Assessment of Approaches to Updating the Social Cost of Carbon

by Judith Curry

Some new analyses are shedding some light on deficiencies in the approach to estimate the social cost of carbon.

The debate surrounding the social cost of carbon was described in a previous post On Trial: Social Cost of Carbon.  My chief concern was that I thought the US IWG used indefensible values of climate sensitivity as input into the integrated assessment models.

New report from the NAS

The IWG has requested that the U.S. National Academies assess the approaches for determine the social cost of carbon.  A preliminary report was just published: The Assessment of Approaches to Updating the Social Cost of Carbon: Phase 1 Report on a Near-Term Update.

Some context from the Executive Summary:

The social cost of carbon (SCC) for a given year is an estimate, in dollars, of the present discounted value of the damage caused by a 1-metric ton increase in carbon dioxide (CO2) emissions into the atmosphere in that year or, equivalently, the benefits of reducing CO2 emissions by the same amount in that year. The SCC is intended to provide a comprehensive measure of the monetized value of the net damages from global climate change that results from an additional unit of CO2, including, but not limited to, changes in net agricultural productivity, energy use, human health effects, and property damages from increased flood risk. Federal agencies use the SCC to value the CO2 emissions impacts of various regulations, including emission and fuel economy standards for vehicles; emission standards for industrial manufacturing, power plants, and solid waste incineration; and appliance energy efficiency standards.

The Interagency Working Group on the Social Cost of Carbon (IWG) developed a methodology for estimating the SCC and applied that methodology to produce estimates that government agencies use in regulatory impact analyses. The IWG requested this Academies interim report to determine if a near-term update to the SCC is warranted, with specific questions pertaining to the representation of the equilibrium response of the climate system in the integrated assessment models used by the SCC modeling structure, as well as the presentation of uncertainty of the SCC estimates. This interim report is the first of two reports requested by the IWG: the second (Phase 2) report will examine potential approaches for a more comprehensive update to the SCC estimates.

From the section Discussions, Conclusions, and Recommendations:

CONCLUSION 2 The relationship between CO2 emissions and global mean surface temperature can be summarized by four metrics: equilibrium climate sensitivity (ECS), transient climate response, transient climate response to emissions, and the initial pulse-adjustment timescale. ECS is less relevant than the other three metrics in characterizing the climate system response on timescales of less than a century. As a long-term, equilibrium metric, ECS alone does not provide an adequate summary of the relationship between CO2 emissions and global mean surface temperature for calculating the social cost of carbon (SCC).

RECOMMENDATION 1 The committee recommends against a near-term update to the social cost of carbon based simply on a recalibration of the probability distribution of the ECS to reflect the recent consensus statement in the IPCC AR5. Consequently, the committee also recommends against a near term change in the distributional form of the ECS.

Rather than updating the ECS in the current framework, the IWG could undertake efforts to adopt or develop a common “module” that represents the relationship between CO2 emissions and global mean surface temperature change, its uncertainty, and its profile over time.

The module’s behavior should be consistent with the best available scientific understanding of the relationship between emissions and temperature change, its pattern over time, and its uncertainty. Specifically, the module should be assessed on the basis of both its response to a pulse of emissions and its response to long-term forcing trajectories (specifically, trajectories designed to assess transient climate response and transient climate response to emissions, as well as high- and low emissions baseline trajectories). Given the degree of assessment they face, including consistency with observational data, the IPCC-class Earth system models provide a reference for evaluating the central projections of a climate module.

For regulatory decision making, it is at least conceptually possible to describe the uncertainty of these inputs in SCC calculations using probability distributions. Ideally, joint probability distributions could be defined for all of the uncertain inputs to an SCC-IAM, and the impact of uncertainty on the SCC could be evaluated using Monte Carlo analysis or a related approach.

One reason for modeling uncertainty is related to nonlinearities. If the SCC calculation involves nonlinearities over the range of uncertain parameters, the average value of the SCC computed from random draws of these uncertain inputs may not be the same as the single SCC computed from the average parameter values. The implications of such nonlinearities may be difficult to know a priori, suggesting it is best to compute the SCC from random draws of uncertain inputs.

In constructing the SCC, the IWG treated some parameters of the climate system and damage functions as uncertain and random and represented these parameters using probability distributions.

RECOMMENDATION 2 When presenting the social cost of carbon (SCC) estimates, IWG should continue to make explicit the sources of uncertainty.

CONCLUSION 4 Multiple runs from three models provide a frequency distribution of the SCC estimates based on five socioeconomic-emissions scenarios, three discount rates, draws from the equilibrium climate sensitivity distribution, and other model-specific uncertain parameters. This set of estimates does not yield a probability distribution that fully characterizes uncertainty about the SCC.

The committee notes that none of the three SCC-IAMs are sufficiently comprehensive to include all of the uncertainties in the inputs that are likely to be important in calculating the SCC. Moreover, explicit distributions for some important inputs (e.g., emission scenarios, economic growth, and population) have not been developed by the IWG for use in estimating the SCC. Factors omitted or not adequately captured by the analysis need to be better characterized. In addition, a single unifying discussion of captured and omitted uncertainty is needed.

RECOMMENDATION 3 The IWG should expand its discussion of the sources of uncertainty in inputs used to estimate the SCC, when presenting uncertainty in the SCC estimates. The IWG should include a section entitled “Treatment of Uncertainty” in each technical support document updating the SCC. This section should discuss various types of uncertainty and how they were handled in estimating the SCC, as well as sources of uncertainty that are not captured in current SCC estimates.

The uncertainties discussed in this section would include the uncertain parameters unique to each of the models, uncertainty about climate change impacts and their valuation, and the risk of potential catastrophic outcomes. The section would also discuss the implicit, equal weight placed on the three IAMs and five socioeconomic scenarios in computing an average SCC, the possible alternatives of unequal weights or alternative models and scenarios, and the motivation for the chosen approach.

CONCLUSION 5 It is important to continue to separate the impact of the discount rate on the social cost of carbon from the impact of other sources of variability. A balanced presentation of uncertainty includes both low and high values conditioned on each discount rate.

JC comments

The report makes several good recommendations, related to a more complete assessment of uncertainty, and de-emphasizing the ECS in favor of other metrics such as TCR.  I am of course in favor of more complete assessment of uncertainty.  And I agree that TCR is a better metric to use for this purpose than ECS, since the TCR is a better reflection of what we can expect in the 21st century.

However, I am gobsmacked that they think the current IWG values of ECS are fine (which were based on the AR4).  There is a raging debate on the discrepancy between climate model estimates of ECS (which the NAS report supports) versus the values derived from historical observations using simple energy balance models.  And it is far more difficult to criticize the values of TCR determined from the energy balance models.

For further info, read the full report (Section 3).  Here is the summary paragraph:

In summary, the change in the ECS distribution between AR4 and AR5 is small relative to the remaining uncertainties in this and other parameters that determine the SCC. This change arose primarily from assumptions about the multicentury adjustment of the climate system to a constant forcing that remain contested in the literature since the AR5. Neglected processes primarily affect the upper bound on ECS, continuing to support a positively skewed distributional form for this parameter such as that used by Roe and Baker (2007). The AR4 did not give a likely range for TCR that is directly comparable to that in the AR5, but the AR5 did reduce the probability of TCR values greater than 3°C from 10 to 5 percent, reflecting greater confidence and consensus on the upper bound for this parameter.

Well, given the huge uncertainties in other aspects of the SCC determination, perhaps discrepancies in the ECS determination are ‘in the noise.’  But they are nevertheless non trivial in terms of the policy implications, since climate sensitivity is the main driver of all this.

But the key issue is this.  There are two credible sources of information on ECS/TCR:  global climate models and historical observations (paleo estimates aren’t relevant for SCC).  These two sources produce different PDFs, and the large tail values in the AR5 (10% likelihood of ECS > 6C) arise from paleo estimates, or historical estimates using flawed methodologies.  The plausible upper bounds from climate models and historical estimates does not exceed 4.5C.  It is very difficult to defend a fat tail out to ECS > 7C (used by the IWG), and the fat tail values drive high SCC values.

New paper

There is a highly relevant new paper by Dayaratna, Mckittrick and Kreutzer entitled Empirically-constrained climate sensitivity and the social cost of carbon.

Abstract. Integrated Assessment Models (IAMs) require parameterization of both economic and climatic processes. The latter include Ocean Heat Uptake (OHU) efficiency, which represents the rate of heat exchange between the atmosphere and the deep ocean, and Equilibrium Climate Sensitivity (ECS), or the surface temperature response to doubling of CO2 levels after adjustment of the deep ocean. Due to a lack of adequate data, OHU and ECS parameter distributions in IAMs have been based on simulations from climate models. In recent years, new and sufficiently long observational data sets have emerged to support a growing body of empirical ECS estimates, but the results have not been applied in IAMs. We incorporate a recent observational estimate of the ECS distribution conditioned on observed OHU efficiency into two widely-used IAMs. The resulting Social Cost of Carbon (SCC) estimates are much smaller than those from models based on simulated parameters. In the DICE model the average SCC falls by 30-50% depending on the discount rate, while in the FUND model the average SCC falls by over 80%. The span of estimates across discount rates also shrinks considerably, implying less sensitivity to this parameter choice.

They use the Lewis and Curry (2015) estimates of ECS [link].  Note that Nic has recently updated the values to account for more recent data and lower aerosol forcing [link].   These new results are not yet published.  Of particular note is that the lower aerosol forcing substantially reduces the ‘fat tail’.

JC reflections

Well, it is certainly a good thing that the IWG’s calculation of the social cost of carbon is being evaluated.  The NAS Committee has made some good recommendations.

The main failing thus far is a serious re-assessment of the values of ECS and TCR to be used in these calculations.  My recommendation is that two separate distributions be used:  one from climate models, and the other from the most reliable of the estimates using historical observations.  The uncertainties associated with aerosol forcing need to be accounted for.  Reductions of the SCC by more than a factor of two, simply by using LC sensitivity distribution, is a significant finding in terms of how we interpret the social cost of carbon.

 

224 responses to “Assessment of Approaches to Updating the Social Cost of Carbon

  1. Even with the current flawed methodology for determining SCC, the govt still has to run their model out 300 years and ignore their own rules on discount rate to get the cost – benefit analysis to work out the way they want it to.

    • Peter Lang

      Yes. That’s a very important point. Over 100 years it doesn’t matter how much you bend the inputs to make impacts of GHG emissions severe, the costs still exceed the hypothesized benefits.

  2. Perhaps, in addition to a “social cost of carbon”, there should be efforts to find cheaper approaches to reducing or reversing the anthropogenic contribution of fossil carbon to the system.

    The present system seems primarily focused on whether the “SCC” justifies very expensive approaches to “mitigation” and/or “remediation”. The current proposals all certainly strike me as very expensive, but perhaps some much cheaper approaches could be found, if people looked a little farther outside the box?

    Rather than just arguing whether expensive approaches are “cost-justified”?

    • There is nothing better than understanding natural climate cycles and tossing all the garbage, non science away.

      About 2000 years ago, there was a Roman Warm Period and then it got cold. About 1000 years ago, there was a Medieval Warm Period and then it got cold. That was called the Little Ice Age. It is warm now because it is supposed to be warm now.

      Oceans warm, Polar Oceans Thaw, Snowfall increases. Ice is replenished on Antarctica, Greenland and Mountain Glaciers. Ice builds up and spreads out, reflecting more energy, dumping more ice and ice cold water into the oceans and on land until earth cools. Polar oceans freeze and the sun takes away ice every year until earth warms again.

      It is a natural cycle and we did not cause it.

      CO2 just makes green things grow better, while using less water.

  3. It’s very concerning that the latest understanding of the science is not used in updating the SCC. The last official update published by the administration increased the SCC dramatically based on AR4 (2007) while the hiatus was in its early years (based on looking back today). I have felt that many of the assumptions in the calculation are flakey, for example, the strong assumption on cost of individuals affected by asthma which is well known to be caused by many factors and not just the small increases in temperature in the forecast assumptions. The 3% (95th percentile) figures for previous SCC versus newly updated SCC are compared below:

    OLD NEW INCR, %
    2015 72.8 109 50%
    2020 80.7 129 60%
    2025 90.4 144 59%
    2030 100 159 59%
    2035 109.7 176 60%
    2040 119.3 192 60%
    2045 127.8 206 61%
    2050 136.2 221 62%

  4. All agreed. We also need a better empirical foundation for the estimates of the impacts of climate change.

    • I forgot to mention the substantial uncertainties in impacts, which is huge

    • Including benefits.

      • Impacts can be either negative and positive.

      • Yes, my first inclination was to search for the word benefits.
        The first hit was on the benefits of reducing emissions and not again until your comment.

        Here’s a risk of cutting emissions:
        Evidently, in JC’s slides, there is reference to increased greening of the planet, presumably from increased CO2. Also, phytoplankton have increased dramatically. Where in the analysis is the die off of biomass induced by reducing CO2?

      • Right, how much of our society has become dependent on the increased calories and decreased water stress? The poorest people in marginally productive land will be hurt the most if we can’t sustain high CO2 concentrations. Would aquifers deplete faster without CO2 increasing humidity at the surface and increasing water cycle efficiency and reducing demand from plants?

        What about the decreased cost of producing fruits and vegetables making nutritious food cheaper (or less expensive might be a better word choice)? Increased resilience? These foods we now favor for nutrition probably not only have become productive, they are probably more resilient and spoil less.

      • Might be a good part of how supply has kept up with our increasing demand for seafood too.

      • aaron,
        “how much of our society has become dependent on the increased calories”?
        Well it’s not just our society:
        “China, which this year overtook the United States as the country with the most number of obese residents – 90 million of them, according to a study published in the Lancet medical journal in April.”
        http://www.channelnewsasia.com/news/asiapacific/china-s-obesity-epidemic/2828036.html
        Meanwhile back in the good ol’ USA:
        “In U.S., 38% of adults and 17% of kids are now obese, CDC study says ”
        http://www.latimes.com/science/sciencenow/la-sci-sn-obesity-in-america-20160606-snap-story.html

        Thanks to the low cost of carbon we can grow more food but it also seems to make humans adopt a more sedentary lifestyle too. Why walk when you can ride? Is this a social cost of carbon?

      • Yes, but as we try to shift from grains to fruits, vegetables and meats; CO2 should help bring costs down. Big reason for obesity is the cost of healthier food choices. Fruits and vegetable are expensive and spoil easily, particularly vegetables. Refined carbs are cheap to produce, last a long time and easy to store and transport. Very convenient. Subsidies and past PR also contribute to over consumption.

        As we develope, we can switch to using these grains and grasses to feed live stock and produce tasty adult beverages and fuel. If we can get CO2 concentrations high enough, maybe biofuels will one day make sense. We might need to ferment just to keep the carbs in our food down ;)

      • aaron,
        It’s ironic in a weird way. Even if you more than doubled CO2 to 900 ppm I doubt the absolute quantity fruits and vegetables would change much over 10%-15%. As it is right now most of these higher quality food sources have a very high manual labor component being largely hand picked and packaged. Today when I think of mechanized farming the first thing that comes to mind are huge tractors and combines sweeping over thousands of acres of mono-culture grains. Maybe what’s missing are the armies of gas powered robots to replace all that inefficient manual labor :)

      • RT ”Impacts can be either negative and positive. “

        The recent flooding of Simbach, Germany was exacerbated by intensive land use for industrial agriculture – in particular growing corn for fuel. It seems that cornfields are more prone to runoff and erosion than other crops, and we need every available acre for the Energiewende.

        There is also a social cost of decarbon.

      • KW, you are right that corn is most prone to erosion. Its inherent in the plant row spacing and very shallow rooting. We have to be very mindful on my farms hilly contours. All corn rows parallel the contours. But if we got rains like Europe last week, would not have helped.

      • German farmers are careful Rud, but if the subsidy is right you can take some risk, no?

        Corn was rare in this region just a few years ago, now it’s everywhere, including marginal land that would otherwise be fallow. (to the delight of the exploding wild boar population)

        Here we have a flood that was demonstrably made worse by efforts to reduce CO2 emissions. I don’t see this cost in the calculation anywhere.

        This is not a Model. These damages are real.

