Why the CO2 reduction pathways are too stringent

by Jacques Hagoort

Why the IPCC carbon budgets in SR1.5 are over conservative, and the CO2 reduction pathways are too stringent.

Abstract Carbon Budgets specify the total amount of CO2 that can be emitted before global warming exceeds a certain threshold. Since the introduction of the Paris Climate Agreement in 2015, prominently featuring the 1,5 and 2˚C global warming limits, Carbon Budgets have become the cornerstone of global warming mitigation policy by CO2 reduction. In the recent IPCC special report on global warming of 1,5˚C from 2018 (SR15), the Carbon Budgets have been substantially upgraded compared with the ones reported in the preceding IPCC Fifth Assessment Report from 2013 (AR5). We have analyzed the new method for estimating Carbon Budgets in SR15 and found it seriously wanting, leading to non-physical future global warming profiles. The net result is Carbon Budget estimates that are over-conservative leading to timeframes for the reduction of CO2 emission to net-zero that are too stringent. A simple alternative calculation method without the shortcomings of the SR15 method yields substantially larger Carbon Budgets and thus more lenient timeframes for net-zero emission. Assuming a linear emission reduction pathway, we estimate that net-zero emission for a global warming limit of 1,5˚C is reached in 2070 instead of 2043 as per the SR15 budget. In the case of a warming limit of 2˚C, net-zero happens in 2125 rather than in 2079.


Since the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC) came out in 2013, Carbon Budget has emerged as a widely accepted and powerful concept in both Climate Science and Climate Policy (IPCC, 2013a). It stems from the observation that in climate model projections, global warming since pre-industrial times shows an approximate straight line when plotted against cumulative CO2 emission, irrespective of the emission scenario. Hence, to limit global warming to a certain threshold there is a limit to the allowable cumulative CO2 emission. This defines the Carbon Budget. Given the straight line, Carbon Budgets can be readily calculated for an agreed global warming limit, such as 1,5 or 2˚C as stipulated in the Paris Climate Agreement.

The metric to characterize global warming straight lines is the Transient Climate Response to Cumulative Emission (TCRE). It is defined as the warming in ˚C per emission of 1000GtC (1 GtC = 109 tonne of Carbon) and is essentially a measure for the slope of the straight line. The TCREs in AR5 are based on global warming projections of Earth Systems Models (ESM), a subset of some 20 climate models that are capable of simulating the global carbon cycle. They show a rather wide spread: from about 1,25 to 3,25˚C/(1000GtC) for the 5-95% confidence interval with a central value of 2,44˚C/(1000GtC). See Figure SPM.10 in the Summary for Policymakers of AR5 WG1 (IPCC, 2013b). These TCREs represent total warming (CO2 warming and the rest) and for this reason are sometimes referred to as effective TCRE as distinct from the TCRE for warming due to CO2 only. Naturally, the CO2-only TRCEs are smaller than the effective TCREs. According to the expert judgement of the AR5 author team the CO2-only TCREs are distributed normally around a central value of 1,65˚C/(1000GtC) with a standard deviation (SD) of 0,85˚C/(1000GtC).

The best-estimate Carbon Budgets per 01-01-2011 presented in AR5 were based on the central effective TCRE of 2,44˚C/(1000GtC). See Table 2.2 of the AR5 Synthesis Report (IPCC, 2014). Following the publication of AR5 in 2013, a steady stream of climate studies appeared that challenged the official AR5 Carbon Budgets because they were based exclusively on climate model projections and ignored observational climate data (Hausfather, 2018a). As the ESMs used for the Carbon Budget calculations in AR5 tend to overestimate global warming and underestimate cumulative emission, the AR5 Carbon Budgets were deemed too conservative (Hausfather, 2018b). The recent IPCC Special Report on Global Warming of 1,5˚C (SR15) assessed the various Carbon Budget studies and came up, not unexpectedly, with a rather drastic upward revision of the AR5 Carbon Budgets (IPCC, 2018a). For example, the Carbon Budget for a warming limit of 1,5˚C increased by a factor five. Exactly how these revised budgets were arrived at, however, was not entirely clear from the report (Lewis, 2018). Fortunately, a recent publication by the responsible author team of SR15 has shed more light on the underlying calculation procedure (Rogelj et al., 2019). It even provides a theoretical framework for assessing Carbon Budgets so that future changes can be more easily traced and assessed.

To better understand the new calculation method used in SR15, we have tried to reproduce the Carbon Budgets reported in SR15. While successful, in the process we have come upon a number of serious shortcomings, which casts doubt on the reliability of the reported Carbon Budgets. This article sets out our reservations about the new SR15 method and shows what to do about it. The outline is as follows. First, we present a brief summary of the SR15 method. Next, we show how the SR15 method has been applied and has led to the reported Carbon Budgets. We then highlight the shortcomings and present an alternative method to overcome these. Finally, we discuss the implications of the alternative Carbon Budgets for the mitigation of global warming by CO2 reduction.

The SR15 method

Figure 1 schematically illustrates the SR15 method for estimating Carbon Budgets as described by Rogelj et al. It shows an (x, y) diagram with the global warming since pre-industrial times on the y-axis and the cumulative CO2 emission since pre-industrial times on the x-axis. The crux of the SR15 method is the observed total global warming (i.e. CO2 warming and the rest) at a certain cumulative CO2 emission, indicated by the blue bullet point. It serves as a calibration point for the linear warming relationships. The light-blue line begins in the origin (zero global warming at zero cumulative CO2 emission) and ends in the calibration point. It describes past total warming but plays no role in the SR15 method proper. The uninterrupted dark-blue straight line begins in the calibration point and describes the best-estimate warming caused by CO2 only. The slope of this CO2-only line is of course less steep than the slope of the light-blue total warming line. Uncertainty in future warming is accounted for by maximum and minimum CO2-only warming straight lines that also begin in the calibration point. The Carbon Budget for a certain total warming limit follows from the intersection of the CO2only straight lines with the horizontal red line at the level of the allowable total warming limit minus the non-CO2 warming. The dark-grey horizontal bar shows the Carbon Budget for the intersection with the best-estimate warming straight line and thus represents the best-estimate Carbon Budget relative to the calibration point. Likewise, the intersections of the horizontal red line with the maximum and minimum warming straight lines result in minimum and maximum values of the Carbon Budget.

Figure 1 – Schematic of SR15 method

The calibration point used in SR15 is the observed average total warming in the period 2006-2015 relative to the average warming in the period 1850 – 1900 at the average cumulative emission during 2005 – 2016 relative to the average cumulative emission during 1850 – 1900. The average warming in 1850 – 1900 is considered representative of the beginning of the industrial era. The warming depends on how global warming is defined. In climate models, global warming is customarily expressed as the average of near-surface air temperatures (SAT) everywhere. The warming reported in observational global temperature series, however, is a blend of near-surface air temperatures over land and sea surface water temperatures (SAT/SST). The observational (SAT/SST) global warming in the period 2006 – 2015 is 0,87˚C. The corresponding SAT global temperature is slightly higher: 0,97˚C. See table 1.1 of Chapter 1 of SR15 (IPCC, 2018b). The average cumulative emission during 2005 – 2016 relative to 1850 – 1900 is 1958 GtCO2 (1 GtC = 3,664 GtCO2). The cumulative emission at the calibration point follows from the CO2 emissions database of the Global Carbon Project (GCP), a consortium of international climate research groups that keeps track of historical global carbon emissions (Le Quéré et al., 2018). The CO2 emissions comprise emissions by the burning of fossil fuels, by the industry, and by changes in land use. In line with the expert judgement of the AR5 author team, the SR15 method assumes that the TCREs for warming by CO2-only are normally distributed with a central value of 1,65˚C/(1000GtC) and a standard deviation (SD) of 0,85˚C/(1000GtC).

