RealClimate logo


Recent trends in CO2 emissions

Filed under: — group @ 14 June 2010

Guest commentary by Corinne Le Quéré, Michael R. Raupach, and Joseph G. Canadell

There is a letter in Nature Geoscience this month by Manning et al (sub. reqd.) “Misrepresentation of the IPCC CO2 emission scenarios” discussing some recent statements about the growth rates of CO2 emissions compared to the IPCC scenarios that informed the climate modeling in the last IPCC report. In it they refer to results published by us and colleagues in a couple of recent papers (Raupach et al. 2007; Le Quéré et al. 2009), and to statements made by others on the basis of our results (Ganguly et al. 2009; Anderson et al. 2008; Reichstein 2010). Specifically, Manning et al object to the claim that “current CO2 emissions from fossil fuel burning were higher than the values used in climate projections by the IPCC”.

We agree with the Manning et al’s main point, and appreciate the chance to provide some clarification on the graph in question and subsequent use of our result. To be specific, recent emissions were not higher than each and every one of the climate projections by the IPCC, as has been claimed by some other studies citing our work, although they were near the top end of the range.

So what is the claim of ‘misrepresentation’ based on?

The IPCC Special Report on Emissions Scenarios (SRES) published in 2000, provided forty scenarios representing plausible futures depicted by common storylines. The IPCC selected six of the forty original SRES scenarios as “illustrative” of the storylines to be used for projections of climate change. In our papers however, we compared recent CO2 emissions with the averages across models depicting common storylines.

Some other studies cited our results assuming that we compared recent CO2 emissions with the illustrative SRES scenarios (unfortunately our figures were not sufficiently clear). The real emissions were above all the scenario averages, while the emissions in one of the six illustrative scenarios was higher than observed. The misinterpretation of our results contributed to claims that IPCC’s global warming projections might be underestimated (Ganguly et al. 2009). Our results do not support such claims.

Why chose scenario averages instead of the illustrative scenarios?

Over the 2000-2010 time period, the trends in CO2 emissions in the illustrative scenarios are dominated by individual model biases. Model averaging is a common way to minimise biases found in individual models and to extract the more robust tendencies and common expectations from a group of equally valid model results. For instance, the A1 storyline depicts a common future based on fossil intensive (A1FI), non-fossil energy sources (A1T), or a balance across all sources (A1B). Logically, one would expect that the fossil intensive scenario A1FI would emit more CO2 than the non-fossil scenario A1T, with the balanced scenario A1B in the middle. This is what comes out of the model averages. In the illustrative scenarios however, the balanced scenario A1B has more CO2 emissions than the other illustrative scenarios during 2000-2010, which reflects more an individual model bias over this time period than a common tendency.

Manning et al. point out that model averages have problems of self-consistency and should not be used. Whereas there are indeed problems with model averages, they have to be weighted against problems of individual model biases and the choice of comparison depends on the issue addressed. As we understand, the problems of self-consistency in this context refer to two things. First, that gases from different models should not be mixed because modelling groups make different choices, for example regarding the future use of land for agriculture. Those choices lead to specific combinations of gases which are lost in the averaging. Second that if models are averaged, it is more difficult to relate back the tendencies to the underlying drivers of the emissions. Both these issues are problematic when the SRES scenarios are used for climate projections, and thus the IPCC rightly selected illustrative scenarios for this purpose. However the issues of self-consistency were less important for our analysis which focused on CO2 only and used other available data to interpret the observed trends. We felt that on balance, the issue of self-consistency seemed less important than issues of biases in individual models in the context of our analysis.

How did CO2 emissions changed in the recent past?

The figure below shows how the CO2 emissions in 2008 (the last year when emissions are available) compared to the 40 original SRES emission scenarios, including both the scenario averages which we used, and the illustrative Scenarios used by the modeling groups to project climate change as reported in the IPCC report. It is clear from this comparison that recent emissions were near the top end of the SRES emission scenarios, whether the comparison is made with the original forty scenarios, with the six illustrative scenarios, or with scenario averages.


CO2 emissions from fossil fuel burning for 2008 in PgC/y. Data are from the Carbon Dioxide Information Analysis Center. Emissions for each of the 40 emission scenarios published by IPCC’s Special Report on Emissions Scenarios are shown. The Scenario names (A1B, A1FI, A1T, A2, B1, B2) correspond to common storylines. The observed emissions are shown in black (uncertainty of about ±6%). Red bars are averages by families of Scenarios. Dark gray bars are the illustrative scenarios used by the IPCC to project climate. See here for a comparison to 2009 projections as in Le Quéré et al. (2009), using the Gross Domestic Product updated by the International Monetary Fund in 04/2010.

The picture is the same if we analyse how fast emissions grew in the past decade. The recent growth in CO2 emissions was 3% per year on average during 2000-2009. This rate includes projected emissions during the 2009 financial crisis, and exceeds the growth estimated by 35 of the 40 SRES scenarios (34 if the trend is computed with end points instead of a linear fit).