        Of course our Greens see all this differently. This year’s cold rainy weather has the same cause as last year’s warm, dry summer. Climate Change of course. They are calling for immediately building more wind turbines to fix the problem.

        Cheers,

    • Mike Jonas

      NB. “including, but not limited to, changes in net agricultural productivity” – that clause alone will deliver substantial benefits to the equation, as NH food production would get a massive boost from the predicted rising temperatures (if those rising temperatures do actually happen).

      As Rud Istvan says – including benefits.

    • David Wojick

      What empirical foundation for the estimates of the impacts of climate change can there possibly be when we are talking about impacts over a 300 year timeframe? The concept is absurd to begin with.

    • David Wojick

      What empirical foundation for the estimates of the impacts of climate change can there possibly be when we do not yet know that our CO2 emissions have any impact? This is all just pure speculation pretending to be scientific fact. Like estimating the number of angels that can dance on the head of a pin.

  5. Judy–why are you surprised about not re-examining the ECS distribution? NAS was created to advise the Federal government by Abraham Lincoln and it has not deviated from that mission. The members of this particular committee are pretty much all on the global warming dole, big time. Why would they behave counter to their interests, which would be to admit that the ECS/TCS distributions are wrong and that the most likely values are near the low end of the present (AR4) distribution? That would be the end of the dole and an admission that billions were wasted on a minor issue whose solution is best left to private investment rather than public taxation.

  6. There is another flaw in SCC beyond that pointed out by McKitrik’s paper. SCC does not net in the benefits of ‘carbon’. There are at least two: lower cost energy, and greening. The one sided cost of externalities perspective is obviously wrong; if fossil fuels had no benefits we would not be using them. India sees no SCC, only SBC (social benefit of carbon) in its plans to massively build out coal generation to lift more of the country out of poverty.

    As a concrete estimate of SBC, consider Exxon. Its market cap todaynis 380.5 billion. Thatnis what investers are paying for their expectation of all its future after tax earnings. In 2015, Exxon produced ~4mboe per day, of which 2.3 was crude and the rest gas. That is ~840 million barrels of crude, and 620 million barrels of natural gas oil equivalent in 2015. EPA provides hand GHG calculators. One barrel of crude is 0.43 metric tons CO2. One BOE equivalent natural gas is 0.031 metric tons CO2. EPA also says SCC is actually computed as SC-CO2. So Exxon produced ~380 million tons of CO2 in 2015, and the market says the SBC is 380 billion/380 million, or $1000/ ton. Now, we have to add in future CO2. Suppose Exxons production and mix stay the same as 2015 for the next hundred years. Then the ‘discounted’ SBC is 1000/100 or $10/mt CO2. Just Exxon. Now add in Shell, BP, Chevron, Chesapeake, Apache, TOTAL, Statoil, Pemex, CNOC, PetroChina, Aramco, KOC, …And one gets a total SBC easily something around $100/ ton CO2 in market based future benefits.

    • Carbon dioxide fertilization is included in the estimates of the social cost of carbon, half-heartedly by two of the three models used by the IWG and explicitly by the third.

      Cheap and reliable energy is a private, rather than a social benefit, and this is indeed best approximated by looking at the market value of the carbon embedded in energy.

      • Curious George

        Cheap and reliable energy is a private benefit … ?? Where do you drive the line between private and social? Imagine being sick in a bitterly cold bedroom.
        https://judithcurry.com/2016/06/07/assessment-of-approaches-to-updating-the-social-cost-of-carbon/#comment-788541

      • Richard Tol: Cheap and reliable energy is a private, rather than a social benefit,

        Is that true? Are there no general benefits beyond those received by the individuals who pay the bills?

      • Cheap and reliable energy is a private, rather than a social benefit, […]

        Is it really? Certainly, my access to cheap and reliable energy is a private benefit to me. And UPS and FedEx’s access is a private benefit to them. But wait! I benefit also from lower shipping costs, and an ability to buy stuff over the internet rather than driving to a local store. I can get lower prices and much more selection.

        Of course, that’s also a private benefit to me. And a private benefit to every customer who takes advantage of those lower energy costs. And a benefit to every business that creates, distributes, or sells stuff they couldn’t sell without the internet.

        And a benefit to everybody who even considers joining the internet buying public.

        Where do you draw the line between “private benefit” and “social benefit”? My answer: there is no line! There’s no such thing as “social benefit”!

        Just private benefits, variously aggregated.

      • “Cheap and reliable energy is a private, rather than a social benefit, and this is indeed best approximated by looking at the market value of the carbon embedded in energy.”

        Interesting, there is a remarkable correlation between food and energy prices that has strengthened with biofuel incentives, so I guess affordable food is one of those private deals as well.

      • AK: Where do you draw the line between “private benefit” and “social benefit”? My answer: there is no line! There’s no such thing as “social benefit”!

        I was thinking of ways that people benefit from low energy prices, even though they are exempt from paying the bills, even indirectly. For example, people who receive subsidized medical care (including vaccines), subsidized housing, subsidized education, subsidized fuel, subsidized travel, subsidized disaster recovery (Haiti, Western Sumatra), subsidized legal assistance, subsidized food, etc. If the energy costs paid by everyone else were higher, then there would be less of this kind of wealth to share with them. “External” benefits like this run in parallel with “external” costs.

      • @matthewrmarler…

        I was thinking of ways that people benefit from low energy prices, even though they are exempt from paying the bills, even indirectly.

        Yes, well, I have great difficulty figuring out how to communicate my ideas in this regard. Basically, the proper symbols don’t exist, except perhaps in mathematics that are somewhat beyond me. And if I did understand the math well enough to use them, almost nobody here would understand.

        Coming from another perspective, the (any) economy is a non-zero-sum game. It is also a highly complex network of actors, many of them passing along the effects of some of their relationships to others.

        As I see, it, cheap, reliable energy is a sort of “force multipler”, or perhaps a “lubricant” that makes positive feedback loops work more efficiently, allowing them to increase overall value more rapidly.

        This is why I’m opposed to trying to make energy more expensive to pay for the supposed externalities. Things that impact the price (or reliability) of energy have their effect multiplied WRT the economy.

        Better to find other ways to pay for the technology change, rather than just making energy so expensive people are willing to invest in technology to avoid the pain.

        Frankly, I don’t believe it would be that expensive, done right. IMO the apparent high cost is due to the fact that nobody really wants to sit down and figure out how to do it cheaply.

      • AK:
        Cheap energy is more efficient. It improves transportation in most cases. It lowers product costs. Growth is problably related to efficiency and non-efficiency is most likely related to negative growth or less growth.

      • What about health care? Education? Defence? Social security? Environmental protection? Food security? Infrastructure? All relying to a large extent on plentiful cheap energy.

      • It must be all true, Steven. No one can ever say that to you.

    • Steven Mosher

      With all that benefit we can of course support a higher cost.
      That’s the point. ExxonMobil is getting a huge benefit while in future others will pay the cost.
      Pointing out the huge benefit just underscores the argument for calculating a true cost.

      • The reason you don’t want to discuss the picture Vostok ice paints is because you don’t like the obvious answer. I will now leave it to you to count the true cost.

      • Not against calculating true costs of externalities. That way we know when to stop reducing them (when cost of further reduction exceeds benefit of further reduction- like the proposed new mercury rules SCOTUS just struck down). With uncertainties. But the SCC game is rigged. NAS just points out the tip of the iceberg.
        Exxon’s market cap does not benefit Exxon. It benefits Exxon’s shareholders, which means much of the general population’s retirement benefits via all the funds the warmunists want to divest Exxon. Calpers, for example. In that sense it is a social, not purely private, benefit.
        And, if SBC is $100 and ‘true’ SCC is $50 (lower ECS, expected value given uncertainty, …) then we should all just go home and relax. SCC is politicized like just about everything else concerning CAGW. NAS simply gently reminds of that.

      • Mosh

        You are being US centric. Power in many other parts of the world is much more expensive than in the US. Would you seriously want to swap power and vehicle bills for a few years with me?

        Tonyb

      • michaelspj

        Like maybe, negative, with low sensitivity as in McKitrick et al today? Mosh–would you then subsidize ExxonMobil? It’s your logic, not mine.

      • Steven Mosher

        tonyb

        wrong.
        try again to get my point

      • …while in future others will pay the cost.

        They also will owe their very existence to the “benefits” we are generating today. Technologies, infrastructures, food supplies, and even abstract knowledge will be passed along to future generations. Perhaps that will be sufficient payment on our “debt” to them for warming the planet, even without a carbon tax (or similar) cost-side adjustment being imposed today.

        But you cannot know the answer without at least attempting to calculate the benefits.

      • Mosh

        Perhaps yo need to explain your point better? Exxon is not a private individual and therefore it does not ‘benefit’. As Rud says;

        ‘Exxon’s market cap does not benefit Exxon. It benefits Exxon’s shareholders, which means much of the general population’s retirement benefits via all the funds the warmunists want to divest Exxon. Calpers, for example. In that sense it is a social, not purely private, benefit.’

        Shell just recently bought British Gas. I had shares in BG and they have now been converted to Shell . I get a dividend. Also substantial amounts of two pensions I will get depend on the performance of various oil companies. They all pay lots of tax.

        Higher Fuel costs drains my resources and makes companies less competitive as we have found in the UK. You appear to want to go down that higher route cost in the belief that it is Exxon rather than general society that benefits.

        If that is not what you meant please explain what you DO mean.

        tonyb

      • Steven Mosher

        its simple tony. however you choose to calculate the benefit
        however you choose to distribute the benefit,
        the benefit is immaterial to the cost

        you guys are trapped in a different argument.

        Smart skeptics just calculate a lower social cost of carbon.

      • Peter Lang

        Mosher,

        I think you don’t understand basic economics. Try the first chapter here for a start: Economics in One Lesson http://steshaw.org/economics-in-one-lesson/contents.html

        Rud Istvan said (correctly in my opinion)

        Not against calculating true costs of externalities. That way we know when to stop reducing them (when cost of further reduction exceeds benefit of further reduction …

        Well, even using inputs that are on the high damages side of the central estimates, GHG abatement is not justified on rational basis. This explains why: http://anglejournal.com/article/2015-11-why-carbon-pricing-will-not-succeed/

        This figure shows the abatement costs would exceed the hypothesized benefits this century.

        The reality would be much worse than the figure shows. When you direct money to be spent on projects that have negative cost benefit (such as GHG emissions abatement) or have less net benefit that alternatives, you slow the rate that human wellbeing improves.

      • Steven Mosher,

        It’s a pity that you can’t actually define the cost in any useful way.

        You still haven’t found your missing clue, it seems.

        Cheers.

      • “ExxonMobil is getting a huge benefit while in future others will pay the cost.”

        Much of the world has nationalized its oil production and distribution. Does that suddenly make that “huge benefit” a “social benefit”? Exxon is only the vendor that converts an underground resource to the stuff in your gas tank. Even if you forced them to do it for free, it doesn’t change the fact that you get a benefit from transportation fuel that you must pay a cost for.
        And it doesn’t change the fact that you must defend your desire to jack up the price of that benefit for a bad SWAG of a cost. Good luck.

      • Steven Mosher

        Peter.
        When calculating the social cost u don’t consider the benefits. Period. It you don’t like those economics consult a dictionary or ask Richard Tol .

        You guys always grab the wrong end of an argument.

      • Steven Mosher wrote, “When calculating the social cost u don’t consider the benefits. Period. It you don’t like those economics consult a dictionary or ask Richard Tol .”

        Earlier Richard Tol wrote, “Carbon dioxide fertilization is included in the estimates of the social cost of carbon, half-heartedly by two of the three models used by the IWG and explicitly by the third.” He also wrote above, “Impacts can be either negative and positive.”

        As you are fond of saying, perhaps reading harder might come into play.

        Maybe if we add the term “net” in front of social cost of carbon it would make more sense.

      • “When calculating the social cost u don’t consider the benefits. Period. It you don’t like those economics consult a dictionary or ask Richard Tol .”

        I don’t think that is accurate. You don’t consider the private benefits, but you consider the external benefits.

        Social cost of carbon is poorly named. More accurately it should be called the net external cost of CO2 emissions.

      • Steven Mosher,

        You wrote –

        “You guys always grab the wrong end of an argument.”

        I see you’re still serving up your five cents worth of free advice. Not only do you apparently have little mastery of physics, you exhibit a similar level of knowledge in the field of economics.

        You still haven’t managed to define costs in any qualitative or quantitative way, let alone specify the population, society, or location where these costs are supposedly to be in evidence, at some unspecified time in the future.

        The US is not the world, nor is it homogenous – climatically, geologically or societally. A cost (however defined) to one person or group may be a benefit to another person or group.

        Nature will decide, I surmise. Not you. Not me. Not Richard Tol.

        Nature frequently makes fools of us all. Climatologists and economists seem especially favoured by Nature in this regard. A Google search for “dismal science” immediately brings a up a page full of references to economics.

        Would you assess climatology as being more useful or scientific than the dismal science? Or less?

        Keep at it, Steven Mosher. I’m sure you could get a paper on economics published, if you tried. You could add “economist” to your “scientist” appellation. Why not?

        Cheers.

      • Steven Mosher

        You gus still don’t get it.
        Grab the right end of the argument and win.
        Nic lewis knows how.
        Tol knows how.
        McKittrick too

      • Peter Lang

        Steven Mosher,

        Peter.
        When calculating the social cost u don’t consider the benefits. Period.

        What on Earth are you talking about? I responded to this comment you made:

        With all that benefit we can of course support a higher cost.
        That’s the point. ExxonMobil is getting a huge benefit while in future others will pay the cost.
        Pointing out the huge benefit just underscores the argument for calculating a true cost.

        Do you recall that bait and switch (i.e. “change the subject”) is Sign 4 of the 10 signs of intellectual dishonesty? https://judithcurry.com/2013/04/20/10-signs-of-intellectual-honesty/

      • The entire world benefits from the efforts of Exxon. We keep warm, we can travel, we can grow more food. Only an id0t would think only Exxon benefits from it’s activities. M0r0n.

    • ==> “The one sided cost of externalities perspective is obviously wrong; if fossil fuels had no benefits we would not be using them. ”

      “Skeptics” like to make facile arguments about the the positive externalities of fossil fuels, but they can’t calculate the ratio of positive to negative externalities, and so actually they actually have no idea whether the balance is positive.

      What would the cost of fossil fuels be if all of the positive and negative externalities were figured into the cost? “Skeptics” don’t know, yet they are quite sure that alternative energy resource pathways are more expensive than fossil fuels.

      It’s rather amusing.

      Consider the massive resources, economic and human, which have been “spent” on keeping oil flowing. Consider the massive resources dedicated to enabling private automobile transportation that is powered by fossile fuels. Consider the massive costs of traffic and congestion, that would be eliminated with alternative energy powered public transportation (which would have many ancillary benefits related to economic development).

      • “Consider the massive resources, economic and human, which have been “spent” on keeping oil flowing. Consider the massive resources dedicated to enabling private automobile transportation that is powered by fossile fuels. Consider the massive costs of traffic and congestion, that would be eliminated with alternative energy powered public transportation (which would have many ancillary benefits related to economic development).”

        Let’s consider flipping a switch and turning all the fossil fuel energy off.

      • Joshua, I take it you don’t own a car and always use public transportation.

      • Joshua

        Where would the energy come from to power the public transportation? I am by no means against appropriate renewables but they remain expensive and unreliable. In Britain, a world leader in renewables, we are now rapidly walking away from heavily subsidised and inappropriate solar and wind. Inappropriate? At our latitude solar is a waste of time and even the head of the wind industry admits we are not windy enough for onshore wind farms!

        Offshore farms may still go ahead but they are the most heavily subsidised of all forms of energy.

        So I repeat my question. Where is the power to come from?

        Tonyb

      • tonyb –

        ==> I am by no means against appropriate renewables but they remain expensive and unreliable.”

        Obviously, the cost is relative to other energy source pathways. I don’t think it’s valid to describe them as “expensive,” which necessarily implies relatively so, if you can’t interalize the external costs (and benefits). I don’t know what the cost of fossil fuels would be if the externalities were internallized, and I don’t know what the relative cost/benefit ratio would be in comparison to other sources, but I do know that there are massive negative externalities which are not internalized. And I know that many of the positive externalities could be realized with alternative energy sources.

