Carbon budget arguments

A slightly more complicated graph following up on the previous one showing how much carbon is left to burn, showing that even that one is unreasonably optimistic.

The curve plots a reasonable estimate of the (Bayesian) probability, given available knowledge, of staying within 2 degrees C above the preindustrial global mean surface temperature. Normally, we base our estimates on the 50% line; to have a 50/50 shot of staying under 2 C, we have used up a bit over half of our available emissions.

Screen Shot 2014-07-04 at 11.06.28 AM

As David Spratt explains, we don’t fly in an airplane with a 1 in 100,000 chance of falling out of the sky. (We have government regulations for that!) But the usual carbon budget is based on a 50% chance of staying within 2 C of warming. If we take a more, ahem, conservative approach, and stick to only a 10% chance of failure, there is no carbon budget left.

I think there are things that mitigate Spratt’s position. But we shouldn’t forget that in the limit of having perfect information about the system, there’s a something on the order of a 10% chance that we may have already passed the 2 C mark by any reasonable definition.


  1. Given the consequent threat to life for very large numbers of people of failing to respect the 2.0C threshold, I've yet to see the case for treating those seriously proposing a carbon budget giving a mere 66% chance of doing so with anything like respect. It perhaps needs to be pointed out that their self-imposed limitation of mitigation options to Emissions Control alone is actually arbitrary and without scientific basis ?

    With regard to Dr Tobis' observation that:
    "there’s a something on the order of a 10% chance that we may have already passed the 2 C mark by any reasonable definition"
    the evidence of a study of Albedo Loss published last January appears to put the issue beyond doubt:
    "Observational determination of albedo decrease caused by vanishing Arctic sea ice" (Kristina Pistone, Ian Eisenman, and V. Ramanathan)

    On the offchance that readers are not familiar with the study, it can be outlined as having identified the warming from the Albedo Loss feedback in the satellite record since 1979 as being on average equivalent to 25% of that from anthro-CO2 during the period. It may be noted that this is consistent with a study in 2011 that found warming from Albedo Loss to equal about 30% of the current warming from anthro-CO2.

    In terms of mitigation strategy, this appears to indicate that even an overnight termination of global anthro-CO2 outputs would already be offset by Albedo loss by around 30%. Given that this is only one of the seven major interactive feedbacks, and that it is evidently accelerating apace, I'm forced to the unwelcome conclusion that both Carbon Recovery and Albedo Restoration modes of geoengineering are now inevitably required alongside stringent Emissions Control in a Troika mitigation strategy. Nothing less appears to offer any serious prospect of respecting the 2.0C threshold.

    However, I am not a climate scientist and would very much appreciate a more skilled evaluation of the issues of controlling the feedbacks' observed and projected contributions.



  2. I have a number of concerns about this argument. I'll look at the paper though. Ramanathan's signature is worth something.

    Regarding artificial CO2 drawdown, I am agreed that it is not very sensible to argue against it. Regarding albedo tweaks I think there are reasons to be very careful about them.

  3. Michael - thanks for your response.

    I look forward to to your thoughts on the implications for commensurate mitigation strategy of the Ramanathan et al paper.

    WRT the application of CDR, I observe that it entails about 3.66 times the tonnage of material as does Carbon Recovery, and does so in the form of liquified CO2 rather than of inert charcoal optimized for use as a soil enhancer. As far as I've been able to compare the scaleability, costs, risks, verifiability and benefits of BECCS, DACCS and CRFS [Carbon Recovery for Food Security] the latter wins by a country mile, though its major co-benefits would depend on good operational design and management.

    A potential weakness of CRFS in addressing the issue of around 170 ppm of airborne and marine (re-emitted) CO2 is the lead-time for native coppice afforestation of non-farmland for charcoal-feedstock, plus the oceans' thermal inertia timelag on the carbon sequestration's cooling effect. Together these imply that while CRFS could help to advance and to lower the peak of CO2ppm it offers no notable impact on realized AGW until late this century. Given that same timelag on a best case of Emissions Control, of say near-zero by 2050, we appear to be facing continued AGW and consequent intensifying climate destabilization at least into the 2080s, thus predictably undermining the viability of the requisite afforestation. (DACCS avoids this vulnerability but among other demerits its costs of around $600/TCO2 and lack of any CO2-free revenues appears to limit its viable scale to far below what is needed).

