Do IPCC’s emission scenarios fail to comply with the precautionary principle?

by Judith Curry

On the uncertainty monster thread, a scenario was defined as a plausible but unverifiable description of how the system and/or its driving forces may develop in the future.  Scenarios may be regarded as a range of discrete possibilities, often with no a priori allocation of likelihood.  An example is the future greenhouse gas emission scenarios used to force global climate models.

I hadn’t paid much attention to issues surrounding emissions scenarios, assuming that whoever was putting these together was doing a reasonable job, with  new emissions scenarios being prepared for IPCC’s 5th Assessment report. Recently, I encountered a paper by Betz, entitled  “Underdetermination, model-ensembles and surprises: on the epistemology of scenario-analysis in climatology” and the first few sentences of the abstract really caught my attention:

“As climate policy decisions are decisions under uncertainty, being based on a range of future climate change scenarios, it becomes a crucial question how to set up this scenario range. Failing to comply with the precautionary principle, the current scenario methodology of the IPCC seems to violate international environmental law, in particular a provision of the United Nations Framework Convention on Climate Change.”

Now I’m no fan of the precautionary principle, but I found this too irresistible not to investigate.

The IPCC’s scenarios of future climate change  have two elements: (1) creation of a suite of emissions scenarios and (2) climate model simulations forced by the emission scenarios.  This post focuses on (1); (2) will be the topic of next week’s post.

Background on emissions scenarios

Basic references that describe emissions scenarios are:

Moss et al. describe emissions scenarios as:

Emissions scenarios are descriptions of potential future discharges to the atmosphere of substances that affect the Earth’s radiation balance, such as greenhouse gases and aerosols. Along with information on other related conditions such as land use and land cover, emissions scenarios provide inputs to climate models. They are produced with integrated assessment models based on assumptions about driving forces, such as patterns of economic and population growth, technology development, and other factors. Over time, the information provided by integrated assessment models and used in climate models has become increasingly comprehensive, including time-dependent emissions of radiatively significant gases and particles, precursor pollutant compounds, and land cover and use. . .  Emissions scenarios for climate change research are not forecasts or predictions, but reflect expert judgments regarding plausible future emissions based on research into socioeconomic, environmental, and technological trends represented in integrated assessment models.

Scenarios used in the IPCC 3rd and 4th Assessment Report (the SRES scenarios) were produced  to provide  a common basis for climate change projections, mitigation analyses, and impact assessments.  The SRES scenarios were developed using storylines (or narratives of the future) derived from a wide range of driving forces.

For the AR5 (Moss et al.) there is a redesigned scenario process that starts with scenarios of radiative forcing for 2100.  The four different forcing scenarios used correspond to the following peak levels of atmospheric CO2: 490 ppm, 650 ppm, 850 ppm, 1370 ppm. These radiative forcing trajectories are not associated with unique socioeconomic or emissions scenarios, and the role of models in the scenario builiding is to develop a time line of emissions and an internally consistent scenario that includes the other long lived greenhouse gases plus aerosols.  Also new to the AR5 are storylines associated with possible mitigation policies.

The Kaya identity

A simple way of thinking about emissions scenarios is enabled by the Kaya identity, which frames the determination of IPCC emissions scenarios using four different inputs:  population growth projections ; Gross Domestic Product (GDP) per capita trends; energy use per unit of GDP; and emissions per unit energy consumed.   The identity is expressed in the form (pulled from the Wikipedia article):

F = P * (G / P) * (E / G) * (F / E) = P * g * e * f

where F is global CO2 emissions from human sources, P is global population, G is world GDP and g = (G/P) is global per-capita GDP, E is global primary energy consumption and e=(E/G) is the energy intensity of world GDP, and f=(F/E) is the carbon intensity  of energy.  Play with the online Kaya calculator here.

Criticisms of the IPCC SRES scenarios

As per the Wikipedia, the IPCC SRES scenarios have been criticized for their choice of exchange rates, estimates of energy intensity, estimates of resource availability, and emission rates after 2000 that are more rapid than projected.

O’Neill and Nakicenovic argue that the range of scenarios is too narrow:  the scenarios should be expanded to address specific questions and needs;  the scenarios do not adequately address the full range of uncertainties in emissions over the next few decades; and there has been inadequate investigation of what might constitute the “barely feasible” scenario and under what conditions such a scenario might be created.

The new scenarios for the AR5  seem to address many of the criticisms, although it is not clear that a CO2 concentration of 1370 ppm in 2100 is high enough to qualify as a “barely feasible” scenario.

Modal inductivism and falsification

At the heart of Betz’s argument regarding IPCC scenarios violating the precautionary principle is the concept of modal logic.

Modal logic extends propositional logic to include the classification of propositions according to whether they are contingently true or false, possible, impossible, or necessary.  Betz argues for the logical necessity of considering future climate scenarios as modal statements of possibilities.

Betz contrasts two general methodological principles for constructing the IPCC climate scenario range: modal inductivism and modal falsificationism. Modal inductivism states that a certain statement about the future is possibly true if and only if it is positively inferred from our relevant background knowledge. By this token, the story lines and models used to generate the IPCC SRES emissions scenarios, along with climate model simulations forced by these scenarios, are scenarios of the future determined from modal inductivism.

Modal falsificationism further permits creatively constructed scenarios to be accepted as long as the scenarios cannot be falsified by being incompatible with background knowledge. Developing a suite of scenarios by modal falsification is a two step process:  the first step is coming up with as many potential future scenarios as possible (using inductive as well as other more creative methods) and then submitting these future scenarios to tests in order to see which ones can be discarded as impossible.  The AR5 scenarios seem more consistent with a modal falsification approach, but it is unclear how the top emission value (associated with 1370 ppm) was determined;   the criteria seems to have been plausibility rather than barely feasible.  The O’Neill and Nakicenovic concept of the “barely feasible” scenario is consistent with modal falsification.

So how does scenario creation by modal inductivism violate the precautionary principle?

Precautionary principle

Definitions of the precautionary principle have two key elements (Wikipedia):

  1. an expression of a need by decision-makers to anticipate harm before it occurs. Within this element lies an implicit reversal of the onus of proof: under the precautionary principle it is the responsibility of an activity proponent to establish that the proposed activity will not (or is very unlikely to) result in significant harm.
  2. the establishment of an obligation, if the level of harm may be high, for action to prevent or minimise such harm even when the absence of scientific certainty makes it difficult to predict the likelihood of harm occurring, or the level of harm should it occur. The need for control measures increases with both the level of possible harm and the degree of uncertainty.

Betz’s argument A18 basically states that if the precautionary principle is the normative premise,  scenarios developed by modal inductivism exclude plausible catastrophic scenarios (anticipating harm) and so violate the precautionary principle.

Possibility distributions

Although not mentioned by Betz, the concept of possibility distribution seems very useful for characterizing a collection of modal statements and therefore to characterizing a group of scenarios.

Possibility theory is an imprecise probability theory driven by the principle of minimal specificity that states that any hypothesis not known to be impossible cannot be ruled out. In contrast to probability, possibility theory describes how likely an event is to occur using the dual concepts of the possibility and necessity of the event, which makes it easier to capture partial ignorance. A possibility distribution distinguishes what is plausible versus the normal course of things versus surprising versus impossible.   Possibility theory can be interpreted as a non-numerical version of probability theory or as a simple approach to reasoning with imprecise probabilities.