        ==> In Britain, a world leader in renewables, we are now rapidly walking away from heavily subsidised and inappropriate solar and wind. Inappropriate?

        I don’t know. But if you haven’t internalized the then I don’t think you can make a determination. Thus, IMO, you should be including the component of risk assessment into your analysis.

        ==> At our latitude solar is a waste of time and even the head of the wind industry admits we are not windy enough for onshore wind farms!”

        Obviously, there are many factors which affect the cost/benefit analysis. I am not suggesting that any be ignored. Quite to the contrary. I am suggesting that any analysis grounded in ignoring hugely important cost (and benefits) are more than likely just a reflection of pre-conceived perceptions – which in turn, are likely grounded in ideological orientation more than clear analysis.

        ==> So I repeat my question. Where is the power to come from?

        It’s a good question, tony. I don’t have the answer. My point, however, is that I think that there are many who are over-confident that they do have the answer.

      • Tony –

        Check out Willis’ comment. He doesn’t know how to quantify the cost to benefit ratio, but he’s sure about the sign. Not an atypical opinion in these pages.

      • J. In your response to TonyB you do realize you use the same arguements warmunists used against skeptics? FUD and all that. Circular reasoning does not become you.
        PlanningEngineer and I have been endeavoring for years now to remove energy FUD by providing verifiable facts. Would sort of recommend SM’s admoniition. Read more. Grok. Then comment less. One of the few times I agree with SM.

      • Many have tried it both ways and the alternative energy resource pathways are more expensive than fossil fuels

      • PCT –

        ==> Many have tried it both ways and the alternative energy resource pathways are more expensive than fossil fuels.

        To make such a statement, then you must be able to provide a definitive cost/benefit analysis of (negative and positive) externalities.

        Do tell.

      • Let’s see,

        “What would the cost of fossil fuels be if all of the positive and negative externalities were figured into the cost? “Skeptics” don’t know”

        News flash Josh, when anyone starts talking about externalities they automatically entire the realm of speculation. That’s the fun thing about externalities. You just make it up as you go.

        Take for example all of your “massive” considerations – just pick and choose anything you want. No justification and certainly no clue as to what costs may actually be. The last one is a great example of why you are seen as such a putz here. How does replacing gasoline and diesel fueled transportation with alternate, non-fossil powered transportation impact traffic and congestion? Answer – it doesn’t. Unless perhaps you couple it with mandatory use of public transportation. I am looking forward to you making the argument for people giving up their cars.

        RE: “It’s rather amusing.”

        Well, they say simple things fascinate simple minds.

      • captdallas,

        Let’s consider flipping a switch and turning all the fossil fuel energy off.

        Ok, let’s. That would be stupidly catastrophic. Next.

  7. How about the benefits.
    “The SCC is intended to provide a comprehensive measure of the monetized value of the net damages from global climate change that results from an additional unit of CO2, including, but not limited to, changes in net agricultural productivity, energy use, human health effects, and property damages from increased flood risk.”
    All the discussions of the models and temperature hide that you could have the same extensive discussions on the benefits of some extra CO2, or the social costs it induces to limit CO2.
    I have not seen any reports or articles that show that reducing CO2 makes energy cheaper, and higher energy price has a social cost.

    The name SCC more or less expects that it is a cost, so all try to find the cost.

  8. Curious George

    To experience a low-carbon economy, try trekking in Nepal. Guest houses have only one heated room – a dining room, also serving as a living room for the family. Your bedroom will be at 3-10 degrees C. There is not enough yak dung to heat the whole house. You are too ashamed to ask for a hot water for washing; they can barely heat enough for tea or coffee.They are building small hydro power stations, but all materials have to be transported on a horseback, larger pieces have to be carried by porters.

    Is this where we are heading?

    • Steven Mosher

      No we are not headed there. ..mitigation alarmism is a really bad skeptical argument.

      • Dunno, SM. To paraphrase Ev Dirksen, former Illinois Senator:
        “A trillion here, a trillion there, pretty soon you are talking real money.”
        If SCC mitigation isn’t appropriate because TCR and ECS are lower than the already falsified and already proven incapable models (computational intractability, hence parameterizarion, hence attribution issue), then for sure we are already talking about the potential waste of real money. $100 billion per year, every year, to the Green Climate Fund per COP21? Would be real money except is only a Tuvalu/Vanuatu/… fantasy.

    • Right out of grad school I worked for a company that developed the market for underground mining vehicles. Nepal was one of the places our equipment was used. The loaders and haulers had to be designed for disassembly so they could be transported up to the mine site on the back of mules.

  9. This is wonderful news. Thank you for the blog post.

    Glad too see the move towards a better treatment of uncertainty, especially the recommendation on Monte Carlo simulations.

    Maybe eventually we move towards using an expected social welfare maximization approach. :)

  10. :( I had a typo. Too instead of to.

    • Re your handle. Rearrange Euler’s formula and you can bring in all five ‘magic’ numbers. e^(i pi) -1 = 0. Zero was the first and most difficult mathematical concept. Recommend Robert Kaplan’s erudite The Nothing That Is, A Natural History of Zero. From cunieform on. Terrific book.

      • Peter Lang

        Rud,

        O/T. Do you know of any authoritative analysis that provides estimates of the global average premature deaths/TWh (or total global deaths per year) for coal, gas and nuclear.

        I already have:

        Wang (2012) http://nextbigfuture.com/2012/06/deaths-by-energy-source-in-forbes.html (This is the only source I have found that gives deaths/TWh by electricity generation technology but it is not peer reviewed and I am concerned that the figures for coal, for example may be total deaths attributable to burning coal, not just those for electricity generation).

        WHO (2016) http://www.who.int/phe/health_topics/outdoorair/databases/en/ (but this does not give the deaths attributable to electricity generation, let alone to the different technologies)

        Markandya and Wilkinson (2007) http://dx.doi.org/10.1016/S0140-6736(07)61253-7 but the figures are not global averages; they are mostly for Europe

        Hirschberg, et al. (2016) http://www.sciencedirect.com/science/article/pii/S095183201500277X
        But this is in YOLL not premature deaths.

        Can you help me on this?

      • PL, let me do more research. Most of the stuff I have read is silly bad. But have not researched your issue in detail. An interesting questiion. I will get back here, or via Judith. Just need some time.

      • Peter Lang

        Rud,

        Thank you.

        For background, I am writing a paper and I need to estimate the counterfactual of deaths that could have been avoided if nuclear progress had not been disrupted from the late 1960’s. Therefore, I need a factor for premature deaths/TWh from coal, gas and nuclear.

        I would also like to refer to an authoritative source that states the estimated number of fatalities globally per year attributed to coal fired electricity generation. At the moment I say in the Introduction: “ I estimate coal-fired electricity generation causes around 0.5 million deaths globally per year. Nuclear power produces comparatively little air or water pollution. Substituting nuclear power for coal for electricity generation could save most of the deaths attributable to coal-fired electricity generation.

        I would like to replace my estimate with a number cited from an authoritative source.

        My estimate of 0.5 million is calculated by: total world electricity generation by coal in 2015 multiplied by global average deaths per TWh for coal fired electricity generation.

        8725.6 TWh http://www.tsp-data-portal.org/Historical-Electricity-Generation-Statistics#tspQvChart (attributed to World Bank)
        60 deaths/TWh (Wang, 2012. http://nextbigfuture.com/2012/06/deaths-by-energy-source-in-forbes.html
        = 523,526 deaths from coal-fired electricity generation in 2015.

      • Peter Lang:

        This all came up on a previous post but I am still unclear whether you are simply updating Kharecha and Hansen (2013) or don’t want to use their numbers?
        http://pubs.giss.nasa.gov/docs/2013/2013_Kharecha_kh05000e.pdf

      • opulso,

        If you’d read my comments or Markandya and Wilkinson, 2007 (which Kharecha and Hansen used for theory source) I think you’d understand their figures are not global averages. You’ve made no constructive contribution so I didn’t bother answering to your comments.

      • Peter Lang:

        Thanks for the response. To be clear, my understanding of K&H (2013) is that they used regional/nationally derived assumptions on deaths per TWh for coal, methane and nuclear generation. They used these inputs to produce global estimates and it was peer reviewed. Hansen’s entire purpose was to produce a justifiable estimate for the number of (premature) deaths that could be avoided if the world switched to 100% nuclear.

        You are wise to crowd-source the research on this. My question was simply why Hansen’s process wasn’t good enough since even Steven Mosher has pointed out the lack of particulate data for most countries. Hansen used assumptions and a calculator to produce a global number and I strongly suspect that is what you will have to do as well.

        Side note: Of greater importance to me was the fact that the august Dr. Hansen challenged the consensus position on “linear no-threshold” theory for low level radiation.

      • Peter Lang

        opulso, you’ve been making a lot of assumptions and giving irrelevant advice when you haven’t a clue what I am doing or what information I need. Unless you’ve got something to offer that is relevant to answering my question, please desist.

      • Peter Lang:

        Apparently I upset you with my initial question on the energy thread. You said:

        Can anyone tell me an authoritative reference for the number of premature deaths (from all causes) from electricity generated by coal, gas and nuclear? I need the total deaths per year caused b each technology for the world from one authoritative source. I also need the global average deaths per TWh for each technology.

        To which I responded with what I consider to be an important question:

        Would that be net of the billions of lives lengthened by these technologies?

        You answered in the negative. The remainder of my comments were in response to Triumph, the Insult Comic Dog who immediately belittled the very idea that benefits needed to be considered. He even claimed that your question implied “…GIVEN we all appreciate the benefits…” which is both imprecise and wrong.

        The way Mosher (and possibly you) focuses on hidden costs to the exclusion of positive feedback benefits is precisely the problem we confront in dealing with regulatory authorities. You are free to disagree.

    • Maybe because of the SCC that you feel this morning, comes from the distilled spirits that we were sold last night?

    • Don’t worry -1=e^iπ it is better than mistakenly using ‘to’ instead of ‘too’ which breaks my universal translation engine and causes me to rescan the sentence and there are people on here who have a degree in English and don’t know the difference between your and you’re (SM) and then there is ristvan who frequently types an ‘n’ or or ‘m’ in place of a space. I think that ristvan might be the pen name of Uma Thurman

      Own up ristvan we need to know these things ;)

  11. e^(i pi) -1 = -2 not 0.

    • Curious George

      Touche!

    • Yeah. Should have been a + 1 on the left side of the permutation. I don’t win them all precisely, but perhaps you got the meaning. Taking a minus 1 to the orher side requires adding plus one to both sides. Yup. My bad.

      • Boy, the peer review here is brutal–and correct.

      • ristvan,

        I salute you! You are obviously not a fanatical Warmist.

        A fanatical Warmist would rather die than admit a minor error. The Warmist tactics of deny, divert and confuse, backed up by links to irrelevant papers published in vanity journals, would be brought into play. Appeals to authority, claims of Nobel Laureateship – anything to avoid saying “I was wrong.”

        I think sometimes that a central tenet of the scientific philosophy is the ability to admit error. As J M Keynes said “When the facts change, I change my mind. What do you do, sir?”

        Cheers.

      • Mike Flynn on June 7, 2016 at 8:10 pm
        +1

  12. The social cost of carbon is defined above as the “damage caused by a 1-metric ton increase in carbon dioxide (CO2) emissions into the atmosphere in that year”. It considers no economic, health, standard of living or other benefit. It appears to have us believe that civilization would have advanced to its present state without “carbon”. From when? two millenia ago? The posters who say there are benefits seem to be weak.

    If it were a true calculation, then you would have to include the impact of “carbon” on world and national economies, quality of life, life expectancy, personal income, medical, industrial and scientific advances. Since it does not the SCC is nothing but a political ploy wrapped in pseudo science.

  13. Willis Eschenbach

    I have to protest against both the term and the analysis of the “social cost of carbon”. That is a dishonest attempt to ignore the other half of a cost/benefit analysis. If we put a true value on the social benefit of carbon, it would eclipse all possible costs. Heck, just the benefit from the additional vegetables and fruits due to the greening effect of CO2 alone is trillions of dollars per year, and that doesn’t begin to touch the direct benefits of fossil fuels.

    If an analysis is only half of a cost/benefit analysis, it is a slanted analysis. You can’t just look at one side of the equation.

    w.

  14. Peter Lang

    Judith,

    My chief concern was that I thought the US IWG used indefensible values of climate sensitivity as input into the integrated assessment models.

    I suggest there are other more important inputs that are much less defensible than climate sensitivity, for example:

    1. It seems we have a very poor understanding of the damage function. The scientists need to explain convincingly whether warming and increasing CO2 concentrations are doing more harm or more good? We know cold is bad. But is warming good or bad. Quantify the net benefits-damages per ppm of CO2 concentration and per degree of global temperature change (up or down). Explain why the current hypothesies show an inflection (from rising temperatures being beneficial to being damaging) right when we happen to be inhabiting the planet.

    2. pdfs for: time to start of the next abrupt change, sign of change (+ or -), rate and duration of change, total magnitude of change

    3. What is the most likely emissions rate and total emissions that could be emitted by future dates (and uncertainties).

  15. Geoff Sherrington

    There are obvious dangers in making regulations that depend on unquantified factors.
    The social cost of regulation could be greater than the social cost of carbon. But both are stupid concepts invented by dreamers to redistribute money flows to their benefit.
    Geoff

    • The social cost of regulation could be greater than the social cost of carbon.

      Even if you ignore the huge costs of carbon regulations, they are likely to be ineffective and produce no measurable reduction in warming.

      I compare most carbon control schemes to the TSA’s expensive “security theater” at airports. These regulations seem mostly intended to make (some of) us feel good and the huge expense is just evidence that we are very, very serious about it.

  16. I believe that burning a hydrocarbon produces, at a minimum H2O and CO2.

    H2O is supposedly responsible for up to 90% of the total greenhouse effect.

    Dihydrogen oxide is a deadly poison (deaths have been recorded from water poisoning), and has resulted in death after being allowed to come into contact with sodium. Even trace amounts can lead to great damage in certain equipment. Of course, deaths from drowning in the stuff, flood damage and the rest, are well documented.

    On the other hand, without H2O, we’d all be dead.

    And so it is with CO2.

    Without CO2, we’d all be dead.

    People who have a fixation about filthy black coal, (James “Death Trains” Hansen, for example), and other natural organic hydrocarbons such as oil and gas, seem to hate the benefits that burning stuff brings.

    Heating, air conditioning, electricity, potable water, transportation – all come at a cost. Anybody who doesn’t think the cost is low enough can push off and live in Tierra del Fuego, or high in the Andes. If that’s a bit cold, try the Libyan desert, or even the Gobi. It’s warmer there – at least during the day.

    Why tax carbon!?Just cut out the middleman, and tax living humans. After all, they burn stuff, directly or indirectly, and even exhale CO2. If you tax them enough, they won’t be able to afford to buy anything to burn, or anything that requires stuff to be burnt to produce it – like food, or water from a tap.

    The supposed damage from burning stuff is supposed to be warmth. I hate to point this out, but warmth is what you get when you burn stuff. When there are seven billion people burning stuff, either directly or indirectly (building wind powered turbines, for example), there is a lot of warmth.

    Thermometers react to this, and show it as increasing temperatures when more stuff is burnt. People of course use other means to produce warmth, like nuclear processes. They produce lots and lots of warmth, both directly, and indirectly if electricity is consumed.

    A spot of global warmth is good. People seem to agree. If you live in a cold climate, you tend to want to cause an awful lot of stuff to be burnt so you can go where it’s warmer – for a while. Then you cause even more stuff to be burnt, so you can go back home.

    Ah, the rich tapestry of life! Miserable buggers want to tax the source of the staff of life, because the rest of us enjoy the results.

    Cheers.

  17. True cost. There’s a utility, a value to a product’s cost. A signal, information. It is one of the most amazing creators of wealth, good information contained in a price. Externalities should be paid for. It is part of the morality of my being a libertarian. It also respects property rights. I don’t want lead or mercury on my land, but it you give me enough money I’ll allow it. What interferes with ‘True cost’? Taxes and regulation. If taxes are low, which they are and regulation is not onerous and it might not be, and regulation is fair across different energy sectors, there is a bit of drag, but something close to a True cost is there, capitalism will work, and there will be wealth. Now we make the jump to looking at the SCC. What about price? The thing that served us so well and made us so well off, what about that? We will not do that so much. Cost, the one we’ve used for a long time, is discounted. Information in a price, is discounted. Signals are discounted. We are turning away from prices to look at SCC. We are trying a new path.

