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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. 1
    prokaryote says:

    Can this be plotted to the total net greenhouse gas uptake? Is it correct that all these scenarios do not account for methane uptake?

  2. 2
    Jim Petrie says:

    I am a scientist but not a climate scientist. My field is medicine. I’ve been reading blogs and books on the topic of global warming and I think I understand at least one of the issues.
    There is one area where there seems to be some uncertainty.
    Low clouds provide negative feedback to the effect of CO2 and high clouds provide positive feedback.More worming means more water vapor and means more clouds.
    I think Phil Jones said that the greatest area of uncertainty in this debate was the effect of clouds.
    If clouds in fact provide a negative feedback to the effects of CO2 of (say) 1% what effect would this have on the computer models? Have the modelers looked at this?
    Wanting to learn.
    Jim

    [Response: This is recent presentation on the subject. But can we please make an effort to stay on topic in this comment thread? Thanks. - gavin]

  3. 3
    Spencer says:

    Very useful post. It points up the severe problem of communicating the IPCC’s findings in general. How many times have we heard that the IPCC predicts a 3-degree C warming when in fact it predicts a range up to twice that? Or, closer to this matter, that temperature rise / ice loss / etc. exceed the projections, where (like CO2) they actually only exceed the bulk of the projections?

    Given that journalists have limited space, and that TV journalists in particular must count each extra word as a severe cost, how do we convey the actual situation? I suggest that in any paper with significant results like the one discussed here, it’s crucial to include an illustration along the lines of your figure, showing the range of IPCC projections against the current result. Even better perhaps would be a shaded graph of projected rise where dark=likeliest or average, shading off to lighter toward the outside values, and with the current paper’s findings (observation and/or projection) superimposed. That would both inform reporters and stand a chance of being picked up by TV and other media.

  4. 4
    Barry North says:

    How is CO2 in the atmosphere measured and how accurate is the measurement?

  5. 5
    Completely Fed Up says:

    Jim, it would probably be a good rule-of-thumb to assume that modellers HAVE included (or considered and rejected as ineffective) something in as a feedback if someone without climate science background can think of it.

    You can find out more in the WG1 section of the IPCC reports (http:/www.ipcc.ch) and under both the Start Here section at the top of this page, but as a good rule of thumb, assume it has been included.

  6. 6
    Nank says:

    This article is very interesting, unfortunately not much effort undertaken by some countries to stop or at least reduce the global warming process today.

    My country is also one of the country that does not seem to care about global warming.

    Thank you, your articles very interesting and inspiring.

    My Blog http://loggingstory.blogspot.com

  7. 7
    Tim Joslin says:

    Surely you need to see at least a whole business cycle to see if the actual emissions exceed the scenario assumptions. Otherwise, we’re not much wiser.

    As we saw, the rate of economic growth to 2008 was unsustainable, and the global economy accordingly went off a cliff in 2009. The bar chart including estimated 2009 emissions referred to in the footnote to the main figure gives a somewhat different impression to the actual figure, showing, as it does, that the actual 2009 emissions were less than the A1B and A1F1 scenario averages.

  8. 8
    Adam R. says:

    @ #4
    Barry North “How is CO2 in the atmosphere measured and how accurate is the measurement?”

    See:

    http://www.skepticalscience.com/co2-measurements-uncertainty.htm

  9. 9
    Walt Bennett says:

    What’s unfortunate in all of this is that, as usual, the real science gets lost. People debate whether current emissions are above or below estimates for certain scenarios among dozens. Of course, the lower CO2 output for the last several years will rebound as soon as the economy does, as we all know.

    But what’s really being missed here?

    Today’s emissions will influence the climate of 10 to 20 years from now. The warming we are experiencing today is merely the final stage in a process which began decades ago. When man made the conscious decision to ignore the increase in atmospheric CO2, and when he decided to exceed the normal high end of that number by a large margin, he committed himself to a warmer planet.

    Which is here.

    Last year’s emissions aren’t affecting this year’s weather. There is no benefit, none at all, to slight annual reductions in emissions. It doesn’t matter whether or not today’s emissions are above or below several of the dozens of scenarios.

    It matters that we are now 50% above nature’s chosen upper limit for atmospheric CO2.

