A look at the debate among climate scientists about global warming

Summary:  For those who like to see both sides of the climate science debate, this article by Judith Curry describes the consensus and shows some of the research challenging it — focusing on the last volley, the results of the Berkeley Earth Surface Temperature (BEST) project.

A key element of the successful propaganda by both the left and right in America lies in their ability to maintain the ignorance of their flock, closing their minds to contrary evidence. In climate science that requires blindness to those scientists who disagree with the consensus (which is not as large as the faux-scientific polls suggest). Here we have another article showing that there is a debate. Like most conflicts in science, eventually we will see clear answers (although perhaps a different ones than anyone today expects). That’s how science works.

Observation-based (?) attribution

By Judith Curry, Professor and Chair of the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology.  Shee is also the cliimatoloogist on the BEST team.
From her website Climate Etc, 30 July 2012. Also see her GIT website, with information about her research and publications.
The opinions expressed in this post do not in any way reflect the opinions of Georgia Tech. This article was reposted here under the terms of the Creative Commons license.


  1. Summary
  2. Introduction
  3. Guidelines from the IPCC attribution workshop
  4. Criticism of the IPCC Ar4 detection and attribution arguments
  5. Observation–based analyses {as opposed to model-based analysis}
  6. Specific issues with the Rhode, Muller et al. analysis
  7. Other opinions on the Rhode, Muller et al analysis
  8. For more information about the climate science debate

(1)  Summary

Attribution of the recent warming remains a challenging problem.  The model-based methods used by the IPCC have numerous problems, but the main advantage is that hypotheses regarding causal mechanisms can be tested (by turning off or enhancing various processes).

Observation based methods are gaining more traction, and increasing recognition is being given to multidecadal natural variability.  The challenge here is that there are lags and nonlinear shifts in the system, making the attribution to external forcing agents challenging.

No one that I listen to questions that adding CO2 to the atmosphere will warm the earth’s surface, all other things being equal.   The issue is whether anthropogenic activities or natural variability is dominating the climate variability.  If the climate shifts hypothesis is correct (this is where I am placing my money), then this is a very difficult thing to untangle, and we will go through periods of rapid warming that are followed by a stagnant or even cooling period, and there are multiple time scales involved for both the external forcing and natural internal variability that conspire to produce  unpredictable shifts.

Maybe the climate system is simpler than I think it is, but I suspect not.  I do know that it is not as simple as portrayed by the Rhode, Muller et al. analysis.


However, this does not stop the team from cheering Muller’s conclusion, see especially the thinkprogress post and the comments.  If the attribution problem was as simple as Muller makes it out to be (curve fitting to CO2 concentration), then why are others wasting all their time with complex modeling studies, data analyses etc as described above?   At least William Connolley and Eli Rabett have stated this analysis is oversimplistic {see section 7 for quotes}.

(2) Introduction

Moreover, it appears likely that essentially all of this increase results from the human emission of greenhouse gases. These findings are stronger than those of the Intergovernmental Panel on Climate Change, the United Nations group that defines the scientific and diplomatic consensus on global warming. In its 2007 report, the IPCC concluded only that most of the warming of the prior 50 years could be attributed to humans.
— “The Conversion of a Climate-Change Skeptic“, Richard Muller (chair of the Berkeley Earth Surface Temperature (BEST) project, op-ed in the New York Times, 28 July 2012

Muller bases his ‘conversion’ on the results of their recent paper. So, how convincing is the analysis in Rohde, Mueller, et al.’s  new paper “A new estimate of the average surface land temperature spanning 1753-2011“?   Their analysis is based upon curve fits to volcanic forcing and the logarithm of the CO2 forcing (addition of solar forcing did not improve the curve fit.)

I have made public statements that I am unconvinced by their analysis.  I do not see any justification in their argument for making a stronger attribution statement than has been made by the IPCC AR4.  I have written MANY posts that critique the IPCC’s attribution analysis.  Here I try to give a sense of the challenges in attributing climate change to causal factors.

(3)  Guidelines from the IPCC attribution workshop

Lets first take a look at how the IPCC approaches the attribution of climate change.  A good summary is provided by the 2009 IPCC Expert Meeting on Detection and Attribution Related to Anthropogenic Climate Change:

Attribution “of causes of climate change is the process of establishing the most likely causes for the detected change with some defined level of confidence” . As noted since the SAR, unequivocal attribution would require controlled experimentation with our climate system. Since that is not possible, in practice attribution is understood to mean demonstration that a detected change is “consistent with the estimated responses to the given combination of anthropogenic and natural forcing” and “not consistent with alternative, physically-plausible explanations of recent climate change that exclude important elements of the given combination of forcings” (Mitchell et al., 2001).

Information about the expected responses to external forcing, so called ‘fingerprints’, is usually derived from simulations by climate models, although the use of simple or conceptual models is possible as well. The consistency between an observed change and the estimated response to a forcing can be determined by estimating the amplitude of a ‘fingerprint’ from observations and then assessing whether this estimate is statistically consistent with the expected amplitude of the pattern from a model. If the response to a key forcing, such as greenhouse gas increases, is also distinguishable from that to other forcings, this strengthens confidence in the attribution assessment. Often, results are based on multiple regression of observations onto several fingerprints representing climate responses to different forcings, and in many cases, the estimate involves a metric that increases the signal-to-noise ratio by suppressing internal climate variability.

Global scale surface temperature is recorded by an instrumental record of 150 years and reconstructed from palaeo data over several centuries. Both compare well with climate model simulations if driven with estimates of external forcing, even on the scale of large regions. This comparison, attribution studies and physical energy considerations led to the assessment that it ‘is extremely unlikely (<5%) that the global pattern of warming during the past half century can be explained without external forcing’.