  18. My recommendation is that two separate distributions be used: one from climate models, and the other from the most reliable of the estimates using historical observations.

    If they are different, throw away the climate model junk.

  19. We build a steel bridge with cement foundations emitting Carbon. It will last 75 years. The future will have CO2 and a bridge. We build a school, lots of cement blocks. The future has smarter people, a school, and CO2. Does construction emit a lot of CO2? If we build buildings, the future has CO2 and real estate to levy property taxes on. We use gasoline to deliver stuff from Amazon. Amazon makes money. They pay taxes. If CO2 helps to create profits, we get to tax them. I start a company that delivers by bicycle. It flops. Very little CO2, nothing to tax.

  20. Here’s another recent estimate, not $37 per tonne, but $220 when you account for reduced growth rates in poor economies.
    https://news.stanford.edu/2015/01/12/emissions-social-costs-011215/
    Just another data point.

    • “If poor countries become less vulnerable to climate change as they become richer, then delaying some emissions reductions until they are more fully developed may in fact be the best policy,” Diaz said. “Our model shows that this is a major uncertainty in mitigation policy, and one not explored much in previous work.”

      Hmmm, delaying some emission reductions could mean that affordable means of reducing emissions could come of age which would change pretty much everything.

      • I don’t think poor countries should be forced to reduce emissions immediately, which is completely unfair, nor are they being asked to by the IPCC. I think the burden to reduce is on those countries that are above the global average, not already below. For most poorer countries, adaptation would be their primary cost.

      • Hmmm, if the burden is on those countries that produce the most carbon, then they might need to stop outsourcing carbon pollution to offset the carbon tax. Works for me.

        http://umdrightnow.umd.edu/news/outsourcing-manufacturing-china-results-high-co2-emissions
        Let’s see and super critical coal fired power plant without carbon sequestration should more than offset low efficiency third world manufacturing and highly polluting shipping of goods. Could even increase employment and improve GDP.

      • A post on outsourcing carbon emissions (along with other pollutants, like particulates), pro and con, would be pretty interesting. Did CaptDallas just volunteer?

    • I’ll have to read ‘Temperature Shocks and Economic Growth: Evidence from the Last Half Century’ when I have time and access to the paywall to see how strong the empirical basis for reduced growth rates is. If its anything like Burke et al. 2015, then it might have flaws, such as not allowing for adaptation time to changing climatic conditions.

      Also, it seems lopsided to include the possibility of higher temperatures affecting long term growth rates but not the possibility of higher energy prices affecting long term growth rates.

      I’ll be honest though, the whole approach to the 2 C target seems immensely dogmatic. Some arbitrary target that was selected over 20 years ago based on maximum global temperatures over the Pleistocene because some German scientists thought politicians were too stupid to understand anything more complex somehow happens to be the correct policy response. This despite all the research over the past 2 decades. It couldn’t be like the results of IAMs, which suggest that following a path where global temperatures peace 3-4C above preindustrial temperatures sometime mid-next century could possibly be optimal… Nah, has to be 2 C.

      • In the Eocene a warming event of 5 degrees over a much longer timescale had a very adverse impact on the global ecosystem. On what basis do you conclude that 3-4 degrees is “optimal”?

      • @Anthony Purcell – While I don’t think the DICE model is perfect, it’s a good start: http://www.econ.yale.edu/~nordhaus/homepage/documents/DICE_Manual_103113r2.pdf

      • Darn typos, I meant ‘peak 3-4C’ not ‘peace 3-4 C’.

      • -1=e^iπ,

        From your link –

        “The economist John Maynard Keynes was criticized for changing his views on monetary policy during the Great Depression. His response is reported to be, “When the facts change, I change my mind. Pray, sir, what do you do?” “

        Exactly.

        Cheers.

      • “… 2 C target seems immensely dogmatic…”

        Yep. The whole CAGW narrative has become scripture. The people need a scripture, and when the old ones are tossed a replacement must be found. It has been found.

      • Peter Lang

        Anthony Purcell,

        Can you tell me what happened to the amount of carbon tied up in the biosphere during the PETM. Did it increase or decrease, and by how much. And how much greater or less was the amount of carbon tied up in the biosphere compared with now (we are currently in an unusually cold period; perhaps the coldest since multi-cell animal life began to thrive.).

      • Peter,

        a) I am unaware of any significant change in biomass. I’m also uncertain how long term changes in biomass can be determined. Many species went extinct but other classes of animals tended to flourish – presumably because they were better suited to the new temperature regime.

        b) Yes, this is an unusually cold phase of Earth’s history. Largely because CO2 concentrations are low. It is also the only phase in which agriculture has been practiced and in which billions of people are dependent on efficient food harvesting.

        c) Grasses did not exist in the Cretaceous. Most of our food crops are grasses, most of our food animals eat grasses. It is unclear how well agriculture can cope with a rapid transition to warm high-CO2 conditions.

        d) The PETM warming was a hundred times slower than that currently observed and still caused an extinction event. That was in an ecosystem where habitats were not isolated, stressed and reduced by human activity. If the current warming were to initiate an extinction event (some would argue that it already has) it would be vastly more severe.

        e) One of Australia’s pre-eminent scientists, a pioneer of environmental science, suggested that due to climate change and overpopulation human extinction by 2100 was inevitable. That used to scare me. Now I would be grateful.

      • Peter Lang

        Anthony Purcell,

        a) I am unaware of any significant change in biomass.

        In that case you should have stated that your assertion in the comment I responded to is your belief, not a supportable fact.

        b) Yes, this is an unusually cold phase of Earth’s history. Largely because CO2 concentrations are low.

        The second sentence is another assertion based on your beliefs, not fact. Plate tectonics and the joining of North and South America is arguably the main cause of the current ice age. CO2 is arguably a follower, not the primary cause.

        c) Grasses did not exist in the Cretaceous. Most of our food crops are grasses, most of our food animals eat grasses.

        Here’s an alternative perspective. Animals did very well in the arm periods. If we warm and have higher CO2 concentrations there’ll be more food; we’ll adapt. The planet is in a very cold period and is not going to get out of it in millions of years. If not for our GHG emissions we’d be on the downhill slope to the next glaciation and the next abrupt climate change would probably be to cooling. Humans have, unknowingly, has practiced excellent risk mitigation.

        d) The PETM warming was a hundred times slower than that currently observed and still caused an extinction event.

        Much to disagree with here: https://judithcurry.com/2016/06/07/assessment-of-approaches-to-updating-the-social-cost-of-carbon/#comment-788674

        You don’t know what the rates of change were over time intervals of decades and centuries. You do not have the records. Your statement is disingenuous. It is wrong to compare the average rate of the PETM over 10,000 years with the rates over decades and centuries.

        Yes, there were extinction events. But many more extinction events in cold times.

        Give up the scaremongering. It does your cause far more harm than good.

        Can you tell me the damage function? (see my comment to Mosher here:

      • Peter Lang

        CORRECTION:

        I posted this link in the wrong place. It should have been at the end of the thread, not where I posted it.

      • Just because the 2C target has no scientific basis doesn’t mean we shouldn’t spend $100 trillion on it.

      • One of the large cost terms is likely related to sea level, which at 3-4 C will be rising fairly rapidly beyond a meter by 2100. Others would be related to crop yields, health impacts, water resources, energy needs, and the economic impacts of more extreme weather. 2 C would be on the up-ramp of these costs.

      • Peter,

        a) You’re suggesting that in some sense a mass extinction event is not an adverse effect?

        b) The second sentence is experimentally verified and entirely consistent with physics as it is currently understood. Your assertion to the contrary defies thousands of publications by eminent and very capable specialists.

        c) You are incorrect. We can easily demonstrate from the record that the PETM warming did not take place on time scales of decades. If climate variability were that large the proxy record would have immense high frequency power – it does not.

        d) As temperatures and human populations rise water requirements will increase significantly. Competition for water will become more intense and will militarise.

        It is no coincidence that Al Shabaab and Boko Haram strongholds are focused on exactly the regions of Africa that have experienced intense drought and desertification over the past decades.

        As more resources are dedicated to military conflict agricultural activities will decline. It is not possible to farm in a battlefield. The affected populations will resort to unsustainable practice and further ecological degradation will occur, intensifying and spreading the problem.

        Maybe humans will not become extinct, but the blithe “we will adapt” hand-waving ignores the fundamental reality of global food security. The whole point of the current debate is to avoid catastrophe, not wait until it happens and then say “yeah, we saw that coming”.

        You want me to quantify all this? I can’t, not my field of expertise. If it’s yours I suggest you do the modelling and quantify the odds of this sequence of events not happening. As you do, bear in mind that we are already seeing the thin end of the wedge. These are not hypotheticals any longer.

      • Peter Lang

        Anthony Purcell,

        No point discussing your religious beliefs, sorry.

        Jim D,

        One of the large cost terms is likely related to sea level,

        No it’s not. It’s a trivial cost. If you think it’s large state the numbers – i.e. the discounted cost of a rise of say 0.5 m and 1 m over the rest of the century and compare that cost with cumulative global GDP over the same period. Explain your numbers and your basis of estimate.

      • There are studies and it is not trivial at all. It amplifies coastal damage from storms at a nonlinear rate with sea-level rise.
        http://www.theguardian.com/environment/climate-consensus-97-per-cent/2016/mar/02/climate-scientists-worry-about-the-costs-of-sea-level-rise

      • Peter Lang,

        Dismissing a long established and observationally robust field of scientific inquiry as “religion” is mendacious, myopic and ignorant.

      • Anthony Purcell,

        I did not dismiss a a long established and observationally robust field of scientific inquiry as “religion”. I dismissed your comments for being statements that demonstrate your beliefs are religious like. From your comments I can see there is no point discussing them any further with you. It would be a waste of time.

      • Your suggestion is false. I have dedicated significant time and energy to reading and understanding the relevant literature and observational data-sets. While you simply dismiss them.

        The influence of CO2 on global and regional climate is theoretically predicted and confirmed through direct observational evidence obtained in laboratory and field experiments over the past 200 years. To describe this as a “belief” is patently ridiculous.

      • @ Jim D – “One of the large cost terms is likely related to sea level, which at 3-4 C will be rising fairly rapidly beyond a meter by 2100. Others would be related to crop yields, health impacts, water resources, energy needs, and the economic impacts of more extreme weather. 2 C would be on the up-ramp of these costs.”

        I’ve looked various quantification of the external effects of climate change. Sea level rise is very small compared to the effects of CO2 fertilization and productivity changes due to changing temperature/rainfall. The external cost due to sea level rise is like less than $1.

        Furthermore, your claim that 3-4C will get you beyond a meter of sea level rise by 2100 is well outside the mainstream scientific view. The IPCC’s position is that sea level rise is going to be ~0.5 +/- 0.25 m under a large diversity of emission scenarios. 3-4 C by 2120 is a medium emission scenario, so you are looking at 0.5 m sea level rise.

        Really, the primary economic justification for mitigation is the productivity effect, which at the moment does have somewhat of a weak empirical basis.

        @ Antony

        “It is no coincidence that Al Shabaab and Boko Haram strongholds are focused on exactly the regions of Africa that have experienced intense drought and desertification over the past decades.”

        Isn’t subsaharen africa supposed to become wetter due to climate change, not to mention is one of the regions that benefits most from CO2 fertilization. It’s not like Saudi Arabia funding Wahhabism across the world could have anything to do with it…

      • Militarist ideologies exist precisely to justify aggressive acquisition of other peoples’ resources. They are not necessarily appealing to a comfortable, satisfied populace. You do not observe similar levels of religious violence in Indonesia for example. Any group trying to forment Islamic extremism will find it much easier with a starving impoverished population whose children are dying of malnutrition.

        What do you mean by “supposed to”? According to whom? I certainly made no assertion or implication to that effect.

      • Peter Lang

        Anthony Purcell,

        You’ve made many really ignorant comments, including this:

        d) The PETM warming was a hundred times slower than that currently observed and still caused an extinction event.

        So, yes, I’ve dismissed you as a waste of time. Find someone else to try to sell you propaganda too. I don’t care how much material you’ve read. It depends what it is and what you’ve done to challenge what you read (as scientists are supposed to do). Waste you time elsewhere, I’ve dismissed you as having anything relevant to offer.

      • The influence of CO2 on global and regional climate is theoretically predicted and confirmed through direct observational evidence obtained in laboratory and field experiments over the past 200 years. To describe this as a “belief” is patently ridiculous.

        The same could have been said for textbook “geology” in the 1950’s.

        •       The science of a century ago may have been justified at the time, but is known to be obsolete today.

        •       The IPCC “consensus” paradigm is based on that obsolete “science”.

        •       The IPCC “science” doesn’t really predict disaster. It just, at best suggests a chance of it.

        •       The “science” behind the certainty of climate catastrophe is on a par with the “science” of “Intelligent Design”.

        •       The “climate catastrophe” meme is an apocalyptic religion solidly in the long tradition reaching back to 1st Cenury (C.E.) Christianity (e.g. Mark 13, copied in Matthew 24). (They, in turn, may have been based on earlier traditions such as Daniel/Maccabean Wars.)

        If you were really concerned about averting disaster, perhaps you’d be yelling about creating ways to find and deal with dinosaur-killing asteroids rather than excuses to shut down the Industrial Revolution.

      • Peter Lang,

        CO2 is arguably a follower, not the primary cause.

        Over the past 800,000 years or so, that is largely not in dispute. All else being equal, atmospheric CO2 concentration is largely a function of ocean temperature. Once in the atmosphere, CO2’s radiative properties become operative. Thinking about CO2 as one and only one parameter may lead to wrong conclusions about causality.

        You don’t know what the rates of change were over time intervals of decades and centuries. You do not have the records. Your statement is disingenuous. It is wrong to compare the average rate of the PETM over 10,000 years with the rates over decades and centuries.

        It would be disingenuous to argue that the probability of high centennial-scale rates of change during the PETM was lower than during the intervals surrounding it.

        Yes, there were extinction events. But many more extinction events in cold times.

        That would be more relevant if a -5 °C change were expected by 2100. As it is, you’ve made an excellent argument for temperature stability here, because extinction events are all associated with distinctly rapid change to multiple environmental parameters, temperature being a common one.

        Give up the scaremongering. It does your cause far more harm than good.

        One wonders how it would be possible to caution against potential future hazards and not be indicted for saying scary things. Issue trigger warnings perhaps?

      • brabdonrgates,

        Point 1: The fact we are in an extremely cold phase, perhaps the coldest ever, together with the fact that we can’t get out of it for millions of years (until North and South America separate) and together with the fact life thrives when the planet is warmer and struggles when colder, suggests the probability of catastrophe or dangerous consequences from GHG emissions is negligible.

        Point 2: life thrives during rapid warming events and struggles during cooling events (at temperatures we could reach this century, not PETM temperatures).

        Point 3. PETM started at a near record warm period in geologic time. There is effectively impossible to get anywhere near those temperatures again in millions, or more realistically tens of millions, of years. Therefore PETM is irrelevant as an indication of what could happen this century.

        Point 4. I don’t understand your argument that seems to be saying that it is valid to compare average global gtemperatures changes over decades with average changes over 10,000 years.

        Point 5. The climate seems to be much more volatile when there is ice at the poles (i.e. now) than when there is no ice at the poles.

        Look at Figure 15.21 here http://eprints.maynoothuniversity.ie/1983/1/McCarron.pdf . It shows the climate in Ireland (also Iceland and Greenland) warmed from near glacial temperatures to near current temperatures in 7 years 14,500 years ago and in 9 years 11,500 years ago. It also shows the temperature has been more stable since the ice sheets retreated. Text and other figures show that life thrived during the warming periods. [this figure is not about average global change, but is relevant because life lives locally and responds to local changes, so it demonstrates the effect of warming and cooling, especially of abrupt climate changes)

        Point 6. McKitrick’s paper shows probability of SCC = $0 is around 50% or negative for realistic discount rates for the world over the long term. that seems to tell us our GHG emissions may doing more harm than good.