    Fifty percent.

    It matters that the persistence of CO2 (due to the limits of the exchange rate with the oceans) will render it, in terms of this discussion, permanent.

    Three degrees, Fahrenheit, is the short term expected increase in global temperature. Since this warming will induce long term feedbacks, the global temperature will certainly continue to rise.

    If we stopped emitting CO2 today. If we took it to zero, this would still be true.

    The inertia which has already been built into the system will result in an ice free planet.

    That’s what is being lost in this discussion.

    And, in my opinion, plays right into the deniers game of making people believe bad science.

    Or at least misleading use of science.

  10. 10
    Walt Bennett says:

    Re: Above:

    Three degrees Celsius, 4 to 5 degree Fahrenheit, is the expected short term increase.

    Mea culpa.

  11. 11
    Completely Fed Up says:

    “Surely you need to see at least a whole business cycle to see if the actual emissions exceed the scenario assumptions.”

    No, we don’t.

    Besides which, a business cycle is 3 months. Plenty of three-month periods done passed by.

  12. 12
    Stephen says:

    Is it not concentrations of CO2 in the atmosphere that is important for climate change, rather than emissions? Have not concentrations of CO2 in the atmosphere risen less quickly than would have been expected by the rise in emissions? Taken out of context, this article runs the risk of being “true but misleading”. An uninformed reader might draw the incorrect conclusion that “emissions higher than values used in IPCC’s projections = higher warming than in IPCC projections”. That is not necessarily the case, given that the biosphere is sequestering more CO2 from the atmosphere than had been anticipated, as I understand it.

    [Response: Concentrations are a very smoothed function of the emissions, and have been rising pretty much exactly as anticipated by the IPCC scenarios. Emissions growth however has implications for longer term changes in concentrations. - gavin]

  13. 13
    Sean A says:

    “How is CO2 in the atmosphere measured and how accurate is the measurement?”

    Also check out the really interesting website linked in the caption to the figure in the article: Carbon Dioxide Information Analysis Center. A good place to start digging for answers.

  14. 14
    Harmen says:

    “How is CO2 in the atmosphere measured and how accurate is the measurement?”

    Let the master explain himself?
    http://www.scivee.tv/node/5044

  15. 15
    Edward Greisch says:

    Thanks for posting this. When will they ever learn?

  16. 16

    Prof. Kjell Aleklett has claimed that all scenarios are more or less impossible due to peak oil and coal restriktions in the media…

    http://translate.google.com/translate?js=y&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&u=http://uppsalainitiativet.blogspot.com/2010/03/brist-pa-olja-och-kol-raddar-inte.html&sl=sv&tl=en

    However here you have a more balanced article from his group:
    http://www.tsl.uu.se/uhdsg/Publications/IPCC_article.pdf

    Any comments from RC on this?

  17. 17
    Completely Fed Up says:

    Magnus, seeing as the scenarios go all the way from “no CO2″ to “lots of Fossil Fuel burning”, how can all the scenarios be more or less impossible?

    Unless he’s thinking

    a) It’s physically impossible to get coal/oil out faster
    b) Media pundits will take the ad money and refuse to allow politicians to move away from oil/coal

    thereby making all scenarios blocked either by mechanics or politicking (as opposed to politics).

  18. 18

    #17

    He is thinking that it is not possible to get coal/oil out fast enough… (however his comments in media are even worse some times claiming that there is not enough coal and oil in the ground…)

  19. 19
    Stephen says:

    Gavin,

    thank you for your in-line comment to my post #12. I note that you agree with my point. Emissions seem to be rising faster than IPPC projections, but concentrations seem to be in line with IPPC projections. Therefore, people must be careful not to draw an overly simplistic conclusion from this article such as equating higher than projected emissions to higher than projected temperatures, because concentrations are not increasing as quickly.

    [Response: Yes, but my point is that concentrations are a lagging indicator. - gavin]

  20. 20
    bibasir says:

    This is a good chart from Jim Hansen that shows the current emissions with respect to the IPCC scenarios.

    http://www.columbia.edu/~mhs119/Emissions/

  21. 21
    Stephen says:

    #19 “are” a lagging indicator or “might be” a lagging indicator? Was not the gap between emissions and concentrations somewhat unexpected? Are people not reasearching the “missing sinks” at this time?