For the minimum and maximum TCRE, SR15 takes the 33th and 66th percentile of the CO2-only TCRE distribution following the IPCC practice that started with AR5. The 33th and 66th percentiles are interpreted by the IPCC as corresponding to a chance of meeting the warming limits of 1 out of 3 and 2 out of 3, respectively. The expected non-CO2 warming in the future at the global warming limits is estimated from the results of projections of climate models of reduced complexity calibrated against the full-fledged ESM climate models. For the 1,5˚C warming limit this non-CO2 warming is about 0,1˚C and for the 2˚C limit it is twice as much.

Table 1 summarizes the results of the Carbon Budget calculations reported in SR15 (Table 2.2) for the reference date of 01-01-2018 (IPCC, 2018c). They are equal to the calculated Carbon Budgets relative to the calibration point minus the cumulative emission from 01-01-2011 to 01-01-2018 of 290 GtCO2. The Carbon Budgets for the 50th percentile represent best estimates and are the main outcome of the SR15 budget calculations. The 33th and 66th percentile Carbon Budgets illustrate the sensitivity of the Carbon Budgets to the selected TRCE for CO2-only warming.

Table 1 – SR15 Carbon Budgets (CB) at 01-01-2018 for different TCRE percentiles

The error margins of the calculated budgets are rather large. In the case of the 1,5˚C warming limit the relative standard deviation (RSD), the standard deviation relative to the best estimate, for SAT and SAT/SST is 67 and 63%, respectively. For the 2˚C case the RSD for SAT and SAT/SSS is 54 and 53%, respectively.

Shortcomings of the SR15 method

Figure 2 displays the total warming since pre-industrial times expressed in both SAT and SAT/SST versus cumulative CO2 emission as inferred from the SR15 Carbon Budget estimation method and its results. For both SAT and SAT/SST the warming consists of two straight lines: one up to the calibration point for past warming and one thereafter for future warming.

In the observational period up to the calibration point the SAT line has an equivalent slope of 1,81˚C/(1000GtC). The equivalent slope of the SAT/SST line is 1,63˚C/(1000GtC), lower than the one of the SAT line and commensurate with the lower calibration temperature.

The straight lines beyond the calibration point follow directly from the reported SR15 Carbon Budgets for 1,5 and 2˚C which are indicated in Fig. 2 by the plus symbols. The slopes of the two warming lines are identical and equivalent to a TRCE of 1,99˚C/(1000GtC). The intercepts differ by 0,1˚C, equal to the difference between SAT and SAT/SST warming at the calibration point.

Figure 2 – Total global warming relationships as per SR15 method

Figure 2 reveals three evident shortcomings of the SR15 method. First, there is a discontinuity of the total warming at the calibration point, which is physically impossible. Second, there is not only a discontinuity in the warming but also in the warming slope. In the case of SAT the equivalent slope jumps from 1,81 to 1,99˚C/(1000GtC) and for SAT/SST from 1,63 to 1,99˚C/(1000GtC). It means that global warming in the future is stronger, i.e. more warming for the same amount of CO2 emission, than in the past before the calibration point. This may not be impossible but at this point there is no evidence for such a change. If we go by the climate model projections reported in AR5, the simulated warming curves are concave down rather than concave up, which means that we may expect a decrease in warming strength as opposed to an increase. See Figure SPM.10 of the SPM of AR5 WG1 (IPCC, 2013b). Third, the difference between future SAT and SAT/SST warming is constant and equal to the difference at the calibration point. This is highly peculiar, if not impossible. The difference is zero at zero warming and zero cumulative emission and has increased to 0,1˚C at the calibration point. Why would this increase stop at precisely the calibration point?

The discontinuity in total warming is due to the CO2-only warming straight line starting at the calibration point for total warming (see Fig. 1), while in actual fact this line should have started below this point. According to AR5, the temperature difference between central total warming and central CO2-only warming at the calibration point is 0,42 ˚C (= (2,441,65)/(1000×3,664)×1958). See again Figure SPM.10 of the SPM of AR5 WG1 (IPCC, 2013b). In reality this difference might be overstated but there must be a marked difference between total and CO2-only warming.   The discontinuity in total warming slope at the calibration point is caused by too steep a slope of the CO2-only straight line of 1,65˚C/(1000GtC). In essence the calibration point narrows the suite of possible total warming straight lines spanning an effective TCRE range 1,25 to 3,25˚C/(1000GtC) to a single straight line with an effective TRCE of 1,81˚C/(1000GtC) for SAT and of 1,63˚C/(1000GtC) for SAT/SST. The effective TCRE of the calibrated SAT straight line of 1,81˚C/(1000GtC) is considerably lower than the original central estimate of the AR5 range of 2,44˚C/(1000GtC). The implication is that the slope of the best estimate of the CO2-only straight line, which is based on the same AR5 climate model projections, must also be less steep and thus lower than the assumed 1,65˚C/(1000GtC). A proportional reduction (=1,81/2,44) would result in a CO2-only TCRE of 1,22˚C/(1000GtC). That the slope of the CO2-only line is too steep is also obvious from the SAT/SST slope for total warming of 1,63˚C/(1000GtC), which is already lower than the CO2-only slope of 1,65˚C/(1000GtC), a physical no-no.

In addition to the inconsistencies in the profiles for total warming, the incorporation of uncertainty in the estimated Carbon Budgets is another issue. In the SR15 method, the uncertainty is accounted for exclusively through the uncertainty in the climate-model derived TCREs for CO2-only warming (the Min and Max lines in Fig. 1). The uncertainty in the CO2-only TCRE is substantial and leads to an equally substantial uncertainty in the Carbon Budgets. Subsequently, to make allowance for this uncertainty, the final estimates of the Carbon Budgets are significantly downgraded from the best-estimate Carbon Budgets.

On a general note, it is debatable whether best-estimate Carbon Budgets should be downgraded at all. The warming limits of 1,5 and 2˚C are no hard physical boundaries but negotiated political compromises laid down in the Paris Climate Agreement. In the absence of any specification in the Agreement, the Carbon Budgets belonging to these warming limits should be, by legal convention, best estimates, i.e. taken at the 50th percentile of the range of possible Carbon Budgets. Taking a stricter estimate, e.g. at the (arbitrary) 66th percentile as in SR15, amounts to an unstated lowering of the negotiated warming limits, disregarding the letter and spirit of the Paris Climate Agreement.

Regardless of the legitimacy of the downgrading, the actual evaluation of the uncertainty in the Carbon Budget estimates in SR15 is flawed on two counts. First, by attributing the uncertainty exclusively to the uncertainty in CO2-only TCRE, the uncertainty in the calibration point and in the estimates of the non-CO2 warming at the warming limits is ignored. As we shall demonstrate in the next section, errors in the calibration point may have a significant effect on the error in the final Carbon Budget and should be part of the overall error analysis. This also holds for the errors in the estimates of non-CO2 warming. Second, the uncertainty in CO2-only TCRE is vastly overstated. Using a calibration point drastically lessens the uncertainty in the effective TCRE. That is exactly what a calibration point is all about. Because the CO2-only TCRE is directly related to the effective TCRE, the uncertainty in the CO2-only TCRE is considerably reduced as well.

All in all, the SR15 method is seriously flawed and used as-is leads to over-conservative Carbon Budgets. The discontinuity in warming effectively lifts the total warming straight line and thus lowers the Carbon Budgets. The inflated warming slopes increase the warming strength of CO2 and thus decrease the Carbon Budgets. Finally, the choice for the 66th instead of the 50th percentile reduces the Carbon Budget even more.