Results from fingerprint studies show that the response to greenhouse gases can be well separated from that to other forcings, and that the recent warming requires a significantly positive and substantial response to greenhouse gas forcing, irrespective of the model used and robust to a variety of technical choices. The fingerprint does not require significant rescaling to match the observed change. All this led to the assessment that ‘greenhouse gas forcing has very likely caused most of the observed global warming over the recent 50 years’. Results for individual continents for the same timeframe show that ‘it is likely that there has been a substantial anthropogenic contribution to surface temperature increases over every continent except Antarctica’.

The AR4 presented strong evidence that recent multi-decadal trends in global near-surface temperatures were very unlikely to have been caused by natural internal variability or natural external forcings from changes in solar output and explosive volcanic eruptions. Since then, the fact that neither 2007 or 2008 has broken the record for warmest year in the instrumental record has been used by some to claim that global warming has stopped or slowed down.

However papers by Easterling and Wehner (2009) and by Knight et al. (2009), have demonstrated that decade long trends with little warming or cooling are to be expected under a sustained long-term warming trend, as a result of multi-decadal scale internal variability. These results underscore the importance of understanding the effects of variability, in addition to external drivers of climate.

Detection of the anthropogenic and natural fingerprints of near-surface temperature change has enabled robust observationally constrained quantification of the contributions of different forcings to global temperature trends and likely ranges of future warming, assuming particular emissions scenarios (Stott et al, 2006). By including multiple climate models to provide estimates of the uncertainty in response patterns, more comprehensive estimates of attributable changes are obtained (Christidis et al, 2009).

Change in most variables of interest has multiple causes, whether in the climate system itself or downstream in natural or human systems. Therefore, attribution to the external forcing of interest must take into account the other forcings and drivers that affect the variable of interest. The effects of external forcings and drivers may be masked or distorted by the presence of confounding influences or factors. Expert judgement based on as complete an understanding as possible of the data, response processes and potential confounding factors and their possible effects should be used to carefully assess the likelihood that the detection and attribution results are substantially affected by confounding factors.

Non-climate drivers can have a significant influence on many natural or human systems. For example, the impact of mass coral bleaching events may be affected by the presence or absence of non-climate related drivers such as fishing pressure and pollution. To the extent that the response to greenhouse gas forcing can be separated from the responses to other external forcings and drivers, the change attributable to greenhouse gas forcing can be assessed and further used to produce probabilistic projections of future change.

Confounding factors may lead to false conclusions within attribution studies if not properly considered or controlled for. Examples of possible confounding factors for attribution studies include pervasive biases and errors in instrumental records; model errors and uncertainties; improper or missing representation of forcings in climate and impact models; structural differences in methodological techniques; uncertain or unaccounted for internal variability; and nonlinear interactions between forcings and responses.

(4)  Criticism of the IPCC Ar4 detection and attribution arguments

In my Climate Science and the Uncertainty Monster paper (Bulletin of the American Meteorological Society, December 2011), we argued that that AR4 attribution statement was overconfident for the following reasons:

  • uncertainties in the models
  • failure to account for uncertainties in external forcing (particularly solar and aerosols) and the use of inverse modeling in determining aerosol forcing
  • inadequacy of the climate models in simulating natural internal variability on multidecadal (>30 years) timescales
  • bootstrapped plausibility and circular reasoning in the detection and attribution arguments

(see also the response by Hegerl et al {Bulletin of the American Meteorological Society, December 2011} and Curry and Webster’s {ditto} response.)

(5)  Observation–based analyses {as opposed to model-based analysis}

For those of you that think climate models aren’t useful for attribution studies and/or prefer observation-based analyses, lets take a look at some of the better analyses. On the Trends, Changepoints, and Hypotheses thread, I described 3 hypotheses that explain 20th century climate variability and change, that have provided frameworks for observation based attribution analysis:

(a)  IPCC AGW hypothesis

20th century climate variability/change is explained by external forcing, with natural internal variability providing high frequency ‘noise’. Best in class:  Lean and Rind {Geophysical Research Letters, 16 September 2008}.  They conclude:

Empirical models that combine natural and anthropogenic influences (at appropriate lags) capture 76% of the variance in the CRU monthly global surface temperature record, suggesting that much of the variability arises from processes that can be identified and their impact on the global surface temperature quantified by direct linear association with the observations.

(b)  Multi-decadal oscillations plus trend hypothesis

20th century climate variability/change is explained by the large multidecadal oscillations (e.g NAO, PDO, AMO) with a superimposed trend of external forcing (AGW warming). Best in class:  “On the time-varying trend in global-mean surface temperature“, Wu et al, Climate Dynamics, August 2011 (see my analysis here).  They conclude:

Depending upon the assumed importance of the contributions of ocean dynamics and the time-varying aerosol emissions to the observed trends in global-mean surface temperature, we estimate that up to one third of the late twentieth century warming could have been a consequence of natural variability.

(c)  Climate shifts hypothesis

20th century climate variability/change is explained by synchronized chaos arising from nonlinear oscillations of the coupled ocean/atmosphere system plus external forcing   Such as:

From Tsonis et al.:

The above observational and modeling results suggest the following intrinsic mechanism of the climate system leading to major climate shifts. First, the major climate modes tend to synchronize at some coupling strength. When this synchronous state is followed by an increase in the coupling strength, the network’s synchronous state is destroyed and after that climate emerges in a new state. The whole event marks a significant shift in climate. It is interesting to speculate on the climate shift after the 1970s event.