    [Response: Huh? The emissions are roughly 9 GtC/yr, into an atmosphere that hold roughly 800 GtC. How can the concentration changes not lag the emission changes? This would not be the case for aerosols for instance, which because of the very short residence time (weeks) have their concentrations effectively set directly by whatever the emissions are. This has nothing whatsoever to do with missing sinks. - gavin]

  22. 22
    Stephen says:

    “Missing sink” is clumsy layman speak on my part. I have in mind the oddity of the airborne faction remaining at 43% (Knorr (2009)), whilst the expectation had been that the biosphere’s capacity to scrub anthropogenic emissions would decline as temperatures and emissions increased.

    [Response: Note that a change in the airborne fraction is not the same as a carbon cycle feedback, rather the roughly constant fraction is a result of exponentially increasing emissions combined with a linear response in the sinks. There will be more papers in due time exploring these connections, but I fail to see how this is relevant to the emissions/concentrations question you raised. - gavin]

    [ I think all that Stephen is saying here is "wasn't there an expectation that the sinks would be non-linear." I think the answer to that is that we don't have enough data to distinguish linear from non-linear responses. It's in the long term, not the short term, that such things will (or not) become clear. I'm not aware of any particular surprises in the data thus far.--eric]

  23. 23

    It’s great to have these clarifications but meanwhile time is ticking by. The attack on climate science is largely political, and it’s hard to see how anything but a political response can counter this: not too late, I hope.

  24. 24
    Edward Greisch says:

    To get CO2 emissions down, we are going to have to be smart about politics. Please read
    http://www.congress.org/news/2010/06/14/how_a_minority_passed_prohibition

    Is that something we can do?

    My comment 15 should have read “when will the denialists ever learn?” Probably not until it is too late. Note that we have another object lesson in GW today: 10 inches of rain in Oklahoma. Ok, so it is only weather. But it is a “500 year” flood, and if they have another one in 5 years, it won’t be a 500 year flood any more.

  25. 25
    ccpo says:

    Magnus Westerstrand says:
    14 June 2010 at 1:29 PM

    Prof. Kjell Aleklett has claimed that all scenarios are more or less impossible due to peak oil and coal restriktions in the media…

    http://translate.google.com/translate?js=y&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&u=http://uppsalainitiativet.blogspot.com/2010/03/brist-pa-olja-och-kol-raddar-inte.html&sl=sv&tl=en

    However here you have a more balanced article from his group:
    http://www.tsl.uu.se/uhdsg/Publications/IPCC_article.pdf

    Any comments from RC on this?

    Kjell is way out of his element on Climate and it shows in his logic, which shows his bias in favor of a PO doomsday scenario instead of a climate change doomsday scenario. Weird that anyone could possibly think there is any value in one or the other being the “right” scenario, but that’s what happens when one marries oneself to a cause, rather than to problem solving in general.

    To be specific, Kjell adheres to the following:

    1. PO is now, climate change is FAR in the future.

    I suggest he observe more of what’s happening in the Arctic Circle.

    2. If it’s not in the IPCC, it’s not legitimate science.

    It’s been explained to him – ad nauseum – that the IPCC reports simply survey and analyze the research available, and doesn’t actually *do* any science, thus, whatever the current science is is what the current science is. He can’t seem to accept this very simple logic.

    3. He has accepted the findings, starting with Rutledge, perhaps, that there simply aren’t enough fossil fuels to do what we all fear via AGW.

    First, Rutledge’s work is flawed in its climate assumptions. Second, Kjell’s assumptions about climate are flawed. E.g.:

    450, 550, 650 ppm or more are OK levels.

    Feedbacks are irrelevant; only FFs matter (at least until the IPCC reports on their lit review, at which time the science apparently gets transmogrified into *real* science).

    These things are strange to me in both the utterly fallacies involved and complete void in logic.

    Cheers

  26. 26
    Gilles says:

    25 : As you understood, I’m basically on line with Kjell Aleklett , for the following reasons
    “1. PO is now, climate change is FAR in the future.

    I suggest he observe more of what’s happening in the Arctic Circle.”