    Conserving the viability of forestry seems to me a third reason to view a program of Albedo Restoration as the necessary and sufficient complement in a Troika mitigation strategy, alongside the objectives of halting the ongoing disruption of global agriculture and decelerating the main interactive feedbacks.

    However, I entirely share your view that much care is needed. In fact I'd go rather further and say that either mode of geoengineering conducted without due care and governance could be extremely damaging. The prospects of the seizure of farmland for highly mechanised forestry with biocide-dependent short-rotation exotic monocultures, serving the financial yields of corporate agribusiness, and potentially for the wrong objective of profitting from the sale of carbon offsets for fossi-fueled energy - in my view makes the case for stringent UN governance of both modes of 'Geo-E' being pre-requisite.



  4. Don't know if this belongs here or in open thread.

    This course, created by a team of energy experts, was unveiled on Tuesday in a report for the United Nations that explores the technological paths available for the world’s 15 main economies to both maintain reasonable rates of growth and cut their carbon emissions enough by 2050 to prevent climatic havoc.

    The interim report:

  5. David, may I ask on what basis you've formed that opinion and what would be the number with which you'd replace it? "Much" lower would be 1 or 0. Certainly something to wish for but extraordinarily unlikely to be realized. So what would be your number for "avoiding the worst consequences?"

  6. AA - your comment's location seems very apt, given that the supposedly "Deep Decarbonization Pathways" report [DDP] actually aims to cut global CO2e emissions by just 85%, but not until 2100, and asserts that this would supposedly give a 66% chance of staying within the 2.0C ceiling.

    Assuming the rate of change was maintained after 2100, this would finally end anthro-GHG outputs around 2114, meaning that it actually proposes an average transition rate of just 1% per year. It would then be another 30 or 40 yrs before the final outputs' warming was realized, due to the oceans' thermal inertia. If the published accounts of CO2 residing in the atmosphere for hundreds of years are correct, this implies that we'd face continuing anthropogenic warming until about 2150.

    However, the inter-governmental scientific assessment on which the DDP report is based reportedly excludes as insignificant forcings and GHG contributions from all but one of the seven main interactive positive feedbacks now observed to be accelerating (these include Water Vapour Increase; Albedo Loss; Fertilized Peatbog Decay; Permafrost Melt; Forest Loss; Soil Desiccation; and Methane Hydrates Melt). It also ignores a further positive feedback whose occurrence is widely predicted, namely the Ocean Heating & Acidification causing the decline of the oceans' carbon sink, thus leaving more of annual anthro-CO2 emissions in the atmosphere, thus adding to ocean heating.

    Given that the published track records of some of these feedbacks show a very significant potential contribution to warming in the next 50 years, the DDP assertion of having a 66% chance of staying under 2.0C by continuing anthro-warming for 135 years looks to me like sheer wishful thinking. I.e., like greenwash serving an ongoing bipartisan Western policy of the postponement of commensurate action to mitigate AGW. Rational discussion of the evidence for that covert policy and of its objective is arguably the largest black hole in the entire climate debate.

    I'd of course agree that scientists have no more and no less right to advocate climate policy than anyone else, but I think they do have a very clear duty to publicly and forensically criticise incompetent climate policy that endangers society. For this reason I'm sorry to see just how many scientists have contributed to the production of the farcical DDP report.



  7. Rob --- I don't know. Also, which of the consequences is 'worst' and so to be avoided?

    I suppose 6 K with anoroxic oceans expressing hydrogen sulfide is the very worst but I am finding the year round temperatures too high already.