An interesting application of possibility theory to the risk of terrorism attacks is here, see especially Fig 3.2 on p 3-7 that illustrates the possibility distribution graphically.

JC’s modest suggestion

The strategy for developing emissions scenario for the AR5 seems to be much improved over the previous strategy used in the SRES.  Nevertheless, Betz’s argument about about the the IPCC emissions scenarios violating the precautionary principle seems valid.  Even if the precautionary principle is not used, other strategies for decision making under deep uncertainty require information on the “barely feasible” worst case scenario.

So how might the IPCC proceed in this regard?  First, the complicated models that develop emissions scenarios don’t seem to be necessary for forcing the climate models; simply specifying a value of CO2 concentration (with the other greenhouse gases and anthropogenic aerosol)  at 2100 along with a simple time trajectory is sufficient to force the climate model. The value of the emission models would be in establishing the “barely feasible” worst case scenario and the conditions under which this scenario might be created, and in rejecting more extreme scenarios.

The individual scenarios in the IPCC scenario suites (both SRES and AR5) are implicitly regarded as equally plausible.   Armed with Kaya’s identity (or the more sophisticated emission models), modal falsification, and the possibility distribution, it seems that there is a feasible and credible method for establishing the relative likelihood of the different radiative forcing scenarios.  Inverse modeling using Kaya’s identity could identify the number of different pathways among the various combinations of possible input variables that could result in a specific radiative forcing scenario (say +/- 10%) .   The number of different combinations of variables that would produce a particular forcing scenario would provide some sense of the likelihood of that scenario (with the barely feasible scenario having only one combination of variables, and so being the least likely).  A further embellishment could be provided by ranking the input values for at least some of the input variables in terms of their likelihood (from necessary to barely feasible).  This would provide a rationale for the size of the bar (on the possibility to necessity scale) related to that particular scenario.

It would also be useful to assess the likelihood for each radiative forcing scenario in terms of the likelihood of exceeding the value of the scenario.  For example, exceeding the 400 ppm scenario by 2100 would probably be classified as necessary, whereas exceeding the barely feasible strategy would be ranked as impossible.

This seems to me to be a plausible way to tame the scenario uncertainty monster, but since I have only been thinking about this for a short time and am no expert on this topic, these ideas could be off the mark in some way.  In any event, Betz makes a compelling argument for including the “barely feasible” scenario, without which the IPCC’s scenarios and their use by the UNFCCC is arguably fails to comply with the precautionary principle.

I look forward to your assessment of this and suggestions on fleshing out these ideas.

63 responses to “Do IPCC’s emission scenarios fail to comply with the precautionary principle?

  1. Steven Mosher

    I love modal logic. Its fun stuff: I first ran into here

    I spent a couple years in undergrad studying his stuff. And no, not a believer but it was an interesting twist on an old argument.

  2. David L. Hagen

    Judith. You cite Betz:

    Modal falsificationism further permits creatively constructed scenarios to be accepted as long as the scenarios cannot be falsified by being incompatible with background knowledge.

    I submit there is growing evidence that natural resource constraints on the production rates of fossil fuels provide hard “background knowledge” limits that falsify almost ALL IPCC scenarios. Following is a selection from the growing literature on this subject.

    Tad W. Patzek (2010)

    • Few understand the ever more stringent daily withdrawal limits imposed by nature on our fossil fuel and biofuel “ATM cards” (oil & gas wells, coal mines, and biofuel plantations).
    • Until we understand our limitations, we will continue to overestimate accessibility of energy and the roles technology might play to increase the global rate of energy production.

    In particular, see:

    Figure 23: The forty cumulative fossil fuel production scenarios by IPCC have been normalized with the multi-Hubbert curve prediction of cumulative fossil fuel production in the world. Barring the lowest 4 scenarios, similar to IEA’s, IPCC suggests that by the year 2100, between 2 and 4 times more fossil fuels will have been produced worldwide compared with the current best base-case prediction. One concludes that almost all of the IPCC scenarios are physically impossible. Sources: (Patzek, 2008), (Patzek & Croft, 2010), US DOE EIA, O&GJ (2009), SRES Report (2000).

    Physical Limitations on Mining Natural Earth Systems, January 19, 2010, Presented at the 2010 AAAS Annual Meeting

    Using multicyclic Hubbert models, T.W. Patzek (2008) models US and world oil production, showing:

    that the rates of oil production in the world and in the United States doubled 10 times, each increasing by a factor of ca. 1000, before reaching their respective peaks. The famous peak of US oil production occurred in 1970, and global oil production probably peaked in 2005 – 2006, with little fanfare.

    Exponential growth, energetic Hubbert cycles, and the advancement of technology, T.W. Patzek Archives of Mining Sciences, Volume 53, Issue 2, 2008, Pages 131-159.

    M. Höök (2009) examined oil production and depletion in detail:
    Depletion and Decline Curve Analysis in Crude Oil Production, Licentiate thesis, 2009-05-01, Uppsala University

    Malallah et al. (2010) fit global oil production with a multicyclic Hubbert model.

    “The analysis of 47 major oil producing countries estimates the world’s ultimate crude oil reserve by 2140 BSTB and the remaining recoverable oil by 1161 BSTB. The world production is estimated to peak in 2014 at a rate of 79 MMSTB/D. . . .On the basis of 2005 world crude oil production and current recovery techniques, the world oil reserves are being depleted at an annual rate of 2.1%. ”

    Forecasting World Crude Oil Production Using Multicyclic Hubbert Model, Ibrahim Sami Nashawi*†, Adel Malallah† and Mohammed Al-Bisharah‡ Energy Fuels, 2010, 24 (3), pp 1788–1800.

    Similarly Zhang et al. (2010) report:

    To forecast the peak time of oil and gas production, we used the methods of multi-Hubbert model forecasting and data forecasting. Our results showed that the world oil production will reach a peak between 2010 and 2015 and the gas production will reach a peak around 2030 Oil peak is coming and gas peak is on the way. The main purpose of forecasting oil and gas production peak is give people enough time for preparing mitigation and adaptation plans. This means taking decisive action well before the problem is obvious.

    Risk-opportunity analyses and production peak forecasting on world conventional oil and gas perspectives, Jian Zhang, Zandong Sun, Yiwei Zhang, Youshun Sun and Toksoz Nafi, Petroleum Science, Volume 7, Number 1, 136-146, DOI: 10.1007/s12182-010-0018-8,

    Patzek & Croft (2010) report similar issues with coal production:

    Based on economic and policy considerations that appear to be unconstrained by geophysics, the Intergovernmental Panel on Climate Change (IPCC) generated forty carbon production and emissions scenarios. In this paper, we develop a base-case scenario for global coal production based on the physical multi-cycle Hubbert analysis of historical production data. Areas with large resources but little production history, such as Alaska and the Russian Far East, are treated as sensitivities on top of this base-case, producing an additional 125 Gt of coal. The value of this approach is that it provides a reality check on the magnitude of carbon emissions in a business-as-usual (BAU) scenario. The resulting base-case is significantly below 36 of the 40 carbon emission scenarios from the IPCC. The global peak of coal production from existing coalfields is predicted to occur close to the year 2011. The peak coal production rate is 160 EJ/y, and the peak carbon emissions from coal burning are 4.0 Gt C (15 Gt CO2) per year. After 2011, the production rates of coal and CO2 decline, reaching 1990 levels by the year 2037, and reaching 50% of the peak value in the year 2047. It is unlikely that future mines will reverse the trend predicted in this BAU scenario.