The standard explanation for the post 1970s warming is that the radiative effect of greenhouse gases overcame shortwave reflection effects due to aerosols [Mann and Emanuel, 2006]. However, comparison of the 2035 event in the 21st century simulation and the 1910s event in the observations with this event, suggests an alternative hypothesis, namely that the climate shifted after the 1970s event to a different state of a warmer climate, which may be superimposed on an anthropogenic warming trend.

(6)  Specific issues with the Rhode, Muller et al. analysis

Judged by standards set by the IPCC and the best of recent observation-based attribution analyses, in my opinion the Rhode, Muller et al. attribution analysis falls way short.  The closest in approach is the Lean and Rind analysis, which considers all of the external forcings (with units, not just curve fits) and discusses their uncertainties.  Looking at regional variations provides substantial insights into the attribution.

Both global and regional attribution studies have been done, but what are we to make of the global land attribution study done by Rhode, Muller et al.? Land has warmed substantially more than the oceans; it does not seem that their same model would explain the ocean  temperature changes.  Also, given the regional variations in attribution, going back to the 18th and 19th centuries tells us what is going on in western europe and eastern north america, which is dominated by ocean circulation patterns in the North Atlantic and high latitude volcanoes. While I like what they have done going back further in time, these regional data are of little use for a global attribution study.

———————–  End of Judith Curry’s article  ——————–


(7)  Other opinions on the Rhode, Muller et al analysis

(a)  Andrew Riekin at the blog of the New York Times:

Muller, who has combined P.T. Barnum showmanship and science throughout his three-year project, chose to break the news in an Op-Ed article in The NY Times (with various leaks and rumors percolating on the Web). There are perils in having publicity precede peer review.

… After the first round of papers went online last fall, some climate scientists, while put off by Muller’s past diatribes and self-promotional zeal, were mildly enthusiastic (see Gavin Schmidt here). But others, notably the climate modeler William Connolley through his Stoat blog, have dismissed Muller’s work — old and new — as “rubbish.

(b)  Climate Scientist Michael Mann, posted at Facebook:

My view is that Muller’s efforts to promote himself by belittling the collective efforts of the entire atmospheric/climate research community over several decades, though, really does the scientific community a disservice. Its great that he’s reaffirmed what we already knew. But for him to pretend that we couldn’t trust this entire scientific field until Richard Muller put his personal stamp of approval on their conclusions is, in my view, a very dangerously misguided philosophical take on how science works. It seems, in the end–quite sadly–that this is all really about Richard Muller’s self-aggrandizement :(

(c)  One of the BEST project’s first round of work was submitted to the Journal of Geophysical Research, a paper by Charlotte Wickham et al. presenting analysis of the effect of urbanization on land surface temperatures.  Ross McKitrick was one of the reviewers. He’s released his referee reports. The first, from September 2011, is here and the second, from March 2012 is hereHe was told by JGR that “This paper was rejected and the editor recommended that the author resubmit it as a new paper.”

(d) Despite the title of his NYT op-ed, physicist Richard Mueller was not a “climate-change skeptic” in any usual sense of the term (and its a dumb term; only a fool doubts that the climate is always in motion). For evidence see the quotes (& links) in these articles at Popular Technology and the Huffington Post.

(8)  For more information about the climate science debate

See the FM Reference Pages about climate change:

Some posts describing research, and statements by scientists:

  1. Richard Feynmann, one of the 20th centuries greatest scientists, talks to us about climate science, 12 February 2009
  2. Big news from NASA about the causes of climate change!, 6 June 2009 — About solar effects
  3. Breaking news: a new analysis blows more holes in the “hockey stick” temperature reconstruction, 15 August 2010
  4. What can climate scientists tell about the drivers of future warming?, 6 February 2012
  5. What can climate scientists tell us about the drivers of future warming?  – part two of two, 10 February 2012
  6. The slow solar cycle is getting a lot of attention. What are its effect on us?, 11 February 2012
  7. A famous scientists makes a startling admission about Earth’s climate, 26 April 2012

25 thoughts on “A look at the debate among climate scientists about global warming”

  1. I’ll look to NOAA and the DOD rather than the NYT, WAPO or WSJ for information on climate change. People can believe that Thing 1 and Thing 2 from the Cat and the Hat Comes Back (great book on particle physics by the way) are the cause for warming and drought and melt or that its some sort of conspiracy. But reality has a dangerous left hook and for the moment “climate change” is undeniably taking place. DOD is preparing for the fallout (esp in ARCTIC along coastlines and for disasters) and NOAA does a great job tracking and explaining it all.

  2. This Defense Science Board report is well phrased and pretty good. “Trends and Implications of Climate Change for National and International Security”, October 2011 (large PDF here). DOD and its legion of affiliated think tanks, universities and associations have cash so it is hard not to consult what they produce. Can’t just ignore it. Now and then they put some good stuff out. The intro language in the report at DSB is well put indicating that climate change will not be “solved” but must be managed. They are right.

    Wall Street is already looking for “fund raising” and money making opportunities that climate change will provide. Here is JP Morgan Transitioning to a low carbon economy. Sure they rip off billions like DOD but they are a key instrument of US national power.

    Agree on the other sites and this one is good too NASA Global Climate Change.

    Anyway, we are living in the Anthropocene. We can now re-engineer ourselves for a resource challenged environment. We can geo-engineer the climate intentionally. Our species is now present over 73% of the world’s landmass. Of course we do not know what the consequences of our actions will be since we don’t give a &^%$ for anything but our own lifetimes, ignoring our kids’ futures. At any rate, DOD will be called in when civilians are overwhelmed by disaster and, as you have discussed so eloquently, we are already becoming some sort of national security state.

