RealClimate logo


Technical Note: Sorry for the recent unanticipated down-time, we had to perform some necessary updates. Please let us know if you have any problems.

Unforced Variations: March 2012

Filed under: — group @ 1 March 2012

This month’s open thread – for appetizers we have: William Nordhaus’s extremely impressive debunking in the NY Review of Books of the WSJ 16 letter and public polling on the issue of climate change. Over to you…


617 Responses to “Unforced Variations: March 2012”

  1. 151
    Ron Manley says:

    Yet more for Florrie.
    On my web site I have plotted 30-year trends for the three major temperature data series and for a 23-model ensemble. I leave it you to estimate ‘how long is long enough.’

  2. 152
    Chris Crawford says:

    Martin (#142), I agree with you that computationally and heuristically it is easier to use the simplification of a heliocentric system. My point is that, in terms of the actual physics, it’s the barycenter that matters. Can we just leave it at that?

  3. 153
    simon abingdon says:

    #143 Hank. Thanks :)

  4. 154
    simon abingdon says:

    #144 Martin Vermeer. Reminds me of the student who asked his professor what the sun would look like if it went round the earth, to be told “much like the moon, only brighter”.

  5. 155
    Brian Dodge says:

    re orbital computations and rent seeking astrophysicists.

    The inaccurate models of planetary motion are so primitive that they can’t even deterministically solve a theoretical three body problem over the long term. With the multibody gravitational attractions of the solar system at work, to claim that there is some “model” that shows that the Earth, or the moons of Jupiter “orbit” around some fictive “barycenter” is complete poppycock; to extend this to suggesting it has any predictive power over Earth’s “climate” is utter foolishness. The only certain way to know where the planets are, or what the weather is like, especially as regards policy decisions, is to look out the window. Anyone who suggests otherwise, especially when they want a grant for a bigger, newer, shinier supercomputer is part of a global conspiracy to feather their nest and inflate their ego.

    sarcasm off &;>)

    If we could magically divide the sun into six equal pieces, and insert them into orbit, sixty degrees apart, at the distance from the barycenter where Venus orbits, would the orbit of Jupiter change? Would Mercury orbit the barycenter? What if we replaced the solar mass with an equal mass shell of unobtanium whose diameter is the same as Venuses orbit; Where would mercury go then?

  6. 156
    Martin Vermeer says:

    Chris #152: I’m certainly willing to stop here. It’s way off topic anyway (but interesting!)

  7. 157

    #150–Dhogaza, I fear the ‘noise’ she intended was *us,* helpfully expanding upon this and that. She just wants to know how long the imaginary non-increasing trend would have to be.

    Period.

    (Not that that stopped me expanding upon what I thought important.)

  8. 158
    dhogaza says:

    Kevin:

    #150–Dhogaza, I fear the ‘noise’ she intended was *us,* helpfully expanding upon this and that.

    Oh,[edit], you’re right, I didn’t read closely enough.

    Well, no point in responding to any more “Florrie” posts. Obviously responses are falling on deaf ears.

  9. 159
    MARodger says:

    David Miller @149

    It sounds very much like a misquoting of yet another Dr James …,
    Just the melting of all the floating ice in the arctic ocean, will add as much heat to the earth, as all the Co-2 we put in the atmosphere to date.” Dr. James Lovelock BBC Interview.
    http://climateforce.net/2012/01/11/bbc-james-lovelock-interview-2011/

    This lower figure is however still too high. Lovelock implies a forcing of 1.88w/sq m or about half that of 2xCO2. But a totally ice-free Arctic Ocean would add 0.7w/sq m & 0.3 w/sq m for an ice-free summer, according to this ref.
    http://www.agu.org/pubs/crossref/2011/2011JD015804.shtml

  10. 160
    dbostrom says:

    Survey piece on the “Fluoride Wars” at the Knight Science Journalism Tracker is intriguing in the comparisons it invites to the climate change fiasco.

    Squint and swap nouns and it’s all very familiar, including odd inconsistencies, refusal to acknowledge facts, etc. I suppose one twist may be that fluoridation probably enjoys overwhelming water treatment industry support?