    A global coal production forecast with multi-Hubbert cycle analysis, Tadeusz W. Patzek, Gregory D. Croft, Energy, Volume 35, Issue 8, August 2010, Pages 3109-3122

    Until physical and economic limitations on natural resources are accounted for, almost all IPCC AR4 and AR5 projections would appear to violate Modal falsification.

    • Patzek & Croft (2010) is behind a paywall, so reading it awaits my Lotto win, but I hope it covers the most neglected yet critical aspect of longevity of energy supplies – accurate forecasts of future consumption, especially of China and India

      • David L. Hagen

        For an available supporting perspective, see: Mikael Höök, Future coal production outlooks in the IPCC Emission Scenarios: Are they plausible? International Pittsburgh Coal Conference 2010

        . . .The Special Report on Emission Scenarios (SRES) from 2000 contains 40 scenarios for future fossil fuel production and is used by the IPCC to assess future climate change.. . .SRES is riddled with future production projections that would put unreasonable expectation on just a few countries or regions. Is it reasonable to expect that China, among the world’s largest coal reserve and resource holder and producer, would increase their production by a factor of 8 over the next 90 years, as implied by certain scenarios? Can massive increases in global coal output really be justified from historical trends or will reality rule out some production outlooks as implausible? . . . Historical data from the past 20 years was used to test how well the production scenarios agree with actual reality. Some of the scenarios turned out to mismatch with reality, and should be ruled out. Given the importance of coal utilization as a source of anthropogenic GHG emissions it is necessary to use realistic production trajectories that incorporate geological and physical data as well as socioeconomic parameters. SRES is underpinned by a paradigm of perpetual growth and technological optimism as well as old and outdated estimates regarding the availability of fossil energy. This has resulted in overoptimistic production outlooks.
        . . . Only the B1 family appears to have any constraints on future coal production compatible with academic studies. . . .

  3. Thanks for this comprehensive summary

  4. Yikes! Are you saying that the modelers failed to use emission inputs that are so dire (in terms of high CO2 emissions), they (the untested scenarios) could be described as being “worse than we thought”?

  5. What is the point of the IPCC preparing new emission scenarios for AR5 when major IAC recommendations have not been implemented? Were these mandatory recommendations not mandatory? Is is business as usual for AR5 – “we are now too far down the track with AR5, will consider them for AR6”?
    Some example IAC recommendations:
     The IPCC should make the process and criteria for selecting participants for scoping meetings more transparent.
     The IPCC should develop and adopt formal qualifications and formally articulate the roles and responsibilities for all Bureau members, including the IPCC Chair, to ensure that they have both the highest scholarly qualifications and proven leadership skills.
     The IPCC should establish a formal set of criteria and processes for selecting Coordinating Lead Authors and Lead Authors.

    • The AR5 is well underway. The IPCC does not seem to be paying attention to the IAC recommendations, latest news sounds like they will keep Pachauri. This is very unfortunate. After I finish with my series of scientific arguments criticizing the IPCC assessment reports, I will start digging into their procedures. Not sure anyone is paying attention, but I want to get the arguments on the table in detail, and open them up to discussion on the blog.

  6. @Judith
    Your faith in the IPCC scenarios is misplaced.

    1. The IPCC scenarios were developed as a Special Report and therefore subject to government approval. As a result, “politically incorrect” scenarios were deliberately excluded. According to the IPCC, there is a zero chance that parts of Africa will remain stuck in poverty. Why? Because Africa has 53 votes in the IPCC.

    2. The models used to generate the scenarios cannot reproduce the main development patterns of the 20th century. In fact, on some indicators (e.g., income convergence), the modelled trend has the opposite sign of the observed trend.

    3. The IPCC developed the scenarios and then asked the same team to assess the scenarios. Unsurprisingly, they thought they had done a great job. They ignored protests by referees and omitted or misquoted dissenting literature.

    4. The same team that developed the scenarios for AR3 and assessed them for AR4 is now building the scenarios for AR5. The models are roughly the same. Outside voices are ignored.

    • Tomas Milanovic

      According to the IPCC, there is a zero chance that parts of Africa will remain stuck in poverty. Why? Because Africa has 53 votes in the IPCC.

      This is so deeply right!
      And according to UN there is zero chance that Pakistan , Ethiopia and several other countries will suffer catastrophic famines despite having the highest population growth and (according to FAO) the lowest agriculture potential.
      How is this contradiction solved?
      Well Russia, Europe and USA have a low population growth and a huge agriculture potential.
      So they will simply feed whoever will need feeding – there are real “scientific” studies saying that, of course wrapped in much jargon.
      I wonder if those “scientists” asked Mr Poutin what is his take on the axiom that Russia has a duty to feed Pakistan …

      What R.Tol is saying about IPCC is true about any activity in the frame of UN.
      UN is the worst possible body for any scientific endeavour because it is completely dominated by the fact that any irrelevant or totaliarian country has 1 vote.
      Be very sure that any scenario where the sea level doesn’t increase or increases too slowly will be vetoed by all those pseudo states composed of 1 island and a handful of fishers.
      And the reason is obviously not scientific because we would know if those pseudo countries had universities, labs and high quality scientists.
      The reason is that their governments (f.ex Maldives) have understood that this is the unique opportunity to get money without giving anything in exchage.
      So even if the science became convinced about a low sea level scenario, they would all vote against it and IPCC would be instructed to immediately balefire all such scenarios.

      How long will it take untill people understand that voting on scientific results is the worst possible way to do science?

    • Richard, thanks for your message. I think AR5 method is much better since they are doing more of an inverse modeling approach. They select the radiative forcing amounts a priori (which is all the climate models need, really). Whatever storyline they establish with whatever flawed models to get to those radiative forcing values doesn’t matter hardly at all for the climate model forcing, as far as I can tell?

      • Not quite.
        If you are interested in the impact of greenhouse gases on the climate system, the IPCC scenarios are adequate.
        If, however, you also interested in aerosols or land cover, then spatial patterns of development matter — and the IPCC models get it wrong.
        If you are interested in the impact of climate change, then development is again very important.
        If you are interested in mitigation, development is important too.
        For instance, the switch from MER to PPP exchange rates changes global CO2 emissions by some 10% in 2100. That’s not a lot compared to the uncertainties. But, that change is almost all in China. So, the relative responsibilities for climate change change too. And SO2 in China goes up as well.
        The IPCC scenarios for AR5 are cosmetically different from AR3 and AR4, but essentially the same.

      • Ahh. . . definitely need the aerosols and land cover.

      • Not sure what you mean here, Judith – are you saying that, IYO,
        “If you are interested in the impact of greenhouse gases on the climate system, the IPCC scenarios are” NOT adequate?

      • Tom, I am saying that the highest scenario might not be high enough.

  7. Leading slightly off topic to the most important topic of all:
    How do you build trust in the people of the IPCC?
    If the people aren’t trusted then it doesn’t matter what they do or write.

  8. “I hadn’t paid much attention to issues …, assuming that whoever was putting these together was doing a reasonable job,”

    And that sums up beautifully how I felt about the whole AGW issue. I suspect I was not alone. :-)

  9. Judith Curry: “The individual scenarios in the IPCC scenario suites (both SRES and AR5) are implicitly regarded as equally plausible”.