    For most of the consequences that are supposed to hit hard the mankind (crops, economic crashes, wars), consequences of the PO will happen much sooner and will impact more directly the life of billions of people. I share the idea that PO has played a key role in the current economic doom

    http://www.theoildrum.com/node/6542

    whereas I haven’t yet seen any proposal that it could be caused by the melting of northern sea ice (because only northern would matter, but not southern, of course).

    ” 22. If it’s not in the IPCC, it’s not legitimate science.

    It’s been explained to him – ad nauseum – that the IPCC reports simply survey and analyze the research available, and doesn’t actually *do* any science, thus, whatever the current science is is what the current science is”

    There are plenty of doubts and uncertainties expressed all along IPCC report. The assessment of “likelihoods” that GW would be caused by that or that is not intrinsically a scientific assessment since nobody has ever demonstrated that there is a reliable method to compute this kind a “likelihood’ – that is just the result of political discussions. So there are enough uncertainties factors to estimate that the science hasn’t proved anything convincingly about the real magnitude of the consequences of a GW.

    “3. He has accepted the findings, starting with Rutledge, perhaps, that there simply aren’t enough fossil fuels to do what we all fear via AGW.

    First, Rutledge’s work is flawed in its climate assumptions. Second, Kjell’s assumptions about climate are flawed. E.g.:

    450, 550, 650 ppm or more are OK levels.”

    IPCC scenarios are flawed by the assumption of continuous economic growth, as if the depletion of resources (not only oil, but almost all commodities in the XXIth century) wouldn’t have any impact on it – that a very strange idea that the only thing that threatens the society is the average temperature of the globe !!

    What does the IPCC say about the “OK” levels of CO2 concentration ?

    What would be the economic consequences of trying to keep below 450 ppm , compared with the consequences to exceed it ? who has a scientific estimate of the marginal cost of each attitude ?

  27. 27
    Completely Fed Up says:

    re 18, then the A1T scenario is not impossible.

    It’s one of the scenarios.

    It’s sounding to me like this is him trying to get attention.

    But in any case, not all the scenarios are impossible.

  28. 28

    #25 CCPO

    It would be interesting to read publications or stories about where and how Rutledge are wrong?

    (Aleklett never mentions any body ells… always takes all the credit for peak oil and stating that the IPCC got it all wrong… etc.)

  29. 29
    Jacob Mack says:

    “High-yield agriculture slows pace of global warming, say researchers
    Yesterday at 5:00pm
    Advances in high-yield agriculture achieved during the so-called Green Revolution have not only helped feed the planet, but also have helped slow the pace of global warming by cutting the amount of biomass burned — and the resulting greenhouse gas emissions — when forests or grasslands are cleared for farming. Stanford researchers estimate those emissions have been trimmed by over half a trillion tons of carbon dioxide.”

    http://www.facebook.com/home.php?#!/pages/Molecular-Biology/83645260842

  30. 30
    Ray Ladbury says:

    ccpo and Magnus,
    I looked at this a few months ago, and if you add all likely CO2 emissions from oil, coal, natural gas, tar sands and oil shale, you come up with a likely upper limit of ~1000 ppmv, assuming the portion going into the atmosphere remains constant. This does not include release from peat bogs, permafrost, clathrates or possible saturation of the oceans.

    You can argue about whether it is realistic to assume 100% consumption. Fine. It doesn’t change the fact that we have sufficient carbon to drastically alter Earth’s climate–not surprising if you think about it. Earth’s climate has been dramatically different in the past, in part due to higher CO2.

  31. 31
    Ray Ladbury says:

    Edward Greisch,
    I think that it is important to remember that prohibition was also overturned–the only amendment ever to be excised from the constitution. We can rely on parliamentary maneuvers or undemocratic tricks, but our opponents are even more adept with these tactics. The one weapon their arsenal lacks is truth, and that has to be our mainstay. For truth to triumph, humans have to become a helluva lot smarter.

  32. 32

    Barry North 4: How is CO2 in the atmosphere measured and how accurate is the measurement?

    BPL: Flask sampling in isolated areas compared around the world, and it is very accurate. Five significant digits are commonly listed.