Alternative method

We propose an alternative method for estimating Carbon Budgets that preserves the strong point of the SR15 method (calibration) and does away with its shortcomings (discontinuities): simply extrapolate the calibrated total warming straight line of the past (light-blue line in Fig. 2) to the future. This goes back to the initial proposition in AR5 to estimate the Carbon Budgets from a single total warming straight line. The only difference is that the slope of the line does not depend on climate model projections as in AR5 but on the observational record as boiled down in the calibration point. What is retained from the climate model projections is the notion that mean global temperatures are a function of cumulative CO2 emission and that this functional relationship is approximately linear.

Figure 3 – Total global warming relationships as per alternative method

Figure 3 depicts the total warming straight lines for both SAT and SAT/SST as defined by the calibration points. The SAT line is steeper with a TRCE of 1,81˚C/(1000GtC) compared with the SAT/SST line with a TCRE of 1,63˚C/(1000GtC). Carbon Budgets follow straightforwardly from the intersection of the straight warming lines with the horizontal line corresponding to the warming limit.

Table 2 – Alternative and SR15 best-estimate Carbon Budgets (CB) at 01-01-2018 and Carbon Budget Emission Ratio (CBER)

Table 2 lists the alternative Carbon Budgets relative to 01-01-2018 for the warming limits of 1,5 and 2˚C along with the comparable best-estimate SR15 Carbon Budgets. Also shown is the Carbon Budget/Emission Ratio (CBER) for the calculated Carbon Budgets. It is the ratio of Carbon Budget at a certain reference date and the annual CO2 emission rate just before the reference date and indicates the number of years a given budget will last if emission continues at the then current annual emission rate. Here the reference date is 01-01-2018 and the current emission rate in 2017 is 41 GtCO2/year. As expected, the alternative budgets are substantially larger than the SR15 budgets. What is also worth noting is that the difference between SAT and SAT/SST in the new budgets is much more pronounced than in the SR15 budgets.

The IPCC has traditionally used the blended SAT/SST as a measure for global warming. See Chapter 1 of SR15 (IPCC, 2018b). In keeping with this tradition, the relevant Carbon Budgets are 1130 and 2250 GtCO2 for a warming limit of 1,5 and 2˚C, respectively. The Carbon Budget for 1,5˚C is almost 50% larger than the comparable SR15 best estimate and about twice as much as the 66th percentile estimate of SR15 (see Table 1). At the 2017 emission rate, the 1,5 and 2˚C Carbon Budgets will be consumed in 27 and 55 years, respectively.

The Carbon Budgets in Table 2 are best estimates. The uncertainty (error) in these estimates is governed by the errors in the calibration temperature and in the calibration cumulative emission. According to Chapter 1 of SR15 (IPPC, 2018) the relative standard deviation (RSD) of the SAT/SST calibration temperature is 13,8% (=0,12/0,87×100). We assume the same RSD for the SAT calibration temperature. We have conservatively set the RSD of the cumulative emission to 1%. Using the Error Propagation Law, we then calculate in the case of SAT for the RSDs in the Carbon Budgets at the calibration point 39 and 27% for the 1,5 and 2˚C warming limits, respectively. For SAT/SST the RSDs become 33 and 24% for the 1,5 and 2˚C warming limits, respectively. The SAT errors are larger than the SAT/SST errors because the SAT calibration temperature is closer to the warming limit. The uncertainty in the Carbon Budgets due to uncertainty in the calibration point is appreciable but not as much as in the reported SR15 budgets due to the uncertainty in the CO2-only TCRE.

Climate policy implications

Carbon Budgets form the core of global warming mitigation policies by CO2 reduction. They define how fast CO2 emissions are to be reduced to net-zero to prevent global warming from exceeding the agreed global warming limits of 1,5 and 2˚C. An often used reduction scenario assumes a simple linear reduction to zero from the current emission rate, called a ‘stylized CO2 reduction pathway’ by the IPCC. Of course such a scenario is not realistic, it is merely a thought experiment that provides uncomplicated but useful insight into the timeframe for CO2 reduction and thus into the urgency of CO2 mitigation. In some countries (e.g. The Netherlands) climate policy is based on such a simple scenario.

To illustrate the implications of the results of our analysis for climate policy we have constructed two stylized CO2 reduction pathways: (1) a base case with the 66th percentile SAT/SST Carbon Budgets as reported in SR15 and (2) the alternative case with the best-estimate SAT/SST Carbon Budgets calculated by the above alternative method. We have chosen the blended SAT/SST Carbon Budgets to conform to the IPCC practice of expressing global warming in SAT/SST. We assume that the reduction pathways start in 2020, the year that the Paris Climate Agreement enters force. The IPCC budgets at 01-01-2020 for the 1,5 and 2˚C warming limits are 488 and 1608 GtCO2, respectively, equal to the 66th percentile of the corresponding SAT/SST Carbon Budgets at 01-01-2018 (see Table 1), minus the estimated total emission in 2018 and 2019 of 82 GtCO2. Likewise, the alternative Carbon Budgets per 01-01-2020 for the 1,5 and 2˚C warming limits are 1048 and 2468 GTCO2, respectively, equal to the SAT/SST Carbon Budgets 21 01-01-2018 (see Table 2) and corrected for the CO2 emission in 2018 and 2019.

Figure 4 depicts the pathways for the base-case SR15 budgets. The orange bullets denote the historical CO2 emission rates from 2000 up to and including 2017 and the assumed emission rates in 2018 and 2019. The green and blue straight lines represent the linear emission paths for the 1,5 and 2˚C warming limits, respectively. Net-zero emission for the 1,5˚C warming limit happens in 2043 and for the 2˚C limit in 2079. At the end of the term of the Paris Agreement in 2030, the reduction in CO2 emission is then 42% of the emission in 2010 for the 1,5˚C warming limit and 12% for the 2˚C limit. The 1,5˚C reduction pathway broadly agrees with the main conclusion in Chapter 2 of SR15: “decline of about 45% from 2010 levels and reaching net-zero around 2050” (IPCC, 2018c). It corroborates the central message of SR15 that limiting global warming to 1,5˚C is within reach, in theory, but would require an extraordinary effort in emissions reduction.

Figure 4 – CO2 reduction pathways for the SR15 base-case Carbon Budgets

Figure 5 shows the CO2 reduction pathways for the larger Carbon Budgets estimated with the alternative method described above. As expected, the pathways to net-zero emission are substantially longer. The net-zero point for the 1,5˚C warming limit happens in 2070 and in 2124 for the 2˚C limit. Logically, the associated reductions in 2030 are not as stringent as in the SR15 base case: 16% and 4%. Hence the larger and more appropriate Carbon Budgets derived in this study offer considerably more latitude in meeting the Paris warming limits than the over-conservative SR15 budgets. As a consequence, the need for reducing CO2 does not seem as urgent as conveyed in SR15.

Figure 5 – CO2 reduction pathways for the alternative Carbon Budgets of this study


  1. The method for estimating Carbon Budgets in SR15 has serious shortcomings, leading to non-physical future global warming profiles.
  2. Used as-is the method gives rise to over-conservative Carbon Budgets and thus to too stringent timeframes to reach net-zero emission.
  3. A simple alternative method without the shortcomings yields substantially larger Carbon Budgets and so more lenient mitigation timeframes.
  4. For a linear emission reduction pathway, net-zero emission for a global warming limit of 1,5˚C is reached in 2070 instead of in 2043 as per the SR15 budget. For a warming limit of 2˚C, net-zero emission happens in 2125 rather than in 2079.