    IPCC SRES: “there is no objective way to assign likelihood to any of the scenarios”. This is even mentioned in the Summary For Policymakers that Curry links to: “There is no single most likely, “central”, or “best-guess”
    scenario, either with respect to SRES scenarios or to the
    underlying scenario literature. Probabilities or likelihood are
    not assigned to individual SRES scenarios.analyses; ”

    So, what gives?

  10. It is wonderful to see that the web is facilitating the emergence of a new form of peer review.
    In this posting, along with the predecessor one on the uncertainty monster, Dr Curry has raised quite fundamental issues with the IPCC documents that seem to have escaped the attention of its authors.
    The conventional peer review, whose purpose is to perform that function for scientific papers, clearly fell well short of adequate standards in the IPCC case.
    Given the scale of the IPCC effort, plus the reality of a fixed time table, it is of course doubtful that a conventional peer review could even be achieved.
    The issues raised on this forum will presumably be addressed in the next IPCC iteration.

  11. Tomas Milanovic


    Betz contrasts two general methodological principles for constructing the IPCC climate scenario range: modal inductivism and modal falsificationism. Modal inductivism states that a certain statement about the future is possibly true if and only if it is positively inferred from our relevant background knowledge.

    I find it really scary. Don’t you?
    Modal logics is to logics what litterature is to mathematics.
    Or a precaution “principle” to a scientific principle.
    So it is not enough that we have non validated climate models but we will have to suffer “modal logics” on top too?
    I do not deny some fun factor to the “modal logics”, but let us be clear it has nothing to do with mathematics or science.
    It’s only a way to wrap litterature in a pseudo mathematical jargon.

    Clearly the relevant background knowledge is just whatever some group of bureaucrats in power (IPCC bureaucrats?) define as such.
    Do they really believe that they will fool people with such jargon?
    I find this evolution really scary.

    If they were serious, they would hire a couple of geophysic experts of exploration&production from Exxon and/or Petrochina and/or Gazprom and they would instantly increase the relevance , understanding and accuracy of emission scenarios 10 fold.
    Those scientists and engineers in coal and oil companies have more forgotten about such issues than the whole IPCC will ever know.
    After all real people and real shareholders depend on the quality of their projections and investment projects what is the most powerful drive to be right that will ever exist.

    • With regards to future energy scenarios, I suspect that there are huge uncertainties, this is something i don’t know much about.

      • Tomas Milanovic

        With regards to future energy scenarios, I suspect that there are huge uncertainties, this is something i don’t know much about.

        Yes Judith.
        I had an opportunity to collaborate on such studies some time ago.
        The principle, like in the climate models is extremely simple.
        Almost everything is strongly correlated to and driven by the energy price.
        If the world’s energy supply has been dominated by coal then gaz then oil it is not only because these energy ressources are the most abundant but also because they are the cheapest.
        China produces 1.5 billions tons of coal/year , that’s about 1 ton per Chinese per year.
        China’s economical growth that’s 4 times the one of the US and the wealth that’s coming with it has been driven by cheap and abundant coal.
        There is absolutely no way that any Chinese who is benefitting from this growth and that’s the majority of the 1.3 billion Chinese will accept to change anything with it.

        So now the (almost) only problem in a long term economical projection is what the price of energy will be, say in 2050.
        The floor is somewhere around 100$/boe because that’s the limit where the non conventional oil&gaz (shales, tar sands etc) can be produced with profit.
        The ceiling is … well nobody knows.
        It depends on what the big producers (Russia, Saudis etc) will do, it depends on how they will arbitrate exports and internal consumption, it depends on the economical growth, it depends on the economical growth differential between oil&gaz producing countries and oil&gaz consuming countries….etc.

        Then there are, like in climate science, unknown (negative) feedbacks – low growth throttles consumption what decreases energy prices what increases growth.
        Of course high growth does the opposite but the transitories are complicated and the system is never in equilibrium. That is one of the reasons why the commodity prices behave like a chaotic system.

        I have even seen some “impact studies” on some crazy and low probability events.
        I recall one which made me laugh – Australia who is a big coal exporter worldwide was imagined to ban coal production and exports for environmental reasons.
        The result was the crash of the Australian economy what was a detail but mostly an important perturbation in the coal balance worldwide and the prices began to behave crazy for a long transient.
        The transients in energy use and production are long because it takes a long time and much money to decide and build significant energy producing facilities.

        From these studies I drew a lesson that:
        – nobody knows what will be the energy consumption and prices in 2050 let alone 2100. And here we talk about incertitudes for the latter which are not measured in % but in orders of magnitude.

        – whatever the real energy&price dynamics will be, CO2 emissions will play no role in it globally even if the CO2 consideration might locally impact significantly the economics of a small number of countries (basically western Europe and perhaps USA).

  12. Richard makes a good point. The UN is an institution whose corruption, massive as it is, is exceeded by its incompetence. I know why it wants to control climate science. I don’t know why any sane person would want it to. Or why any scientist would want to be part of it.

    • David L. Hagen

      “Or why any scientist would want to be part of it.”
      1) $50,000,000,000 obtained to date.
      2) Asking for expenditure of $65,000,000,000,000 with a “modest” administrative fee. (Impolitely known as a “tax”.)
      3) Creating a world government.
      See Lord Monckton Is Obama Poised to Cede US Sovereignty?

    • Alex Heyworth

      “I don’t know why any sane person would want it to. Or why any scientist would want to be part of it.”

      stan, maybe you should try reading Thomas Sowell’s “The Vision of The Anointed”. It is a little old now, but peculiarly apposite to the politics of climate change.

  13. One of the weasel tactics used by one of the leading AGW promoters is to claim we are going to become Venus if we do not accept his radical demands. But if you read him closely, he always slips in something about ‘if we burn all of the fossil fuels’.
    So he gets it both ways: to make a world destroying apocalyptic claim that is utterly false under any reasonable scenario, but hedge it so that if confronted, he can claim it is only a extreme scenario.

  14. David L. Hagen

    IPCC is breaching precautionary principle

    . . . under the precautionary principle it is the responsibility of an activity proponent to establish that the proposed activity will not (or is very unlikely to) result in significant harm.

    The “activity proponent”, the IPCC, is advocating a rapid reduction in fossil fuel use. It must establish that this reduction in fossil fuel use will not result in significant harm.

    I submit that historic evidence is to the contrary. Even a reduction in growth of transport fuel use, (let alone a rapid reduction), has caused massive economic harm, especially to the developing world.

    Global demand for transport fuels is VERY inelastic in the short term. E.g. OPEC’s 5% reduction in supply caused a 400% increase in price during the 1973 oil crisis. Every reduction in oil supply or constraint on the growth of oil in the last generation has caused a major increase in the price of oil with an immediate and consequent economic recession.

    Four of the last five global recessions were caused by huge spikes in oil prices.
    And the world economy is coming off the mother of all spikes. Over the past expansion, real oil prices rose over 500%, twice the climb in real oil prices that produced the two biggest recessions in the post-war era: the 1974 recession and the double-dip recession in 1980 and 1982. If oil shocks half the size of the recent one caused the worst recessions in the last fifty years, they’re a pretty obvious explanation for the recessions in oil-dependent Japan and Euroland earlier in the year.

    Just How Big is Cleveland? by Jeff Rubin. StrategEcon. Oct. 31, 2008.