    1. (1) “DOD and its legion of affiliated think tanks, universities and associations have cash so it is hard not to consult what they produce. Can’t just ignore it.”

      Everybody reads the sources they personally find useful. But that statement makes little sense to me. You can “just ignore it” because there are many far superior sources of scientific analysis, far less biased. Our fetish about the military, that they’re the first source for everything, is IMO exaggerated.

      (2) “Now and then they put some good stuff out.”

      Yes, but that’s hardly a ringing endorsement.

      (3) “The intro language in the report at DSB is well put indicating that climate change will not be “solved” but must be managed. They are right.”

      The climate has always been changing — the important fact which AGW propaganda seeks above all to conceal. The debate in climate sciences concerns the extent to which the net effect of human actions (eg, co2, aerosols, land use changes) has changed our climate since WWII (and to a smaller degree over the past century), and forecast the effect of conjectural future changes. Conjectural because there are many variables, such as the extent of buring fossil fuels — which in turn depends on the extent of reserves and development of new technology.

      There are many unknowns and many variables. History suggests that the degree of confidence expressed by experts provides an unreliable guide to their accuracy. Even scientists.

      That is especially so when these things are still debated by scientists (the point of this and so many other posts on the FM website). And that is the peril of relying on climate change reports by non-relevant institutions. They almost always ignore the debate among scientists, and assume one side is correct.

  3. bear with me, I’m going to delve into dream land a bit here…..

    In recongnition of climate change, why don’t the developed nations of the world perform our own experiment and rapidly build renewable energy infrastructures and set up new incentives for people to live more “sustainable.” Then take records of the weather for two to three decades and see what changes take place. After this we may be able to fully understand if climate change is entirely due to human activity or not.

    Plus, we just set up the infrastructure for all that necessary renewable energy and low-and-behold……conserving our fossil fuels becomes much easier, almost habit.

    1. I assume that in your dream the Blue Fairy pays for this experiment?

      Otherwise it’s mad to spend trillions on an experiment to convert the developed nations’ infrastructure to renewable energy.

      (1) The cost would be fantastic, even if done over decades. We’d need to build the infrastructure to build the new infrastructure. To mention just one of many: new mines to produce the rare earths to feed the new factories making batteries for the new cars.

      (2) It might not be practical or even possible. Converting transportation and electric power on such a scale might be beyond our current abilities, at any reasonable cost. Current electric grids cannot handle the varing output of solar and wind above 5% or 10% of total. There are solutions, but not cheap.

      (3) Renewable energy is almost always more expensive — often far more expensive — than current sources.

      (4) It’s mad to spend such vast sums on what today is a possible problem, when we face so many certain problems. Visit India or much of Africa to see for yourself what real needs look like. Poverty, resource exhaustion, pollution — they have it all.

    2. I know I understand, but we’ll have to use renewables eventually and we’ll need the fossil fuels to build it all right? Unless fusion turns out to be our savior in the coming decades. Plus, in the process, create the incentives to make most of our needs met as local as possible. Greatly limiting our need for travel. For instance: give land back to the public (free of charge) with the stipulation that it must be used to grow food for the local population, giving a small salary to those who work the land – more hands, less machines – (or everyone participates in order to take groceries).

      1. “I know I understand, but we’ll have to use renewables eventually and we’ll need the fossil fuels to build it all right?”

        “Eventually” is the key work, and could be a long time away. Time is the key variable. Starting as a massive program now, rather than a slow evolution as technology evolves, looks crazy based on available knowledge. Consider the results if we’d attempted a crash conversion to petroleum starting in 1830.

      1. “do you really feel it’s a long way away?

        That’s an important question, and goes directly to one of the key divisions among people. There are those with strong opinions on technical issues outside their personal expertise, and those that refuse to take strong stands on such issues.

        I am in the latter group. The great theme of articles on the FM website about climate change and energy is that there is debate among experts, but the public tends to see this as teams. Red and blue, shirts and skins. Go team! Booo!

        IMO that’s degranged. If the experts debate these issues, then we should recognize the debate an adopt positions that recognize this uncertainty. This refusal to see the world in dogmatic black & white terms has produced some of the strongest discussion (and some of my most interperate responses, which I’m working to avoid).

        There are two other kind of debates often seen here. Some concerns values. Is torture good, for examample (quite a few long comment threads, to which my horrified reaction was to shut down comments for a while (some opinions I’d rather not know).

        The other is about the future. Forecasts. Both of these are pure discussions, unresolvable except by time — the universal solvent.

  4. Climate change is just one of the potential undesirable side effects of relying on fossil fuels for our energy supply. We also have to consider political instability in the Middle East, which could lead to war and oil price shocks; the possibility of peak oil price shocks as increasing demand from the rapidly industrialising BRICs could outstrip supply; pollution incidents like the Gulf of Mexico; destruction of the Appalachians by the coal mining industry; etc.

    Fabius – would adding this bigger picture of the changing costs & benefits of fossil fuels alter your assessment of the urgency of our situation?

    1. I’ve said this many times, and probably will again. We cannot prepare for climate change as yet because we don’t adequately understand its causes, timing, magnitude, effects, or mitigation strategies. To pick one of a thousand questions, melting of polar ice has many effects (eg, changing Earth’s albedo) — including rising sea level from possible melting of greenland’s ice cap. How much of that is from changing wind patters, deposition of black carbon particles on the ice’s surface, natural warming (continuation of the 2 century-long cycle), and anthropogenic warming from CO2 emmissions? How much will feasible reductions of CO2 emmissions affect that melting? Inspired guessing, no matter how dressed up with fancy models, doesn’t help determine how much of our scarce resources to invest.

