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On mismatches between models and observations

Filed under: — gavin @ 13 September 2013



  1. The observations are in error
  2. The models are in error
  3. The comparison is flawed


1. Observational Error



2. Model Error



3. Flawed Comparisons










Update: From the comments:

“our earth is a globe
whose surface we probe
no map can replace her
but just try to trace her”
– Steve Waterman, The World of Maps



167 Responses to “On mismatches between models and observations”

  1. 151
    Bradley McKinley says:


    You say:

    You are setting an special (and probably impossible) bar for this issue that is never set for any other decision. Are the consequences of current economic policies (which have a much bigger impact on the poor) being worked out at the ‘level of precision’ you are demanding? The answer is obviously not.

    I’m not sure I understand the basis for this claim. Cost benefit analysis is a standard requirement whenever a commitment of resources of this magnitude is contemplated. There is simply no other way for governments to determine how to best allocate the resources at their disposal. The fact that numerous peer reviewed studies have attempted to quantify impacts (e.g. Yohe et al. [2007]) demonstrates that even if you do not understand the need to conduct this type of analysis, others do.

    [Response: Ha. I'm actually well aware of the literature on cost-benefit studies and that most (even from Nordhaus) suggest that action is warranted. But the point I am making is somewhat different; namely, I do not think that cost-benefit analyses are anything but a rough guide to different pathways. Damage functions in these analyses are simplistic and mostly untested for the magnitudes of change projected, their ability to balance economic costs and social costs involve ethical judgements that are both opaque and not universal. The other point is that government decisions are made all the time with huge consequences with no such modeling being done - was the TARP bail-out assessed for it's impact on the African poor? Is the EU CAP? etc. So while I am all for policy-specific impacts modeling, I recognise it's limitations. - gavin]

    Additionally, I am unclear as to where your confidence in exactly what impact climate policies will have on the poor comes from. It is easy to imagine policies that price carbon and use the funds to reduce regressive taxation that is a huge burden.

    The confidence comes from the fact that third world countries have consistently voiced their objections to certain mitigation efforts such as carbon taxes on grounds that they, not the industrial world, would bear the brunt of the burden.

    [Response: Where does this come from? Most actions being contemplated are related to western use of fossil fuels for western consumption of transport and electricity. Impacts of a carbon price in the US say, are not going to be predominantly felt in Somalia. - gavin]

    Similarly, the poverty that you rightly condemn in Africa and other areas is far more associated the very endemic institutional issues than it is with energy poverty. That is a symptom, not a (primary) cause. But even there, there are large parts of rural Africa where local solar (for instance) is already cheaper than extending the grid to supply fossil energy.

    I agree that energy poverty is a symptom of the institutional issues. However, you cannot deny that anything that makes energy more expensive will have severely negative impacts on the third world. If local solar is indeed cheaper than fossil fuels, there is no need for carbon taxes to make fossil fuels more expensive–market forces will ensure the switch all by themselves.

    [Response: Not true. The biggest handicap in rural poverty is lack of access to capital - even if new projects are enormously beneficial on even a standard cost/benefit analysis, they still do not get done. The idea that market forces automatically do the best thing in these cases is a fallacy. - gavin]

    The idea that climate must be balanced directly and exclusively against the global poor is a false dichotomy. And none of this has anything to do with models.

    I never claimed that climate must be balanced directly and exclusively against the global poor.

    [Response: Good. - gavin]

  2. 152
    Mal Adapted says:

    Tamino’s on a roll. Referring to the 15-year span from 1992 – 2006 when the rate of surface warming was greater than the long-term trend,


    How did these evil denizens of global warming react? Did they use that result to push world government based on soshalism [re-spelled to get past the spam filter; he spells it correctly], so that they could destroy our economy by taxing the super-rich out of some of their hardly-earned riches? Did they run screaming through the streets yelling about how we’re all going to suffer spontaneous combustion by the year 2100?

    “Hardly-earned riches”. I am so stealing that.

  3. 153
    prokaryotes says:

    Bradley McKinley #148

    …it is not enough to simply say “we know that increasing CO2 levels will make the world warmer and that is a bad thing”, you need to be able to specify how much warmer and quantify the impacts with some level of precision.

    We can quantify past impacts based on the sea level feedback (cryosphere response). This tells us that with the current climate forcing we established at least a Pliocene climate response, which was triggered by anthropogenic induced energy imbalance. And that is a very bad thing, because paleoclimate data tells us that the Pliocene regime 5 mil years ago had 15 meter higher sea level. Further do we know from proxy records (corals) that the slow ice sheet feedback includes non-linear episodes, when ice sheets disintegrate and abruply cause SLR.