  8. Rob -

    if one assumed that the use of the Albedo Restoration mode of geoengineering was off the table, then with 0.85C realized and with a stringent Emissions Control regime giving phase-out emissions worth say 0.45C, plus pipeline warming giving 0.6C, plus the end of fossil sulphate emissions closing the cooling 'Sulphate Parasol' and unveiling another 0.5C, we'd be looking at 2.4C. These figures are of course debatable, with some saying they're very optimistic, and others the reverse.

    However, they do not include the contributions of six of the seven interactive positive feedbacks that are now observed to be accelerating. For instance, consider this account of the forcing since '79 from the Albedo Loss feedback (which has yet to be realized in the SAT) being on average equal to 25% of that from anthro-CO2 stocks over the period.

    Given that this feedback alone gave that warming input while realized AGW was between ~0.4C and 0.85C, and given that it is inherently non-linear with increasingly juvenile arctic sea ice being increasingly vulnerable to melting, it seems fairly clear (to me) that as 'anthro warming' rises towards ~2.4C the sum of the feedbacks' outputs would inexorably rise to offset our best efforts at Emissions Control. At present those outputs are evidently advancing much faster than is our global rate of emissions control.

    From this perspective if we are to avoid sailing straight past 3.0C then we have to apply Geo-E alongside stringent Emissions Control - and that has to mean both Carbon Recovery and Albedo Restoration if we are to cleanse the direct CO2 cause of AGW from the atmosphere while also, in the interim, controlling its self-reinforcing symptoms.

    Thus in answer to your question of what ceiling would avoid "the worst outcomes" I'd suggest that given the application of Geo-E in 2025 by the collective decision of UN member states, after a decade of RD&D stringently supervised by a mandated UN scientific agency, we'd have a very good chance of peaking SAT warming at around 1.25C, and bring it to zero before 2030.

    Alternatively, an arbitrary refusal to undertake the requisite research would leave us facing as far beyond 3.0C as the feedbacks care to take us. Or, in my view more probably, facing the emergency deployment of the only demonstrated AR technique - being Teller's sulphate aerosols - regardless of their side effects.
    At the point when the rising regional crop failures happen to coincide to give of the onset of serial global crop failures that generates chaotic geopolitical instability, concerns about side effects would predictably count for nothing.

    I would add that I don't welcome this position and have campaigned against arriving at it for the last three decades. But now that we're here anything less than a rigorous assessment of just what mitigation strategy is commensurate with the predicament would be simply futile.

    It is also worth noting that the use of both modes of Geo-E in a Troika strategy cannot entirely guarantee a benign outcome, however long the R&D period, since we have no firm information on how large the response the Methane Hydrates Melt feedback will be to the sum of ocean warming that is already penetrating the seabed plus that from the several decades of further warming as the natural sea temperatures are slowly restored. Uncertainty over this factor, as well as concern over rising climate impacts on people, on farming & fisheries and on biodiversity, adds to the case for the mandating of the UN Geo-E research-supervision agency being a matter of paramount priority as part of an equitable and efficient climate treaty.

    Should there be aspects of this prognosis that seem to you weak, unclear or incomplete I should be glad to discuss them further. OTOH, if it happens to make sense to you I'd be interested and grateful to know which aspects you find most convincing.





  9. Which are the "seven interacting positive feedbacks", and on what basis do you argue that they aren't accounted for in current prognoses?

    On what time scales do they operate? Is there time to draw down the carbon before they kick in?

    Are there any negative feedbacks according to this analysis?

    I do not find claims that IPCC is especially complacent on one hand or alarmist on the other plausible in the absence of comparable amounts of effort, which nobody has done.

  10. Michael - thank you for your questions.
    I’ll address them in sequence and have numbered them for clarity. For the interest of any lay readers I’ll also include some extra background for context.

    1. "Which are the "seven interacting positive feedbacks"
    The seven major interactive positive feedbacks listed below are selected for each having an estimated potential to provide a forcing of at least 2.0GtCO2e/yr (0.55GtC/yr), thus making them potentially significant in offsetting society’s efforts at emissions control.