Manning and colleagues rightly highlight that the emission scenarios were designed to cover long term trends rather than short term fluctuations. As the CO2 emission scenarios are the primary drivers of climate change in model projections, it is important to monitor deviations from the observed trends, and in particular to identify if the underlying drivers of the deviations have any foreseeable long-term implications. In Raupach et al. (2007) we identified, based on 2000-2005 data, that the recent trends were largely caused by increased use of coal in China and other developing economies, uncompensated by additional improvements in energy efficiency elsewhere. This situation persisted at least until 2008 (Le Quéré et al. 2009). An expansion of the world’s coal-based industry locks energy production in CO2-intensive infrastructure for decades, and thus it has long-term implications for future global CO2 emissions and climate, and in particular for prospects of reaching the most ambitious climate targets.

159 Responses to “Recent trends in CO2 emissions”

  1. 51
    Ray Ladbury says:

    Meteor, I checked several sources for coal–which makes up about half the rise. Petroleum, I relied on an average of several estimates, including the BP estimate. Natural gas is commensurate with petroleum. I also assumed about half the CO2 produced would wind up in the atmosphere.

    Perhaps the main source of disagreement is the unconventional fossil fuels. I tried to hit the mid-range here. However, if the Orinoco reserves are realized, we’re easily over 1000 ppmv.

    The thing is that we have no good alternative to fossil fuels. I see no strong action coming any time soon, so I see nothing that takes us off of the fossil fuel track. And since fossil fuels are currently indispensible (not I said currently, Gilles) not just for energy but also to feed the 7 billion people on Earth, I would contend that people will find a way to use the nonconventional reserves rather than simply allow civiliaation to collapse. What is more, since the extraction will be more energy intensive, we’ll be emitting more CO2 per dollar of production. Hell, even if we run out of fossil fuels, I don’t see us stopping until we burn the last tree. Humans are as voracious as locusts–and collectively about as intelligent. They’ll consume ’til everything’s gone, all the while telling themselves that everything will be alright.

  2. 52
    Ray Ladbury says:

    Ric Merritt, about that breadbasket moving north. Big problem: The topsoil from up there emigrated from Canada with the last glaciers. In some places it was 6-9 feet deep until we let it all blow and wash away. So farmers trying to plant in Canada will find the Canadian shield a rather poor farming belt. Now, I agree, this won’t be a disaster by 2020, but by 2050, winter wheat could be a thing of the past on most of the US side of the border.

    That is the problem we have–we can’t reliably bound risk, and probabilistic risk assessment says when you can’t bound it, you gotta avoid it.

  3. 53

    # 49 and 50

    well the problem is that his stamens in media is not backed up by publications…

    You could find publications that talks about Oil peaks later then the IPCC you can find publications that talks about lots of unconventional oil… and what about methane… added to that and the same goes for coal… This in it self does not prove that it will be economically good to mine it… or that it is the best projection of what will happen links in my post above. and see #35

    then of cause you will have the people saying that we only use a small % of the GDP on energy and that a bit more will not be a catastrophe and that humans have worked wonders before when under pressure to solve problems…

  4. 54
    flxible says:

    AnonC: “rather than a gradual “movement of the North American breadbasket agriculture northward” over 10-20 years, we might experience an escalating torrent of extreme weather events”

    Right at the moment the northern part of the breadbasket is under water, Saskatchewan wheat growers are facing the wettest planting period in 100 years, there will likely be little if any wheat from an area that normally exports tons around the world. Ric might not lose his particular job over it, but he’ll be paying more for grain based foods by this time next year.

  5. 55
    john says:

    Re: #24: There was a ‘500 year hurricane’ in UK in 1988. Any bets on when the next one will be?

  6. 56
    John E. Pearson says:

    I read somewhere that Craig Venter thinks he can pump genetically engineered bacteria into coal seams and turn coal into methane. The idea being that we’d then burn the methane instead of coal and that methane produces something like 1/10th the CO2 that coal does for the same number of kWh. I don’t know if that idea is still alive but I am curious as to how a stop-gap measure like that would play out. It doesn’t strike me as entirely distinct from Freeman Dyson’s idea of growing soil to keep CO2 from going too high. Dyson claims that if we grew our top soil by 1/100 inch per year that that could absorb all the CO2 that we are currently emitting. I’ve seen it written here on RC that Dyson is a “denialist” but he isn’t. He is way way too smart to join the idiot forces of Motl WUWT, etc.. From my reading of Dyson he isn’t a denialist but a cornucopiast. Lately RC has been bumming me out, not so much because of the usual gang of denialist idiots but because of the total lack of imagination regarding solutions.

    [Response: It may be fair to take us to task if we have called Dyson a denialist, though I’m not sure we have. But he’s said some pretty foolish and inaccurate things about the science, and his ideas about solutions are more Star Trek than science. As for *our* alleged lack of creativity re solutions, this isn’t what we are particularly experts in, and we probably will all disagree with one another. What you may be referring to is that we tend to be dismissive of poorly thought out quicky technical fixes, usally coming from people — whether they be left-leaning physicists or right-leaning economists — that seem not to have the foggiest notion of the complexity of the climate system, nor any concern for other aspects like ocean acidity. When those same people defend their ideas on the basis that we don’t like geoengineering because it doesn’t fit our alleged leftist anti-SUV agenda, well, we’re doubly unimpressed. Sorry for ranting but … really!.–eric]

  7. 57
    ccpo says:

    To ALL:

    1. Peak Oil
    A. We’re already seeing the melt and such that we weren’t supposed to see for a looong time. Thus, 450, 550, 650…? Irrelevant. The bleeping methane is coming out of the ice, folks. The tipping point done tipped, if you ask me. A little Occam’s Razor is in order.