    I noted in a paper published in the Journal of Political Economy in 1983 that at that time, 7 out of the 8 postwar U.S. recessions had been preceded by a sharp increase in the price of
    crude petroleum. Iraq’s invasion of Kuwait in August 1990 led to a doubling in the price of oil in the fall of 1990 and was followed by the ninth postwar recession in 1990-91. The price of oil more than doubled again in 1999-2000, with the tenth postwar recession coming in 2001. Yet another doubling in the price of oil in 2007-2008 accompanied the beginning
    of recession number 11, the most recent and frightening of the postwar economic downturns.
    So the count today stands at 10 out of 11, the sole exception being the mild recession of 1960-61 for which there was no preceding rise in oil prices.

    Nonlinearities and the Macroeconomic Effects of Oil Prices, James D. Hamilton

    See the Oilwatch Monthly
    Especially note that NonOPEC crude oil production plateaued from 2004. Simultaneously, OPEC constrained the growth in its crude oil production in 2005. Global oil production has thus been flat for the last six years. Those fundamentals together drove up the price of oil which brought on the financial crisis.
    We are rapidly heading for declining oil production with consequent higher prices and economic depression. Strongly recommend reading:
    The Impending World Energy Mess Robert L. Hirsch, Roger H. Bezdek, Robert M. Wendling, Apogee Prime (October 1, 2010) ISBN-10: 1926837118

    The huge economic impacts associated with impending oil shortages are brought into sober, balanced perspective and readers are given tools to minimize the impending negative impacts on their personal lives. In the next five years, world oil production will begin to decline – which means less and less oil will be available each year. The result will be annually deepening worldwide economic damage.

    There will be no quick fixes. Even crash program mitigation will take more than a decade to impact.

    Societal priorities will change dramatically. Compromises will be required. Years of energy hopes and fantasy will have to yield to pragmatism.

    Oil and energy issues are complicated. You need to understand the situation in order to make intelligent choices for yourself and those close to you.

    To be forewarned is to be forearmed. With over a hundred years of combined experience in energy and economics, the authors provide you the straight story, including realities that others have been reluctant to discuss.

    IPCC must show a transition to renewable fuels that does NOT cause economic harm. Cap and Trade is the epitome of forcing transition by constraining supply. This method of reducing CO2 will inherently cause major shortages of transport fuels with consequent recessions.

    Our challenge is to rapidly transition to alternative transport fuels/methods without global economic catastrophe. This requires all focus on providing alternative transport fuels NOT a reduction in fossil use in electricity. By focusing on possible but remote climatic consequences, the IPCC has diverted attention and funds from the critical issue of transitioning to alternative transport fuels. The present environmentalist concentration on “renewable” electricity is directly withholding funds and focus from the essential need to transition to alternative fuels.

    IPCC’s diversion of focus from this essential goal of alternative transport fuels has already caused immense economic harm. Its actions are directly contrary to the precautionary principle. We critically need to focus all resources on this essential transition to alternative transport fuels sufficient to keep our economies growing. We especially need to develop alternative fuels fast enough to reduce prices and enable economic growth in the developing world – the 3,000,000,000 people who survive on $2/day or less.

    • David,
      I was hoping you could clear something up with your argument. I think I’m equally concerned about the coming crisis in fuel costs (especially re transportation) – this will have more effect on emissions or standards of living than any climate treaty.
      But how do you square these predictions with your claim that “the IPCC must show a transition to renewable fuels that does NOT cause economic harm. “?
      It seems to me that the market is indicating there will be severe economic harm regardless of what the IPCC (or more accurately, the UNFCCC) does. Let’s take cap and trade out of the equation, since I don’t think it’s going anywhere fast in a way that will constrain energy supply –
      What solution can you propose on the scale needed to address this problem that will not result in harm to somebody? Is there not an argument to be made for pre-emptive harm now to lessen the shock later?
      I just have a hard time imagining scenarios where everybody wins.

      • David L. Hagen

        “Let’s take cap and trade out of the equation”
        Unfortunately, political correctness to “control” global warming is already pouring massive funds into “carbon collection and sequestration” (CCS). This is “sequestering” massive research funds that need to be put into alternative fuels. Except for Enhanced Oil Recovery (EOR), this is the most effective way I know of to pour trillions of dollar into a hole and “bury” it. That harms most fuel users by default through skyrocketing fuel prices and plummeting GDP, leaving OPEC in control.

        Re: “there will be severe economic harm regardless of what the IPCC ”
        I agree. I should have said:

        “IPCC must show a transition to renewable fuels with the least economic harm.”

        Re: “What solution can you propose on the scale needed to address this problem that will not result in harm to somebody?”

        * Natural Gas – T. Boone Pickens and others are touting natural gas as a bridging transport fuel. See the Pickens Plan.

        * Bitumen – With 5-6 trillion bbl resource, “oilsands” is one interim option. China is clearly voting with its pocket book. Mr. Chengbao He, Deputy Director General of Technology Development – PetroChina Company Limited stated that he expects China’s oil use to increase 7.7%/year through 2020. He is counting on NO oil available from the Middle East to China. Consequently, PetroChina is already building six megarefineries by 2020 (every 18 months) capable of processing 1 million bbl/day of heavy oil/bitumen (aka “oilsands”). China is investing both in Canada and Venezuela.

        * Coal can provide some fuels. See Sasol in South Africa.

        Solar thermal liquid fuels Concentrated solar thermal to make liquid fuels has potential to be cost effective and large enough with suitable investment. See Sandia’s Sunshine to Petrol project
        and the Sandia Alliance

        Unfortunately, all three will be bogged down by environmental feet dragging while US and OECD fiscal sovereignty is transferred to OPEC.

        Re: “not result in harm to somebody?”
        This issue is not some harm to “somebody”, but the least harm to everybody, especially the developing world.

        Re: “Is there not an argument to be made for pre-emptive harm now to lessen the shock later?”
        What do you mean by “pre-emptive harm”? I agree on massive investment in alternative fuels to keep our economies from totally tanking.

      • But what are we transitioning to? That Sandia idea seems neat but I’ll believe it when it works. As far as I know there are no good alternative fuel options at this point (not scalable enough enough), and while one might be engineered, there’s a lot more on the table right now for alternative energy sources. Sure it would take a lot of time and investment to better link the power and (land) transportation grid, but it might be worth it.
        But really, none if this is worth worrying about if OPEC will be running the world soon. Oh wait, Monckton in your clip above said it would be the UN that would create a OWG. But that was supposed to happen last year…

      • David L. Hagen

        Re: Sandia/Solar fuel. See: Solar Thermochemical Water-Splitting Ferrite-Cycle Heat Engines Believe it.

        The EU is funding the HYDROSOL Project. Japanese are similarly pursuing ferrite based solar H2. This has the largest solar fuel potential.

        Bill Gates is promoting traveling wave nuclear power. Existing uranium “waste” could have thousands of years of energy. This might be available to apply to fuels in several decades.
        See Terrapower

        Re: “none if this is worth worrying about if OPEC will be running the world”
        Au contraire, that is exactly the reason to worry. Remember 9/11? Former CIA director Woolsey reported:

        Estimates of the amount spent by the Saudis in the last 30 years spreading Wahhabi beliefs throughout the world vary from $70 billion to $100 billion. . . .The U.S. in essence borrows about $2 billion a day, every day, principally now from major Asian states, to finance its consumption. The single largest category of imports is the approximately $1 billion per working day borrowed to import oil.