    Water Vapour Increase - started around 1800 in response to the earliest realized warming occurring after the 30 to 40 year timelag on GHGs' effect due to ocean thermal inertia. It's the only one of the seven whose growth is linear, rising by 7% for 1.0C of warming of the surface air temperature [SAT], and, in part for this reason, is also the only one included in the calculation of the scenarios reported in AR5 by IPCC. Water vapour is not only a highly potent GHG but it increase has also recently been shown to have a serious potential for reducing cloud formation in the tropics and thus advancing Albedo Loss.

    Albedo Loss - can be inferred to have started around 1950 from the logs of cryosphere decline (ice & snow cover retreat). It is arguably one of the most advanced of the seven in its impacts, with a 2011 GRL report putting its warming effect as equivalent to around 30% of atmospheric anthro-CO2, and the recent report putting albedo loss from arctic sea-ice decline since '79 as providing a forcing equivalent on average to that from 25% of the anthro-CO2 levels during the period.

    Fertilized Peatbog Decay - first observed globally in '62 in the 6%/yr rise of outflow streams’ Dissolved Organic Carbon [DOC], this is the only major feedback driven by raised CO2 rather than by warming. The gas has a fertilizing effect that causes one microbe to have a population boom, causing another that eats it to boom as well and to produce larger amounts of an enzyme for digesting its prey that happens to dissolve the carbon out of peat - which then flows out in streams as DOC from where it rapidly outgasses as CO2. When this mechanism was finally identified and reported in Nature (and then NS) around 2000 its 6%/yr increase had held steady, and the author stated that while this exponent showed signs of rising, if it held steady the feedback’s annual CO2 output would equal the anthro-CO2 output for 2000 by around 2064.

    Permafrost Melt - became a concern in Russia during the 1970s with the edge of the permafrost retreating northwards, and is now accelerating quite strongly in most permafrost areas. With permafrost covering 25% of global land area, massive stocks of un-rotted biomass are starting to unfreeze each summer and their resulting decay releases both CO2 and CH4. The latter is 34 times as potent a GHG as CO2 over 100yrs, and 86 times as potent over 20 years (the difference reflecting the quite short residence in the atmosphere of the average CH4 molecule). The fraction of carbon released as CH4 is thus critical - 3% of carbon output as CH4 roughly doubles the warming of all the carbon being output as CO2, and the more saturated the area the higher the fraction of anaerobic decay by methanogenic bacteria. By my own calculation, with 67% of the methane's warming over 100 years occurring in the first 35 years, about 2/3rds of each tonne's total warming is going into the oceans, from where it directly accelerates several other major feedbacks.

    Forest Loss - can be seen to have started globally during the 1980s, due to droughts, heatwaves, surface ozone concentrations, pests and wildfire, and is accelerating quite strongly. The boom of N American beetles is one major concern, as the vast boreal forest holding over 2/3rds of global forest biomass is now vulnerable, for example by the mountain pine beetle having crossed the species barrier to infest and kill the Jack Pine. Beside the CO2, CH4 & N2O outputs from rotting wood, wildfires release these and black carbon, with the latter adding to Albedo Loss by darkening snow and ice and accelerating their melting.

    Soil Desiccation - as a result of rising global areas under extreme drought and heatwave, was first observed in the 1990s. Very large carbon stocks are held in the world's soils (~2,100GtsC) and carbon’s outgassing as CO2 & CH4 (alongside N2O outputs) has a malign impact on soil fertility as well as advancing AGW.