    James Hansen explains Earth energy imbalance

    Earth’s energy balance
    In response to a positive radiative forcing F (see Appendix A), such as characterizes the present-day anthropogenic perturbation (Forsteret al., 2007), the planet must increase its net energy loss to space in order to re-establish energy balance (with net energy loss being the difference between the outgoing long-wave (LW) radiation and net incoming shortwave (SW) radiation at the top-of-atmosphere (TOA)). Assuming that this increased energy loss is proportional to the surface temperature change T, we can write F = λT + Q (1) where λ is the climate feedback parameter.

    Complete restoration of the planetary energy balance (and thus full adjustment of the surface temperature) does not occur instantaneously due to the inherent inertia of the system, which lies mainly in the slow response times of the oceans and cryosphere. Therefore, prior to achieving a new equilibrium state, there will be an imbalance, Q, between radiative forcing and climate response. This imbalance represents the net heat ﬂux into the system, with nearly all of this heat ﬂux at present going into the ocean (Levitus et al., 2005).


  4. 154
    Mal Adapted says:


    Have I understood correctly that the models do not predict the ENSO phenomena but simply place it randomly, and that when it is placed correctly the model works THAT well?

    That’s what I’ve gathered from KX13 and discussions of it (especially John Nielsen-Gammon’s), and I’ve been using it against a couple of “15-year pause” parrots elsewhere. I’m eager to read RC’s post on it, even if I find out I’ve got it backwards 8^}.

  5. 155
    Jeffrey Davis says:

    re: 151 and Cost Benefit Analysis

    I remember the famous 2% Doctrine of the Bush era, i.e. if there were a 2% chance of WMDs, we had to intervene.

    And then there’s Luke 19:22.

  6. 156
    SecularAnimist says:

    Gavin wrote: “… there are large parts of rural Africa where local solar (for instance) is already cheaper than extending the grid to supply fossil energy.”


    Carbon taxes have been proposed in developed countries as a mechanism to internalize the environmental and public health costs of burning fossil fuels, which are currently externalized and foisted off on the public. As such, carbon taxes ARE a “market force”. They simply “correct” the market by forcing it to reflect the true cost of fossil fuels. Failure to do that amounts to a massive public subsidy to fossil fuels, which is why they appear to be (but actually are not) “cheaper” than renewable energy.

    None of which has anything to do with poor people in rural Africa that Gavin wrote about — people who use little or no fossil fuels, and who would therefore not pay any carbon taxes, even if someone were to impose such taxes in rural Africa, which no one has suggested doing.

    The reality is that many of those people, and millions of others like them throughout the developing world who have NO access to electricity, will NEVER have access to fossil-fuel-fired electricity because no one is ever going to build the centralized power plants and the grid to deliver electricity to them. The ONLY way they will ever have electricity is with distributed renewable energy, principally photovoltaics — which are vastly less expensive than building a whole new grid-based electricity generation and distribution infrastructure.

    And in fact, although it doesn’t get a lot of media attention, there is an ongoing revolution in rural solar electrification in the developing world, where low-cost systems as simple as a few solar panels and batteries are providing power for electric lights, refrigeration, medical equipment, radios, cell phones, satellite TV and Internet access, and more, to entire villages.

  7. 157
  8. 158
    Doug Bostrom says:

    Arguments about impact on the poor due to CO2 mitigation ring hollow, as usual, because of the choices we make on a daily basis to blow off massive amounts of hard cash on the useless and the pointless .

    Shiny for us equals starvation for others but it’s a choice we make every single day. The expensive but useless layer of chrome applied to the plastic grille of an automobile is an opportunity cost. Can you eat hair gel? How many are fed with the $23 billion spent in the US per year on cosmetics? How does a 32″ television taste and what vitamins does it provide, compared to a 70″ set? What’s the nutritional value of $80/month for ESPN Sports Center?

    Imagining just a little bit of restraint in our self-indulgence makes the costs of dealing with CO2 mitigation appear rather smaller.

    Meanwhile, money doesn’t vanish; the person now operating the machinery to produce aerosol cheese could be employed doing something useful, such as installing solar energy collection apparatus.

    Strip away the moralizing about hurting the poor with CO2 mitigation and it’s true that the argument here is still actually about the money vector. The trouble is, the desired outcome is antithetical to what the moralizers are talking about.

  9. 159
    Steve Fish says:

    Re- Comment by Doug Bostrom — 25 Sep 2013 @ 3:18 PM

    What you say is so inconvenient.


  10. 160
    Hank Roberts says:

    Another mismatch with an interesting possible explanation:

    Research Spotlight
    Gravity waves could explain powerful thermospheric cooling
    Colin Schultz
    online: 24 SEP 2013
    DOI: 10.1002/2013EO390007
    Eos, Transactions American Geophysical Union
    Volume 94, Issue 39, page 348, 24 September 2013

    For the past few decades the upper reaches of Earth’s atmosphere have been cooling much faster than researchers anticipated. While the rising atmospheric concentration of carbon dioxide is heating the air near the ground, that same increase is expected to cool the thermosphere—the atmospheric band that stretches from around 80 kilometers altitude to the exosphere at 500 kilometers—by emitting heat into space. However, while carbon dioxide should theoretically cool the thermosphere by around 2 kelvins per decade, the observed cooling was around 10 times this rate. Building on recent theoretical and modeling work, Oliver et al. lay out a mechanism that could explain the observed cooling.