    B. We’ve already peaked. And? Tell me, if we see a worsened economic crash due to additional effects of Peak Oil, and people can’t buy what they need to cook/heat/what have you, just what do you think is going to be burnt for those purposes? Or, if things continue on as they are, or anything like they are, and we get to 450 ppm, which we know can be correlated with Greenland being (nearly?) ice free, what in tarnation are you expecting to see happen?

    Etc.

    Ice: Already affected enough to be in a feedback loop, and the warming associated is correlated to melt a thousand miles (km?) inland, giving yet another feedback loop.

    Essentially, the argument over how much we can burn is irrelevant, and this is where Kjell, et al., are fubar in their thinking. MAGICal even: Feedbacks don’t matter because IPCC V hasn’t been written yet, and (contrary to reality) the changes expected are far off.

    Goodness…

    It simply doesn’t matter whether we hit the “worst” cases of the scenarios, because our models obviously can’t calculate the true planetary sensitivity/reaction to what we are doing to it. We have already pushed the system too hard too fast. The question now is, will 450 ppm, which seems to be virtually assured given current and future emissions and the methane feedbacks already underway, goose the system in any substantive way?

    To answer the question on Rutledge, see above. Also, search threads for his name on The Oil Drum.

    Cheers

  8. 58
    Walt Bennett says:

    Re: #57:

    Thank you.

  9. 59
    Edward Greisch says:

    31 & 51 Ray Ladbury: “For truth to triumph, humans have to become a helluva lot smarter.”
    Roger that.
    “I would contend that people will find a way to use the nonconventional reserves rather than simply allow civilization to collapse.”
    Except that doing so is exactly what will cause more CO2 which will cause more GW which will collapse agriculture.
    “Humans are as voracious as locusts–and collectively about as intelligent.”
    Roger that.

    54 flxible: “Right at the moment the northern part of the breadbasket is under water”
    Roger that.

    Which brings us back to the horns of the dilemma: We have got to find a way to STOP the production of so much CO2! The trend in CO2 production is in the wrong direction. We are a very small minority and we don’t have a lot of money or political savvy. The only thing I can think of to capitalize on is weather events such as that which flxible mentioned and we can do that only if the weather event extends in time long enough to become quasi-climatic. That puts us on the ragged edge of sticking to Science. So we have to mention weather events in a way that makes them add up to a shift in the climate and show that agriculture is suffering because of the climate shift. Then we have to imply that prices at the grocery store will be impacted in a really serious way. [Guidance please?]
    And newspaper editors often don’t to publish our letters or comments.

  10. 60
    Gilles says:

    #51 “Meteor, I checked several sources for coal–which makes up about half the rise. Petroleum, I relied on an average of several estimates, including the BP estimate. Natural gas is commensurate with petroleum. I also assumed about half the CO2 produced would wind up in the atmosphere.

    Perhaps the main source of disagreement is the unconventional fossil fuels. I tried to hit the mid-range here. However, if the Orinoco reserves are realized, we’re easily over 1000 ppmv.

    Ray, it is not only a question of summing reserves, it is also a question of pace, and how long the civilization will be able to extract them. Most of these reserves are unconventional and needs sophisticated techniques to be extracted – you can currently see what drilling a hole under 5000 ft of water really means.

    I repeat my question, that remained unanswered : taking your “likely” estimate of global liquids production, if you try to fit it with a reasonable production curve, which peak production do you predict and at which date, and how does it compare to current production curve ?

    I am merely asking to apply the methodology presented for CO2 emissions in the introduction post, but restricted to liquids only. It should be rather simple to take a subset of data , shouldn’t it ?


    The thing is that we have no good alternative to fossil fuels. I see no strong action coming any time soon, so I see nothing that takes us off of the fossil fuel track. And since fossil fuels are currently indispensible (not I said currently, Gilles)”

    Yes, and which consequences of GW aren’t estimated with “current ” knowledge, basically extrapolating them without any fundamental change ? are you able to predict the evolution of mankind concerning the use of new energy sources, but not concerning its adaption to temperature ?

  11. 61

    This is all very disheartening, the increase in CO2 emissions. If only people would have started reducing back in 1990, they would have saved money, lots of money, without lowering productivity or living standards, perhaps avoiding the severity of the current economic crunch, and we would have mitigated many other environmental and nonenvironmental problems in addition to AGW.

    I know where the higher emissions are coming from — people are taking their money and burning out on their front lawns like so many autumn leaves. That’s what I tell denialists they are doing by failing to become energy/resources efficient/conservative and go on alt energy.

    Like a Carrier AC commercial, where the family comes running out of their house crying, “We’ve been robbed” (bec their AC was so inefficient).

  12. 62
    Greg says:

    #50 Meteor:

    Assuming you are in fact using “reserves” from the BP report–lay people tend to use “reserves” and “resources” interchangeably, which is a source of error–you need to bear these things in mind:

    1. “Reserves” is an economic term. It describes what can be produced using current technology at prevailing prices. If prices go up, reserves go up. If technological development lowers costs, reserves go up.