References [References]

Moderation note: As with all guest posts, please keep your comments civil and relevant.


87 responses to “Why the CO2 reduction pathways are too stringent

  1. If this goes mainstream, especially in our education system (big if) we all now could breath a bit easier as we’d have approx. two generations to reach the elusive net zero emissions goal.

    • I don’t think mainstream (whatever that means) is of much significance.

      The reasoning behind the setting of carbon budgets is, of course, open to question. It is good to see this is being done.

      At the moment, we are not meeting the budget anyway, so it is more or less business as usual. I happen to feel that this is potentially dangerous. As our experiment with the atmosphere continues and as work like that detailed here is done, my ‘feel’ will evolve. At least I will be better informed!

      • The Author should have cited my work, because the conclusions are about the same. The difference is that my work was published 11 years earlier.

    • Mainstream or not – it is all seems unworldly. The core of Paris is not 2 degree or whatever but the Nationally Determined Contributions (NDC’s). It is first of all a little late in the game to lament that the country commitments are insufficient to meet an arbitrary and ill defined objective. Secondly – budgets that neglect technical feasibility and political and economic pragmatism are worse than useless – they are a distraction from effective responses.

      Electricity and heat production is 25% of the problem of greenhouse gas emissions. Rather than CO2 budgets – to be effective a multi-gas and aerosol strategy is required – carbon dioxide, CFC’s, nitrous oxides, methane, black carbon and sulfate. Along with ongoing decreases in carbon intensity and increases in efficiency and productivity across the board. And technical innovation across sectors – energy, transport, industry, residential and agriculture and forestry. This is in fact what is happening in the real world.

      Additionally – good policy would focus on development priorities. Each of the Copenhagen smart development goals have implications for population growth.


      But while these priorities are excellent – ultimately what is needed is not aid or philanthropy – but solid economic growth. That requires energy – and we get back to the real world reality of Paris accord NDC’s.

      “The ASEAN region is rich in coal resources, which are cheap to develop and use and constitute an important part in satisfying ASEAN’s increasing energy demand.” https://aseanenergy.org/study-on-cleaner-coal-utilization-roadmap-in-asean/

  2. Pingback: NY Times Climate Info: Help to Preserve Forests – Climate Narrative

  3. “Carbon Budgets specify the total amount of CO2 that can be emitted before global warming exceeds a certain threshold. Since the introduction of the Paris Climate Agreement in 2015, prominently featuring the 1,5 and 2˚C global warming limits, Carbon Budgets have become the cornerstone of global warming mitigation policy by CO2 reduction”.

    A case of re-arranging the furniture on the Titanic. The carbon budget is a fatally flawed metric that has no interpretation in the real world.



    • I would have thought the role of the carbon budget in the world was obvious; hence the value of this article. Putting too much carbon into the air involves risks. Overly stringent restrictions will cost much for little benefit; the cost would be better incurred elsewhere.

      Finding reasonable reactions to the situation we are in and critiquing them is a good approach.

      • ” Putting too much carbon into the air involves risks.”
        The subtitle for the last reference mentioned that you are questioning says
        It seems that the risks you allude to ( I can’t name any that have been demonstrated with empirical data) would be better addressed using different analyses that employ corrected math procedures.

      • “…that the role of carbon budgets in the world was obvious”.

        If it is obvious then it does not need mathematical proof. On the other hand, if mathematical proof is provided then the prood must not contain mathematical errors.

      • Curious George

        I am afraid that the IPCC did not use the best available astrology.

      • I will, of course defer to your expert knowledge of astrology. I will therefore accept your evaluation of astrological methods implemented in the generation of any report and I hope you will forgive me for not spending any more time on the matter. I am here to read what I hope is a reasonable commentary on, er, climate.

  4. Jacques, Thanks for the post. Nic Lewis has a youtube video of a talk he gave recently that uses observations to constrain the carbon budgets. His budgets are much larger than the IPCC ones. Don’t recall how they compare to yours though. His TCRE is 1.05 C.

  5. Carbon (sic) budgets can work … sometimes too well …

    Greenhouse gas emissions drop in Spain as power plants ditch coal

    It looks cold. All that “thing of the past” lying on the ground …

    • Much easier to accomplish if the country is reducing its electricity generation.

      If we all take the path of de-growth this should be a breeze.

    • Energy costs in Spain are among the highest in Europe

      https://www.expatica.com/es/living/household/energy-costs-108518/ “But there are ways in which you can reduce your energy costs in Spain so that you’re not paying through the nose.”

      CA’s Gavin Newsome seems to have been listening, he has ideas too.

      Energy costs making California unaffordable for too many
      (Why does one need energy anyway, if they can’t afford a home to use it?)

      Every CA citizen provides “investment” towards the states carbon reduction future; importantly these investments have organic tentacles; they encourage the growth of the low carbon citizen. This can be seen with the expansion of tent cities, and through the uptake of low carbon push carts (easily procured grocery store technology). Who needs an expensive home anyway, invest in yourself, go tent! This organic growth continues to give back to society in myriad ways, what’s not to like.

  6. It should be mentioned that Jacques Hagoort is well qualified to write on this topic, having had many decades of experience in the petroleum industry. He is the 1975 recipient of the prestigious Rossiter W. Raymond award, http://www.aimehq.org/programs/award/member-society-administered/aime-rossiter-w-raymond-memorial-award and is the author of the 372-page book Fundamentals of Gas Reservoir Engineering, which appeared in 1988 as Volume 23 of the series Developments in Petroleum Science. He is the principal of the Dutch company Hagoort & Associates B.V. The Netherlands is of course well-known as one of the leading countries in the petroleum industry.

    • Classless comment attacking the credentials of the writer instead of actually pointing out facts against the writers conclusions.

      • I’m sorry. How is this an “attack”? There has been much debate in this forum about what is and is not possible with fossil fuels, much of it by people with little or no background in the subject. It is therefore a pleasant change to hear from someone whose credentials demonstrate that he actually knows what he’s talking about.

        In case you haven’t noticed, it is common practice to highlight the credentials of authors. Do you really take seriously every long article by people who for all you know are totally ignorant of what they speak? That says more about you than about them. You should be celebrating that this post is from someone completely at the opposite end of that spectrum!

      • ycalitran@gmail.com

        I don’t think that it’s a “classless comment attack”, but acknowledgement that the writer has knowledge of energy pathways. He probably realizes that limited fossil fuel (oil, cola, etc) will hit us before long, making that a bigger issue than climate change

      • ycalitran@gmail.com

        cola -> coal (typo)

      • @ycal: ” He probably realizes that limited fossil fuel (oil, cola, etc) will hit us before long,”

        Actually I’d be interested to know Hagoort’s expectations for the economics of abiogenic petroleum between now and 2100. I would expect that as someone who wrote the book on gas reservoir engineering a third of a century ago he’d have as good an understanding of those prospects as anyone.

        The 2002 article “Abiogenic formation of alkanes in the Earth’s crust as a minor source for global hydrocarbon reservoirs” by Sherwood Lollar et al is pessimistic about those prospects for economic gas reservoirs. What is deemed “economic” however can be quite demand sensitive, and it would interesting to know how the industry views its prospects today, 18 years later.

      • ycalitran@gmail.com

        I looked up what “abiogenic” means. What I found is that it is impossible to create the complex hydrocarbon molecule chains of petroleum in any way other than organic means. They say that methane is possible because it is a simple molecule, 1 carbon and 4 hydrogen atoms.