      Also, how do we weight this against known problems: pollution (an many-headed hyrda), poverty, our rotting infrastructure, and natural disasters.

      Speaking of the latter group… How much should we invest to mitigate earthquake risk from the New Madrid fault (itself a controversial debate), the San Andres fault, and the Cascadia fault? How about preparing for giant tsunamis from quakes on the western border of the Pacific “rim of fire”? What about the risk of a California superstorm (here and here). What about the many other such risks we can easily list?

      When any of those strike, perhaps causing billions — or tens of billions of dollars in damages — and killing thousands or tens of thousands of people, we’ll be told (as after the New Orleans flooding) how often we’d been warned. How often we ignored the warnings. And then we’ll spend fortunes on that threat…

      So just list the dollars the US should invest for each of the above, by year, for the next decade. Be sure to show your calculations and cite adequate and sufficient sources!

    2. When facing a multiple-headed hydra problem, it is best to locate the heart of the problem and strike at that, rather than flail at the heads. I see climate change as simply a single head of our deeper problem of the consequences of our reliance on fossil fuels and our wasteful use of natural resources as a whole. As such, it is not necessarily the case that measures to mitigate and cope with climate change will be in opposition to efforts to deal with our other problems. We may not know all we wish about climate change yet, and we cannot know the future, but to fail to plan is to plan to fail. We should therefore seek sensible courses of action which could have beneficial and synergistic effects on a number of areas.

      For example, a strategy of steadily promoting better energy efficiency would cut our fuel bills, lower our CO2 emissions and, by reducing the overall quantity of fuel we use, would also reduce overall pollution and lower our susceptibility to fuel supply shocks. A program to help achieve this by helping households and firms to insulate and weatherise their buildings to good standards would also protect people against extreme weather and create many jobs, which would in turn improve the economy.

      With regards to financial costs, I am with Keynes that if we fix the unemployment then the finances will take care of themselves. The economy starts with real people doing real work in the physical world, making real products and services that people want, having new ideas and translating them into new things. Money is only some little green pieces of paper coming from a printing press. For some peculiar reason these pieces of paper can be waved in front of a human, causing it to stop what it was doing to chase after them to do something else. There are many millions of unemployed people at the moment and many other resources lying idle in this recession. Put them to work doing useful things and the economy will lift again.

      1. (1) “For example, a strategy of steadily promoting better energy efficiency”

        Yes and no.

        The closest thing we have to an energy plan for America is “Peaking of World Production: Impacts, Mitigation, and Risk Management“ (aka “Mitigations”), commissioned by the Dept of Energy, Co-authors are the economists Roger Bezdek and Robert Wendling, February 2005. That makes a strong case for a 20 year large-scale program to prepare for peak oil.

        But much of that involves tapping our vast lower-quality deposits of fossil fuels, since there probably is no viable alternative during the next few decades. That’s the opposite of carbon-emmission reduction. As so often in the real world, our serious problems have contradictory solutions.

        (2) “With regards to financial costs, I am with Keynes that if we fix the unemployment then the finances will take care of themselves”

        That’s not accurate, unfortunately. Many economists today believe that fiscal policy has tighter limits for its effectiveness than Keynes thought, hence all those debates about the Bush/Obama stimulus programs. It seems likely that to the extent that we have underutilized resources, putting them to work via government borrowing can be net beneficial for society. But that also assumes that the government budget is balanced over the full business cycle (Keynes was clear about that!).

        Borrowing to fund projects that improve our energy infrastructure probably will be optimal until unemployment returns to normal levels — assuming they use unemployed people. Real estate brokers, people building homes during the bubble, teachers, salespeople. Concentrated sector projects have to be relatively small scale and short-term to qualify as stimulus programs. Rebuilding our energy infrastructure fits only a weak way, as it requires skilled people (engineers, scientists, technicians) few of whom are unemployed today.

        That’s why the case for rebuilding our core infrastructure is so strong: we can borrow at near-zero rates to put unemployed construction industry workers to work repairing roads, bridges, etc.

    3. Interesting report, but I can see on a brief read that it concentrates on transportation and peak oil.This is an important part of our problems for sure, but my critique still be that it falls short of a comprehensive strategy review. The closest I have found to what I am looking for would be David MacKay’s Sustainable Energy Without the Hot Air (http://www.withouthotair.com/). If we cannot avoid gas fracking and tar sands without putting out the lights then we will have to use them but with a knowledge that they are only a stop-gap. We have many options to move away from fossil fuels. None are easy. All involve tradeoffs. All would take considerable effort and time. I still maintain that having a broad brush Grand Strategy to increase our energy efficiency and reduce our energy usage year by year would concentrate minds and set a direction of travel. The less energy we use, the easier our problems in supplying it will be.

      As to the economists, perhaps our first action should be to find ouselves a nickel and buy a better bunch of economists? My choice would be the Modern Monetary Theorists. Not just because they tend to say things I like (although that is always nice!) but because they seem to me to have had a good track record of making testable predictions which then come true (failure of the Euro, unsustainable private sector debt levels will lead to a crash, bank bailouts would not cause hyperinflation, interest rates on bonds will not rise but fall except in Europe, …).

      I believe they would say that in a country with a trade deficit using fiat currency, Keynes’ strictures about balancing the government budget no longer apply. Attempts to balance the government budget, let alone achieve a government budget surplus, can be actually dangerous to the real world economy in these circumstances. The aim of functional fiscal and monetary policy should be to achieve the public purpose in the real world and not to target some particular set of financial indicators. When there is rotting infrastructure then we should replace the rotting infrastructure, in spite of the wailing and gnashing of teeth that will invariably come from some economists at the very thought of spending any money whatsoever on any public purpose whatever.