    2. Miners and oil producers do just enough exploration to be able to plan development and production over the next 20 to 30 years. More expense than that is needless. “Reserves” is not a measure of what is in the ground.

    3. Excluded from reserves is a lot of already-known coal that is in too-thin seams, or in unstable rock, or too deep, or that has other difficulties that stops it being included in reserves. Technology improvements that are in train will bring many of these deposits into reserves in due course. This would double reserves without need for further exploration.

    Thus, although total resources are unknown, they are known to be large, and potentially orders of magnitude above reserves. There is no reason to think A1FI and/or 1100 ppm are impossible, or even unlikely. Quite the reverse.

  13. 63
    Ray Ladbury says:

    John Pearson,
    Freeman Dyson is undeniably a smart guy. However, he has his eyes so firmly fixed on “the future” that he doesn’t see the brick wall that lies in our path toward that future. In that sense, he reminds me of the joke about the engineer, physicist and mathematician who decide to share a room to save money at a conference. So, in the middle of the night, as they are nestled all snug in their beds, a fire breaks out in a trashcan. The engineer wakes up, sees the flames and runs and grabs the fire extinguisher. He sprays the extinguisher all over the place, makes a big mess, but gets the fire out. Or so he thought… The fire starts again from a tiny ember left in the trash can. This time the physicist wakes up. He runs to his desk, writes down a couple of equations, runs over and grabs the extinguisher, sprays three short blasts at the base of the fire and it goes out. Or so he thought… Again the fire reignites. This time the mathematician wakes up and sees it. He looks over and sees the fire extinguisher and says, “Oh, a solution exists.” He then rolls over and goes back to sleep. You can guess which one most closely resembles Dyson. We don’t know how to grow the topsoil at .01 inches a year on a global scale. We don’t know how to make genetically engineered carbon-gobbling trees. We don’t know how to geo-engineer a solution with sulfate aerosols or what the side effects of that solution would be. We don’t know how to bound risks of climate change. We do know how to proceed in the face of such uncertainty: Risk avoidance while we reduce uncertainty and come up with effective mitigation. It ain’t sexy, but it is standard risk mitigation procedure.

    [Response: Ray, well said.–eric]

  14. 64
    Ray Ladbury says:

    Gilles, your question is ambiguous. The fossil fuels in the tar sands and in the Orinoco are “liquid”, but not free liquid. If all had to worry about was natural gas and petroleum, we’d probably stay below 550 ppmv. However, even this number is not firmly set, but technology dependent. Even 15 years ago, the idea that we’d be sucking oil our of 15000 foot wells under a mile of ocean through a soda straw would have seemed far fetched. Fracking has increased US gas reserves by several fold in less than 10 years–as well as demonstrating that we are willing to put up with just about any level of environmental degradation to obtain it. I see no good excuse to assume technology will remain static.

    Also, you are assuming that CO2 emissions will go down as fossil fuels get harder to extract. In fact, the opposite may occur. Coal is much dirtier than natural gas or petroleum. Oil shale and tar sands even moreso.

    In my experience the effects of crises rarely cancel each other out–the interference is much more likely to be constructive.

  15. 65
    dhogaza says:

    Eric:

    What you may be referring to is that we tend to be dismissive of poorly thought out quicky technical fixes, usally coming from people — whether they be left-leaning physicists or right-leaning economists — that seem not to have the foggiest notion of the complexity of the climate system, nor any concern for other aspects like ocean acidity. When those same people defend their ideas on the basis that we don’t like geoengineering because it doesn’t fit our alleged leftist anti-SUV agenda, well, we’re doubly unimpressed.

    This reminds me nothing more than of the stream of “solutions to the BP gulf gusher” being put forward by people who are often quite smart and skilled in their field (lots of engineers) but absolutely clueless as to what’s involved in trying to stop a well 5,000 feet under water, pressure at the bottom of the well of 12,000 psi, and 18,000 feet of well capped with a fragile, damaged device that has to be babied so it doesn’t blow out entirely and become uncontainable and unkillable via the relief wells.

    Sometimes smart people have to recognize that outside their knowledge domain, maybe they’re really not smarter than the experts.

  16. 66
    Gilles says:

    Ray : #64 : thank you for your interesting digressions, but I am not asking for a detailed philosophical and/or economic dissertation. “Liquid” is a relatively well defined notion, even if you can discuss if pressurized butane is liquid or gas, this doesn’t matter very much. I’m just asking for NUMBERS. You made a statement about a “likely” integral amount of oil (actually you made a statement about a CO2 concentration increase, but I assume you know how to convert it, since the basic quantity is more the volume of hydrocarbons than the CO2 concentration).

    So again i’m not “assuming” anything : again, I’m just asking for very simple numbers, not philosophy ! : for this “likely” amount of liquids, and a likely shape of the overall curve, can you estimate an approximate interval of a “likely” peak volume and date ? this shouldn’t be very hard to compute (much less complicated than global climate modeling of course).

  17. 67
    David Miller says:

    In #56 John Pearson says I read somewhere that Craig Venter thinks he can pump genetically engineered bacteria into coal seams and turn coal into methane. The idea being that we’d then burn the methane instead of coal and that methane produces something like 1/10th the CO2 that coal does for the same number of kWh.