    Methane Hydrates' Melt - was first observed to be accelerating during the last decade, with sufficient ocean warming reaching the hydrates in the sea bed of continental shelves off Norway and eastern Canada, where the hydrate stocks are vulnerable to newly warmed currents. (With respect to observations of large and previously unknown CH4 emissions from the ESAS, to my limited understanding these appear more likely to be trapped geological methane venting through sea-bed permafrost perforated by warming than to be from major hydrates’ melting). Given that much of the CH4 dissolves in seawater and doesn’t reach the atmosphere, its microbial conversion to CO2 is liable to raise acidification as well as advancing the decline of the oceans’ carbon sink. The scale of the hydrate stocks is such that if the oceans continue to warm and even a small fraction was released to the atmosphere it would pose a potentially very large warming effect. It is notable that this feedback is arguably the most difficult to control due to the period of several decades that would be required to restore the upper oceans' natural temperature by an Albedo Restoration program lowering the surface air temperature.

    There is also an eighth candidate for the group of major interactive positive feedbacks, Ocean Heating & Acidification, potentially causing a decline of the ocean carbon sink’s efficiency, of which there is only one published field-observation that I’ve found, but which has widespread support for the prediction of its future operation, due in part to the first comprehensive history of the sink showing that its efficiency is already falling.

    Ocean Heating & Acidification – of which the heating component has to have preceded the raised surface air temperature around 1800 that drove the first water vapour increase. It has been recorded since the 1960s in terms of both rising ocean temperature and rising acidity, both of which reduce the capacity to remove CO2 from the atmosphere, thereby advancing AGW and further ocean warming. The reduction to date of the annual ocean CO2 sink from about 28% to 25% of anthro-CO2 output may well be due to these two effects, but this is still debated.

    These eight major phenomena are the primary interactive feedbacks as far as I understand them, but besides their delayed interactions by the warming from each after the ~35yr timelag then accelerating almost all of them, they are also being driven by a great many direct coupling mechanisms with little or no timelag. (I've identified over 80 significant couplings in the literature without trying very hard, of which four are mentioned above). A fifth example is of arctic Albedo Loss causing warmer seas and thus warmer winds blowing inland where their signature has been identified in increased rates of Permafrost Melt up to 1500kms from the coast.

    These coupling mechanisms are in my view wrongly being called feedbacks in their own right, (and not only by defeatist hysterics like McPherson) when in fact they function interactively as direct drivers of the majors listed above. A critical aspect of the feedback issue that seems still to be largely overlooked is that the couplings mechanisms are so numerous that no major feedback can be seen as acting independently – By acting in concert via the direct driver couplings and via the delayed drivers of timelagged warming the feedbacks together form a single integrated interdependent organic system, which logically has a strong potential for an abrupt acceleration of its outputs under the unprecedented rates of anthro-GHG accumulation since 1800.

    In this context, to continue your delightful metaphor of Hendrix “flirting with the feedback” from his amplifiers, if his contribution were called anthro-CO2, then for the coupling mechanisms we have members of the audience approaching each of the main amps with plugged-in guitars.

    2. "On what basis do you argue that they aren't accounted for in current prognoses?"
    To clarify any misunderstanding, here is my remark on this issue, referring to the IPCC’s four RCPs: “However, they do not include the contributions of six of the seven interactive positive feedbacks that are now observed to be accelerating.”

    The IPCC’s AR5 indicates that, apart from the Water Vapour Increase feedback, permafrost melt and the other main feedbacks were viewed as being insignificant to the outcome of the RCP scenarios. This is despite clear and unrefuted accounts in the literature of the track record of the acceleration of several of the feedbacks, and formal projections of both Permafrost Melt and Fertilized Peatbog Decay, which show levels of output that are plainly highly significant. The potential for the ocean sinks’ decline is ignored in favour of an hypothesis that the sink’s efficiency would actually rapidly start increasing in response to a reduction of anthro-CO2 outputs and a lack of significant feedback CO2 outputs.

    3. "On what time scales do they operate?"
    Given that the feedbacks in question are both non-linear and also interactive, as in intricately interdependent, there seems no prospect of reliably forecasting a specific date when they would offset a total termination of anthro-GHG outputs under a given emissions control regime. The question can be applied to individual feedbacks’ advance, in that beside the AGW driver this is both near-immediate via the direct drivers in the form of coupling mechanisms, and also long-delayed via the oceans’ thermal inertia timelag on a feedback’s warming output being realized in the SAT whereupon it reinforces almost all the feedbacks.