  11. 161
    Chris Crawford says:

    Brian Dodge (#155): Arg!!! The question you raise has a complicated answer. I do have a fairly good dodge in the fact that such a system would be stable only under the most contrived circumstances; any perturbations would start the solar fragments oscillating around their equilibrium points, and the oscillations would grow in amplitude until they broke out of their arrangement.

    However, that’s a dodge. If we indeed contrive our circumstances (say, by reducing the mass of all the other bodies in the solar system to negligible values, so that we need not concern ourselves with the effects of their gravitation on the solar fragments), then I don’t know what the motions of an object inside the orbit of the solar fragments would be. Objects many orbital radii away (and confined to the plane of the solar fragment orbit) would orbit the barycenter in the normal fashion. However, the motions of the objects outside the orbital radius by only a small amount would again behave in a fashion I cannot theoretically explain. My guess is that their orbits would be some sort of crazy epicyclic shape. I know that there have been tons of simulations of all manner of weird arrangements, and you can get lots of beautiful patterns when you arrange the masses just right. There have even been lots of simulations in which the exponent varies from 2.

  12. 162
    Stranger says:

    Phil Jones said in his BBC interview, “So, in answer to the question, the warming rates for all 4 periods are similar and not statistically significantly different from each other.”

    What I’m confused about is that I’m under the assumption that the rate of global warming is increasing at a faster rate but Jones figures indicate they’ve been pretty even. What am I missing?

    [Response: you are missing the fact that attribution and projections are not based on linear trend analysis of a single variable. - gavin]

  13. 163
    Stranger says:

    Thanks Gavin. I’ve found a couple articles on attribution here so I’ll read up and see how much it fills in the cracks.

    Also, could anyone give me approximations on how long peer review usually takes and then how long it is until it’s published?

  14. 164
    dbostrom says:

    Chris Crawford says: My guess is that their orbits would be some sort of crazy epicyclic shape. I know that there have been tons of simulations of all manner of weird arrangements, and you can get lots of beautiful patterns when you arrange the masses just right.

    Sounds like an ideal candidate for an Xscreensaver hack…

  15. 165
    Florrie says:

    148 Ray Ladbury says:
    Seventeen years [of a non-increasing trend] would be sufficient to indicate a problem with the theory

    OK, that’s a straight answer, thank you.

    –that certainly would not mean that we abandon the idea of CO2 as a greenhouse gas
    Indeed not, that bit of the physics isn’t disputed anywhere as far as I am aware.

    , and it likely would not mean that we abandon the idea of substantial positive feedback in the climate energy balance.
    That of course is highly disputed.

    The changes would depend on precisely HOW the theory failed.
    By long-enough-term temperature trends failing to move (or move enough) with CO2 concentration. You’d then surely want reconsider the positive feedback issue.

    ( The “CO2-control-knob” is not my term. And since it is being mistaken for implying a belief that CO2 is the only forcing, I will drop it).

  16. 166
    Florrie says:

    And one or two posters have made the argument that when you remove “known” natural forcings, in the current 10+ years of flat temperatures, the residual anthro effect is still seen to be upwards.

    This though just assumes what needs to be proven – ie that the positive feedback and natural forcing calculations are correct. And if the 10 flat years go to 17, or 30, or … what would you then say ?

  17. 167
    Hank Roberts says:

    > approximations on how long peer review usually takes
    Each journal will have their own answer, but if you use Scholar, some papers shown at journal sites will show dates when they went through various steps.

  18. 168
    Anonymous says:

    (I apologize if this has already been posted – I cannot tell if I was previously successful. If so, please feel free to delete my duplicate efforts.)

