably but this is your ”presentation” not mine and again there is an absence of ”falling emissions.” We have a partisan citation (which you manage to forget you set out in a comment thread far far away) and mention of some unquantified level of emission-CO2-rise decoupling (relative to the usual view that the CO2-rise equals the Emissions x AirborneFraction) of which you are ”inclined to believe,” along with a willingness to wait for things to develop.

        Then you set out the view that a ”decadal increase” is adequate to represent rates of CO2-rise. This is an exceedingly bold suggestion rolling back our exchange to the week-before-last over at RealClimate. I don’t know how you propose to assess a ”decadal increase.” But if I were to suggest a monthly assessment of the annual change in annual CO2-rise, this monthly value averaged over a decade: that would yield decadal average values of change in CO2-rise of:-
        1967-77 … +0.09ppm/yr/yr
        1977-87 … +0.00ppm/yr/yr
        1987-97 … -0.06ppm/yr/yr
        1997-07 … +0.08ppm/yr/yr
        2007-17 … +0.05ppm/yr/yr
        You might be reasured that the latest 10-year period does have a positive acceleration for the decade although weaker relative to the previous decade. But go back just two years and the last 10-year period would show a deceleration and a rate of weakening acceleration since the 1970s.
        1965-75 …+0.05ppm/yr/yr
        1975-85 …+0.06ppm/yr/yr
        1985-95 …+0.05ppm/yr/yr
        1995-05 …+0.02ppm/yr/yr
        2005-15 … -0.01ppm/yr/yr
        Of course, you may have other methods in mind. Or, and I think it more likely, perhaps you were relying on a large dose of wishful thinking.
        Or maybe we have somehow been ”making the most of carbon sinks” (the ones you mentioned) all along.

      • well, Al. I will disengage from discussion with you. I wish you all the best.

  27. HG said: “Then, perhaps, there’s an environmental maturity needed here. Who among us, with kids flung to the four winds on different continents, will pass up a trip by plane to visit them because of the extraordinary emissions of such aircraft and their particular impact upon climate? What about people who are just trying to keep their families warm at a reasonable price?

    To the degree use of fossil fuels is structurally intertwingled with modern life, maybe those of us who known it’s a really bad thing should cut those who don’t know, or don’t believe they can choose otherwise a little slack? And, therefore, maybe we ought to look at these negative emissions technologies and pathways more closely. After all, if there’s any moral hazard in doing do, it’s already been embraced.”

    This is brilliant. So wise and pragmatic. Glad I took a minute and read your post carefully.

  28. Reblogged this on
    With some remarks:
    Don’t freak out, be still more straight.
    Try to compensate your own emissions via an offset website, it’s dirt cheap still, because the cheap offset projects aren’t yet exhausted.
    Sometimes, be a party pooper, i.e. when friends are going to fly to Thailand.

    • Kinimod: I think your suggestion is graceful and can help you feel good about yourself. It is worth doing. It will not overcome the structural global economic issues and systems that are driving CO2 accumulation in atmosphere and oceans. I just think it’s important to be clear about what can be produced by different approaches to the problem. I guess I am a serious party pooper, I haven’t been on an airplane in more than 20 years, mostly because of the carbon footprint. I drive a prius and I am primarily vegetarian because of the carbon footprint. Most of my friends do the same and/or more. So what? CO2 has continued to increase and the rate of increase has been accelerating (that’s for you, Al). Give me a carbon tax. Only a large scale approach like that can put us on a different path imho.

      • I find it interesting that some will always cheer on ‘individual choice’, whether in the second person–*Why don’t you go live in a cave?”–or the third–“Folks who believe in AGW are hypocrites if they don’t live in a cave, burning dinosaur dung for heat!”

        I wonder how much of it is that such ‘separatism’ would render null and void vocal opposition to them, and how much of it is ideological reification of individual choice as opposed to cooperative (or as they would undoubtedly term it, ‘collective’) effort.

        But you’re right, either way–systemic malformations can’t be overcome purely by individual choices in isolation.

  29. Now this</em. is what I like!

    G. P. Peters, C. Le Quéré, R. M. Andrew, J. G. Canadell, P. Friedlingstein, T. Ilyina, R. B. Jackson, F. Joos, J. I. Korsbakken, G. A. McKinley, S. Sitch, P. Tans, Towards real-time verification of CO2 emissions”, Nature Climate Change 7, 848–850 (2017).