      • @ycal: “it is impossible to create the complex hydrocarbon molecule chains of petroleum in any way other than organic means.”

        If https://en.wikipedia.org/wiki/Clarke%27s_three_laws are any indication this must have been said by the sort of person mentioned in his first law:
        “1. When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.”

        The abstract of the paper “Abiogenic Petroleum Generated by Serpentinization of Oceanic Mantellic Rocks” by Charlou et al at http://www.searchanddiscovery.com/documents/abstracts/2005research_calgary/abstracts/short/charlou.htm states the following. “In ultramafic-hosted sites, such as Rainbow (36°14’N) on the mid-Atlantic Ridge, the fluids exhibit a mineral and gas composition different on many aspects from basaltic-hosted fluids. Particularly, they contain a very high hydrogen concentration (13 mmol/kg), associated with high concentrations of methane and other light hydrocarbons. In addition, many families of hydrocarbons are identified in the fluids by GC/MS, including linear saturated hydrocarbons, alcohols, aldehydes, ketones, aromatics, and cyclic compounds.”

        In other words, far more than merely methane.

        When you have CO2 and H2O at high temperatures and pressures in rocks of great variety, the statement that it is impossible to create anything more complex than methane other than from former lifeforms would surely be extremely difficult to prove!

        But even if all complex petroleum turns out to be almost all of biological origin, there still remains the question of when its extraction will cease to be economically viable. How certain are you that this will occur before 2100, and what is the basis of your certainty given the ongoing reports of newly discovered reserves at various sites around the world that we keep reading about?

        I have yet to see any definitive answer to this question from anyone with a level of expertise in this field equivalent to that of Jacques Hagoort.

      • ycalitran@gmail.com

        I recall reading that somewhere. Maybe what the true statement is that it is impossible to create petroleum inorganically at any rate that would match the rate of depletion by man. It likely takes thousands of years for anything substantial to be created because it has to collect in the right places, but here we have mankind extracting it all in a hundred years or so. Nothing new is really being found.

    • A background in the oil industry is widely regarded as suspect – as Vaughan must be aware of. I expect that he is amusing himself as a skeptic provocateur. Abiotic oil and all. And nor is a background in oil much qualification for quantifying future emissions. That depends on many socioeconomic factors. Hence the new ‘Shared Socioeconomic Pathways’ feeding into AR6.


      I suspect that SSP5 was intended as a cautionary tale – but although I would express it more colorfully it seems an inevitable future. Except in my world human ingenuity succeeds in a context of markets and democracy.

      “SSP5 Fossil-fueled Development – Taking the Highway (High challenges to mitigation, low challenges to adaptation) This world places increasing faith in competitive markets, innovation and participatory societies to produce rapid technological progress and development of human capital as the path to sustainable development. Global markets are increasingly integrated. There are also strong investments in health, education, and institutions to enhance human and social capital. At the same time, the push for economic and social development is coupled with the exploitation of abundant fossil fuel resources and the adoption of resource and energy intensive lifestyles around the world. All these factors lead to rapid growth of the global economy, while global population peaks and declines in the 21st century. Local environmental problems like air pollution are successfully managed. There is faith in the ability to effectively manage social and ecological systems, including by geo-engineering if necessary.”

      I’ve been doing geoengineering for decades. It isn’t brain surgery – at which I would be horrible.

      I was going to drop another video in – but there are a few of my favorites on the front page of my WordPress site. – https://watertechbyrie.com/

      My alternative ‘narrative’ – btw – is a cyberpunk future.


      • @RIE: ” I expect that he is amusing himself as a skeptic provocateur.”

        While I admit to doing so with idiots so long as their idiocy is evident to non-idiots, as a matter of principle I would never do so with a widely acknowledged expert in any field whatsoever. If the world of bank robbers acknowledged Jacques Hagoort as their master I would take his every word at face value. I might even learn a trick or two about how best to rob banks.

        My only complaint about fossil fuels is how the average user of them is content to dump their waste products directly into the atmosphere. Blaming the fossil fuel industry for the bad behavior of their customers is no better than blaming the plastics industry for the bad habit of their customers of tossing plastic into the ocean.

        The denizens of Climate Etc. do not represent the fossil fuel industry. They represent their customers who would prefer not to be hassled about polluting the atmosphere with CO2. This is why they prefer to argue, contrary to the US Supreme Court, that CO2 is not a pollutant. They find that ruling terribly inconvenient.

      • So we have established what you are. Now it’s time to discuss price?

        What we need to do is accept that SSP5 is best social, economic and environmental path to a future for the planet, its people and its wild places – and accelerate technical innovation across sectors – energy, transport, industry, residential and agriculture and forestry.

        What I don’t accept is that SSP5 is the worst of all worlds.

  7. Go progressive! It’s mud huts for everyone!

  8. What’s surprising in Figure 2 is that it’s linear and places weight on the historical as near as I can tell. I’ve argued with my son that you just use the historical data and a straightedge to draw a line. Then make your plans. That’s what we get for all this money. It’s hard to argue with history. This happened. Compare to, We think this will happen. I win every time. What happened? I can tell you what a house sold for. What can I tell you about what it will be worth in three years or ten years? The best data is historical, or I could argue the only data is historical. What else have you got better than that? With data you can say, this happened and this happened. We can have theories until the cows come home like some opinion show host about what will happen.

    Of course there’s Mosher. We don’t even plan for the past. No, we dream up a future and panic. And then we say, it’s science.

    • Weather forecasters routinely compare the predictions from their numerical models to what would be expected if the historical average were to prevail. The models are better. A simple reliance on historical data is less accurate.

      When Fitzroy (skipper of the Beagle) first started issuing primitive weather reports the British fishing fleet found they helped reduce loss of life and damage in the industry. They didn’t need averages, they needed information they could act on in the present. Cheaper fish resulted. What we get for our money are cheaper flights, less money spent on fuel in the armed forces and timely emergency warnings etc. etc.

      It’s not perfect, these are models, not the real thing. It is proper that we debate their uses and their costs. They can be misused. But it would be very expensive to abandon them.

      Eleven years ago, in my part of the world, the users of the “straight edge” gave advice on how to deal with a fire emergency. There was horrific loss of life. This time (so far) we have had much lower mortality despite the fires being both more extensive and more intense. Our ability to avoid the temptation to skimp and rely on extrapolation, but to use models instead has probably saved hundreds of lives. The expenditure on modelling has repaid itself handsomely. A return to averaging and extrapolation would be seen to be the height of irresponsibility.

      • I don’t think that’s how it works. And am puzzled by the conflation of weather forecasting and emission scenarios.

      • No conflation. An illustration, addressed to … someone else … who had asserted that this modelling nonsense can be done away with in favour of good old extrapolation.

      • Weather forecasts are initialized and probabilistic. That’s how they work – not as you claimed. Hence the video.

      • @PT: “The models are better. A simple reliance on historical data is less accurate.”

        This makes no sense.

        The best models are Bayesian run to convergence.

        But they must be initialized to some prior.

        If you don’t look to historical data for your priors, how can you be sure you models are better? It seems like a religious belief in the power of modeling!

      • I was speaking much more simply. The prior here is a simple average. Model does better than that.

        The comment to which mine was addressed was to the effect that measuring a few events, then running a straight edge across them is better than all this modelling stuff. I was trying (evidently failing) to say “not necessarily”.

      • We are modelling the future beyond the weather modelling limit. It depends on how much you think CO2 time X equals the GMST? Let me make that my rule though I stole from of all people, Salby.

        Many people have plotted CO2 versus the GMST. Now I want to do that and predict. My input is historical. And I have a plan. A simple one. That policy makers can probably understand. At least their hipster advisors with a science IQ above 95.