    This paper appears to state that if we continue to use all of the coal-fired generation in the world (1 TWe), it will result in 0.3 degree mean temperature increase in 100 years.

    http://iopscience.iop.org/1748-9326/7/1/014019/pdf/1748-9326_7_1_014019.pdf

    http://thinkprogress.org/romm/2012/03/01/428764/ddrop-in-warming-requires-rapid-massive-deployment039-of-zero-carbon-power-not-gas/

    Is 0.3 degrees in 100 years the mainstream understanding? (With additional increases due to additional coal generation.) If so, it seems like we could focus on meeting new demand with carbon-neutral generation, instead of trying to replace current coal, with all of the political backlash that this effort would bring.

  19. 169
    dhogaza says:

    Florrie:

    This though just assumes what needs to be proven – ie that the positive feedback and natural forcing calculations are correct

    No, it's not circular. You could begin by recognizing that observations aren't model calculations. Do you really think a tautological approach would've been published?

    Please, quit digging yourself in deeper. We really *don't* want to laugh at you.

    You're undoubtably smart enough to research this stuff and learn on your own. Give up the notion that you're smarter than the thousands of professional climate scientists.

  20. 170
    Ray Ladbury says:

    Florrie: “That of course is highly disputed.”

    Actually, it is not. It is extremely difficult to construct a model that looks Earthlike and doesn’t have a significant amount of positive feedback. Indeed, you cannot get 33 degrees of warming over and above the blackbody temperature without positive feedback. You don’t get the minor changes in insolation from Milankovitch cycles causing glacial-interglacial cycles.

    What is more we know with certainty that there are significant positive feedbacks–water vapor, decreased albedo, etc.

    It appears that you believe that it would be easy to construct a model without positive feedback and no significant warming from CO2. Ask yourself: why hasn’t this been done, then? Such a model would certainly be of great theoretical interest whether or not it was useful. And yet, none of the couple dozen models has these characteristics. You are getting some bad information about how cimate models work and are constructed.

  21. 171
    Hank Roberts says:

    For Florrie: http://www.nature.com/ngeo/journal/v5/n1/full/ngeo1327.html

    Try to find a least common denominator on the science, rather than trying to convince people the physics is arguable.

    You can for example agree with Spencer

    on the basic physics — he still thinks the future may turn out better than most scientists studying this.

    But – he’s clear that the basic radiation physics is understood — which explains your laser printer, your CD player, and global warming.

    Try to follow him and get clear about what’s not arguable. You should find him copacetic: Dr. Spencer is “the official climatologist of the Rush Limbaugh show” — but that stuff is his politics.

    He can explain the basic physics.

    More Musings from the Greenhouse

    There is the reality we share — the basic physics. No extrapolation, no modeling, no hypotheses. Just how the world works. Including your laser printer and CD player.

  22. 172

    Hey, I’ve got an idea, let’s discuss the Younger Dryas!

    Didn’t think so.

  23. 173
    t_p_hamilton says:

    Anonymous, the Myhrvold-Caldiera paper is calculating only the extra warming that is specific to replacing coal plants with 1 TW of alternative energy. In other words, replacing coal with natural gas will not have much benefit until far down the road because building extra infrastructure requires energy which is currently supplied by carbon-intensive sources.

  24. 174
    Chris Colose says:

    Florrie-
    And one or two posters have made the argument that when you remove “known” natural forcings, in the current 10+ years of flat temperatures, the residual anthro effect is still seen to be upwards. This though just assumes what needs to be proven – ie that the positive feedback and natural forcing calculations are correct. And if the 10 flat years go to 17, or 30, or … what would you then say ?

    Actually, for attribution studies you need to go beyond the global mean surface temperature and see how the resultant forcings leave their fingerprint in both time and space. The consistency between modeled and observed temperatures is nice, but there’s a number of possible solutions that are all consistent with the modern climate when you factor in aerosol forcing uncertainty, uncertainty in the rate of ocean heat uptake, as well as in the ‘true’ equilibrium climate sensitivity.

    Attribution results therefore go beyond modeling uncertainties and are impacted also on observational uncertainties, and indeed positive attribution can be biased toward well-sampled regions. You can also account for possible errors in the amplitudes of the external forcing and the model response by scaling the signal patterns to best match the observations without influencing the attribution from fingerprinting methods, and this provides a more robust framework for attributing signals than simply looking at the time history of global temperature in models and obs and seeing if they match up or not.