    However, the individual rates of acceleration to date are in some cases fairly well documented (e.g. Albedo Loss and Fertilized Peatbog Decay) while forward projections have been published for the latter and for Permafrost Melt, but acting only in response to elevated CO2 and to AGW.

    As an example of the feedbacks’ significance during this century, the landmark NOAA/NSIDC 2011 study of Permafrost Melt by Schaefer et al is worth considering here. It adopted a moderate anthro-emissions scenario from AR4 as the AGW input, but set arbitrary constraints on its findings by excluding the greenhouse gas outputs’ warming from the assessment of the permafrost’s rate of melting, and by assuming that only CO2 was emitted - which allowed the projected future output to be stated in simple carbon tonnage. Moreover, the study excluded the direct reinforcements of the rate of melting by all other feedbacks and its delayed reinforcement by all but the Water Vapour Increase feedback. Even under these constraints it showed an output of about 1.6 GtC/yr by 2080, which as 100% CO2 would be about 5.9 GtCO2/yr and would equal about 17% of present global anthro-CO2 emissions.

    However, if the CH4 output is limited to 8.3% of carbon emitted - as was observed in 2013 across the Yedoma areas of Siberia - the permafrost’s annual 1.6GtC output by 2080 would equal over 20.6 GtCO2e/yr, which is about 59% of present anthro-CO2 outputs. Yet that still excludes the acceleration of Permafrost Melt both by its own emissions’ warming effect and by its direct and timelagged reinforcement by other major feedbacks. With these drivers’ assistance, under a moderate emissions control regime, that level of output equal to 59% of present anthro-CO2 could potentially be passed some decades before 2080, and would offset over half of a termination of society’s present annual CO2 emissions.

    4. "Is there time to draw down the carbon before they kick in?"
    With the Albedo Loss feedback being reported in 2011 as providing a forcing equivalent to about 30% of anthro CO2, that is already equivalent to about 35ppm of CO2, I’d suggest that some at least are already kicking in quite severely. This perhaps reframes the question as:
    “Could we draw down carbon faster than the feedbacks advance ?”

    Even using the best of the known Carbon Recovery techniques, CRFS (Carbon Recovery for Food Security) that sequesters only about 27% of the tonnage that BECCS & DACCS would have to address in disposing of CO2, and that maximizes the utility of the carbon and thus the revenues offsetting costs, the scale of the task remains huge and faces timelags both of lead time and effect.

    In terms of feedstock for CRFS, the global area of non-farmland and non-forest suitable for afforestation was found to be around 1.6Gha.s (4.0 billion acres) in a recent joint study by WRI &WFN. Even with strong international co-operation afforesting this large an area with native species for coppice forestry to serve CRFS would probably take a minimum of 20yrs averaging 80Mha.s/yr. With a further 10 years of growth before harvesting the last areas planted and processing the yields in local retort yards, we thus face at least a 30yr lead time to full flow sequestration.

    Assuming a best case of Emissions Control plus CRFS of peaking CO2 in 2050 at 450ppm, cleansing the atmosphere back to the stable natural level of 280ppm would mean recovering about 170ppm plus around another 50ppm re-emitted by the oceans. Achieving the recovery of 220ppm of CO2 by 2100, and thereby conserving at least a fraction of marine life by steadily reversing acidification, would mean sequestering around 9.2GtsC/yr for 50 yrs, which would almost certainly require the local processing of additional biomass from urban, farm and forestry wastes.

    Yet even this huge and necessary scale of operations still faces the 30 to 40yr timelag on the cooling effect of carbon drawdown due to the oceans’ thermal inertia. Together with a 30yr lead-time to full flow, this implies that we shouldn’t see even the start of any cooling from Carbon Recovery until the 2080s. Sadly there thus appears to be no prospect of drawing down the carbon faster than AGW and the feedbacks’ mutual self-reinforcement accelerate their CO2e outputs.