        IN SUMMARY: We are in an unusually cold period (geologic time scale) and there is negligible chance of catastrophe or dangerous consequences of warming.

      • Okay, I read ‘Temperature Shocks and Economic Growth: Evidence from the Last Half Century’ and there are a few issues with it.

        1. The first, is that they only have linear temperature terms for how temperature affects the level of economic output and the growth rate. Unless you think that the optimal temperature for economic output and growth rate is not somewhere between -1.5 C and 28.5 C, then this does not make economic sense. At the very least, they should include quadratic terms. They do mention in their robustness checks that “We have also conducted additional analysis of nonlinear effects of the average temperature variable, finding little evidence for such non-linearities.” But they don’t provide the results in the appendix. If they aren’t getting statistically significant results, it could be due to point #3 (see 3).

        2. They don’t allow for a linear time trend in the growth rate. Any long term trend in growth rate must necessarily be due to temperature in their model, they don’t allow for the possibility of something else to affect the long term growth rate (such as say the aging of the population, catching up to other countries economically, changing a government style, or technological change). Given that growth rates have gradually been slowing over time globally, their model will necessarily find that temperature increases necessarily reduce growth rates. This is especially bad given their period of observation (post 1950). Just look at the economic growth rates of countries like Japan or South Korea over this time. In the first part of the period they grew rapidly, then as they approached the same level of economic development as the west, their growth rates slowed down since they had less room to catch up. The model used will explain this effect as being due to a combination of temperature increases, random chance and nothing else.

        3. They don’t take autocorrelation into account. I’ve done enough time series regressions, especially with things like GDP per capita, to know that time series data will generally have significant autocorrelation. It would have been better to perform a Cochrane-Orcutt regression instead of a linear regression. This doesn’t really bias the results one way or another, but one of the main impacts is that it probably results in an overestimation of the error, which could have led to them finding non-linear temperature effects to not be statistically significant.

        I also found this comment amusing:
        “the upward trend in temperature has occurred globally with similar magnitude in both hot and cold countries. ”

        I guess polar amplification does not exist in their universe.

    • Their alternative formulation incorporated recent empirical findings suggesting that climate change could substantially slow economic growth rates, particularly in poor countries.

      Interesting. When it comes to “slowing economic growth rates” most people (AFAIK) would think first of the mitigation efforts. And so:

      The pair’s IAM also shows that developing countries may suffer the most from climate change effects. “If poor countries become less vulnerable to climate change as they become richer, then delaying some emissions reductions until they are more fully developed may in fact be the best policy,” Diaz said. “Our model shows that this is a major uncertainty in mitigation policy, and one not explored much in previous work.”

      They note two important caveats to their work, however. First, the DICE model’s representation of mitigation is limited. It doesn’t take into account, for example, the fact that clean technologies take time to develop and deploy.

      Second, while it explores the effects of temperature on economic growth, the model does not factor in the potential for mitigation efforts to also impact growth.

      “For these two reasons, the rapid, near-term mitigation level found in our study may not necessarily be economically optimal,” Diaz said. “But this does not change the overall result that if temperature affects economic growth rates, society could face much larger climate damages than previously thought, and this would justify more stringent mitigation policy.”

      Hmm… I wonder how air conditioningaffects economic growth rates”?

      • Yes, not rapid mitigation. Gradual is what the IPCC is proposing, perhaps too gradual, but certainly not rapid by any measure. That rapidity of change fear needs to be allayed. There is a middle ground between too slow to be effective and too rapid for the efficient technology to be developed.

      • Gradual is what the IPCC is proposing, perhaps too gradual, but certainly not rapid by any measure. That rapidity of change fear needs to be allayed.

        What you (and the IPCC, AFAIK) are missing is the typically exponential nature of technological growth/advance.

        Solar PV has been doubling its deployment (world-wide) every 30-36 months. At that rate, given that it’s already at around 1% of current electricity usage, in another 20 years it’ll be at 100%.

        IMO, with proper attention to Wright’s “Law”, the problem could be solved within 3-4 decades without any impact to energy prices or continual life-style improvement, especially in the “developing” world.

        There is a middle ground between too slow to be effective and too rapid for the efficient technology to be developed.

        A much wider “middle ground” than you seem to realize.

  21. Pingback: El “coste social” del CO2 es mucho menor, y podría ser negativo | PlazaMoyua.com

  22. Geoff Sherrington

    Above I mentioned the balance of whether the Social Cost of Regulation exceeds the Social Cost of Carbon.
    Some in Australia are going public this way.

  23. Geoff Sherrington

    Ooops, it goes on. Just the apology was meant for here, the first 3 mins. The rest is ABC TV routine guff.

  24. I emailed McKitrick but he may be too busy so I’m just throwing this out there to see if anybody knows what’s wrong the tables in the paper (maybe nothing).

    ‘I’ve taken a look at the new SCC paper and there’s something weird in tables 5 and 6. For a 5% interest rate using empirical ECS, FUND model, the cost in 2040 is still negative (-0.26). But checking table 6, it turns out the probability of a negative SCC under the same situation is given as 49.6%; in other words you would still expect a (marginally) positive SCC at 50% probabilities, assuming that’s what the ‘mean’ represents.

    Is this because the probability distribution in fact has different mean and median? Conceivably the mean could fall on -0.26 while the median at the same time fell just over zero. But this would be strange because if anything one would expect the mean to be higher than the median, just as happens with sensitivity distributions.’

    • Just to be clear, in the paper a positive SCC represents a net cost, so if the probability distribution of costs resembles that of climate sensitivity, conceivably the mean could fall above zero (cost) while the median fell below (benefit). But the reverse happening is implausible.

  25. Not sure it hasn’t been linked to already, but Reason had a critique of SCC and the IWG last year.

    http://reason.org/files/social_costs_of_regulating_carbon.pdf

  26. David Wojick

    Has anyone seen a simple graph of the SCC damages over the next 300 years? For one ton of emissions as well as total anthro emissions for one year?

    Not discounted or cumulative, just decade by decade, or in fifty year increments, or some such. My impression is that they grow steadily larger, reaching stupendous proportions toward the end, mostly due to sea level rise. (This is how the discount rate is defeated.) But I have never seen these fundamental figures actually laid out. Probably because they are absurd.

    Then too, the total undiscounted damages from a single ton of present emissions, accumulated over the next 300 years, might also be an amusing number.

  27. SCC would be moot if emissions were zero. It might make more sense to price carbon in terms of the expected costs of its replacements.

    • What do you mean by zero?

    • Your claim doesn’t make sense. Even if net emissions were zero, it would still make sense to tax CO2 emissions at the social cost of carbon dioxide emissions.

      • -1=e^iπ,

        Even if net emissions were zero, it would still make sense to tax CO2 emissions at the social cost of carbon dioxide emissions.

        Presumes we know, or will know, the “true” SCC. All we need know to hold net emissions to zero is the cost of reducing them and/or removing and sequestering them. We can start with an estimate based on, e.g., the LCOE of gas-fired vs. nuclear plants etc., and revise as we go. Nothing reduces the uncertainty of future risks so much as actually doing something to mitigate them.

      • Brandon, you claim doesn’t really debunk what I wrote. If there is a hypothetical scenario where net emissions are zero, it still makes sense to tax CO2 emissions at the rate equivalent to the social cost of carbon dioxide emissions. If this turns net zero emissions into net negative emissions then so be it.

        Holding net zero emissions isn’t necessarily optimal. It may be optimal to have net positive or net negative emissions.

      • -1=e^iπ,

        Brandon, you claim doesn’t really debunk what I wrote.

        Your response doesn’t address my challenge: your argument presumes that SCC is known or will be known.

        If there is a hypothetical scenario where net emissions are zero, it still makes sense to tax CO2 emissions at the rate equivalent to the social cost of carbon dioxide emissions. If this turns net zero emissions into net negative emissions then so be it.

        I think we can assume the overt intention of imposing a cost on carbon is to bring net emissions as close to zero as possible, as quickly as possible.

        Holding net zero emissions isn’t necessarily optimal.

        Indeed, but figuring out optimal is hard. Getting the entire planet to agree on optimal is harder. “Making” optimal happen is likely impossible.

        It may be optimal to have net positive or net negative emissions.

        Right. So it may not be optimal to discuss putting a price on emissions until we’ve figured that out. In the meantime, that should not prevent us from figuring out the cost of replacements since we’ve already begun actually implementing some of them.

      • “I think we can assume the overt intention of imposing a cost on carbon is to bring net emissions as close to zero as possible, as quickly as possible.”

        I completely disagree. The purpose of a pigouvian tax is to internalize the externality.

      • -1=e^iπ,

        The purpose of a pigouvian tax is to internalize the externality.

        You still have not addressed the …

        Measurement problem

        Arthur Pigou said: “It must be confessed, however, that we seldom know enough to decide in what fields and to what extent the State, on account of [the gaps between private and public costs] could interfere with individual choice.”[22] In other words, the economist’s blackboard “model” assumes knowledge we don’t possess – it’s a model with assumed “givens” which are in fact not given to anyone. Friedrich Hayek would argue that this is knowledge which could not be provided as a “given” by any “method” yet discovered, due to insuperable cognitive limits.[citation needed]

        William Baumol as well as Polodoo (2008) have argued that it is extraordinarily difficult to measure the social costs of any externality, especially because many costs are psychological and individual.[23] Even if a measurement of the psychological effect of some externality did exist, it would be impossible to collect that data for all individuals affected and then find the optimum output level. Since it is not possible to find the optimum output level, it is not possible to find the optimum Pigovian tax level to achieve that optimum. In the end, Baumol argues that the best solution is to set a minimum standard of acceptability for negative externalities, and create tax systems to achieve those minimum standards. Baumol points out that government committees have a tradition of agreeing on minimum standards, so the practicality of this solution is reasonable.

        Peter Boettke brings forth that “The Pigouvian remedy was to bring marginal private costs (subjectively understood) into line with marginal social costs (objectively understood). The problem, James M. Buchanan pointed out, was that the analyst had to specify the conditions under which objectively measurable costs could be ascertained by economic and policy actors. In general competitive equilibrium there are also no deviations between marginal private costs and marginal social costs. In other words, Buchanan (like Ronald Coase) pointed out that Pigovian tax remedies are either possible and redundant, or impossible to set because the conditions presupposed for their establishment either eliminate their necessity or (if absent) preclude their enactment.” In other words, “Karen I. Vaughn has pointed out the dilemma involved in this situation. To calculate the appropriate corrective tax, the policymaker must know the equilibrium price; yet the situation demanding correction implies a disequilibrium situation.”[24][25]

        *My* overt intention is to bring net emissions to as close to zero as soon as possible. All I need to know is the cost of carbon’s replacement and/or removal after it’s been emitted, which seems to me a much easier estimate to make that can be revised as required to obtain the desired result. We don’t need to know TCR/ECS to +/- 0.01 K/2xCO2 or SCC to the nearest penny to cost out the replacement solutions and actually implement them.

      • *My* overt intention is to bring net emissions to as close to zero as soon as possible. All I need to know is the cost of carbon’s replacement and/or removal after it’s been emitted, which seems to me a much easier estimate to make that can be revised as required to obtain the desired result.

        What if it could be done much more cheaply by taking a little longer, then letting it go negative for a while to make up for it?

        Once you’ve developed and deployed ambient CO2 extraction technology, there’s no real reason to shut it down once it’s balanced fossil emissions. Or even stop growing deployment.

      • “You still have not addressed the …

        Measurement problem”

        See my blog post on expected social welfare maximization. That provides a methodology to obtain a best level of taxation even under uncertainty.

      • AK,

        What if it could be done much more cheaply by taking a little longer, then letting it go negative for a while to make up for it?

        Then that would be my preferred option.

        Once you’ve developed and deployed ambient CO2 extraction technology, there’s no real reason to shut it down once it’s balanced fossil emissions. Or even stop growing deployment.

        Capturing it as it comes out of the stack would be my first choice. That would also mitigate particulates, SO2, NOx, etc. issues. I don’t think that’s a viable solution for surface transport, which is especially my concern for very high density urban areas where vehicular smog is a problem.

      • -1=e^iπ, I don’t know where to find your blog.

      • Capturing it as it comes out of the stack would be my first choice. That would also mitigate particulates, SO2, NOx, etc. issues.

        But the advantage of capturing it from ambient air is that once the technology is mature, it can be used to drag back CO2 that was dumped into the system while it was maturing. Sort of borrowing on future removal capacity.

        I don’t think that’s a viable solution for surface transport, […]

        Or most air transport for that matter.

        But surface transport brings up another issue: transporting the CO2 you’ve extracted from flue gasses. If it’s extracted from ambient, that can be done on-site,where it’s going to be used.

        The thing is, everything needed is part of a complex network of exponentially developing technologies. Finding a way to make small-scale ambient CO2 extraction profitable right now could allow Wright’s “Law” to work bringing down the costs (“learning curve”), which means that by the time the technology is mature the cost will be much lower.

        Using ambient CO2 extraction to provide the carbon for “renewable” hydrocarbons would potentially provide an exponentially growing market for the technology.

        Those hydrocarbons could eventually be fed into combined cycle gas turbines (CCGT), the same power technology that uses fracked natural gas today.

        This would have several advantages:

        •         CCGT technology, which is already competitive with coal, could be rolled out at maximum pace, without any immediate impediments for the sake of fossil CO2.

        •         At the same time, the technology for capturing ambient CO2 and combining it with hydrogen from solar PV/electrolysis could be growing and maturing.

        •         At some point, as the cost of solar PV continues its exponential decline, and Wright’s “Law” works to reduce the price of the other technology, “fossil-neutral” gas from this source will be come competitive with natural gas.

        During and after the entire process, investments in infrastructure for storage, transport, distribution, and power generation from gas will be protected against being “sunk costs”, since they will continue their value when fed from “fossil-neutral” hydrocarbons.

        I’ll admit, at first glance, the low energy efficiency (~30% bus-to-bus AFAIK) would seem to mitigate against it, but energy efficiency isn’t the same as cost-efficiency. When the PV technology gets cheap enough, it’ll be worth deploying 3-10 times the capacity, for the sake of high-energy fuels, which the existing infrastructure can use. Including vehicles.

        And at that point, that mature CO2 extraction technology can be deployed to drag the extra CO2 out of the system (e.g. air and ocean surface) for sequestration. If necessary.

      • AK,

        But the advantage of capturing it from ambient air is that once the technology is mature, it can be used to drag back CO2 that was dumped into the system while it was maturing. Sort of borrowing on future removal capacity.

        Ok, I’ll explore that a bit with you. My requirements would still be practically zero particulate, SO2 and NOx emissions, which would favor natural gas but would be plausibly cheaper to implement than on site CCS and thus could still leave coal competitive. Ambient capture and storage could be more centralized, which could lead to cost/benefit efficiencies. Best way to know would be to try it both ways and then maximize the ones which work best for various locations.

        That all said, my favored energy portfolio is nuclear, solar, wind and geothermal all of which have very low lifetime emissions compared to their fossil fuel equivalents as well as practically none of the particulates and other nasties. All of those things are far more technologically mature *now* than any proposed CCS scheme I’m aware of. Seems to me that leveraging that R&D already spent is the past of least resistance with the better chance of success.

        Borrowing on future removal capacity is betting on two big unknowns — unproven technologies which mainly only exist on paper, and the effects that the unabated emissions will have in the interim period until they can be drawn back down.

        Or most air transport for that matter.

        And corn/soybeans/sugar cane for fuel is not the answer to that question either. I focus mostly on the grid because those solutions are far more obvious and have the most immediately viable solutions.

        But surface transport brings up another issue: transporting the CO2 you’ve extracted from flue gasses. If it’s extracted from ambient, that can be done on-site,where it’s going to be used.

        That is an excellent point.

        The thing is, everything needed is part of a complex network of exponentially developing technologies. Finding a way to make small-scale ambient CO2 extraction profitable right now could allow Wright’s “Law” to work bringing down the costs (“learning curve”), which means that by the time the technology is mature the cost will be much lower.

        Same arguments apply to nuclear, solar, wind and geothermal, do they not? I see you give a nod to that below so I think we’re actually more on the same page here than either of us might think.