    (This is about the Thermosphere — very thin up there, not many molecules involved — so I doubt a geoengineering control knob would be possible here.)

  11. 161
    Retrograde Orbit says:

    Very hollow indeed. Especially because we probably won’t live to see any negative consequences of our current use of fossil fuels – only our children and grandchildren will.
    Having said that though, at least it’s rational. To say “let’s just continue to do what is best for us (the well off, not the poor …) and leave any negative consequences for our children and grandchildren to solve” is a perfectly rational point of view. Cold-hearted maybe, but rational.

  12. 162
    Jeannick says:

    The problem is not philosophical or even scientific it’s political, the graphs of the models were extensively used to form government policy they were widely circulated as hard predictions

    Politicians in Australia and Germany have to take into account the brickbats thrown at them , this above discussion is ,for them ,vacuous in the extreme.

    [Response: I strongly doubt that policy was made on the assumption that models are perfect (evidence?). Uncertainties have been discussed in respect to climate predictions since the beginning of the policy debate. - gavin]

  13. 163
    Jacob says:

    In my comments I never talked about global warming and it’s effects. I talked only about the topic of this post, which is: the mismatch betweem model results and observations, and it’s implication for model uncertainty (since the mismatch cannot be attributed to observation errors). I also stated that the wide spread of model results further increases uncertainty.

    Gavin implicitly agrees about model uncertainty and states that climate change is also proven by other lines of eivdence – like paleoclimatology. Fine.

    Then Gavin says:
    “The odd thing is that people seem to think if there is some huge unknown in climate that models don’t capture that this makes things better somehow. ”

    Uncertainty is what it is. It’s not a matter of “better” or “worse”. (“Better” for what?)
    There is a high degree of uncertainty in model results. We should be able to agree (or dissagree) on this, based on the model facts, without reference to our general opinion about global warming.

  14. 164
    t_p_hamilton says:

    Jacob says:”Uncertainty is what it is. It’s not a matter of “better” or “worse”. (“Better” for what?)”

    Uncertainty IS worse, because when you plan for the worst, and you think the worst is worse than it really is, you spend more effort than needed.

  15. 165
    Radge Havers says:


    “There is a high degree of uncertainty…”

    So you assert. Yet other than being alarmed by the word ‘mismatch’, I don’t see you backing that up or putting it into some proportional context — which is why I, for one, am starting to doubt that you have any idea about what level of uncertainty best characterizes what is known and how it is taken into account in research and literature reviews.

    FUD: Fear, UNCERTAINTY, Doubt.
    A well known set of rhetorical tactics used by fake AGW skeptics to paralyze sensible discussions, mischaracterize scientists, and generally poison the political atmosphere.

    Perhaps if you asked some good, straightforward, specific questions and did a little less lecturing and maneuvering, the discussion might advance more smoothly.

  16. 166
    SecularAnimist says:

    Retrograde Orbit wrote: “we probably won’t live to see any negative consequences of our current use of fossil fuels – only our children and grandchildren will”

    What in the world are you talking about?

    We are already seeing negative consequences of our use of fossil fuels, on a massively destructive and costly scale, all over the world.

    Which is not to say that “our children and grandchildren” will not experience far worse consequences.

  17. 167

    #60 “[Response: Nice thought. If such principles can be found, they might indeed be useful. However, I am not optimistic - the specifics of the small scale physics (aerosol indirect effects on clouds, sea ice formation, soil hydrology etc.) are so heterogeneous that I don't see how you can do without calculating the details. The main conservation principles (of energy, mass, momentum etc) are already incorporated, but beyond that I am not aware of anything of this sort. - gavin]“

    Well, something must be there, because main conservation principles are unable to account for the observed extremely precise match between all sky hemispheric albedoes, while clear sky albedoes are vastly different. It must be an emergent phenomenon fuelled by phenomena on all scales. Whenever one runs into a symmetry of this kind, it suggests the possibility of simplification in theory, which is not utilized yet.

    Journal of Climate, Volume 26, Issue 2 (January 2013)
    The Observed Hemispheric Symmetry in Reflected Shortwave Irradiance
    Aiko Voigt, Bjorn Stevens, Jürgen Bader and Thorsten Mauritsen

    “Climate models generally do not reproduce the observed hemispheric symmetry, which the authors interpret as further evidence that the symmetry is nontrivial.”

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