        I am suggesting a value approach. Whose approach is more valuable when considering costs? Think diminishing returns, and failed message delivery. Here’s a CMIP6. Fail. No one understands that. Okay a few people here do. Gavin Schmidt arguing for one more 1/10 C. And having his posse agree with him. Fail. It doesn’t sell. No one understands Schmidt. Marketing.

        The alarmists have met the enemy. Themselves.

      • In Australia, the alarmists are meeting fire. It looks like a disaster to us. It is more intense, more extensive than any previously experienced.

        But we shouldn’t worry, apparently. It’s natural. We were wrong apparently to try to save life and property, we should just let it burn.

        We should roll over and accept advice from fools from afar with no experience, as we sizzle and with our dying breath thankfully repeat the mantra.
        “It’s natural”.

        Look, the point is, fewer people have died in this conflagration than the smaller one in 2009 because we learned. Much of the learning has been incorporated into models. Resisting (ignoring, actually) the urge to do nothing because Gödel, chaos, Heisenberg and all the reasons why models cannot work, we developed tools that helped predict. When the fire season ends (it hasn’t started in some parts) there will be enquiries, finger pointing, learning, despair and all the normal human behaviour. There will be better models. We will need them because the warming has barely begun.

        I do not understand the lunacy that would have us go unprepared.

      • “As our nonlinear world moves into uncharted territory, we should expect surprises. Some of these may take the form of natural hazards, the scale and nature of which are beyond our present comprehension. The sooner we depart from the present strategy, which overstates an ability to both extract useful information from and incrementally improve a class of models that are structurally ill suited to the challenge, the sooner we will be on the way to anticipating surprises, quantifying risks, and addressing the very real challenge that climate change poses for science. Unless we step up our game, something that begins with critical self-reflection, climate science risks failing to communicate and hence realize its relevance for societies grappling to respond to global warming.” https://www.pnas.org/content/116/49/24390

        This is Tim Palmer – a global doyen of climate computing. And he can’t stop preaching simplistic nonsense long enough to listen and understand. And he still hasn’t said what he wants to do about it – apart from selling AR5 on street corners.

      • Yes, my simplistic remark was a short answer to the notion that nothing was to be gained from models that couldn’t be obtained by running a ruler over historical data.

        That we need to re-evaluate models is self-evident, as is the need for models themselves

      • There is a class of models – and the ensuing opportunistic ensembles – that are not just wrong but dangerously so. And then you prattle on about them.

      • JC SNIP Tim I have been reading for decades. As a hydrodynamic modeller – I have been aware of the huge limitations of the current generation of climate models for decades. There is a new generation that is far more promising.

  9. The Author should have cited my work published 11 years earlier. The conclusions are about the same

    • The “Author” is an authority in his field. Unless some other authority in the field has previously cited your work in the intervening 11 years, why would any reasonable person expect him to be the first?

  10. Ireneusz Palmowski

    The NOAA/NASA co-chaired, international panel to forecast Solar Cycle 25 released their latest forecast for Solar Cycle 25. The forecast consensus: a peak in July, 2025 (+/- 8 months), with a smoothed sunspot number (SSN) of 115. The panel agreed that Cycle 25 will be average in intensity and similar to Cycle 24.

    Additionally, the panel concurred that solar minimum between Cycles 24 and 25 will occur in April, 2020 (+/- 6 months). If the solar minimum prediction is correct, this would make Solar Cycle 24 the 7th longest on record (11.4 years).

    • The solar forecast is from a month ago. April 2020 ± 6 months is from October 2019, so a minimum in 2019 is not out of the cards for them either.

  11. Ireneusz Palmowski

    In three days there will be an unusual drop in temperature on the northwest coast.

  12. As I “only” have a Ph.D. in Psychology and as English is not my mother langage, I find it difficult at times to fully grasp the highly scientific exchanges between you people. Therefore I am somewhat confused about climate. Two questions: 1) Is the relationship between Co2 and global temperature definitely established from a scientific standpoint? 2) Is there an established relationship between the rise in global temperature and the occurrence of extreme meteorological events? Thank you for you contribution to my knowledge on the climate issue.

    • Hello Pierre.

      I think that climate and all earth science differs from psychology and medicine in terms of empirical evidence. Medicine attempts to categorize the strength of scientific evidence such as:

      Near the top of this hierarchy is “randomized control trials”.
      Equivalent climate experiments with CO2 and the earth are not possible.
      We have only one ongoing experiment which, since n=1, is not randomized , nor blinded, nor controlled for other factors which are changing simultaneously.

      Still, some things are known. The radiative properties of CO2 are testable in a laboratory. The constituency of the atmosphere is repeatably measurable. And since energy is not transferred convectively at the top of the atmosphere, we know that the only process which balances incoming solar radiation is outgoing infrared radiation.

      So, as to:
      “1) Is the relationship between Co2 and global temperature definitely established from a scientific standpoint? “

      the radiative balance of earth is roughly described as:

      Net = In – Out

      In is mostly a function of
      Solar Radiation, Clouds, and Snow

      Out is mostly a function of the profile of :
      Temperature, Humidity, Clouds, Dust, CO2, and other gasses

      It’s possible that things other than temperature could change to balance a change from CO2, but it would seem that since temperature is a direct response to radiative imbalance, temperature increase would be the most likely way.

      So, I would say that the relationship is not definite, but very likely.

      As for:
      “2) Is there an established relationship between the rise in global temperature and the occurrence of extreme meteorological events? “

      The radiative forcing of question 1 is a consideration at the top of the atmosphere, where motion is near zero.
      The extreme events of question 2 are near the bottom of the atmosphere, where motion is great and determines these event. You may be familiar with so called ‘chaos theory’ in which motions are not predictable. That is the case with atmospheric motions. But that is true regardless of what the CO2 level is.
      Global average temperature is not a term in the equations of motion, so there’s no direct causation of global warming and extreme weather. There’s some speculation about the gradients of temperature which do determine the general circulation, but the models indicate one thing and observations another. Indeed, there’s not evidence of much change, one way or another with hurricanes, tornadoes ( in the US ), floods, droughts, or storms.

    • The answers are:
      1) No. Nobody knows how much the Earth should warm in response to an increase in CO2, although a lot of people pretend that they know when they say that a certain increase in emissions will take us to a certain temperature. It is fiction. What we do know is that there has been times in the history of the Earth when CO2 levels were increasing and temperatures where decreasing, like between 6000 and 600 years ago.
      2) No. The statistics of extreme weather events do not allow to say with sufficient certainty that global warming has increased their occurrence. The only exception is heat waves. As they are defined in terms of temperature, an increase in average temperature results in a higher frequency of heat waves unless the definition is adjusted to the new higher mean temperature.

      Nevertheless if precipitations increase there should be a higher frequency of floods, and if they decrease there should be a higher frequency of droughts, so any change in precipitation should have an effect at least in theory.

      • @javier: “Nobody knows how much the Earth should warm in response to an increase in CO2”

        Psychologists call this “projection”. “I don’t know how neutrons can become protons by emitting an electron, therefore nobody on the planet knows how this can happen.”

      • Psychologists call this “projection”

        Psychologists know little about climate science.

        How much the Earth should warm in response to an increase in CO2 is what we call climate sensitivity. Since nobody knows the value of climate sensitivity, nobody knows how much the Earth should warm in response to an increase in CO2.