    5. "Are there any negative feedbacks according to this analysis?"
    There are of course well documented minor negative feedbacks in operation, but very few possible mechanisms have been identified for negative feedbacks with a potential to control warming to any significant extent, despite this being a subject of keen interest for governments whose fossil fuel reserves have for 25 years given a strong motivation for funding scientific research on the issue. Of the three best hopes two have proven groundless and the third highly undesirable.

    – The first, being raised water vapour causing a hypothetical rise of cloud cover shading the planet, was shown by exhaustive research of the empirical data to be very likely a minor positive feedback due to clouds trapping a little more heat, with very low probabilities extending to it being a moderate positive feedback or a minor negative one. More recent research shows how Water Vapour Increase is likely to cause a major loss of tropical cloud cover, giving a potentially strong positive feedback, as well as accelerating the ruinous ‘Migration of Rainfall’ out of the tropics and away from the regions’ agriculture.
    – The second, being the observed change of some trees’ CO2-enhanced growth storing more carbon in their standing wood, is of very limited potential and is not rising at anywhere near the rate of the countervailing increase since 1980 of the impacts on forests of droughts, heat waves and surface ozone concentrations in terms of growth-suppression and of pests, ailments, dieback and rising frequency, duration and intensity of wildfires.
    – The third, being the observed destabilization of the geosphere due to both the pace of terrestrial ice loss and relatively sudden and uneven climatic redistribution of the oceans’ mass, with a consequent rise in seismic events and in volcanoes’ cooling sulphate emissions, which have (according to Prof. McGuire, adviser to Munich Re on vulcanism risks) accelerated slowly on a 1.25% /yr trend over the last 30 years. – However, if in the absence of mitigation these events eventually rose to provide a substantial cooling, it could be highly variable year to year and thereby impose severely damaging global temperature fluctuations, and it could also be at the cost of a related scale of volcanoes, earthquakes and tsunamis destroying more of society’s infrastructure.

    It is worth noting here that while there is a clear possibility of additional significant negative or positive feedbacks emerging in coming decades, apart from the ocean sink’s decline they are not currently predicted by the scientific literature.

    6. "I do not find claims that IPCC is especially complacent on one hand or alarmist on the other plausible in the absence of comparable amounts of effort, which nobody has done."

    In response to your observation I’d note that the overall scale of effort cannot automatically confer reliability on specific areas of study, particularly when the published papers in that area are dismissed as “unclear”. Those who have undertaken the studies are quite liable to have a superior understanding of the issue compared to those compiling a report of the global overview.

    That said, I would make clear that I have a profound respect for the scientists whose diligent and stressful work forms the basis of the IPCC’s reports, yet the system that relies on their efforts is arguably unfit for purpose, as its assessments of the threat of AGW and of the action needed for its mitigation appear to reflect a variety of arbitrary assumptions. For instance, the assumptions that:

    – it was rational to provide four scenarios in the AR5 report ranging from the outcome of a free market regime to that of a ‘best case’ global mitigation policy that offered only a 2-in-3 chance of respecting the 2.0C threshold of dangerous climate change, despite all nations being pledged to respect that threshold; - given that there is no scientific premise for assuming 2.0C of warming to be safe, and that with less than 1.0C of warming to date climate impacts already threaten the very dangerous threshold of global food security, the IPCC has plainly acted arbitrarily in excluding the mitigation options that would allow the drafting of a 99% reliable mitigation scenario for 2.0C, and a second scenario reflecting the demand by two-thirds of UN member-states that the official threshold of dangerous warming be revised down to 1.5C;

    – that the fundamental mitigation issue of advising UNFCCC to establish a global carbon budget could be ignored for the last 20 years, and that when it was finally addressed in the recent AR5 report it should be in so vague and convoluted a manner that delegates at the UN in turn dismissed it, while of the media that gave it any coverage at all many reported a budget far larger than that which the scientists actually proposed;