      1. (1) “but my critique still be that it falls short of a comprehensive strategy review.”

        It’s all we have; and its been ignored — so an even broader review probably would be ignored even more. Also, transportation — using liquid fuels — is by far the most problematic part of the energy picture in terms of potential for serious price increases and potential scaricty. Therefore it’s the logical place to start.

        (2) “We have many options to move away from fossil fuels.”

        Can you cite an any expert analysis saying such a thing (not one guy speculating in a book)? Just limiting the question to replacing petroleum in transportation is difficult enough; raising the goal to include ALSO replacing other uses of fossil fuels (ie, replacing coal and natural gas in heating and electrical generation) moves it beyond the capability of current technology. Unless you mean “move away” in the sense of “very slowly” — ie, over generational time frames” (generation = 20 years).

        MacKay’s Sustainable Energy book (see his website for details) illustrates the difficulty of replacing fossil fuels. The most specific recommendation he gives is a 1/3 mix of solar/wind/nukes. Europe has invested heavily in solar and wind, with mixed results (considerable anger esp about the poor results of wind); including the cost of back-up power for these interruptable sources makes them VERY expensive. Add onto that the cost of “long distance cables connecting the Sahara to Surrey, with a capacity 25x the existing England-France interconnector” — that’s roughly 1,700+ miles (along existing roads), crossing two bodies of water and the Pyrenees AND Atlas mountain ranges (the cost includes construction, operation, and the energy lost over the cable’s length).

        As for a massive expansion of nukes … good luck selling that. IMO MacKay’s book is an interesting thought-starter, but not to be taken seriously.

        (3) “to have had a good track record of making testable predictions which then come true”

        What is your source for this list of predictions?

        (4) “Keynes’ strictures about balancing the government budget no longer apply”

        It’s not just “Keynes strictures”, it’s almost every economist, always. And MMT’s liberation from accouting reality accounts, IMO, for much of its popularity. More generally, times of stress often result in popularity of fringe theories offering wonderful things. Such as those of economist John Law (see Wikipedia).

        The proof for a claim must in some sense be commensurate with the character of the claim. Thus an extraordinary claim requires “extraordinary” (meaning stronger than usual) proof.
        — Marcello Truzzi, “Zetetic Ruminations on skepticism and anomalies in science“, Zetetic Scholar, August 1987

    4. 1) I don’t disagree.

      2) I perhaps should have said that “We have many options to move away from fossil fuels, but some will prove to be lemons”. We surely have many potential candidates for alternative energy sources, ranging from geothermal to varieties of solar, wind, nuclear etc. but, perhaps like the early development of the bicycle or the aeroplane, it is still difficult to judge which of these early and peculiar contraptions may prove to be useful and which to be potentially expensive blind alleys.

      And yes, I do mean move away in the sense of “very slowly”. This is a huge undertaking. I guess my difference with you may be that I view our energy & CO2 problems as more serious and suspect that government, oil and energy companies interpretation of “very slowly” will be “stationary” or even “backwards”. As such, I have to advocate strong government action in the hope of moving them at least an inch in a positive direction. At some point, we will just have to take risks and start to build and I would prefer sooner rather than too late, even at the risk of wasting some money on turkeys. As to MacKay’s book being an interesting thought-starter, but not to be taken seriously, I would disagree strongly. It should be taken seriously, but even more serious to me is that government ministers are plainly not taking these issues seriously at all.

      3) MMT predictions are scattered through the blogs, from memory. I would have to refer you to
      and http://bilbo.economicoutlook.net
      Mosler’s links about the euro are here: http://www.mecpoc.org/2012/07/a-word-on-the-explanatory-power-of-mmt-the-euro-crisis-explained-before-it-happened/

      4) Beg to differ re “MMT’s liberation from accounting reality”. Wynne Godley’s sectoral balances approach, which forms part of the core of MMT, is surely an accurate description of accounting reality whereas the neoclassical models usually fail to be stock-flow consistent? (“TOWARDS A RECONSTRUCTION OF MACROECONOMICS USING A STOCK FLOW CONSISTENT (SFC) MODEL“, Wynne Godley, May 2004)

      In the UK we have spent millions this year on bombing the Libyans, holding an extravagant Jubilee for the queen and are now spending millions more on the Olympics. At the hospital where I work we have spent several million on some of the most up-to-date radiotherapy equipment in the country and are being fleeced daily by a private wheel-clamping firm who charge us and the patients outrageous amounts to park in our own car park. But the masonry of the balcony outside my office is collapsing and the water pipes in the roof tend to burst and flood our offices several times a year. We have many unemployed construction workers in the country following the collapse of a housing bubble and government’s decision to axe many infrastructure projects.

      Management’s solution to this problem is to tell us that “the building is 100 years old”. We reply “yes, we know. So fix it before it falls down”. Their reply is always “but we haven’t got any money”. They have locked our exits to the back lawn instead, to keep us safe from falling masonry. I can’t help but feel that there is a metaphor here for our current woes in the western world as a whole. Economists may differ, but I have a hunch that our problems are not so much financial, but are surely unprintable.

      I guess this wraps up this interesting discussion for me. Hasta la Vista.

      1. (1) “And yes, I do mean move away in the sense of “very slowly”.”

        Then I think most people will agree with you. A multi-generational perspective gives us hope, but doesn’t help much in the 10-20 year time horizon on which most planning takes place. That’s a rather firm operational constraint, since forecasts longer than that have a VERY low accuracy rate — and so provide an unreliable basis for planning large, expensive, vital projects.