    • 1. CO2 in the atmosphere is produced by nature, and man for about the last 10,000 years. I believe it has little to no effect on Ice ages.
      2. Mother Nature is controlling the Ice Ages, She is taking water vapor from the oceans to the poles and dropping it as frozen water. This is how she keeps a relatively constant surface temperature of the earth’s surface during the Ice Making Stage, which we are in now.
      When the true defination of BLACK SKY RADIATION is understood it will all fall into place.

    • “Earth’s energy budget describes the balance between the radiant energy that reaches Earth from the sun and the energy that flows from Earth back out to space. Energy from the sun is mostly in the visible portion of the electromagnetic spectrum. About 30 percent of the sun’s incoming energy is reflected back to space by clouds, atmospheric molecules, tiny suspended particles called aerosols, and the Earth’s land, snow and ice surfaces. The Earth system also emits thermal radiant energy to space mainly in the infrared part of the electromagnetic spectrum. The intensity of thermal emission from a surface depends upon its temperature.” https://www.nasa.gov/feature/langley/what-is-earth-s-energy-budget-five-questions-with-a-guy-who-knows

      The law of conservation of energy states that energy can neither be created nor destroyed – only converted from one form of energy to another. Sunlight strikes the planet, warms it and energy is emitted at lower frequencies. The interaction of photons – literally packets of energy – with molecules in the atmosphere differ with frequency. Greenhouse gas molecules absorb and emit photons in the infrared frequencies that would otherwise escape to space. More gases mean more interactions and a warmer atmosphere – which then warms the surface.

      But Earth’s oceans and atmosphere is a turbulent fluid flow problem in which patterns form and reform in spatio-temporal chaos as energy is transported into, around and out of the Earth system. Eddy should note the pressure term in the Navier-Stokes equations.

      e.g. http://www.ds.mpg.de/LFPB/chaos

      Climate shifted in the mid 1970’s – shown here in rainfall anomalies in Australia with a shift in mean and an increase in variance. Although in principle unpredictable – the system is one that is hugely variable and sensitive to small change.

    • For extreme weather, use Roger Pielke:
      Fossel fuels >> Wealth >> Ability to deal with extreme weather
      I’d like some of these people to get firewood from a forest using horses to haul it for each North American Winter they live through. Cutting it with handsaws and splitting it with wedges.

      • All hypeing should stop, of course. It has no place in science. Perhaps some of your North American woodsmen could come to Australia and help us clean up the six or seven million hectares of burnt countryside.

        Our bureau of meteorology tells us that record high temperatures and record low rainfall (measurement, not hype) may have something to do with the situation. Getting a handle on what is behind such catastrophes is a serious business. There is much to gain on succeeding and much more to be lost if we get it wrong.

      • Paul Tikotin:
        In Australia they can do something with or without climate change. Preventive clearing of brush or whatever they call it. That Australia burns seems natural.

      • I think you’ve been sold snake oil. Do you actually believe that primitive tribes knew how to control bushfires in conditions that included record heat, severe, prolonged drought, and strong winds?

      • I think our 1st peoples would object to JCH calling their ancestors primitive. But yes – they have a sophisticated understanding of ecological responses to fire stick farming evolved over some 60,000 years.

        Cool season burning reduces fine fuel litter while leaving the canopy and soil carbon relatively unscathed. Waru is the Pintupi/Luritja word for fire.


      • Well, Ragnaar sounds like you are a fan of Trump’s rakes.

        Let’s say that there is only another million hectares at risk, now that six or seven have burned. Work out how much you can rake in a day, and let me know when you would be finished. Meanwhile I will keep well clear!

        There is a serious point to be made. A little numeracy goes a long way here. A serious argument will be held in Australia about land clearing and how it should be conducted. As mentioned elsewhere, Australian people survived here for thousands of years and fire was one of their tools. There is a clue. But Australia has changed. Traditional methods, if they can still be used, will have to be adapted.

        The relevance of all this to modelling of carbon budgets is unclear. However, if, as some believe, the concentration of atmospheric CO2 is relevant then that is of interest. Good modelling is helpful, bad modelling may be dangerous.

        Fire is natural in the Australian landscape. Bubonic plague is natural on the earth. There is evidence that human activity can affect both. It is worth understanding how. Lives are at stake.

      • He wants to reduce CO2 emissions? Whoopee. Whenever I ask how there is a bit of foot shuffling and mumbling. And the trump card. Boring. Now he treats this tragedy brought on by Kyoto as an opportunity for further misguided, dangerous, smug and obnoxious preaching.

        “Yirralka Rangers fuel reduction burning, Laynhapuy Indigenous Protected Area © Copyright Yirralka Rangers/Laynhapuy Homelands Aboriginal Corporation”

        “The Climate Solutions Fund will provide a further $2 billion to continue the success of the Emissions Reduction Fund. This funding will boost agricultural productivity, support jobs for Indigenous communities and improve biodiversity and water quality, and reduce greenhouse gas emissions.”



        So let’s see some practical ideas He’d better include cool season burning – such as has been curtailed by bureaucrats, climate activists, greens and urban hipster pissant progressives for 20 years. With inevitable consequences that were predicted.

      • Paul Tikotin:
        My suggestion is that fire is natural. And has many benefits. We can’t save the planet by suppressing it. I suggest the bias should be towards back to the 1600s for Australia while not having a connection to the area. I am a let it burn advocate. Now Australia can do more about its fires than it can do about the GMST.

      • Ragnaar, “My suggestion is that fire is natural. And has many benefits. We can’t save the planet by suppressing it.”

        While my heart aches for the billion creatures lost to the fires in Australia, I agree with your thoughts.

        It wasn’t that long ago in the historical record that when a wildfire started, it burned, burned, and burned until it either exhausted its fuel, or a fortuitous rain squelched it. There were no DC-10’s in 1850 dropping 11k gallons of fire retardant a pop; nor smokejumpers, heavy equipment, or legions that could be sent to a scene of a blaze at a moments notice to mitigate wildfire damage. There was little means to direct efforts to put out blazes, and also little in the way to quantify damage (humans call it damage). Spectacular expanses of wilderness burned, and did so mostly without witness.

        But we know that fire is also a fundamental reality that nature uses to reinvigorate ecosystems. Yet human reality is usually near sighted and naturally governed by heartfelt responses as a species to protect what we value.

        Outside of the destructive natural forces of fire, per a November study published in Nature: the amount of forest area worldwide grew by 2.24 million square kilometers from 1982-2016. Net loss in the tropics was “outweighed by a net gain in the extratropics”.

        Whatever media narratives may communicate, woodland expansion continues. Interestingly, woodland expansion also dovetails to the roughly 20-30% increase in crop yields, overlapping the period of reforestation in the Nature study.

      • Ahhh, the good old 1850s.

        I can see your 1850s and raise you $10

        The good old 1250s, small pox, bubonic plague, nature’s way and all that.

        We have a civilisation to protect, my child. It relies on many, complicated things. It has been built on a tacit assumption that the climate is stable. There are adults trying to maintain it. There are foolish children imagining its success is inevitable and that a stable climate is their birthright. Some even imagine that the climate is in an equilibrium so profound that nothing can disturb it.

      • “At the scale of observation,woody vegetation cover increased in all lowland woodland and coastal ecosystems over the 16-year period. Thus,
        published examples of encroachment in selected coastal and woodland patches do appear to reflect widespread increases in woody vegetation cover in these ecosystems. This densification appears to be associated with changes in land management rather than with post-fire vegetation recovery and is likely to be ongoing and long-lasting, with substantial implications for biodiversity conservation and ecosystem services.” https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2699.2009.02255.x

        These woody weeds go off like a bomb.