        I guess the difference is that you want to do the most immediate spending on the CCS solutions in lieu of pushing on replacement generating technologies. How about I just say: that would make me nervous.

      • @brandonrgates…

        Let me start with your next-to-last point, then work others out-of-sequence:

        I see you give a nod to that below so I think we’re actually more on the same page here than either of us might think.

        I see discussions like this as more of a non-zero-sum game than a straight-out debate.

        My requirements would still be practically zero particulate, SO2 and NOx emissions, which would favor natural gas but would be plausibly cheaper to implement than on site CCS and thus could still leave coal competitive.

        I don’t see any way coal can be competitive. Unlike CCGT, it’s not a good fit for mixing with solar (or wind). CCGT can ramp up and down fast, to buffer changes in intermittents. (You’d just need a little storage to fill in the short-term mis-matches.)

        Best way to know would be to try it both ways and then maximize the ones which work best for various locations.

        I’m thinking more in terms of (decade-scale) timing than location, but that too I guess (see below).

        That all said, my favored energy portfolio is nuclear, solar, wind and geothermal all of which have very low lifetime emissions compared to their fossil fuel equivalents as well as practically none of the particulates and other nasties. All of those things are far more technologically mature *now* than any proposed CCS scheme I’m aware of.

        Well, no. Nuclear has decades of R&D to go before it’s ready for prime time again (given the concerns many have).

        I don’t regard wind and geothermal as scaleable. Geothermal because it’s too slow (that rock cools down when you extract heat from it), and wind because large-scale deployment will probably have a worse effect on the climate than massive fossil CO2. (It increases surface flow at the boundary.)

        Solar is the biggie. And it’s certainly not ready for prime time yet. Not the way it will be in 10-20 years. Right now it’s barely achieved parity (in $/MWHr, in some places) with CCGT: the ideal mix is equal capacities with CCGT able to pay for its (relatively) high capital investment, despite not being used when solar can, while every KWHr of solar produced pays for itself with money not spent on gas.

        A decade or so from now, when solar capacity is at rough parity with CCGT, the cost of solar will probably have come down by a factor of 3-4 (at least), and power→gas (or liquid) fuel will be cost-effective even at the currently proposed ~30% energy efficiency.

        (Remember that hydrolysis uses DC input, while PV produces DC output. With proper design, you can eliminate inverter technology, just hook up the right number of solar panels in series with the right number of hydrolytic cells.)

        Borrowing on future removal capacity is betting on two big unknowns — unproven technologies which mainly only exist on paper, […]

        Well, no. All the necessary technologies have been demonstrated in pilot plants. What remains just “on paper” is the effect of Wright’s “Law” in bringing down the costs. (Along with a host of potentially superior competitors which probably make investors a bit nervous.)

        [… A]nd the effects that the unabated emissions will have in the interim period until they can be drawn back down.

        Well, this might be an issue. But IMO the roll-out of fossil generation capacity in the next 2-3 decades is already “locked-in”. That carbon is going to be emitted. What seems most important is to develop technologies that not only allow that capacity to be replaced with fossil-neutral, but to do so in a way that will make drawing that “locked-in” emission back down.

        I focus mostly on the grid because those solutions are far more obvious and have the most immediately viable solutions.

        My solution for the grid is massive investment in CCGT and gas infrastructure. Use fracked natural gas until solar power→gas/liquid hydrocarbons is ready for prime time, then feed the gas from that right into the mature infrastructure.

        I still have to gather the proper evidence to prove it here (there are links in comments I’ve made in the past, but I haven’t had the time to track them down), but transporting power in the form of gas is orders of magnitude cheaper than big long-distance electric transmission. (And with less NIMBY.) A distributed grid, with smaller CCGT plants (10-20 MWatt rather than 100’s,) and local cross-connections to neighboring grids to help with fluctuations, would probably be cheaper to implement, have more room for early rolll-out of solar power, and retain most of its value once solar power→gas reaches maturity.

        That also helps solve the problem of locations that aren’t right for solar: ship “fossil-neutral” gas from locations that are, and plug it into their mature gas-based infrastructure.

        I guess the difference is that you want to do the most immediate spending on the CCS solutions in lieu of pushing on replacement generating technologies. How about I just say: that would make me nervous.

        Nope. What I see as most important is spending on ambient carbon capture. Short-term, sequestration can wait (for necessary R&D), while the captured CO2 is converted to fossil-neutral fuel.

        2-3 decades down the pike, when the capture technology is mature and widely deployed, and most CCGT is already fossil-neutral, then we can think about sequestration.

      • AK,

        I don’t see any way coal can be competitive.

        I can, but only in a scenario where nuclear and renewables don’t eventually compete with natural gas.

        Nuclear has decades of R&D to go before it’s ready for prime time again (given the concerns many have).

        I assume that there will always be nuclear opponents no matter what improvements are made. They will simply need to be outvoted. Gen II+ reactors are plenty safe and economical so long as they’re not subject to undue regulatory burdens. On paper the Gen III reactor designs are less complex with more passive safety, but every project I know of is behind schedule and over budget. Hopefully that’s just growing pains. I really don’t think it makes any sense to hold out for Gen IV designs.

        I don’t regard wind and geothermal as scaleable.

        They obviously both have limits. Here’s the thing, we don’t necessarily need to know them beforehand. IOW, saying they’re not scalable to 100% is not a good reason to not deploy them.

        Existing geothermal wells have been extended by fracking with waste water. I would not rule out technology improvements allowing for deeper drilling. Still, I would see wind, solar and nukes as the least risky.

        Solar is the biggie. And it’s certainly not ready for prime time yet. Not the way it will be in 10-20 years.

        I don’t entirely understand. Yes, R&D can be expected to bring improvements. But technologies only really become mature by deploying them. Economies of scale alone can bring costs down. In sunny southern locations, solar’s peak output coincides neatly with peak demand, especially in summer.

        (Remember that hydrolysis uses DC input, while PV produces DC output. With proper design, you can eliminate inverter technology, just hook up the right number of solar panels in series with the right number of hydrolytic cells.)

        That’s an excellent point.

        All the necessary technologies have been demonstrated in pilot plants. What remains just “on paper” is the effect of Wright’s “Law” in bringing down the costs.

        We seem to be going in circles on this point. :-) Wright’s law also applies to wind and solar which have already seen significant deployment (see just above).

        But IMO the roll-out of fossil generation capacity in the next 2-3 decades is already “locked-in”. That carbon is going to be emitted.

        In the US, fortunately most of those new plants are natural gas. Keep in mind that much (if not most?) of that new capacity is being built to replace old plants due to be decommissioned. Bringing the grid to near-zero in three decades is on the low end of what I would think possible. Five is more likely. I give it good odds that those new plants would earn back their investment as baseload and then eventually peaking/backup plants.

        What seems most important is to develop technologies that not only allow that capacity to be replaced with fossil-neutral, but to do so in a way that will make drawing that “locked-in” emission back down.

        I don’t disagree. I’m only balking at prioritizing CCS over solar and wind deployment because as I said … those solutions are far more obvious and have the most immediately viable solutions. Again, this seems to be our main sticking point. On the plus side, you’ve written plenty of things with which I agree, but which I had not previously considered. So thanks for that. Cheers.

      • @brandonrgates…

        We seem to be mostly in agreement, perhaps more than you realize. Let me address a couple points where I don’t seem to have communicated clearly:

        I assume that there will always be nuclear opponents no matter what improvements are made. They will simply need to be outvoted. […] On paper the Gen III reactor designs are less complex with more passive safety, but every project I know of is behind schedule and over budget. Hopefully that’s just growing pains. I really don’t think it makes any sense to hold out for Gen IV designs.

        AFAIK the strongest advocate of nuclear here (Peter Lang) optimistically predicts 2-3 decades before learning curve brings costs down to be competitive with current natural gas/CCGT.

        And that’s assuming the political issues are dealt with soon. IMO by that time the cost of solar PV will have come down so far nuclear simply won’t be able to compete. But I agree nuclear should be vigorously pursued as a fallback in case solar PV doesn’t pan out. (And, there are applications where it could be superior even at much higher cost.)

        Assuming the proliferation and terrorism risks can be mitigated.

        IOW, saying they’re (geothermal & wind) not scalable to 100% is not a good reason to not deploy them.

        Perhaps. But I don’t see them as something for me to spend time on.

        Solar is the biggie. And it’s certainly not ready for prime time yet. Not the way it will be in 10-20 years.

        I don’t entirely understand. Yes, R&D can be expected to bring improvements. But technologies only really become mature by deploying them. Economies of scale alone can bring costs down.

        This is actually the main point I’ve been pushing here for over a year. The costs of solar PV have been declining by around 50% every 5-6 years. Deployment has been doubling every 2-3 years.

        Given even the improvements that are on the lab bench or in pilot, I see every likelihood this trend will continue.

        Currently, solar provides around 1% of the total MWHrs used worldwide. Extending the trend by a decade or so, it’ll be providing around 10% of the total MWHrs used worldwide, with panel prices (at the factory gate) perhaps 1/3-1/4 what they are now. (Capacity maybe 5-6 times as much as penetration, due to the low capacity factor of solar.)

        That’s prime time. At those prices, it’ll be cost-effective to convert solar power to gas/liquid hydrocarbons, and feed the result into an existing gas infrastructure, replacing fossil.

        Meanwhile, as CCGT rolls out, it offers a market for solar at roughly equal capacity, where solar will provide around 15-20% of the total MWHrs used. With each MWHr paying for itself in saved fuel costs.

        That gives solar time to mature. As the cost comes down, solar deployment can continue, at a profit, supplying gas to the existing infrastructure in place of fossil. Eventually (2-3 decades), it can supply all the energy. There’s almost no sunk costs: the infrastructure remains valuable, the fracked wells would have run out anyway, the rate of new wells would just taper off to zero.

        (You could count the obsolescence of fracking technology as a sunk cost, but by then it’ll have had a good run, more than paying back the investment.)

        We seem to be going in circles on this point. :-) Wright’s law also applies to wind and solar which have already seen significant deployment (see just above).

        Yes, the application of Wright’s “Law” to solar has been my chief hobbyhorse around here for over a year (see above).

        I think the only issue is that I haven’t been able to communicate one of the main implications I see.

        Bringing the grid to near-zero in three decades is on the low end of what I would think possible. Five is more likely. I give it good odds that those new plants would earn back their investment as baseload and then eventually peaking/backup plants.

        I’d say 2-3 decades is more like it. Remember that once those CCGT plants are burning gas made from ambient CO2 and solar power, they’re at zero net emissions.

        I’m only balking at prioritizing CCS over solar and wind deployment because as I said … those solutions are far more obvious and have the most immediately viable solutions.

        Again, I don’t seem to have communicated my main point: I’m not talking about spending money on CCS, I’m talking about a focus on ambient carbon capture to use converting solar power to fuel. Part of the reason for this is to provide a large and growing market for solar power as/after it reaches full penetration alongside CCGT.

        The actual alternative I would like to see downplayed is massive investment in a hydrogen infrastructure. Converting electrolytic hydrogen to methane (or liquid fuels) imposes an energy efficiency cost of only about 15%.

        Being able to use the existing natural gas (and liquid) infrastructure, for vehicles, CCGT, and combustion for heating, would probably be a big enough plus to justify the extra effort on ambient carbon capture.

        And then, 2-3 decades down the road, some of that technology could be applied to removing it for sequestration.

        If necessary. Which the science will have another 2-3 decades to figure out.

    • Peter Lang

      brandonrgates,

      to cost out the replacement solutions and actually implement them.

      What in your opinion are the replacements solutions that are closest to being viable?

      What in your opinion the most likely cost of solutions (through to 2100) to reduce GHG emissions to the level you believe is needed?

      If those solutions were implemented, what do you believe would be the measurable benefit in terms of avoided climate damages (in say 2010 US $)?

      • I think that besides nuclear there is at this time no alternative “renewable” energy source available that can reliably power a modern economy without the help of dispatcable fossil fueled power generation.
        So I am also curious what Brandon’s answer will be.

      • Peter Lang,

        What in your opinion are the replacements solutions that are closest to being viable?

        In the US for electricity in order of most to least economically competitive: geothermal, onshore wind, hydro, nuclear, solar. See the average difference column in Table 4 of this document from the US EIA. A positive difference means each marginal unit of capacity adds value by displacing more expensive technology. Geothermal has the only positive difference, problem is that it has limited scalability.

        The “actual” viability will depend on more than just the cost estimates. For instance, nuclear is politically unattractive, has byzantine regulatory requirements, takes a long time to build and always goes over budget … all of which adds up to prohibitive up-front capital risks. On the plus side it’s a mature and proven technology with a high capacity factor and virtually no limit for scalability. Thus, it’s actually my favorite of the bunch for the medium and long term, particularly because it’s best suited to provide baseload power. For the short-term, I think we should be ramping geothermal (particularly because it’s dispatchable), wind and solar because nukes — if they happen — will take a while.

        What in your opinion the most likely cost of solutions (through to 2100) to reduce GHG emissions to the level you believe is needed?

        I don’t have a good answer for that at present.

        If those solutions were implemented, what do you believe would be the measurable benefit in terms of avoided climate damages (in say 2010 US $)?

        That’s an even more difficult question to answer, particularly because of the word “measurable”. At best it can only ever be estimated, and those estimates would need to include what the rest of the world did, or is expected to do.

      • Brandongates,

        I got to your first sentence and stopped

        In the US for electricity in order of most to least economically competitive: geothermal, onshore wind, hydro, nuclear, solar. See the average difference column in Table 4 of this document from the US EIA.

        You do not understand what you are reading. You cannot compare LCOE of nondispatchable with dispatchable technologies. You have to compare on an equivalent basis. You need to compare on the basis of total system cost to achieve a certain objective, such as: meet all system requierments plus reduce GHG emissions from electricity by say 50%.

        As soon as you compare on a properly comparable basis, and exclude all subsidies, you find wind and solar are enormously expensive. Compare the subsides per MWh would be a good start: http://www.eia.gov/analysis/requests/subsidy/pdf/subsidy.pdf
        $2.10/MWh for nuclear, $42.90/MWh for non-hydro renewables.

        Plus, solar and wind are not sustainable. They are entirely dependent on fossil fuels. They don’t produce enough energy through life to power modern society and reproduce themselves: https://bravenewclimate.com/2014/08/22/catch-22-of-energy-storage/#comment-456601 (read the links if you want more).

      • My appologies. I misread your first sentence as advocating that renewabes are economic. My mistake. Sorry.

        I’ve now read your whole post and it’s mostly OK. I disagree with this, though “nuclear takes a long time to build”. Actually, nuclear is by far the quickest way to build capacity to generate low emissions electricity. France got to 75% of it’s electricity generated by nuclear in about 30 years. If the accelerating global deployment rate that prevailed up to 1976 had continued to now, nuclear would be supplying 70% of global electricity. Renewables cannot provide a significant proportion of global electricity (see reasons in previous comment).

      • Regarding the cost of mitigation, it greatly exceeds the benefit, even when using inputs that calculate to high damages. Therefore, mitigation cannot be rationally justified (see my reply with chart, here: https://judithcurry.com/2016/06/07/assessment-of-approaches-to-updating-the-social-cost-of-carbon/#comment-788674

        We know if GHG emissions are good at the moment and this may continue all this century. We don’t know. We are reducing the risk of an abrupt cooling event. The expected value of this needs to be offset against the hypothesized climate damages of warming. The McKitrick paper cited in the post at the head of this thread mentions that with certain defensible assumptions the cnetral estimate of SCC is about zero, and negative with 5% discount rate (arguably a low rate for the world for the long term).

      • Peter Lang,

        I got to your first sentence and stopped

        You should have kept reading. I understand quite well that LCOE isn’t directly comparable between dispatchable and non-dispatchable generation technologies. Table 4 of that document attempts to address that by subtracting LCOE from LACE. The “most viable” replacement technology from a cost perspective the one where that difference is greatest.

      • Did you seem my post here: The main point is that all or mostly nuclear, and no new weather dependent reneables, is the least cost way to reduce GBs emissions to meet their proposed targets. The lesson has wide applicability even though there are substantial differences between regions, latitudes and electricity systems.