  25. 175
    David B. Benson says:

    Florrie @166 — The climate system contains some positive, i.e., enhancing feedbacks. There is no dispute or uncertainty. There are many fine textbooks which will explain the relevant physics to you. Alternatively, listen/watch David Archer’s videotaped lectures; available on his website.

    If you then need more, dig into Ray Pierrehumbert’s “Principles of Planetary Climate”.

  26. 176
    Chris Crawford says:

    Florrie (#166) if the 10 flat years go to 17, or 30, or … what would you then say ?

    I believe that it was the Athenians who sent a written warning to Sparta with stern warnings about what would happen if Sparta failed to satisfy Athenian demands. The letter threatened that, if Sparta refused to comply, they would send a large army, and lay waste to Spartan lands, pillage Spartan towns, kill the men and enslave the women.

    The Spartans sent back a letter containing one word:

    “If”

  27. 177
    simon Abingdon says:

    #170 Ray Ladbury. “decreased albedo”? Global cloud cover varies but is typically 60-70% of the earth’s surface area (or so it seems). What makes you sure that increasing CO2 emissions will not make more water vapour available for subsequent cloud formation to increase albedo?

  28. 178
    David B. Benson says:

    Clovis comet is back:
    http://www.sciencedaily.com/releases/2012/03/120305160814.htm
    I opine this eevidence looks fairly solid.

  29. 179
    Martin Vermeer says:

    Brian Dodge #155:

    If we could magically divide the sun into six equal pieces, and insert them into orbit, sixty degrees apart, at the distance from the barycenter where Venus orbits,

    Not doable. Even accepting the magic, and rods connecting the pieces rigidly, you wouldn’t be able to move the centre of mass of the Sun (i.e., now the common centre of mass of the six pieces) to the barycentre and expect that to sit still — remember the definition :-)

    Alternatively, you could put the pieces orbiting the old location of the Solar centre, which in turn wiggles around the barycentre. Then, you could say that the Solar pieces also “orbit” the barycentre, but only in the trivial sense of shining on it from all sides… the barycentre is just a point in space (actually, a geodesic on spacetime), not a physical centre of attraction.

    would the orbit of Jupiter change?

    Yes, a little. You’re replacing a central force field with one having strong zonal harmonics. That will cause at least additional precession of the line of apsides and the line of nodes.

    Would Mercury orbit the barycenter?

    Eh, Mercury would be in big trouble :-)

    The only way I see to make Mercury orbit the barycentre, in a real, physical sense, is to steer the planet to well outside the orbit of Neptune. In the limit for large distances the barycentre becomes an effective centre of attraction, of the Solar system as a whole.

    What if we replaced the solar mass with an equal mass shell of unobtanium whose diameter is the same as Venuses orbit; Where would mercury go then?

    Mercury would transit from its orbital ellipse into a straight line and crash into the shell from the inside, as gravitation inside a hollow shell vanishes.

    Again assuming as above that the shell is centred on the current Solar location, Jupiter’s orbit in this case would be unaffected (assuming the Sun to have a spherically symmetric mass distribution).

    BTW a correction to my earlier comment,

    will be 1/125000 of the Solar attraction … 1/200 of the Solar attraction

    rather, 2/125000 part, 2/200 part, maximum values. Left as an exercise for the reader :-)

  30. 180
    simon abingdon says:

    #176 Chris Crawford. Forgive my saying so but it wasn’t “if Sparta refused to comply” but rather the Spartans responding to Philip II’s threatening message “If I enter Laconia, I will raze Sparta”, with their eponymously laconic reply “If”.

  31. 181
    MARodger says:

    Anonymous @168
    To be a bit clearer (or perhaps just more complicated) than t_p_hamilton @173 & to answer your question with a few added numbers:-
    Burning coal is effectively burning just carbon so it is more CO2 intense than oil or gas. It is responsible for about 40% of our CO2 emissions from fossil fuel use (about 33% of total emissions) but gives less than 30% of the (primary) power. Coal emissions are not far off 4,000mtC pa. Back-calculating I make that very roughly 2TW deliverable electric (but not all coal is used for electric generation) or 5TW primary power.