    I’d like to see the original research on that idea because it doesn’t pass the straight-face test as a means of reducing carbon emissions.

    The basic problem is that bacteria don’t magically take the energy encapsulated in in carbon and turn it into energy encapsulated in hydrogen without significant losses along the way.

    Yeast makes about 60% of the energy available in starches and sugars available as ethanol; the rest goes into CO2 and yeast biomass. If the coal-eating bacteria was nearly as efficient (round to 50%) then half the energy in the coal would be available in the methane. To break even the natural gas generation would have to be twice as efficient as the coal generation would have been. I believe modern coal plants are in the 35-40% range, so the natural gas plant would need to be in the 70-80% range.

    The basic problem from an emissions perspective is that a lot of CO2 would be produced in order to make the CH4.

    There are lots of other considerations to make about the economics and feasibility and peak vs baseload, but those aren’t relevant to the emissions discussion here.

    Unfortunately, there’s no quick fix.

  18. 68
    Walter Manny says:

    “Freeman Dyson is undeniably a smart guy”

    To put things into perspective, I would say Ray Ladbury is undeniably a smart guy, whereas Dyson is a brilliant guy. Neither is a speci alist in this field, so arguably neither is worth listening to, but it’s hardly unreasonable to ponder what Dyson has to say.

  19. 69
    Completely Fed Up says:

    “but it’s hardly unreasonable to ponder what Dyson has to say.”

    It’s hardly unreasonable to decide, after such ponderings, that Dyson has got it completely wrong.

  20. 70
    Doug Bostrom says:

    Neither is a speci alist in this field, so arguably neither is worth listening to…

    One apparently lacks the important virtue of humility. If you don’t subscribe to omniscience, choose carefully.

  21. 71
    John E. Pearson says:

    67: David I think I can find the reference when I get back home in a few days. I’m pretty sure i read the Venter thing in Stewart Brand’s book … Eco-pragmatist yada yada. I didn’t do any analysis at all and wondered if it passed the simple tests, but usually I’ve found that few simple tests are that simple in practice.

    Hold the press:

    googling for “Venter methane coal” turns up this:

    http://www.microbeworld.org/index.php?option=com_jlibrary&view=article&id=761

    in which someone claims that it’s already being done.

  22. 72
    John E. Pearson says:

    I have no idea if Dyson is wrong or right on growing soil at a rate of 0.01 inches per year. What I think is that it can’t hurt to try it. I don’t agree with the notion that all we have to do is adopt SSX (single strategy X) and that we probably ought to be willing to try everything we can. I dislike geoengineering in principle but I can imagine cases in which we might be forced to it, say if the methane clathrates started melting and belching up really really enormous quantities of methane (which i guess they might be doing now?) Is there no case in which geoengineering makes sense as an emergency measure? (Here by geoengineering I’m thinking specifically about spraying sulphur dioxide not growing dirt, or windmills, etc, which all could qualify depending on how you want to define terms.)

    Didn’t get to read more than 2 posts up and saw that at least people are talking about this stuff which i think is a good thing.

  23. 73
    Anonymous Coward says:

    John (#72),
    Developing and evaluating methods to “grow” soil (with measurements of changes in carbon content, nutrient content and so forth) could have agricultural applications as well. People have long worked on this but it definitely seems like something worth funding more extensively. But, for the purpose of long-term geoengineering, it’s a bit dicey because, if it were actually workable to store huge amounts of carbon in living soil, climate change could lead to uncontrollable releases of that carbon down the road. There are more stable ways to sequestrate carbon. But that of course doesn’t mean it’s not worth doing as some kind of complementary measure.
    And you’re of course right about geoengineering. Given the forseeable trend in CO2 emissions and the uncertainties regarding the ultimately recoverable fossil fuel resource as well as regarding the slow climate feedbacks, it would be prudent to fund R&D. And, though it’s not politically correct, I think convective uplift should at least be considered as a method to deliver stuff to very high altitutes.

  24. 74
    Doug Bostrom says:

    By the way, speaking of physicists wandering off their reservations, check out the neatly hermetic The temperature rise has caused the CO2 increase, not the other way around item now being messily disassembled not only at Skeptical Science but even at WUWT. Internal party dissonance between Eschenbach and Hocker is causing rusty mental gears to turn: is Hocker the roader or is it Eschenbach? The former says C02 is created by mathematical phlogiston, the latter says humans done it, meanwhile the the regulars don’t like it when family members disagree, shoulder-to-shoulder solidarity is more comforting. Somebody’s going to have relearn the peasant virtues or maybe volunteer for samokritika.

  25. 75
    Ray Ladbury says:

    Gilles, surely you are not so naive that you think one can estimate a “peak date” or emissions curve without assuming a scenario, are you?

    If you make the unreasonable assumption that we will simply burn all the oil and natural gas until it is gone and then wait for civilization and the human population of 9 billion to collapse, you get peak emissions sometime around 2050 and probably a peak CO2 content around 550 ppmv around 2100, by which time, human population ought to have more or less stabilized to about 50-100 million gloabally. That assumes a scenario.

    A more reasonable scenario assumes we’ll burn whatever we can lay our hands on to keep civilization going and postpone collapse, further damaging global carrying capacity and probably stabilizing below the above population estimate.