        Is nuclear the cheapest way to decarbonise electricity? https://judithcurry.com/2016/01/19/is-nuclear-the-cheapest-way-to-decarbonize-electricity/

      • Peter Lang,

        I should have kept reading, I apologize for missing your apology.

      • Accepted. No worries. Enjoying the exchange.

      • Brandongrgates,

        This quote from McKitrick’s paper supports my contention that we don’t know whether our GHG emissions are doing more harm than good.

        The mean SCC estimates are lower under both parameterizations, and under the empirical LC15 coefficients are, on average, negative at 5 percent or higher discount rates out past 2030. This implies that carbon dioxide emissions are a positive externality, so hat the optimal policy would require subsidizing emissions. Also, in contrast to the DICE model, use of the LC15 coefficients increases the average standard deviation, indicating higher uncertainty. The increased uncertainty includes a much larger lower tail, implying a larger probability of a negative SCC.

        This just adds to and supports a long list of reasons why I do not support spending a dime on the ‘climate industry’, other than on ‘no regrets’ policies – i.e. where the policy would deliver net benefits, that exceed expenditure on any other policy, irrespective of any hypothesized benefits of avoided climate damages.

        This is the policy position Australia took to the 1992 Rio Earth Summit:

        11 October 1990: The Australian Government adopted an Interim Planning Target to stabilise greenhouse gas emission at 1988 levels by 2000 and to reduce emissions by 20 per cent by the year 2005 based on 1988 levels (known as the Toronto target). An important caveat was included in this target. This stated that measures which would have net adverse economic impacts nationally or on Australia’s trade competitiveness would not be implemented in the absence of similar action by major greenhouse gas producing nations. Actions would be taken if benefits were realised in addition to the greenhouse gas emission reduction benefits, for example energy conservation. This became known as the ‘no regrets’ strategy.

        http://www.aph.gov.au/About_Parliament/Parliamentary_Departments/Parliamentary_Library/Publications_Archive/Background_Papers/bp9798/98bp04

        I’d suggest all countries should adopt the important caveat.

      • Peter Lang,

        Enjoying the exchange.

        As am I; it’s been refreshingly cordial. AK and -1=e^iπ, same for you both. More substantive responses are forthcoming.

  28. Peter Lang, I promised to get back with help on premature FF/ Nuclear deaths. I spent all day today trying to run that down and find something convincing. Failed utterly. There are two fundamental problems IMO:
    1. What is meant by premature. We all die somewhen. So you get into probability distributions of somewhen. It is incorrect to say anything left of the mean or median or mode is premature. Its half of reality. So, what is? Well, most papers just make it up, or use some logical fallacy related to the left (shorter lifespan) side of the distribution. And lots of that is in terms of only a few arbitrary years.
    2. Attribution of cause of death. An example. ‘Premature deaths from indoor smoke in the third world’ would require an autopsy of all below average deaths in Africa to determine COPD/lung cancer from malaria, other diseases, malnutrition, snakebite, childbirth death, whatever. No data, just dubious assumptions. And, there are all the linear versus threshold dose response controversies. Most of the first world ‘premature mortality’ stuff I looked at is linear, when all of the evidence suggests threshold. Radiation, second hand smoke, PM2.5, mercury, ozone, all embed this controversy.

    Specific with concern to coal, another issue is where. China has a PM2.5 problem. It obviously also has a smog problem related to sulfur aerosols. Those are not only related to coal electricity generation. Coal is an industrial fuel and a home heating and cooking fuel. US has neither problem now. We clean up generationg station stack gasses, and coal is not a home heating or cooking fuel. So even valid regional data (I could not find any) are NOT valid generalizations.
    Had hoped to be of more help.

    • ristvan,

      Excellent summary, IMHO.

      I was going to add more, but your comment stands nicely by itself.

      Cheers.

    • ristvan,

      ‘Premature deaths from indoor smoke in the third world’ would require an autopsy of all below average deaths in Africa to determine COPD/lung cancer from malaria, other diseases, malnutrition, snakebite, childbirth death, whatever. No data, just dubious assumptions. And, there are all the linear versus threshold dose response controversies. Most of the first world ‘premature mortality’ stuff I looked at is linear, when all of the evidence suggests threshold.

      Did “all the evidence” suggesting threshold come from doing autopsies on everyone?

      • My point, which you missed, was that none does that I could find. So, per above, if you cannot assign cause of death, to try to compensate via epidemiological statistics is gibberish. Do you have a reading comprehension problem? Or have you found data I did not?

      • ristvan,

        So, per above, if you cannot assign cause of death, to try to compensate via epidemiological statistics is gibberish.

        Which again leaves me wondering how you’ve concluded that “all of the evidence [you’ve reviewed and accepted] suggests [a] threshold” for PM exposure.

        Do you have a reading comprehension problem?

        Not that I’m aware of. Do you have a problem answering direct questions directly?

        Or have you found data I did not?

        Doubtful anything that would meet your extraordinary standard of proof. Otherwise, difficult to answer — I don’t know what data you’ve found.

    • Steven Mosher

      “Specific with concern to coal, another issue is where. China has a PM2.5 problem. It obviously also has a smog problem related to sulfur aerosols. Those are not only related to coal electricity generation. Coal is an industrial fuel and a home heating and cooking fuel. US has neither problem now. We clean up generationg station stack gasses, and coal is not a home heating or cooking fuel. So even valid regional data (I could not find any) are NOT valid generalizations.
      Had hoped to be of more help.”

      All PM2.5 is not created equal. PM2.5 merely refers to the size of the particulate.

      http://berkeleyearth.lbl.gov/air-quality/embed.php?z=1&x=150.78125&y=-49.94602&m=h&c=y&f=n&t=2016060900&e=l

    • Steven Mosher

      Peter I would start with this

      http://www.pnas.org/content/110/32/12936.full.pdf

      First and foremost to clear your mind of some of the claptrap you will hear from skeptics.

      • Steven Mosher, from your citation:

        This paper’s findings suggest that an arbitrary Chinese policy that greatly increases total suspended particulates (TSPs) air pollution is causing the 500 million residents of Northern China to lose more than 2.5 billion life years of life expectancy. The quasi-experimental empirical approach is based on China’s Huai River policy, which provided free winter heating via the provision of coal for boilers in cities north of the Huai River but denied heat to the south.

        [whistle] My but was that carefully worded.

      • Peter Lang

        Steven, Thank you. I’ve read that. It does not answer my question. You love telling other to read harder! please consider doing it yourself.

        China is 77 deaths/TWh, India 99 deaths/TWh from coal fired electricity generation. OECD much lower. I want the global average. And from an authoritative source, not bits and pieces for individual countries or other info I have to do an estimate with. I’ve already said that in at least two previous comments.

    • Peter Lang

      Rud,

      Thank you for trying on this. Much appreciated. I failed completely too. However, my problem is I can’t find a reference that provides the figures I need for the global average deaths per TWh from coal, gas and nuclear electricity generation. There are stacks of references for US, Europe etc. from as far back as 1983 (e.g. <Herbert Inhaber (1983). Energy Risk Assessment which I have on my bookshelf). Life expectancy, distribution by age and lots of other inputs are part of the analysis for YOLL. But I am not trying to calculate the numbers myself. I just want a reference for the global average dearths/TWh by electricity technology type and can’t find one.

      Markandya and Wilkinson, 2007 and ExternE and many others have done it for Europe, USA and other countroies – e.g. see Table 2 here: https://www.researchgate.net/publication/5965940_Energy_and_health_2_Electricity_generation_and_health_Lancet ) but not for global average.

      These are the numbers Kharecha and Hansen (2013) used for their analysis.

  29. Steven Mosher,

    You wrote –

    “You gus still don’t get it.
    Grab the right end of the argument and win.
    Nic lewis knows how.
    Tol knows how.
    McKittrick too”

    Nature doesn’t care about debate results. Winning as many arguments as you wish, changes not one physical fact. I’m sorry that an obsession with argument winning seems to occupy so much of your time. What does winning an argument achieve? Personal satisfaction I can understand, but not much else.

    All the personal satisfaction in the world, plus $5 will probably buy you a cup of coffee. Just a thought.

    Cheers.

    • “Just a thought”

      You over-estimate yourself.

      • Anthony Purcell,

        I know. I’d appreciate you telling me something I don’t know. Stating the blindingly obvious for no particular reason is a common Warmist trait. You seem to be a relatively new acolyte of the Warmist a Church of Latter a Day Scientism, so well done!

        In the fullness of time, you may be allowed to participate in the Examination of the Tree Entrails, performed by that other world famous geophysicist Michael “I really deserve a Nobel Prize” Mann.

        I wish you well in your spiritual and metaphysical endeavours.

        Cheers.

      • Anthony Purcell,

        Apologies. A couple of typos.

        Obviously, I meant you seemed to be an acolyte of the Warmist Church of Latter Day Scientism.

        Cheers.

  30. Peter Lang

    using the LC15 distribution, the probability of a negative SCC jumps to about 40%. Remarkably, replacing simulated climate sensitivity values with an empirical distribution calls into question whether CO2 is even a negative externality.

    Dayaratna, McKitrick and Kreutzer (2016), p5. file:///D:/Downloads/SSRN-id2759505.pdf

  31. I sent an email to the three authors of this study on May 12, 2016. Most of it is copied below:

    I have reviewed your paper “EMPIRICALLY-CONSTRAINED CLIMATE SENSITIVITY AND THE SOCIAL COST OF CARBON”. Your study uses estimates of equilibrium climate sensitivity (ECS) from a paper “Lewis and Curry 2015” (LC15) and the two Integrated Assessment Models (IAM) DICE and FUND to calculate new estimates of the Social Cost/Benefit of Carbon (SCC).

    I agree that the ECS estimates used by the IWG are far too high and should be based on a realistic empirically based estimate. However, I find your paper deficient on account of the following four reasons;

    1. The use of the DICE model is inappropriate because that model fails to account for the CO2 fertilization effect and it assumes that the optimum climate for humanity was the pre-industrial climate of 1900, which was near the end of the Little Ice Age. CO2 fertilization is an known physical effect documented by thousands of published papers. Testimony by Dr. Mendelsohn shows that there is no evidence that the temperature increase since 1900 caused any damages, and such damages would be easily detectable. The model does not include most benefits of warming [and CO2 fertilization], which should disqualify the use of it. The DICE model produces future sea level rise values that far exceed mainstream projections and exceed even the highest end of the projected sea level rise by the year 2300 as reported in the AR5 report. Your paper should not include the DICE model. The FUND model is the only IAM that should be used to determine a SCC.

    2. The climate sensitivity estimated in LC15 is too high for three reasons giving estimates of SCC that are too high. A study by Nic Lewis used new estimates of aerosol forcing. Nicholas Lewis writes, “a compelling new paper by Bjorn Stevens estimating aerosol forcing using multiple physically-based, observationally-constrained approaches is a game changer.” Using the new aerosol estimate reduces the mean estimate of ECS from 1.64 to 1.45 ºC. By failing to use the best and most current aerosol forcing estimates you have overestimated climate sensitivity.

    3. Dr. Ross McKitrick with Steve McIntyre published excellent papers that broke the “hockey stick” and restored the Medieval Warm Period and Little Ice Age natural temperature variability to history. Numerous peer reviewed papers show the large natural millennium scale climate cycle. It is indefensible to ignore natural climate change due to the millennium cycle. Climatologist Dr. Richard Lindzen writes, “Lewis does not take account of natural variability, and, I suspect, his estimates are high.”

    4. The HadCRUT4 temperature index used in LC15 is contaminated by the urban heat island effect (UHIE), and this effect must be subtracted from the recorded temperature change to determine the effect of greenhouse gases. Numerous studies show the this UHIE contamination, most notably, McKitrick and Michaels 2004 and McKitrick and Michaels 2007. Correcting for the effects of points 2, 3 and 4 reduces the ESC to 1.02 ºC as shown in my report. http://www.friendsofscience.org/index.php?id=2205

    Applying the four corrections listed above would reduce the SCC best estimate to -$16.6/tCO2. The likely range is -19.3 to -11.5 US$/tCO2, and it is extremely likely to be less than -4.3 US$/tCO2. The benefits of CO2 fertilization, reduced cold weather related mortality, lower outdoor industry costs such as construction costs, increased arable land area and reduced heating costs greatly exceed harmful effects of warming on a global basis.

  32. Note that Nic has recently updated the values to account for more recent data and lower aerosol forcing [link]. These new results are not yet published.

    What is the status of publishing these results? Even these results of ECS and TCR are too high as they fail to account for natural recovery from the LIA and UHIE.

  33. Peter Lang,

    [posted out of sequence for scroll]

    Point 1: The fact we are in an extremely cold phase, perhaps the coldest ever, together with the fact that we can’t get out of it for millions of years (until North and South America separate) and together with the fact life thrives when the planet is warmer and struggles when colder, suggests the probability of catastrophe or dangerous consequences from GHG emissions is negligible.

    Here’s an interesting plot [1]:

    I think it’s difficult to make generalizations based on temperature alone.

    Point 2: life thrives during rapid warming events and struggles during cooling events (at temperatures we could reach this century, not PETM temperatures).

    Point 3. PETM started at a near record warm period in geologic time. There is effectively impossible to get anywhere near those temperatures again in millions, or more realistically tens of millions, of years. Therefore PETM is irrelevant as an indication of what could happen this century.

    My position is based almost entirely on rate of change, not absolute levels or direction of change. Benthic foraminifera took it in the shorts during the PETM; according to this paper, which is worrisome. At least one relevance to today is the massive release of CO2.

    Point 4. I don’t understand your argument that seems to be saying that it is valid to compare average global gtemperatures changes over decades with average changes over 10,000 years.

    I’m saying I don’t think it’s necessarily invalid to make that comparison.

    Point 5. The climate seems to be much more volatile when there is ice at the poles (i.e. now) than when there is no ice at the poles. Look at Figure 15.21 here […] It shows the climate in Ireland (also Iceland and Greenland) warmed from near glacial temperatures to near current temperatures in 7 years 14,500 years ago and in 9 years 11,500 years ago.

    Temperatures in the North Atlantic are quite volatile compared to lower latitudes, especially during periods of deglaciation.

    It also shows the temperature has been more stable since the ice sheets retreated.

    Rapidly melting ice is associated with unstable climate.

    Text and other figures show that life thrived during the warming periods.

    As one would expect when moving from full glaciation to a far more temperate seasonal climate.

    [this figure is not about average global change, but is relevant because life lives locally and responds to local changes, so it demonstrates the effect of warming and cooling, especially of abrupt climate changes)

    I would say that it more shows the benefits of glacial retreat for terrestrial species in land areas previously covered with ice. Humans these days are far more numerous and have a lot of infrastructure and cargo, which makes migration more difficult and costly.

    Point 6. McKitrick’s paper shows probability of SCC = $0 is around 50% or negative for realistic discount rates for the world over the long term. that seems to tell us our GHG emissions may doing more harm than good.

    I think you meant more good than harm. Anyway, this looks to be McKitrick’s main argument:

    General circulation models (GCMs) historically yielded sensitivities in the range of 2.0–4.5 °C, and (based largely on GCMs) RB07 yields a central 90 percent range of 1.72–7.14 °C with a median of 3.0 °C and a mean of 3.5 °C (see comparison table in IWG 2010, p. 13). But the median of recent empirical estimates has generally been between 1.5 and 2.0 °C, with 95% uncertainty bounds below the RB07 average. […] Remarkably, replacing simulated climate sensitivity values with an empirical distribution calls into question whether CO2 is even a negative externality. The lower SCC values also cluster more closely together across difference discount rates, diminishing the importance of this parameter.

    Obviously shrinking the uncertainty range for ECS will reduce sensitivity to other parameters such as discount rate, and driving down the central estimate of ECS will increase the probability of low or even negative SCC values. The ECS range of 1.72–7.14 °C McKitrick cites comes from Roe and Baker (2007). Yes, mostly based on models, but their distribution fits well with numerous paleo studies.

    ———————

    [1] The bottom figure is after Rhode and Muller (2005).

    • These replies do not address my points. Point 4 is especially important. Perhaps you haven’t understood the point I am making. You have to compare rates over similar time periods.