        Former CIA director testifies before Senate on oil and foreign policy, by R. James Woolsey
        At present rates we are rapidly transferring the majority of the world’s wealth from the US and EU to OPEC. That would rapidly reduce the US & EU to 2nd world nations or worse.

        Integrating electricity and transport would take far too long.
        Besides, China has about cornered the market on critical
        rare earths essential to electric car motors and batteries.

        Re: “Monckton . . . said it would be the UN that would create a OWG. ”
        Fortunately enough delegates heeded, applied the precautionary principle, and rejected this OWG.

  15. David L. Hagen

    Corrections on links:
    Just how big is Cleveland?

    Nonlinearities and the Macroeconomic Effects of Oil Prices,

    The Impending Energy Mess

    • David L. Hagen

      Lloyds warns:

      Energy markets will continue to be volatile as traditional mechanisms for balancing supply and price lose their power. International oil prices are likely to rise in the short to mid-term due to the costs of producing additional barrels from difficult environments, such as deep offshore fields and tar sands. An oil supply crunch in the medium term is likely to be due to a combination of insufficient investment in upstream oil and efficiency over the last two decades and rebounding demand following the global recession. This would create a price spike prompting drastic national measures to cut oil dependency. . . .

      “A supply crunch appears likely around 2013 . . . given recent price experience, a spike in excess of $200/bbl is not infeasible.” Professor Paul Stephens, Clatham House

      Froggatt, Anthony & Lahn, Glada, SUSTAINABLE ENERGY SECURITY
      Lloyds/Chatham House, 2010

  16. We seem to be experiencing a hockey stick rise in citations!

    Is that due to the application of the precautionary principle?

    PS How about scenarios based on reality?….. No!…. Just a passing thought.

  17. Alexander Harvey

    This seems to relate to something that I am struggling with elsewhere and making a bit of a hash of but here goes:

    Based on the “Moss et al. The next generation of scenarios for climate change research and assessment”:

    In the scenario chain from “Socioeconomic scenarios” through to and including “Impact, adaptation, vulnerability studies” we have expansion of what is possible in the outcomes due to a one-many mapping at each stage that is a single Socioeconomic scenario can lead to several plausible Emissions scenarios, etc. down the chain, potentially leading to many different Socioeconomic scenarios mapping to more ore less the same point in Climate Model Scenario result space.

    If using impact, adaptation, vulnerability studies we can alocate a decsion of acceptable/unacceptable to a model output, we only need to find a single path through the chain that gives an unacceptable result to give a verdict on the originating socioeconomic scenario. Once we have found that a socioeconomic scenario has a possibility (or barely-plausible, etc.) mapping onto the unacceptable set we need to look no further we can mark that originating scenario as having a possible (or barely plausible, etc.) mapping to an unacceptable outcome and cease pursuing further paths throught the chain.

    If we can start at the far end and decide what is unacceptable then the socioeconomic scenarios can be reduced very radidly and in a targetted way.

    Surely we do not need to investigate all possible socioeconomic scenarios that do not violate what is physically possible but only those which give acceptable outcomes.

    It seems quite likely that the set of acceptable socioeconomic scenarios is a very small subset of possible ones, but even if not, knowing that one only has to find one mapping and not calculate an exhaustive set of mappings must be a benefit.

    I would suggest that if one took the 1370 ppm scenario it would be difficult to come up with the a path to model output by picking a forcing mapping and a particular model that was more or less bound to result in unacceptable impacts.

    I can see why this would not work as it stands, as adaptation would need to be moved to the socioeconomic scenario end, that is make it a planned for adaptation to the rest of the socioeconomic indicators, but I think that would be more logical anyway or at least more useful.

    I think that veiwed this way the prcautionary principle reduces the difficulty of computing the limits of the “acceptable” socioeconomic space, and hence reducing the size the acceptable socioeconomic space rapdily provided that adaptation is not allowed to mushroom through lack of constraint, (e.g. some adaptations are not acceptable such as simply dying out, or terminal regression via the stone age to living up trees).

    Like I said I am struggling with this, but I see the precautionary principle and the use of possible instead of probable, would vastely reduce the workload necessary to characterise points in scenario space as accpetable or unacceptable.

    Surely this is not an acedemic excercise in finding all the possible ways of leading to an unacceptable result. I thought it was an excercise in finding the subset of scenario space that cannot lead to an unacceptable result.


    • Alexander Harvey


      I would suggest that if one took the 1370 ppm scenario it would “NOT” be difficult to come up with the a path to model output by picking a forcing mapping and a particular model that was more or less bound to result in unacceptable impacts.


    • Alexander, there are two different logics underlying the development and use of the scenarios, and they are not entirely compatible. The first application is in forcing the climate models to try to understand the magnitude of the risk that we might be facing under various scenarios (demographic, economic, technological, etc.) The second application is to use the scenarios to develop and assess policies for reaching various emissions stabilization targets. Its the second application where the complicated modelling is necessary. Am I addressing your question, I’m not sure?

      • Alexander Harvey


        I am not sure whether I have got the wrong end of the stick or just the other end of the stick.

        If we can constrain what is an acceptable path through impact space then we can use of the precautionary principle coupled with posibility to start to work backwards and I believe save an enormous amount of computation at the climate model stage. On the basis that it only takes one model to give an unacceptable output to mark the originating socioeconomic scenario as unacceptable, we do not have to map it through all permutations of forcing and climate models; for even if the other paths lead to acceptable outcomes the criterion of a possible path to an unacceptable result has already been met.

        For instance if we can determine the existence of a single climate model that leads from a 490 ppm emission scenario to an unacceptable path through impact space due to excessive warming then I can not see why one would look at any 850 ppm scenarios at that stage, for surely one has to get through 490 to reach 850, nor at further runs with that model or any other model at 490.

        It is not quite that simple but given the lack of computational resources would one not look first at the constraints that 490 ppm imposes on socioeconomics scenarios and planned adaptation. Basically if 490 is a no-no (e.g. there exists just one climate model that has producd a run with an output that gives a trajectory through impact space that is at any point unacceptable) then 490 and all greater CO2 emission scenarios are already in the no-no category. We simply do not have to do those runs.

        For instance, it could well be that there exists a model that will rule out all the socioeconomic scenarios in the input set at its first attempt, i.e that even the scenario considered most likely to give an acceptable trajectory, doesn’t.

        That is the power of using the possibility criterion coupled to the precationary principle. I did note that I used the word “considered” which is a fudge.

        Given the cycle time of the IPPC process, it would seem logical to me to use early model results as a criterion for iteratively redefining the socioeconomic input set/adaptations. Otherwise one risks there having to be another umpteen IPPC rounds before we find out what the prudent path would have been. I view the current process as luxurious and not optimised, but then I do not know what goes on in head of state’s heads perhaps the process is optimise towards never needing to reach an agreement.

        If, a big if perhaps, we agree that any trajectory (when attached to acceptable limits of adaptation) that leads to a further 1.5C of warmingat any point in the future is unaccpetable then most of the scenarios may not need looking at.

        I realise that I am begging a lot of questions but given that an IPCC type process is agreed upon and that the decision method would be based precautionary principle and possibility, it would be a logical way of proceeding. In fact I doubt whether the next IPCC round as laid out will achieve anything as we have ruled out almost all but the most punitive scenarios on a “1.5C for all time target” already.