  33. 33
    Tim Joslin says:

    CompletelyFedUp #11 quoting my #7: As was your response to a post of mine on another thread, that’s a misleading comment. If you don’t have any idea what the business cycle is perhaps you shouldn’t be posting on the subject.

    The business cycle is from recession to recession or peak of growth to peak of growth, which has been about 10 years over the last few decades (though not necessarily synchronised globally). Maybe actual emissions should be tested against model predictions over such a period, as identified from economic indicators (even though this might not be methodologically straightforward).

    There was a period of unusually fast global economic growth in the 2000s, so over the long term the IPCC scenarios do not necessarily underestimate carbon emission trajectories.

  34. 34
    Gilles says:

    RL#30 :”ccpo and Magnus,
    I looked at this a few months ago, and if you add all likely CO2 emissions from oil, coal, natural gas, tar sands and oil shale, you come up with a likely upper limit of ~1000 ppmv”

    Could you please give more precisely the “likely” value for oil only entering your addition, and convert it in a “likely” value for the date of the peak (with a “likely” shape), together with a uncertainty interval for both ?

    If you can’t , what is your meaning of “likely” ?

  35. 35

    Ray,

    I did look quite deep in to the question ( http://translate.google.com/translate?js=y&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&u=http://uppsalainitiativet.blogspot.com/2010/03/brist-pa-olja-och-kol-raddar-inte.html&sl=sv&tl=en ) and we definitely have enough fossil fuels to put us well over ipcc levels.

    I think it is fair to say that there could be big problems with peak oil, gas and coal… however we can not say that for the next 100 years we will not see any brake through techniques in the fossil fuel are that makes it easier to get up from the ground, we do not know if politicians will put the infrastructure needed for increase in output out in time… we don’t know if they will move national parks and therefore cant rule that out. (same thing here, short time fluctuations don’t mean the long trend must be wrong, and it is always easy to point out wrongs in short periods with complex things like scenarios something which I think IPCC acknowledges).

    However it would be interesting to see scenarios where these considerations are taken to see how that would affect the economic consequences… for handling CO2 emissions. E.g. high cost on fossil fuels probably would make a fast transition to alternatives cheaper.

  36. 36
    pete best says:

    Re #35, Dont be fooled by what politicians might be deciding for the process is very complex and the procedure takes a long time to decide anything. Here in the UK for example we are already heading for a energy deficit as we mothball our nuclear and aging coal fired power stations. However replacements are a concern. Is it Nuclear, Wind, etc or more coal and gas but lead times are long and if left to energy companies fossil fuels would win out.

    If we tax Co2 then renewables win, if not then nuclear might or we all might lose for if climate change does not then peak energy will.

  37. 37
    Completely Fed Up says:

    “The business cycle is from recession to recession or peak of growth to peak of growth, which has been about 10 years over the last few decades ”

    We’ve had plenty of 10-year business cycles.

    (that would be the length of time for a new CEO to stuff up the company and move on under a golden parachute, yes?)

    And each 10 year average has been warmer than the previous 10 year average.

    So too has the ice area reduced for each 10 year average.

    Your position is untenable under ANY proposition. You still state “oh, this could mean that we get return to normal ice” when you’ve supplied NO mechanism to do so.

    [edit]

    [Response: This thread is about emissions, not ice. Please stay on topic. - gavin]

  38. 38

    #34–THIS is the sound of goalposts moving. The question was total, not trajectory.

  39. 39
    Gilles says:

    #38 Kevin
    I don’t see the goalpost moving. Ray said “and if you add all likely CO2 emissions from oil, coal, natural gas, tar sands and oil shale”, and I just asked for the specific contribution of oil in the addition (or more exactly liquid) in the total.
    Now for a given total, I would be pleased to know the kind of realistic curve Ray or you are expecting, within for instance the IPCC scenarios that are supposed to encompass all possible scenarios.