  34. Peter Lang,

    [posted out of sequence for scroll]

    Point 1: The fact we are in an extremely cold phase, perhaps the coldest ever, together with the fact that we can’t get out of it for millions of years (until North and South America separate) and together with the fact life thrives when the planet is warmer and struggles when colder, suggests the probability of catastrophe or dangerous consequences from GHG emissions is negligible.

    Here’s an interesting plot:

    The bottom figure is after Rhode and Muller (2005). I think it’s difficult to make generalizations based on temperature alone.

    WordPress ate my longer reply to your post, so I’ll go with this for now.

  35. brandonrgates,

    Thanks I am familiar with the plots of global temperature over Phanerozoic. I gave links to several in the previous thread.

    Your second and third charts are plots of extinction events and biodiversity, not a plot of the amount of C tied up in the biosphere which is what is relevant to whether life thrives or struggles times of warming or cooling from current temperatures.

    Point’s to note from second chart:

    1. Ordovician-Silurian and Pleistocene ice ages were the coldest. CO2 concentration during the Ordovician-Silurian ice age was 4000-5000 ppm (10x the present 400 ppm). Suggests CO2 is not the primary driver, not the ‘control knob’, not likely to cause catastrophic warming. other factors are at play, especially plate tectonics.

    2. Even at extreme temperatures, life did not die out. There is no possibility of reaching those temperatures, so catastrophe is not credible.

    3. End Ordovician and End Cretaceous extinction events occurred at the end of cooling events, not warming events. There is no extinction event coinciding with the 18O peak at about 265 MYa.

    The volatility of the climate (on short time scales, not shown by your chart) has moderated as life developed over the period.

    From what you’ve posted I see nothing to change what I said above: Life thrives during warm periods and warming (other than at exceptionally high temperatures which cannot be reached with the present configuration of the tectonic plates). Life struggles during cold and cooling times (as during the last glacial period when the Neanderthals became extinct). Therefore, GHG emissions are not dangerous. There;s virtually no possibility of catastrophe or extreme danger, so whether or not to spend money on GHG abatement should be purely a cost benefit analysis.

    SSC is declining and I expect it will continue to do so. McKitrick’s analysis with the FUND model and 5% and 7% discount rates suggests abatement policies, other than no regrets policies, are not justified.

    • The sun was 4-5% weaker in the Ordovican ice age. When you take the steady solar brightening into account, the net forcing is fairly flat, and that period has weaker forcing than our Ice Ages. This points to a geological/chemical thermostat between rocks, temperature and CO2, because when temperatures are higher, chemical/geological processes act faster to remove CO2 from the atmopshere, and these processes become more dormant at colder temperatures until geology or mankind returns the CO2 to the atmosphere from deep.

      • Jim D,

        The sun was 4-5% weaker in the Ordovican ice age.

        Nonsense! Provide an authoritative source for statements like that.

      • The astrophysicists say that sun-type stars brighten about 1% per 100 million years. It’s a big factor over these time scales. 1% is equivalent to a CO2 doubling, so 4% is like 16 times CO2.
        http://descentintotheicehouse.org.uk/tag/carbon-dioxide/

      • The astrophysicists say that sun-type stars brighten about 1% per 100 million years.

        Jim D, it doesn’t explain the Ordovician-Silurian ice age. You’d have to argue changing sun output explains all the temperature highs and lows over the Phanerozoic.

      • As they said, it isn’t just the sun, it is geology too which along with temperature determines CO2 levels on million-year time-scales. There’s a geological negative feedback to warmer temperatures.

    • “McKitrick’s analysis with the FUND model and 5% and 7% discount rates suggests abatement policies, other than no regrets policies, are not justified.”

      5% and 7% are not consistent with observations of the after-tax riskless interest rate and are not consistent with the Ramsey equation.

      • We’ve been through your opinions about that at great length on previous threads. You never managed to answer my simple question (about implied historical discount rates used in making infrastructure investment decisions as a reality check) and repeatedly dodged my question and then incessantly talked about the Ramsey Equation. In the end all you could argue was that choice of discount rate was a based on moral or ethical values. I gave up on trying to discuss anything with you.

      • @ Peter Lang –
        I answered your question many times. It’s not my fault if you don’t like the answer.
        Believe it or not, cost-benefit analysis has a theoretical foundation and the discount rates used should be justified. If you wish to ignore that foundation, that is your choice. But choosing unjustified high discount rates to get a conclusion you want seems dogmatic.

      • We’ve been through all this and I rebutted it. You wouldn’t or couldn’t answer my questions. So, why are you trying to rehash it again?

        You seem to be stuck in a box and can’t see outside. The low discount rates you are advocating are not appropriate. They the global average used for deciding between infrastructure investment options, nor between various options for spending public money. I know you can’tr or won’t answer the question I asked, so there is no point continuing.

      • “What discount rates are used in the World Bank” (Slide 5)

        Energy Sector = 10%-12%
        (published 2004): Google: “Choice of discount rates used in World Bank projects”

        Table 2.1 here has a list of discount rates used by 16 countries and five development banks. The development banks use 10%-12% (published 2013) http://www.pc.gov.au/research/supporting/cost-benefit-discount/cost-benefit-discount.pdf

    • Peter Lang,

      Your second and third charts are plots of extinction events and biodiversity, not a plot of the amount of C tied up in the biosphere which is what is relevant to whether life thrives or struggles times of warming or cooling from current temperatures.

      If you know of a timeseries of that metric covering the same interval of time, I’d appreciate a reference to it. I’m inclined to believe on a theoretical basis alone that biomass production tends to be higher during warmer periods than cooler, but temperature isn’t the only factor. Thus, I’d like to see a time series.

      1. Ordovician-Silurian and Pleistocene ice ages were the coldest. CO2 concentration during the Ordovician-Silurian ice age was 4000-5000 ppm (10x the present 400 ppm). Suggests CO2 is not the primary driver, not the ‘control knob’, not likely to cause catastrophic warming. other factors are at play, especially plate tectonics.

      You’ll notice that literature does not argue that CO2 has been the control knob for every known period in the Earth’s history. When you drop qualifiers, you create strawmen.

      2. Even at extreme temperatures, life did not die out. There is no possibility of reaching those temperatures, so catastrophe is not credible.

      See again rate of change.

      3. End Ordovician and End Cretaceous extinction events occurred at the end of cooling events, not warming events. There is no extinction event coinciding with the 18O peak at about 265 MYa.

      See again that I don’t dispute that rapid cooling events are not hazardous. The end-Devonian and end-Permian extinction events coincided with warming.

      The volatility of the climate (on short time scales, not shown by your chart) has moderated as life developed over the period.

      Correct, but it’s not a terrible inference that periods of low extinction rate coincide with relatively stable climates, a major component of which is obviously temperature.

      From what you’ve posted I see nothing to change what I said above: Life thrives during warm periods and warming (other than at exceptionally high temperatures which cannot be reached with the present configuration of the tectonic plates).

      Look harder. Extinction rate shows a clear downtrend over the past 500 million years, diversity is on a clear upswing over the past 200 million. There is no clear temperature trend over the entire interval. Absolute value of temperature alone does not explain what you’re attempting to force it to explain.

      Life struggles during cold and cooling times (as during the last glacial period when the Neanderthals became extinct).

      Their extinction due to rapid cooling is plausible, but not the only possible explanation. There is no requirement for there to be one and only one causal explanation.

      Therefore, GHG emissions are not dangerous.

      According to you, CO2 isn’t the control knob and we’re at risk of cooling sometime within the next century. So talking to you about the potential risks due to anthropogenic warming is the wrong discussion to be having. The right discussion is OT for this thread.

      • brandonrgates,

        Re more C tied up in the atmosphere in warm time, I recall a statement along those lines in IPCC AR4 WG1 Chapter 6. I dont have the page number or exact quote to hand.

        hen you drop qualifiers, you create strawmen.

        Therefore all your responses to me were a combination of strawmen, dodging the point And giving simplistic disingenuous responses.

        The rest of your comments are statements of your beliefs. I don’t see anything that refutes the points I’ve made.

      • IPCC AR4 WG1 Chapter 6 https://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch6s6-4-1-4.html

        6.4.1.4 How Realistic Are Simulations of Terrestrial Carbon Storage at the Last Glacial Maximum?

        There is evidence that terrestrial carbon storage was reduced during the LGM compared to today. Mass balance calculations based on 13C measurements on shells of benthic foraminifera yield a reduction in the terrestrial biosphere carbon inventory (soil and living vegetation) of about 300 to 700 GtC (Shackleton, 1977; Bird et al., 1994) compared to the pre-industrial inventory of about 3,000 GtC. Estimates of terrestrial carbon storage based on ecosystem reconstructions suggest an even larger difference (e.g., Crowley, 1995). Simulations with carbon cycle models yield a reduction in global terrestrial carbon stocks of 600 to 1,000 GtC at the LGM compared to pre-industrial time (Francois et al., 1998; Beerling, 1999; Francois et al., 1999; Kaplan et al., 2002; Liu et al., 2002; Kaplan et al., 2003; Joos et al., 2004). The majority of this simulated difference is due to reduced simulated growth resulting from lower atmospheric CO2. A major regulating role for CO2 is consistent with the model-data analysis of Bond et al. (2003), who suggested that low atmospheric CO2 could have been a significant factor in the reduction of trees during glacial times, because of their slower regrowth after disturbances such as fire. In summary, results of terrestrial models, also used to project future CO2 concentrations, are broadly compatible with the range of reconstructed differences in glacial-interglacial carbon storage on land.

  36. -1=e^iπ,

    [posted out of sequence for scroll]

    See my blog post on expected social welfare maximization. That provides a methodology to obtain a best level of taxation even under uncertainty.

    Ok I read it. It’s a lot to absorb and I’m afraid my learning curve won’t allow me to do it justice. However, your closing paragraph makes quite a bit of sense to me:

    P) Which Moral Judgements Should be Made?

    Ultimately, determining the SWF depends on moral judgements. In particular, one likely needs to choose η and ρ. I leave it to the reader to decide, based upon the information in this post, what η and ρ should be, although I would advise against being risk averse about the values of η and ρ as human risk aversion itself depends on η. However, η outside of [0.5,2.0] is inconsistent with empirical observations and the Ramsey equation suggests that ρ lies in the interval [0.2%,2.4%]. Given the uncertainty of these two moral parameters, what researchers could do is perform expected social welfare maximization for different values of η and ρ and leave it up to policy makers to choose the appropriate moral judgements.

    What I don’t understand is how setting a tax using a social cost model differs in terms of leaving policy makers to choose what *they think* is the appropriate moral decision. IOW, I’m not seeing how we avoid the measurement problem by this method either.

    I was amused by your comment on the potential absurdities of a strong precautionary principle:

    For example, one cannot exclude the possibility that a giant flying spaghetti monster may appear and try to destroy New York; therefore, the US government should spend economic resources to ensure that it can fend off any attack by a giant flying spaghetti monster.

    Nor can we rule out that Russell’s Teapot will some day become sentient and powerful enough to destroy us either. Maybe invisible farting unicorns are causing GW (IFUGW) and there’s nothing we can do about it, so we may as well live as if there’s no tomorrow.

    For example, if one uses the strong precautionary principle to decide whether or not a new drug should be allowed on the market, one runs the risk of disallowing many perfectly good drugs, causing harm to society. Thus the strong precautionary principle has a risk of causing harm to society so should not be allowed under the strong precautionary principle.

    An extreme form of this argument is captdallas’ comment upthread: Let’s consider flipping a switch and turning all the fossil fuel energy off.

    That clearly would be catastrophic if we did not at some point turn the lights back on. I’m not much for binary thinking, and think of the problem in terms of using a dimmer control. The Wikipedia article on the Precautionary Principle couches this in terms of reversibility:

    Weak precaution holds that lack of scientific evidence does not preclude action if damage would otherwise be serious and irreversible. Humans practice weak precaution every day, and often incur costs, to avoid hazards that are far from certain: we do not walk in moderately dangerous areas at night, we exercise, we buy smoke detectors, we buckle our seatbelts.

    … or my favorite example: we slow down on dark foggy roads, especially when approaching a blind curve.

    So here’s how my risk-aversion calculus works. If one risk is plausibly irreversible AND the action to mitigate that risk is reversible, do the mitigation. Just because we implement policy to transition to non-fossil fuel energy technologies does not mean that the fossil fuels or our ability to use them will completely vanish.

    Again I propose a simple model: SCC is the estimated cost of replacing emissions with satisfactory equivalents. The longer we delay such a transition, the less time we putatively have to do it and at a potentially much higher cost.

    • “What I don’t understand is how setting a tax using a social cost model differs in terms of leaving policy makers to choose what *they think* is the appropriate moral decision.”

      If someone tries to argue for moral parameters that are outside of empirical observations then they will have a difficult time convincing others. Given that most countries are democracies, it will be hard in the long term for those that advocate policies that are not in agreement with the preferences of the people to remain in power. Empirical evidence constrains what moral parameters are reasonable, and it may be possible to get a majority of people to agree to use the parameters that are in best agreement to empirical observations (since most people in society will tend to have preferences that correspond to these parameters).

      “So here’s how my risk-aversion calculus works. If one risk is plausibly irreversible AND the action to mitigate that risk is reversible, do the mitigation. Just because we implement policy to transition to non-fossil fuel energy technologies does not mean that the fossil fuels or our ability to use them will completely vanish.”

      So if I apply this to transgender people, are you suggesting that transgender people should not be allowed to have sex change operations, because they are irreversible?

      I think it makes sense to take into account the probably, benefits and risks of all outcomes when making decisions such as climate change policy. The weak precautionary principle is pretty much just a lazy approximation to expected social welfare maximization that works in some cases, but that doesn’t men you should apply it to all scenarios.

      “Again I propose a simple model: SCC is the estimated cost of replacing emissions with satisfactory equivalents.”

      But that isn’t the definition of SCC. SCC is the net external cost of CO2 emissions.

      • -1=e^iπ,

        If someone tries to argue for moral parameters that are outside of empirical observations then they will have a difficult time convincing others.

        I understand that. What I’m not getting is your implied argument that this applies only to a social welfare maximization model.

        So if I apply this to transgender people, are you suggesting that transgender people should not be allowed to have sex change operations, because they are irreversible?

        Only if allowing people to have sex change operations has a global social cost which is plausibly on the order of unabated CO2 emissions. Perhaps a better example is the nearly universal principle that use of deadly force in self-defense is moral. Or … even better, capital punishment vs. life imprisonment with no parole for murder.

        I think it makes sense to take into account the probably, benefits and risks of all outcomes when making decisions such as climate change policy.

        That would be ideal. The perennial problem is knowing *all* (your word) outcomes of a given course of action.

        I can very easily flip your argument. I think it makes sense to take into account the probable benefits and risks of all outcomes when making the decision to purchase a tank of gasoline.

        The weak precautionary principle is pretty much just a lazy approximation to expected social welfare maximization that works in some cases, but that doesn’t men you should apply it to all scenarios.

        Nor did I say it should. I’m arguing that it makes sense when the risk of one action is reversible and the other one plausibly is not. In that case, the rational choice is the reversible decision.

        But that isn’t the definition of SCC. SCC is the net external cost of CO2 emissions.

        Objecting to my on-the-fly redefinition doesn’t address the argument I’m making. But so as to not create undue ambiguity, simply replace SCC with SCR (social cost of replacement).

      • -1=E^IΠ

        Given that growth rates have gradually been slowing over time globally …

        You say the period of observation is since 1950. What would conclude if the duration included the periods when major energy transitions took place (e.g. the start of the Industrial Revolution)? The reason I ask is because there is a massive energy transition ahead – to fuel that is 20,000 to 2 million times more energy dense than fossil fuels. What this will do for humanity is unimaginable.

        Question: can you give a simple equation and a figure for the damage function such as change in world GDP per degree of change of global average temperature (for both cooling and warming)?

  37. Given this range of possible “damage functions,” combined with significant uncertainty concerning the costs of limiting emissions of carbon dioxide and other greenhouse gases — costs which may, among other things, slow down the rate at which poor countries develop, thereby making the inhabitants of those countries more susceptible to climate and other changes — the social cost of carbon should be set at zero.

    http://reason.org/files/social_costs_of_regulating_carbon.pdf

    Indeed!

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