    – that there was no intellectual case for AR5 to recommend policy-makers’ use of methane’s global-warming-potential value of 86 times CO2 equivalence [86CO2e] over a 20 year period, rather than that of 34CO2e on a 100 year period, despite the latter’s radical underestimate of growing commercial methane emissions’ early ocean warming and its consequent early acceleration of other feedbacks via direct coupling mechanisms;

    – that, unlike the Water Vapour feedback’s easily calculated linear growth which AR5’s scenarios incorporate, the other six main non-linear feedbacks could be assumed to make no significant difference to the scenarios’ outcomes, despite multiple, clear and un-refuted lines of published evidence to the contrary.
    Thus like previous IPCC reports AR5 fails to include even the track records of the acceleration of those six potentially major non-linear positive feedbacks that scientists in the field observe to be active, let alone including any rational estimate of their combined potential to offset society’s efforts at emissions control.

    In this light it appears that there is a systemic optimism bias operating in the IPCC which, while it is almost wholly unexpected of scientists, is not that surprising among the governmental component of the organization. There is also the factor of the conservative influence of established schools of scientific thought shaping the reports’ agendas, as is observed in the somewhat cynical proverb that “Science advances one funeral at a time.” The reports are written in the knowledge that they must be cautious enough to be presented as the consensus of scientific opinion, as well as in the knowledge that they must withstand a line-by-line editorial veto by member governments’ representatives, who may lack any interest in publicizing the actual prognoses for climate destabilization.

    Together these factors, along with the accelerating rate of climate change, in my view make it not at all surprising that the reports have excluded cutting edge scientific advances which inherently appear to be outliers from an orthodox perspective, to the extent that the reports are increasingly out of date on publication. A classic case in point was the discovery that field observations of the loss of arctic sea ice showed that by 2007 it had advanced to a level predicted by the mean of models of that loss as occurring in the 2100s, while that mean was used as the consensus projection in AR4.

    A further problem afflicting the IPCC’s fitness for purpose is the long intervals between its reports while climate destabilization is accelerating. For example, the absence from AR5 of last January’s Ramanathan paper indicating a large and very significant Albedo Loss feedback forcing cannot be rectified until about 2019 under the current system of periodic IPCC reports advising the UNFCCC as to the climate predicament. Without remedial action, this would mean at least another five years before that feedback forcing is even considered as a serious component of the problem that mitigation strategy must address.

    Perhaps the simplest remedial action is for climate scientists, particularly those working in areas of climate research not fully addressed in AR5, to co-operate in producing an annual ‘vanguard science’ report of the year’s developments, as both an update and an expression of constructive dissenting opinion. In lacking any governmental veto as well as any need to describe the consensus of opinion, this would have the potential to be far more candid on the unaffordable risks that governments are running, while also being far nearer to real-time reporting. Being without the shield of official endorsement, that co-operative effort would earn credibility with the public and decision-makers only by its track-record of the accuracy of its prognoses, meaning that it would be at least as dependent on the proper use of the scientific method as the IPCC.

    These are my answers to your six points Michael, and I hope they may be of interest to you. I do not expect to be correct in every detail – a layman reading a scientific report inevitably gets less information than would a skilled scientist – but I hope to have the balance of the arguments about right.

    My aim is rather to make the case that :

    - it would be highly imprudent to continue assuming the major interactive feedbacks can reliably be managed by emissions control despite the information available on their interactive acceleration;

    - that the individual limitations of the Carbon Recovery and Albedo Restoration modes of Geo-E mean that both are requisite to a mitigation strategy that is commensurate with the predicament and that is compliant with UNFCCC members’ commitments to precaution and equity;

    - and that the time-lags of both modes’ necessary R,D&D, along with the lead-time and delayed effectiveness of Carbon Recovery, imply that a governance protocol mandating a UN scientific agency to stringently supervise the options’ research and eventual selection for accreditation (for UNFCCC members’ collective decision on deployment) should be agreed by the CoP 21 in Paris alongside the primary goal of agreeing the national allocations of stringent emissions controls.

    Looking forward to your discussion of these issues,



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