        I can see that the next IPPC report will occur and then, and only then, will we make up our minds whether the outcomes are acceptable.

        Surely we can construct a spectrum of possible impacts and get people to work out what constitutes an acceptable subset now.

        Otherwise it is a bit like building a myriad of houses, finding that they are all unacceptable because the customer wanted one built from terracotta, which they knew in advance but neglected to mention.

        It might be possible to determine fairly rapidly that the combination of the precationary principle and possibility as a criterion leaves the socioeconomic scenario subset empty, in which case we know that these are not a useful as a criterion. I really do worry that the current scheme is not fit for purpose, if that purpose is to navigate a tollerable path through time.

        I still need to see if I can make sense of what I am saying, but I do feel that we are doing a lot of “what if”s and then considering the impacts, when we could consider what impacts are acceptable, and work backwards.

        That is I have gotten hold of the other end of the stick. I think I am being deductive:

        Given the “evidence” i.e. acceptable outcomes, what “were” the circumstances that gave rise to them. Which makes sense to me as a strategy.


      • Alex, i’m working on a post on decision making under climate uncertainty for next week, there are decision making strategies that are potentially robust in the face of major uncertainties.

      • Alexander Harvey


        Thanks I will wait, as I must.

        I wish I could express things better, I am tired, aging, and lucidity is no perhaps longer the norm, and certainly not a given.

        This is not the correct thread for this but I have to say that I have no confidence in a timely “evidence based” resolution to the problem in hand.

        I do not see AGW theory as essentially evidence based, or should I say it is not well characterised by the global temperature record.

        If much depends on determining the climatic sensitivity I will state the following conjecture.

        The uncertainty in climatic sensitivity at best declines according to the inverse of the square root of the length of the experiment, if one relies solely on the evidence of the temperature record.

        I.E. if one regards the experiment as being say 40 years (1970-2010) then on temperature evidence alone, the uncertainty by 2050 will be no better than 70% of its current value.

        Can anyone disprove this? Disprove it either theoretically or based on the measured rate of decline in the uncertainty?

        I can see that it may be possible to have a break-through from the theoretical side, but unless there is, waiting for sufficient temperature evidence is unlikely to lead to a timely resolution.

        Furthermore shackling GCMs to the temperature record could be seen as counter-productive in that it would condemn them to be subject to the conjecture.


      • Alex,

        I think your logic may be a bit off here. Knowing and successfully modeling past temperatures does not provide any true indication for future projections. This is a common problem with computer analysis of real systems. As an example, we could probably come up with a eighth or tenth order polynomial fit to that 40 year temperature record that looked pretty good. However, in all likelihood, a temperature projection past 2010 would probably run off to near either positive or negative infinity by 2020 or so.

        I doubt we have sufficient knowledge of our climate system to claim a projection skill any better than few degrees either way for a span approaching a century.

  18. Given the recent annoucemnets that IR% may be even more uncertain, amd somehow, action becomes more urgent..

    The scenario of short to medium global cooling – and much more adverse effects of this on humans…. The precauitionary principle must be applied to cooling as well.

    Or are the solar physicists so ‘certain’ of cooling, then by IPCC logic we should NOT apply it….

  19. Predicting future events by mankind reflects an effort to know the unknowns, deal with uncertainty. Prognosticators abstract past events as they understand them, sprinkle a little “fairy dust” (modelling) and behold, this is your future. The selling of such a constructed projection is by someone who is also the most believable. Infact, being “right” plays little in the veracity of the projection, because after all, it is a belief that this or that will happen in the future. Today climate people have developed General Circulation Models to which multiple scenarios are applied and projections made. For climate people, models usually help in making decisions. Nothing new here.
    Adding to the usefulness of climate models is the belief that we should be play safe than be sorry. Invoking the precautionary principle carries the baggage as to what we should “do” given this scenario or that scenario. However, reading this thread, I have seen only tangent remarks to a corollary embedded in the precautionary principle: Opportunity Lost Cost. That is, expending resources upon something or a set of activities which will not change what it is you want to change. You won’t have the money or energy to address problems where you guessed wrong. The Opportunity Lost Cost is inherent in every endeavour, the bigger the endeavour, the larger the potential lost cost. Therefore, the use of the precautionary principle in big picture modeling requires inclusions of scenarios where your assumptions may be wrong; and the number of wrong assumption scenarios in the analysis should be similar to those for whom you want to believe, just opposite in sign.
    Being pro-active, why not make mini-projections over very short time spans using real time observations as a way of validation of the scenario; evolving a decision tree allowing one to pursue one scenario over another. Always baby steps, maybe even a constrained random walk.

  20. What is the purpose of the scenarios? Aren’t they just to have a shared baseline for models, policy recommendations, etc? If so, then what is wrong with the AR4 SRES methods?

    One issue that has come up with the scenarios, is the part where they say that no probability is assigned to the individuals scenarios. Some scientists took that statement as an opportunity to average them together(Raupach et al).
    However, no probability assigned is different from equal probability, isn’t it?

    • @MikeN
      A scenario is a not implausible realisation of the future. A proper set of scenarios spans the space of non-implausibility.

      The SRES scenarios span that space for carbon dioxide emissions — and for carbon dioxide emissions only.

      For other aspects, the SRES scenarios either have a rather narrow view of what might happen, or venture into implausibility if not impossibility.

  21. China produces 1.5 billions tons of coal/year , that’s about 1 ton per Chinese per year. China’s economical growth that’s 4 times the one of the US and the wealth that’s coming with it has been driven by cheap and abundant coal. There is absolutely no way that any Chinese who is benefitting from this growth and that’s the majority of the 1.3 billion Chinese will accept to change anything with it.

    It is no coincidence that a price is sought on carbon, at this very threshold that a lot of CO2 is about to be released into the atmosphere.

  22. @Judith,
    Must say having recently stumbled across your blog that i’ve found it to be a very interesting read so far.
    Also, the commentors that i have read to date all seem very polite, to the point and on the main raise interesting or pertinent points.

    I may stick around ;-)

    On the subject of uncertainties, it’s interesting that we’re discussing only the higher range possibilities and it would seem that if anything trying to match the precautionary principle to the IPCC methodology would only increase the number and prominence of the ‘worst case scenarios’. While i understand the reasons for doing it (though perhaps not, condone), i fear it may distort the reality of the situation.

    Given that the IPCC has been criticised for overplaying the worst case scenarious and down-playing the ‘better’ case scenarios, do we not think that trying to shoe-horn the precautionary principle (a political device) into what is effectively a scientific review (if we take all the issues with the IPCC et al out of the equation for the moment) will only increase the risk of the more ‘alarmist’ predictions?

    Incidentally, to explore this idea more (the robust application or the PP) and to try to twist it further out of recogintion would it not also apply to the, for lack of a better term, null hypothesis? I.e. were the catastrophic anthropogenic global waming to turn out to be flase should the PP be applied to the economic damage that could be caused in following a set of actions that may/may not turn out to be necessary?

    I’m not trying to suggest one way or another, it was just a thought.

    • My eventual goal is to try and put the possible/plausible worst case scenarios into an appropriate perspective, but first we need to figure out what that is. What we should do about it is something altogether different. In trying to figure out how to sequence the presentation of my overall arguments, there is a real chicken and egg problem in trying to do this in a sensible way.

  23. Does the precautionary principle apply only to climate change and environmental policy?

    Or does it apply to the lives of ordinary people as well?