    Me, I’d like to assume that somehow we reach sustainability, gradually reduce population and that we continue to try and resolve the Fermi Paradox by analysis rather than experiment. But that, too, is probably unrealistic.

  26. 76
    Ray Ladbury says:

    John E. Pearson says, “I have no idea if Dyson is wrong or right on growing soil at a rate of 0.01 inches per year. What I think is that it can’t hurt to try it.”

    OK, John, gonna play devils advocate here. Let’s say we start growing topsoil at 10 mils a year using some genetically engineered microbe. How do we stop it? How do we keep it from growing much faster than 10 mils a year? How do we stop CO2 from dropping below 200 ppmv?

    Not saying it’s a bad idea. Just that even if we come up with a viable mechanism, we have to 1)validate it, 2)failsafe it, 3)know how to stop it if unintended consequences are unacceptable. Mitigations usually work best when they use the mechanisms in the system that we know best. That’s CO2. We know how it gets into the atmosphere. We know what it does. We know how the system responds if we start to remove it. The problem I have with most geoengineering strategies is that they use the forcings and mechanisms that we understand least–e.g. the aerosols, the biosphere…

    Arthur Clarke said that technology sufficiently advanced is indistinguishable from magic. What I worry about is people proposing magic solutions and us mistaking them for technology.

    Walter Manny, I can cite many, many examples of utterly brilliant men and women (ok more men than women) who were nonetheless utterly batshit crazy on some matters where they pontificated without studying the matter in sufficient depth.

  27. 77
    wili says:

    Ric at 48–

    The Arctic may seem a long way from you, but an ice free Arctic Sea, as far as I understand it, will probably alter the climate of the entire northern hemisphere. No one knows when this will happen, but since ice thickness has collapsed in the last few years, random weather events and wind patterns any year now could probably get us pretty close.

    And of course, there is the possibility (probability?) that we could face a major discontinuity, even this year, if, as some claim, there are ten thousand gigatons of free methane under a very thin and already-melting layer of clathrates at the bottom of the very shallow waters north of Siberia.

    Watching from west to east the Barrents, Kara, Laptev, and eventually East Siberian Seas melt in sequence on Cryosphere Today and other sites feels a bit like watching the fuse burn toward the bomb.

  28. 78
    Ed says:

    To 72 John E. Pearson

    It would be great to increase soils. I think Ray was meaning that Dyson hasn’t got an effective plan for doing that on a global scale (I don’t know if he has or not). If you want to learn more about growing soil resources, investigate permaculture. Some academics who have published on building carbon in soils are Pete Smith of Aberdeen University and Rattan Lal of Ohio State Uni.

    There are some assessments of geoengineering out there. Depending on what you can access over the net, there is

    The Royal Society (2009) Geoengineering the Climate: Science, Governance and Uncertainty

    or alternatively

    Lenton TM & Vaughan NE (2009) The radiative forcing potential of different climate geoengineering options. Atmospheric Chemistry and Physics Discussions 9, 2559–2608.

    I have been joining in Tim Lenton’s GeoEngineering Assessment and Research (GEAR) group as I am doing a life cycle analysis of biochar (from UEA’s new biomass CHP plant). Briefly, geoengineering consists of SRM (solar radiation management) and CDR (Carbon Dioxide Removal) techniques. My very brief take on these techniques is that the SRM ones especially are prone to requiring ongoing maintenance over the centuries to avoid reversion to full climate impacts. For sulphur aerosols in the atmosphere, a few weeks would be enough for them to wash out. Also, SRM techniques tend to offer no help with ocean acidification. So I personally would mainly consider these in a national security context, of invading other countries to STOP them implementing these methods. CDR, on the other hand, includes some more sensible options eg incorporating biochar in soil, expanding forested areas (massive co-benefits unlike launching endless rockets full of mirrors or sulphates into space/the atmosphere) or more untried but still fairly safe and predictable options such as dumping biomass on the ocean bed or air capture/carbonate weathering approaches.

    Re previous posts about looking for evidence of the economic cycle in global carbon emissions. I wonder if people are expecting to see a replica of the US economic cycle – that is unlikely because most growth in economic output, fossil-intensive energy production and emissions are from developing countries. At the moment, governments are suffering from too much debt, but they don’t all suffer simultaneously like synchronised swimmers – the trouble reverberates around and is phased between different countries/regions.

  29. 79
    Gilles says:

    Ray :”Gilles, surely you are not so naive that you think one can estimate a “peak date” or emissions curve without assuming a scenario, are you?”

    If you let the total amount as a free parameter, yes. But for a given total amount, the curve is much better constrained. Different scenarios differ vastly from each other by their total amount of each fossil type. But you told of a likely amount, so I ask again : once you have fixed what you consider as a ” likely ” value, (only for liquids I remind you), which peak volume and peak date are associated with this value ? I cannot imagine that you didn’t ask yourself this question !

    unless you consider that there is absolutely no relationship between the integral value and the shape of the curve, but then what is the relevance of the study presented in the introducing post ???

  30. 80

    Gilles 60: we have no good alternative to fossil fuels.

    BPL: No matter how many times you say this, it still won’t be true.