  40. 40

    # 37

    Regarding long time for decisions… this publication is interesting and a way that tries to give a clearer picture for politicians to act on
    http://www.pnas.org/content/early/2010/01/08/0903797106.full.pdf+html

    “In a scenario with high demand for energy and land, being below 2 °C with 50% likelihood requires a 50% reduction in emissions below 2000 levels by 2050, which is only barely feasible with known technologies in that scenario”

  41. 41
    Barry North says:

    Adam R. Thank you for the link, which I’ve read and largely understood. Now I need to go away, think about it for a couple of weeks, and then come back with another dumb question :)

  42. 42
    Ray Ladbury says:

    Gilles,
    No, it is a fair question. I believe that petroleum alone cannot get us above 500 ppmv. Add methane, and I think you can get to ~600-650. Oil shale and tar sands to about 700-750, and coal is the rest. That’s from memory and it was a few months ago. So, coal is about half.

  43. 43
    Gilles says:

    Ray : thanks ; I would be interested in converting the value in ppm CO2 into a value of total amount of GtC, and try to fit this total value with a realistic curve, for each FF and especially the “all liquids” curve (oil/tar sand/oil shales).

    Which growth rate do we expect for the next decades, and which maximal production rate and peak date do you consider as “likely” ? given the 1-sigma error bar you evaluate, how likely is a close peak of all liquids ? (could you for instance compute an approximate likelihood of a maximal peak < 90 Mbl/d before 2015, with these values?)

  44. 44
    meteor says:

    Ray Ladbury

    No, if we burn all the known reserves of fossil carbon (1500 GtC since preindustrial era), CO2 will increase between 550 and 600 vpm.
    And the temperature will increase at 2/2.5°C max.
    OK it’s a personal computation (http://www.climat-evolution.com/article-depasse-t-on-2-c-si-on-brule-toutes-les-reserves-de-carbone-fossile-45331893.html)

    The problem is the fossil carbon resources.(>1500GtC)
    And in this domain this is, as we say in french, the “flou artistique”.
    I think that IPCC could give us some realistic scenarios based on the actual knowledge of the resources.

  45. 45
    Tim Joslin says:

    CompletelyFedUp #37: You’re totally muddled. Not only does your comment address my comments on two separate threads, you’re once again misrepresenting my position (on the other thread).

    Here, you seem to imply I’m some kind of denialist. I’m not. I did not “state” “oh, this could mean that we get return to normal ice”. This is neither a quote nor does it correctly represent my position. And I’ve gone to a great deal of trouble on the other thread to explain the processes that could cause cyclic Arctic sea-ice and related climate behaviour around an underlying warming trend.

    [Response: This thread is not about ice. To both commenters, further dispute on off-topic issues on this thread will be deleted. - gavin]

  46. 46
    Jim Eager says:

    Meanwhile, the NOAA State of the Climate Global Analysis for May 2010 is out today:
    http://lwf.ncdc.noaa.gov/sotc/?report=global&year=2010&month=5&submitted=Get+Report

    quote/
    The combined global land and ocean average surface temperature for May 2010 was 0.69°C (1.24°F) above the 20th century average of 14.8°C (58.6°F). This is the warmest such value on record since 1880.

    For March–May 2010, the combined global land and ocean surface temperature was 14.4°C (58.0°F) — the warmest March-May on record. This value is 0.73°C (1.31°F) above the 20th century average.

    The combined global land and ocean average surface temperature for January–May 2010 was the warmest on record. The year-to-date period was 0.68°C (1.22°F) warmer than the 20th century average.

    The worldwide ocean surface temperature for May 2010 was the second warmest May on record, behind 1998, 0.55°C (0.99°F) above the 20th century average of 16.3°C (61.3°F).

    The seasonal (March–May 2010) worldwide ocean surface temperature was the second warmest such period on record, 0.55°C (0.99°F) above the 20th century average of 16.1°C (61.0°F).

    The global land surface temperatures for May and the March–May period were the warmest on record, at 1.04°C (1.87°F) and 1.22°C (2.20°F) above the 20th century average, respectively.

    In the Northern Hemisphere, both the May 2010 average temperature for land areas, and the hemisphere as a whole (land and ocean surface combined), represented the warmest May on record. The Northern Hemisphere ocean temperature was the second warmest May on record. The average combined land and ocean surface temperature for the Northern Hemisphere was also record warmest for the March–May period.
    /quote

  47. 47
    Ray Ladbury says:

    Meteor, are you sure. There’s ~1 teratonne of remaining coal alone–which puts us over 560 ppmv. Proven oil reserves take us above 600 ppmv. Also, there could be a lot more oil out there–the Orinoco Basin may have more oil than the Middle East. Oil shale and natural gas (proven) take us up over 750-800 ppmv. Other unconventional ois reserves could take us above 900 ppmv. If we assume that other sources of CO2 continue in about the same proportion (e.g. cement production, etc.), we’re easily above 1000 ppmv.