    In the last 2 decades, something like half a billion people or more left the world of earning about $1 per day, and entered some level of working class to middle class comfort. It looks from here to be the greatest alleviation of dire poverty the world has ever seen in such a short time. Probably 2/3s of these people are in China.

    3 billion more people await the same benefit, mainly in Asia and Africa. But they can’t do it without energy. And we don’t have widespread alternative energy forms, yet, that don’t emit CO2 and are economically feasible in such places.

    If we were to actually, somehow, crack down on CO2 emissions — which today will come at a very high price — we will stifle economic growth, and therefore keep tens to hundreds of millions in abject poverty.

    Is that what the precautionary principle would argue for?

    If so, it is saying that human lives today don’t matter. But something in the future that might or might not come about and might or might not have net adverse consequences does matter.

    Footnote 1: China has approximately 9 times the amount of coal burning electricity generation than the US (about 2950 gigawatts vs. about 350 gigawatts), and is building new plants all the time.

    Footnote 2: Let’s say that we really are near “peak oil,” which I find plausible. Let’s say peak coal will occur sometime in the next 50 years. Peak natural gas is far, far beyond those dates, because there is so much in methane hydrates all around the world’s oceans. Natural gas can be made into motor fuels, although it takes energy and CO2. So to be serious about reducing CO2 emissions growth in the long term, both nuclear and solar look necessary, to reduce CO2 emissions from the electricity sector in the long run.

  24. What is it that makes the “precautionary principle” legitimate? It seems to be an illogical means of supporting flawed political or policy decisions.

    • Well, it has become “legitimate” because it is included in an international treaty (for better or for worse). The precautionary principle is a complex beast, there are many versions of it and different interpretations (some of which make more sense than others). I will pick this issue up in two weeks.

      • There is a rather long tome on the subject, but the bottom line is that the PP lacks the need to conduct relative cost/benefit assessment, and even if it did, the value of a (which?) human life must be calculated in monetary terms. Flawed and very dangerous as it carries the power to stop almost anything, with no scientific basis. The ultimate anti-development (or even status quo) tool. From the UN, right up there with IPCC. Sigh.

  25. As a non-scientist my thinking is the 100 year 1370 ppm scenario is completely implausible. It may be barely plausible if the entire globe also burned. In which case we would have no worries at all.

    I wonder if it is even possible to achieve that 1370 ppm figure if we consumed all the recoverable fossil fuels in existence.

    1998 was the peak year for annual co2 growth rate at about 2.9 ppm. In the last 10 years the average has only been around 2 ppm. The first 10 years of the record averaged around 0.8 ppm.

    I graphed the growth rate for entire Mauna Loa record and will link to it in a separate comment. As a newbie here I’m not sure if the inclusion of the graph link in this comment might be flagged as spam. Please retrieve if it gets sent to spam.

  26. Graph of co2 growth rate at Mauna Loa.

  27. Roger Pielke, Sr. Has a post today (Fri. 10-15) titled “Comment On The Science Paper “Atmospheric CO2: Principal Control Knob Governing Earth’s Temperature” By Lacis Et Al 2010”
    Pielke rightly laments “… their paper does not present new scientific insight but is actually an op-ed presented in the guise of a research paper by Science magazine. ” However, he also says “The paper is an interesting model experiment …”. This is perpetuating the falsehood that model simulation runs are experiments. The paper itself is quoted as stating, “different contributors to the greenhouse effect comes from radiative flux EXPERIMENTS THAT WE PERFORMED using Goddard Institute for Space Studies (GISS) Model-E.” [EMPHASIS MINE]

    When are real experimental scientists who make real observations and manipulate natural and laboratory variables going to stop letting these guys get away with dignifying themselves as experimental scientists?

    Computer modeling of climate and other complex systems is certainly valuable, it may even be science; however, model simulation runs are not, never have been, and never will be experiments in any sense of the pre “post-normal science” use of ‘experiment’.

  28. Well, experiments can be conducted with models; they are numerical experiments not laboratory experiments. So this is a legitimate use of the word experiment. google “numerical experiment”, this term is used a lot.

  29. One might suggest that the IPCC threat analysis work is no longer an intellectual exercise in logic, possibilities or probabilities. The direct claim is that the science is “settled”, that CAGW is happening, and that the only question is how much the damage will be, or when what particular catastrophic event will be reached. I do not suggest that a deconstruction of IPCC statements and procedures will not find internal contradictions, but that such inspection is no longer appropriate. The IPCC role is no longer (if it ever was) in determining whether something would happen, but what that something would be and when, to be determined by the actual rise in CO2.

    The Precautionary Principle is the overarching Principle that set the IPCC mandate, mood and modis operandi. That some “reasonable” level of possibility exists for a CAGW is undeniable (unlike the science itself) in that the Principle gives the benefit of doubt to the pessimistic layering of negatively (in the IPCC/Green mind) perceived changes consequent of another pessimistic amount of increase of a GHG considered, pesimisstically, to be harmful, through a pessimistically viewed level of induced-temperature increases. That’s a lot of pessimistic views of events and their consequences, all resultant from the Precautionary Principle being applied to the process of threat assessment by the IPCC groups. As is obvious, there is no “faint possibility” that the greatest increase in CO2 will be offset by counteractive, dynamic responses of the planet.

    What might be more useful, though less of an intellectual enterprise, would be for the level of precaution or pessimism to be identified at each stage of our stated descent into madness and grief. The mathematical probability of the final assessments based on the more deductively determined probability of each sequence in the threat chain must be tiny, indeed, when each step has uncertainties. How the process takes contingent statements, each with a error bar and comes up with a conclusion with an error bar equal to or less than each of the statements is something I cannot understand.

  30. David44 – Thanks for reading my weblog post. The term “numerical experimentation” is, as Judy summarized, common terminology used within the modeling community. It simply means that the models are exercised by changing parameterizations, numerical solution techniques, etc. It is not (and must not be) a substitute for testing the models against real world data.
    This issue is discussed further in posts on my weblog; e.g. see

  31. Drs. Curry and Pielke,

    Well, it’s a use of language analogous to grade inflation. Because it’s widely accepted in the modeling community doesn’t mean that it’s accurate or universally accepted: I will read your previous posts, Dr. Pielke, but I think that Cambridge Professor and Oxburgh Panel member, Michael J. Kelly puts it succinctly:

    “I take real exception to having simulation runs described as experiments (without at least the qualification of ‘computer’ experiments). It does a disservice to centuries of real experimentation and allows simulations output to be considered as a real data. This last is a very serious matter, as it can lead to the idea that real ‘real data’ might be wrong simply because it disagrees with the models.”

    • David, the assumption that model simulations produce “real data” that can be used is a substitute for observational data is obviously wrong. However, scientists who collect data in a controlled laboratory environment have a much easier job that scientists collecting environmental data in the field, where there are many confounding factors outside the scientists control and there is not hope of collecting a sufficient space-time sample of the data. Hence, models are used in state estimation whereby models assimilate data to more completely specify the state of the system in a way that would not be possible only with sparsely sampled data.

  32. Thank you for your response, Dr, Curry. Color me stubborn, but IMO unless the activity involves direct manipulation or observation of the real world, it is a simulation not an experiment and should be referred to as such. I cannot speak for Dr. Pielke, but the views expressed in the post he refers to above would appear to agree.