  31. 81
    Neil says:

    I have seen that if we exclude the feedback mechanisms doubling CO2 from pre-industrial levels would approximate to a 1.2C rise in temp? Can anyone comment on if this is correct?

    Many Thanks

    [Response: Yes. But excluding feedback mechanisms is not anything to do with the real world where we have a lot of evidence for the fact that the feedbacks are amplifying. It’s like discussing the impact of a bus hitting you assuming that it isn’t made of steel. Possibly interesting, but hardly relevant. – gavin]

  32. 82
    Completely Fed Up says:

    Or, in other words, how do we stop the water vapour rising when we warm the planet?

  33. 83
    Gilles says:

    “Or, in other words, how do we stop the water vapour rising when we warm the planet?”
    it would be enough to assume that the effects of clouds could overcome that of water vapour. I don’t know if it’s true, but i don’t see how it can be easily dismissed. Remember BTW that “warming” concerns primarily high latitude zones, mainly in winter, that contribute very few to the global evaporation of water. I don’t think the zeroth order theory of GHG is wrong – i am much more cautious with the “feedbacks”.

  34. 84
    Completely Fed Up says:

    Ah, now how do clouds form?

    Dropping below dew point.

    How does dew point drop change when you increase temperature and let humidity rise to the same %?

    It gets bigger.

    So how do clouds form without increasing vapour content again?

    It’s sad seeing someone who claims science fail so hard at it.

  35. 85
    David Miller says:

    In #71 John points us to http://www.microbeworld.org/index.php?option=com_jlibrary&view=article&id=761

    Interesting, but they basically say “we found a microbe that can eat coal and release methane”.

    My fear is that this is just a biological implementation of in-situ processing. If it reduced the carbon emissions relative to just burning the coal I might think it a good thing. What it feels a lot like, at this point, is a way to mine coal that might otherwise be uneconomical to extract.

    We really need to leave the carbon in the ground, not find other ways to extract it without mining.

  36. 86
    Ric Merritt says:

    wili @ 16 June 2010 at 8:53 PM (#77):

    Well sure, it’s pretty easy to imagine sudden but immense change, within a period of say a decade or less. Just acknowledge that you are talking about events not seen in recent centuries, including the known warming period, and don’t get too far beyond the professional literature or you’ll be in Hollywood.

    It’s hard to propose a solid bet on these things, because definitions and attributions are messy, but I would be happy betting that most folks in flyover America, not to mention most people anywhere, will see a greater impact on their daily lives by 2020 or 2030 from peaking fossil fuels than from climate change. And that’s from a perspective accepting mainstream climate science.

  37. 87
    Jim Eager says:

    Gilles wrote: “it would be enough to assume that the effects of clouds could overcome that of water vapour. I don’t know if it’s true, but i don’t see how it can be easily dismissed.”

    You might start with the fact that the negative forcing of clouds did not prevent Earth from experiencing much higher temperature levels and much higher CO2 levels for most of its history.

  38. 88
    Completely Fed Up says:

    “i am much more cautious with the “feedbacks”.”

    Uhm, cloud increases are feedbacks. No caution there. Thrown to the winds.

    You’re extremely INcautious about feedbacks.

  39. 89
    Ray Ladbury says:

    Gilles, Surely you realize that fixing a single value for a resource is unrealistic. It depends on pricing and demand. It depends on technology. It even depends on climate! I can give an answer–the question is whether the answer means anything. And whether it means anything depends on whether the assumed model is reasonable. The thing is that you are assuming a model–you just seem not to realize it.

  40. 90
    MartinJB says:

    I would posit that, if there really were no alternatives to fossil fuels, that we would suck every last bit of accessible fossil fuels out of the ground. The increasing cost of extraction will be outweighed by the increased price due to scarcity.

    [Response: Hmmm. Wasn’t there a movie series about this? -mike]

  41. 91
    MartinJB says:

    Mike, I never thought of the Road Warrior as a cautionary tale about resource overconsumption. I LIKE it! So, let that be a lesson to us all… if we don’t mainstream alternatives to fossil fuels, we’ll end up speaking in an Aussie accent.

    More seriously, as fossil fuels become more expensive, alternatives will start becoming more and more attractive and start eating into demand for fossil fuels. I would rather we start accurately pricing the cost of fossil fuels (i.e. a price on carbon), so the transition will not be driven entirely by the ruinous impacts of scarcity. Since energy infrastructure takes a long time to replace, one can easily imagine a scenario in which market and political failure leaves us ill-prepared for the transition, causing massive disruption. That scenario is also the worst-case climate scenario, since it likely means we’ll have extracted a maximum of fossil fuels. So, doubly worst case.

    Makes the choice pretty obvious.

    Cheers!

  42. 92
    Anonymous Coward says:

    Martin (#90),
    This is a common misconception. I don’t recall whether Mad Max is sufficently didactic about this point so let me spell it out: the extraction of fossil fuels consumes, directly and indirectly, a certain amount of fossil fuels. Therefore, as the price of fossil fuels rise, so do the costs of extraction. If you were to hold the technological and social factors steady, extraction from some deposits would consume more fuels than others. Every last bit of accessible fuel will therefore not be extracted, irrespective of price. Mad Max is, I think, particularly didactic about the indirect fossil fuel consumption involved in fossil fuel extraction. In the Mad Max world, deposits which would economically recoverable in the Star Trek world can’t be exploited for lack of an adequate social and technological infrastructure. The amount of fossil fuels needed to maintain the current infrastructure is very, very high so more efficiency improvements, renewables, nukes and so on will be needed to sustain fossil fuel production.
    These and other complications make it very hard to reliably project BAU emissions trends over more than a few decades. Knowing the size of the phyiscal deposits doesn’t tell you how much can be economically extracted. Nor does divining the amount which will be economically extractible in the future give you the peak of the production curve (pace Hubbert).