        (2) “MMT predictions are scattered through the blogs, from memory. ”

        If MMT advocates had made so many fantastic predictions, you could find their predictions VERY easily. My guess is that you (or they) exaggerate very greatly.

        (3) “beg to differ re “MMT’s liberation from accounting reality”. Wynne Godley’s sectoral balances approach, which forms part of the core of MMT, is surely an accurate description of accounting reality…”

        You must be kidding us. That’s an accounting identity, and so obviously not the issue! When someone questions the government’s ability to expand the debt almost without limit, addition works is not a logical rebuttal.

        (4) “Economists may differ, but I have a hunch that our problems are not so much financial,”

        Your last paragraphs are IMO right on target. To use the common paraphrase of Keynes’ work, our problem is that we have a fine engine — but it has a burnt-out alternator. All the stomping and yelling — all the pain and suffering — will not make this technical repair.

  5. I won’t stick around to engage in flaming and counterflaming, but your choice of Judith Curry, not a climate scientist, who actively encourages threats against climate scientists (death threats amusing) does nothing but damage to your own argument.

    The science supporting anthropogenic global warming is overwhelming. Given that fact, I can only hope that you are being rewarded by AEI or some other radical rightist group (I will not use the word “conservative” for a radical agenda), for if you are lukewarming for free, it speaks poorly of your intellectual skills.

    The arctic ice is setting new record lows, for the third time in five years, in spite of weather not particularly conducive to melting.

    In the past ten years, western Europe, Russia, Australia and North America have suffered heat waves and droughts unprecented in the record.

    At the same time, record rains and floods have occurred in Australia, Central Asia and East Asia.

    You may not believe in global warming, but DOD does, and so does the insurance industry.

    However, doing nothing to mitigate global warming does present a plausible scenario for its cure:

    Increasing tension over scarce water resources at the world’s highest elevations leads to armed conflict between China and India. India is forced to withdraw troops from Kashmir to serve on the China front. Pakistan, seing a chance, invades Kashmir. India, with too few forces to defend the province, threatens to nuke Islamabad, to which Pakistan replies with a quick nuclear strike on Jaipur. This quickly (three hours or so) degenerates into a three-way exchange (after India tosses a bomb into eastern China) that lasts less than half a day, but the eight or ten bombs that have been exploded create enough dust thrown into the stratosphere to cause nuclear winter.

    See, global warming problem solved.

    1. Let’s take your comment in two parts.

      (1) “I won’t stick around to engage in flaming and counterflaming”

      Not allowed here. Facts and logic are valued. You can also express you values and speculation. That’s about it.

      As for sticking around, you might learn something.

      (2) “Judith Curry, not a climate scientist”

      On what basis do you make that remarkable assertion? Let’s look at her CV.


      • 1982 Ph.D., The University of Chicago, Geophysical Sciences

      Work History

      • 2002-now – Chair, School of Earth and Atmospheric Sciences, Georgia Institute of Technology
      • 1992-2002 – Professor, U of Colorado-Boulder, Dept of Aerospace Engineering Sciences, Program in Atmospheric & Oceanic Sciences Environmental Studies Program
      • 1989-1992 – Associate Professor, Dept of Meteorology, Penn State
      • 1986-1989 – Assistant Professor, Dept of Earth & Atmospheric Sciences, Purdue U
      • 1982-1986 – Assistant Scientist, Dept of Meteorology, Uof Wisconsin-Madison


      • 2004 – Fellow, American Geophysical Union
      • 2002 – NASA Group Achievement Award for CAMEX-4
      • 1997 – Elected Councilor, American Meteorological Society
      • 1995 – Fellow, American Meteorological Society”
      • 1992 – Henry G. Houghton Award, the American Meteorological Society
      • 1988 – Presidential Young Investigator Award, the National Science Foundation Councillor

      Professional Activities (last five years)

      World Meteorological Organization / International Council of Scientific Unions / International Ocean Commission / World Climate Research Programme

      • Global Energy and Water Experiment (GEWEX) Radiation Panel (1994-2004)
      • GEWEX Cloud System Studies (GCSS) Science Steering Group (1998-2004)
      • Chair, GCSS Working Group on Polar Clouds (1998-2004)
      • Chair, GEWEX Radiation Panel SEAFLUX Project (1999-2004)
      • Science Steering Group, Arctic Climate System (ACSYS) Programme (1994-2000)
      • Steering Committee, IGAC/SOLAS Air-Ice Chemical Interactions (2003- )

      American Meteorological Society

      • Executive Committee of the Council (1998-2000)
      • Councillor (1997-2000)
      • Awards Committee (1995-1997)
      • Editor, Journal of Applied Meteorology (1993-1996)

      National Science Foundation

      • Panel to review National Center for Atmospheric Research (2002)
      • Co-Chair, Science Working Group, Surface Heat Balance of the Arctic (SHEBA) (1993-1996)
      • Atmospheric Sciences Observing Facilities Advisory Panel (1994-1997)
      • Arctic System Science (ARCSS) Steering Committee (1993-1995)

      Department of Energy

      • Executive Committee, Atmospheric Radiation Measurement (ARM) Program (93-96) Chair (1997-2000) and Member (1993-2000), Science Steering Committee, ARM Alaska site

      National Aeronautics and Space Administration (NASA)

      • Lead Mission Scientist, FIRE Arctic Cloud Experiment (1996-1999)
      • Technology Subcommittee of the Earth System Science and Applications Advisory Committee (1997-2003)
      • Review Team, Earth System Science Pathfinder Missions (1998-1999)

      And so forth. More honors and responsible positions, long list of publications in major peer-reviewed journals.