    Those who claim Peak Oil will cancel the climate crisis ingore the fact that humans are extremely ingenious when it comes to screwing up the environment–and the fact that because unconventional fossil fuels require greater processing, they may actually accelerate CO2 production.

  48. 48
    Ric Merritt says:

    To ccpo @ 14 June 2010 at 10:25 PM (#25) and others thinking along similar lines:

    When I read Magnus W’s comment @ 14 June 2010 at 1:29 PM (#16), I skipped the link to what sounded like the more extreme rhetoric and just read the “more balanced article”. I suggest we spend our time on the possibilities that are more central and more likely, as shown by more evidence and common sense. I saw little connection between your criticisms and the article I read.

    One crucial point still inadequately acknowledged by most, including many commenters here, concerns the profound feedbacks from peak fossil fuel production, led by peak oil production. We are already seeing the leading edge of those effects. The higher-emissions SRES scenarios are dubious at best.

    None of this changes the central thrust of climate science. It does challenge a lot of conventional economics that is looking increasingly mythical. It is perfectly reasonable to accept mainstream climate science and still point to peak oil as the more immediate threat to prosaic activities over the next decade, such as, say, my job and the jobs my young-adult children are looking for. No one can seriously and reasonably extrapolate the climate changes of the last 3 to 10 decades over one or two more decades and identify anything that would kill my job within that time. Arctic ice melt, movement of the North American breadbasket agriculture northward, and rising seas are not likely to have a greater effect over the next 10-20 years than they have over the past 100. (To everyone planning an intemperate reply concerning decades after 2020, just squelch the impulse please. For the umpteenth time, I have no reason to doubt mainstream climate science, being on the contrary an intense supporter of it, and advocate of public policies accordingly.)

    The mini-argument brewing between “peak oilers” and “climate campaigners” is especially silly because both phenomena are manifestations of limits to human activities in an effectively finite system, and the sensible reactions to both overlap to a huge degree.

  49. 49
    SecularAnimist says:

    Ric Merritt: “No one can seriously and reasonably extrapolate the climate changes of the last 3 to 10 decades over one or two more decades and identify anything that would kill my job within that time. Arctic ice melt, movement of the North American breadbasket agriculture northward, and rising seas are not likely to have a greater effect over the next 10-20 years than they have over the past 100.”

    You seem to be assuming a gradual, steady rate of change as opposed to abrupt, extreme changes. I would suggest that given what we can see happening right now, that is not a safe assumption.

    E.g. 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, including intense, prolonged and extreme drought leading to widespread crop failures next year.

    We are already seeing an upsurge in AGW-driven extreme weather events that are already an “immediate threat to prosaic activities”. Just ask the folks in Nashville.

  50. 50
    meteor says:

    Ray

    my source for the reserves is the BP 2009 report.

    natural gas :127 GtC

    oil and Canada bituminous sands:164 GTC
    coal: 826 GTC

    sum: 1117 GtC

    we already emit about 460 GtC since preindustrial (with land use and cement: source CDIAC)

    My scenario was hence 1500 GTC emission since preindustrial with a peak at 12 GtC/y in 2030-2040 and a decreasing after.
    1500GtC because I supposed a rest in the reserves and land use emissions as in SRES scenarios.
    I precise that the model gives me 385 ppm with the 460 GtC already released.

    With the Bern 2.5 C model (simplified equation) the maximal concentration, with 1500GtC emissions, is 550 ppm obtained in 2090/2100.
    Maybe there is an little underestimate but not very high (20-30 ppm)
    I precise that the model is good for the A1B scenario.

    I am not a peakoilist or a sceptical man, but my problem is the realism of scenarios which imply the use of unproven or estimated resources.
    I think that the IPCC must work on this theme for its next report to gain credibility.
    I don’t know an new evaluation of resources since Rogner 97 (An assesment of world hydrocarbon resources).

    And you?


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