  43. 93
    MartinJB says:

    Umm, AC, I did stipulate that this was in the absence of alternatives. That rather changes the economics of the situation. And I think any reasonable definition of “accessible” supply would presume only supplies that produced more energy than it cost to extract using available technology.

    Heck, we’re already exploiting oil-sands, deep-water drilling (far deeper and through less friendly substrate than that in the Gulf of Mexico), oil shale and the goop that maintains Donald Trump’s hair-do. Even with available alternatives then, we’re going pretty deep into our fossil fuel reserves.

  44. 94
    Anonymous Coward says:

    Martin (#93),
    You were apparently referring to a discussion about there being “no good alternative” (in the aggregate) which isn’t the same thing as there being “no alternatives” (in particular cases).
    You seem to be thinking in terms of energy returned on energy invested but I’m not talking about EROEI, which is irrelevant if you have different energy sources with different characteristics. EROEI also doesn’t take all indirect energy costs into account.
    What you don’t seem to be taking into account is that alternatives affect both the supply and the demand picture. Deposits which weren’t “accessible” by your definition become would become recoverable with cheaper (relatively to fossil fuels) nukes, renewables and so on. The exploitation of oil-sands would be a good application for nukes for instance and could be economically profitable even if the operation consumed more energy than burning its products would produce. And if one considers the indirect energy costs, there’s a lot more potential to displace fossil fuels and therefore to increase ultimate total emissions with alternatives (in a BAU scenario).

  45. 95
    Gilles says:

    “How does dew point drop change when you increase temperature and let humidity rise to the same %?

    It gets bigger.

    So how do clouds form without increasing vapour content again?

    It’s sad seeing someone who claims science fail so hard at it.”

    What a strong scientific argument , I’m impressed !

    tell me CFU, if more water evaporates, it also means that more water condensates and falls on the ground, since this is a closed cycle. How can you do that without more clouds ?

  46. 96
    Gilles says:

    “You might start with the fact that the negative forcing of clouds did not prevent Earth from experiencing much higher temperature levels and much higher CO2 levels for most of its history.”
    This is absolutely not contradictory with negative, or simply weak feedbacks … For instance, the feedback from water vapour could only increase by 10-20 % the forcing, and the rest could be explained by other complex phenomena linked to a modification of ocean circulation, albedo, that could be dependent on astronomical parameters and not constant throughout the history of the Earth (and so not relevant on the decadal scale). I don’t see simple arguments to dismiss these possibilities.

  47. 97
    Gilles says:

    RL “Gilles, Surely you realize that fixing a single value for a resource is unrealistic”

    Ray, it’s strange that you persistently refuse to answer such a simple question. YOU told about a “likely” value of 1000 ppm, and I only asked you how much liquids contributed to these 1000 ppm , and what is the likely maximum of the liquid production curve corresponding to YOUR value. I did’nt “fix” anything, I’m just asking for the value corresponding to YOUR 1000 ppm. If you change your value, you will change of course also the peak value.

    The only point was about the word “likely”. If you consider the 1000 ppm value as “likely”, whatever your criteria are,my question is : which corresponding “likely” value of the peak liquids (max production and date) do you estimate accordingly ?

    It is just a matter of consistency …

  48. 98
    Neil says:

    Gavin Reference reply to #81

    Many Thanks – not trying to make any point here just wanted get some “baselines” for my own understanding. Are the main feedback mechanisms as follows (in no particular order) or are there additional onee?
    – Ice Cover
    – Water Vapour / Clouds
    – Out gasing of CO2 from the oceans
    – Weathering of Rocks

    Many Thanks

  49. 99
    Ray Ladbury says:

    Gilles, I’ve said repeatedly that if you assume only known reserved + petroleum, you keep CO2 below 550 ppmv. I don’t know how to state it more clearly. I have also stated that this is not realistic. Coal puts us between 800 and 850. Nonconventional fossil fuels do the rest. Perhaps you could suggest why you are having trouble reading what I think is expressed quite clearly.

  50. 100
    Completely Fed Up says:

    “Are the main feedback mechanisms as follows (in no particular order) or are there additional onee?”

    Neil, can you think about that question.

    It doesn’t make much sense.

    If they are main ones, then you’re saying there ARE others, just not considered main. But where’s the definition of main? How were these mechanisms measured against that standard?

    The query makes no sense because no answer can work without failure.

    Better would be: Are these the major mechanisms: $LIST? Even that has nothing. If answered “yes”, what have you learned? If answered “no”, is there any answer that isn’t a dissertation that will complete the education?

    Questions need a GOAL.

    When asking “are there additional ones?” what is the GOAL of an answer? What do you want from the answer that will then close that inquiry to your satisfaction?