      1. “Judith Curry, not a climate scientist”

        Let’s consider this statement, for it tells us much about America today.

        (1) It is the essense of trolldom, making a outlandish statement — and when called on it, feign amnesia and reply with still more misinformation. Quiet astonishing for someone claiming to be a retired professor.

        (2) This displays one of the most characteristics and revealing aspects of lay believers in AGW: scientists are authorities, unless they disagree with AGW orthodoxy — then they’re cranks (#8 on the list here). We can easily understand the reasoning.

        Lawy AGW believers demand massive and immediate public policy action to reduce CO2 emmissions in order to slow global warming. To do so they must believe that the science is settled. That’s contradicted by the debate among scientists about the causes of the past warming and forecasts of future warming. How to eliminate this cognitivie dissonance (Wikipedia)? Deny that these eminent climate scientists (eg, Judith Curry, Roger Pielke Jr, etc) are climate scientists. QED! Easy for a true believer.

        (3) This phenomenon is seen in both Left and Right of America today. The flock is led by placing blinders on their minds. On the Right believers are taught not to read Keynes or Krugman — who are not just wrong, but evil. Just as medievel priests told their flock what the Bible said — and discouraged reading the Bible — today’s conservatives learn and believe outlandish things about Keynes’ and Krugman’s theories.

        Ditto about health care. Conservatives are taught that european health care systems only appear to provide equivalent care at 1/2 to 2/3 the cost as ours. In reality those nations are hell holes, people subject to death panels (an example by Glenn Reynolds here). Learning is a dangerous thing.

        It’s used by both Left and Right because both are composed of Americans. Something in our character today makes us vulnerable to this manipulation.

    2. Now let’s examine notjonathon’s comment about climate science.

      (1) “The science supporting anthropogenic global warming is overwhelming. Given that fact…”

      Your comment shows that you are not a climate scientist (or even slightly familiar with the debate) — so your opinion doesn’t get to overrule that of climate scientists. Even climate scientists don’t get to overrule each other, as science is a process of debate and analysis.

      (2) “I can only hope that you are being rewarded by AEI or some other radical rightist group”

      I see why you expected flaming. Let’s ignore that foolishness and more on.

      (3) “The arctic ice is setting new record lows, for the third time in five years, in spite of weather not particularly conducive to melting.”

      • But the Southern Hemisphere ice extent tells a different story: it’s increasing (see the National Snow & Ice Data Center graph).
      • Short-term police ice changes are largely a function of wind patterns (see the research cited in section 3 here).
      • Black dust deposits (aka soot) on the polar ice might explain much of the melting during the past decade, with China a likely culprit. Again see Section 3 above.

      (4) “In the past ten years, western Europe, Russia, Australia and North America have suffered heat waves and droughts unprecented in the record.”

      The world has been warming for the past 2 centuries. Only in the past century, as esp since WWII, have CO2 levels spiked.

      (5) “At the same time, record rains and floods have occurred in Australia, Central Asia and East Asia.”

      See #3. Increase precipitation is the clearest (and probably only) sign of substantial climate change to date, and is an expected consequence of the warming.

      (6) “You may not believe in global warming, but DOD does, and so does the insurance industry.”

      Wrong guess. The debate among climate scientists concerns the magnitude and causes of the past warming, and estimates of future warming. The answers require better understanding of human-caused impacts, such as land use changes, c02 emmission, and aerosols. And the many natural cycles at work, some of which are poorly understood (ie, feedbacks from clouds, solar influence). Understanding of the net relationships is in its infancy, but improving fast.

      (7) “Increasing tension over scarce water resources at the world’s highest elevations leads to armed conflict …”

      Interesting wild guesses, but not a basis to do anything. We don’t know the odds that there will be such a climate change (eg, increased rain is a known effect of increased warming, and might offset that). Or what might be its magnitude. As for the political effects, that’s beyond guessing — just scary stories.

  6. Just one more time, then back to lurking.

    Not a climate scientist, true. Just a cranky old retired college professor–humanities, at that.

    Nevertheless, I find the reasoned work of Drs. Michael Mann, Gavin Schmidt and Michael Tobis far more convincing than Dr. Curry’s uncertainty principle or her occasional “it would be irresponsible not to speculate” denialism.

    As for global ice, Tamino has the latest over at Open Mind

    Regarding Antarctica, try Tamino on polar ice:

    The data are clear: sea ice extent declined dramatically during the 20th century in both hemispheres. The arctic sea ice decline has accelerated to the point that it can truly be described as “alarming.” And, those who claim that in the mid-20th century the arctic was “practically ice-free” are contradicted by the data.

    I do follow the debate. For those who are interested in the science, I recommend <a href="http://www.realclimate.org/"Real Climate, Planet 3.0, Open Mind. For arctic ice, no one is more thorough than Neven at <a href="http://neven1.typepad.com/"Arctic Sea Ice.

    1. I deleted my previous response, and will try again.

      (1) “I find the reasoned work of Drs. Michael Mann, Gavin Schmidt and Michael Tobis far more convincing than Dr. Curry’s ”

      I am more interested to see you justify your statement that Dr Curry is “not a climate scientist”. Esp as you claim to be a fellow academic, so you should understand the seriousness of your statement.

      Since you are not a climate scientist, which side of the debate you prefer is not meaningful IMO. Esp since you appear unaware of the most important aspect of the debate, which is that there is a debate among climate scientists.

      (2) “Antarctica”

      Your response suggests that you didn’t understand what I wrote. Let’s repeat — again: the Earth has been warming for two centuries, with only the post-WWII era subject to large human influences.

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