        Mostly to do with clearing laws on private land and the lack of resources on public and indigenous lands. So we get back to pig ignorant bureaucrats, climate activists, greens and urban hipster pissant progressive who think that 5 minutes on an ABC TV web page means they are informed.

      • How many of the alleged arson fires were started by landowners/civilians who have been persistently hearing this completely unproven nonsense about lack of prescribed burns being the problem?

        Misled into hating the evil greens so they started a fire at the worst possible time.

        The PM says all he’s hears is “not enough prescribed burns.” It’s Australian madness.

      • The proof of a lack of burning and clearing to conserve the ecological balance of open woodland is in the increase in woody weeds – that I have not only linked to biological science on – but have seen with my own eyes over much of eastern Australia – and to my despair – over the past 20 years. So take your pig ignorant opinion – and accusations of farmer arson – and stick it where the sun don’t shine.

      • Oh – and climate is not stable and never has been.

      • Tikotin: “Ahhh, the good old 1850s…We have a civilisation to protect, my child. It relies on many, complicated things. It has been built on a tacit assumption that the climate is stable. There are adults trying to maintain it.”

        So, adult, pick a century; the time period here merely serves as a perfunctory date to illustrate the human cultures desire to control certain sensibilities for perceived negative human outcomes, here based on the unproven relationship of wildfires caused from AGW; and how we should resolve the issues relative to what you believe humans intrinsically are culpable for. Your illusion is that humans must control these predetermined unnatural events in nature as a consequence of human causation, and that control would be good. You have an unnatural fixation based on: “There are adults trying to maintain it.” But first, can you prove that AGW increases the incidence of wildfires?

      • According to law enforcement, there is a problem with landowners/civilians doing unauthorized burns (arson.) Why are they doing them? Maybe because they’re listening to propaganda about lack of prescribed burns being the cause of the out-of-control fires.

      • We end up switching sides. I think restoring prairies and river systems is a good idea. If the prairie catches fire, let it burn. The roots will fine, and it will come back. Natural prairies evolved to survive burning. A prairie on fire kills baby trees I suppose trying to invade. We have floods, and it’s partly North Dakota’s fault with whatever they’re doing across from Minnesota. Let it flood. Don’t build in a flood plain. It will all work out and the fishing will be better. We build berms and then bridges get taken out by ice floes. Good plan. It’s going to rain and it’s going to burn. Nature will win.

      • I’m for all proactive measures to improve the environment, and common sense good stewardship. And by all means we should do our best to mitigate forest fires. My argument is the blame game complex where cause and effect is flippantly utilized as a political methodology to coerce outcomes for policy. These often have little to do with the underlying purpose for the policy being lobbied for, other than serving as a premise to launch, or build a case from, i.e. here, where AGW meets wildfire.

  13. I don’t get a lot of this logic. First, the author claims a straight line accumulation of CO2. Charts I have seen pegs the CO2 curve as a rising one. First, from 1910 to 1945 12 ppm with 0.5 deg C rise. Then a temperature DROP! of 0.1 deg C with a corresponding CO2 RISE of of 20 ppm for the 1945 to 1975 and finally a rise of 0.94 deg C with a CO2 increase of 71 ppm until 2016 (NASA Goddard global land-ocean temperatures with 5-year lowess smoothing). Where is the temperature-CO2 correlation?
    Paul Tikotin argues for modeling, instead of extrapolation from history. Go find the graph from Professor Christy from the University of Alabama. He plotted the average of 102 CIMP5 model runs predicting mid-tropospheric temperatures from 1977 on until 2014 and compared actual balloon data sets. Model scenarios show up too high by a factor of 5.4! So much for confidence in modeling.
    Lastly there is the assertion of temperature increase attribution to CO2 rise, while forgetting the much more significant water vapor and cloud effects. Reciting Bjorn Stevens: “The mountains of water vapor slowly moving across the sky are the bane of all climate researchers. First of all, it is the enormous diversity of its manifestation that makes clouds so unpredictable. Each of these types of clouds has a different effect on climate. And above all: they have a strong effect…. If the fractional coverage of low-level clouds fell by only four percentage points, it would suddenly be two degrees warmer worldwide.”

    • Sure, water is a powerful actor. That does not mean CO2 is not an actor at all. Is that the case and if so, to what extent is the question.

      If you don’t buy into the discussion over CO2s place in the climate system then of course, you won’t be interested in the discussion of carbon budgets.

      Why do you think this article is here at all and why would you bother commenting? Surely a simple “irrelevant” would do. Of course, you may have a deeper insight and explain where scientists have got it wrong and why someone like Judith Curry, for example, is mistaken.

  14. Figure 4 is what I call the impossible pyramid: https://www.cfact.org/2019/12/02/the-uns-impossible-climate-action-pyramid/

    Politically, economically, socially and physically impossible (absent nuclear war).

  15. Ireneusz Palmowski

    Heavy winter attack in central US.

  16. Ireneusz Palmowski

    A fast-moving cyclone attacks the US from the northwest.

  17. This carbon budget game is about to get hairier, because the new generation of models has CO2 sensitivity of around 6 degrees C. AR6 has to decide whether to take them seriously or not, with not being hard.

    See https://www.sciencenews.org/article/why-climate-change-models-disagree-earth-worst-case-scenarios

    • The IPCC will choose its path with AR6.
      About 40% down on this page:
      The spread increases from the 5s to the 6s. The uncertainty using only the 6s is greather than the AR5 assessment. I do not call this progress. The CMIP 6s our worse than the 5s compared to only the AR5. AR5 has a broader spreader than the CMIP 5s. With the 6s, the spread is now greater than AR5. To the extent the CMIPs drive the AR’s assessment of sensitivity, the situation is worse. I expect the next assessment to have a broader range. Unless the relative weight of historical, increases for the assessment. This would make sense. The more bleeped up the CMIPs, the more you rely on something else. This is not to throw the CMIPs away. It is to realize they aren’t doing the job. The IPCC’s problem is sales. CMIP. Can’t sell that except to some scientists. Warmest year ever. Can sell that. The IPCC needs to sell the historical. Which means things like the Lewis and Curry study. This tells us something. One of our strongest cards to play is historical. They play something else.

      • Sales!?

        I stand on street corners making a motza (Australian fortune) selling IPCC reports. Inundated!

        And not one buyer has asked about CMIP.

        Where do you het your ideas on selling?

      • Paul Tikotin:
        The IPCC is selling. Summary for Policymakers. Use this. They can sell history or sell predictions and projections. Above if one looked at the plot at the link, comparing the CMIP5s and 6s to AR5, you’ll see their projections are harder to sell in my opinion if based substantially on the 6s. I ask, what are policymakers supposed to buy? New stories? Celebrities opinions? I bought the IPCC’s two middle emission scenarios for SLR through about 2090. 2.3 inches per decade. They sold it. I bought it. Evidence of buying is found on people’s rooftops and in windy rural areas. The $64 question is what does one sell? The correct answer earns one a participation trophy. The answer I am looking for is a broad one. Think of whom one is selling to.

    • ” Sensitive dependence and structural instability are humbling twin properties for chaotic dynamical systems, indicating limits about which kinds of questions are theoretically answerable. They echo other famous limitations on scientist’s expectations, namely the undecidability of some propositions within axiomatic mathematical systems (Gödel’s theorem) and the uncomputability of some algorithms due to excessive size of the calculation (see ref. 26).” https://www.pnas.org/content/104/21/8709

      I wish people would learn something about modelling before indulging in such empty vessel rattling.

      Here’s a new one from a doyen of climate modelling.

  18. Ireneusz Palmowski

    Thunderstorm line separates Arctic air masses from the warm from Gulf of Mexico.

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