    The idealised model from Myhrvold & Caldeira is looking a 1TW of deliverable electric which is “the order of magnitude of the global electrical output currently generated from coal.
    When modelling the effect on global temperature, they are using the equivilant of 3.18 deg C equilibriom sensitivity which is par for the course.
    Their 0.325 deg C in 100 years (from fig 3) is thus only for the contribution of part of (about half) of our coal burning as of today. And it also ignores oil & gas & non-power sources any increases which will occur in at least in the near future.
    You could use these numbers to calculate a 100 year constant-emissions-scenario global temperature rise (which does look perhaps a tad low at 1.95 deg C) but it is of the correct order of magnitude & give the numbers I’m offering here as inputs, that is certainly all you can ask. (And it also assumes I’ve not made any arithmetical gaffs here.)

  32. 182

    #177–And what makes you sure that any increase in cloud won’t be predominantly at higher altitudes, resulting in a *positive* net forcing? And come to think of it, why would we even expect clouds to increase, given that relative humidity is actually declining slightly over land, and staying constant over the oceans (as AR4 informs us?)

    There is an observed trend of increasing specific humidity. Is there an observed trend in cloudiness? How does it scale with humidity, if so?

    Unfortunately, Norris and Slingo (2009) say: “Previous investigators have documented multidecadal variations in various cloud and radiation parameters, but no conclusive results are yet available.” (That’s because we don’t yet have suitable measurement capabilities.)

    Consequently, as they say slightly earlier in the abstract: “At present, it is not known whether changes in cloudiness will exacerbate, mitigate, or have little effect on the increasing global surface temperature caused by anthropogenic greenhouse radiative forcing.”

    Obviously, this is an uncertainty that one wishes remedied. But as Ray has repeatedly pointed out, uncertainty means that we are not able to bound the risks that we are (IMO) recklessly assuming.

    AR4 on humidity trends:

    http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch3s3-4-2-1.html

    Norris & Slingo:

    http://meteora.ucsd.edu/~jnorris/reprints/02_Norris_and_Slingo.pdf

    However, there is a lot of work on clouds ongoing: here is the list of CLOUDSAT-related journal articles from 2011, for example:

    http://cloudsat.atmos.colostate.edu/publications/2011

  33. 183

    It appears to be a considerably smaller comet this time around, though. Several hundred meters, certainly sub kilometer. They really had to dig, but it appears they took the time to address the previously aired complaints. I would think that the sample preparation techniques themselves can be considered as an advance.

  34. 184
    Ray Ladbury says:

    Simon Abingdon, I was referring mainly to decreased albedo at the poles. However, we also have strong evidence from multiple independent lines of data that CO2 sensitivity is between 2 and 4.5 and at some compelling evidence that net feedback due to clouds is positive.

  35. 185
    Chris Crawford says:

    Simon Abingdon (#180) Yes, thanks for correcting my faulty memory. I should have known that my recollection was faulty, because my version doesn’t have much punch.

    And the correct version sharpens the point for Florrie.

  36. 186
    Dan H. says:

    Simon,
    That is the main unanswered question in the entire debate. The increased water vapor will almost certainly result in increased cloud formation, thereby, increasing the albedo – negative feedback. Some contend that the temperature increase will result in decreased cloudiness, thereby further increasing temperatures – positive feedback. Which of these processes dominate will determine the net feedback. I tend to agree with your post that the albedo will increase.

  37. 187
    vukcevic says:

    Climate modellers often fail since they look at a far too short time period, do not take fully into the account role of the North Atlantic’s importance to the global temperature movements, and finally do not have sufficient knowledge of the reasons for the Atlantic Oscillations.
    http://www.vukcevic.talktalk.net/CGNh.htm
    http://www.vukcevic.talktalk.net/GNAP.htm

  38. 188
    simon abingdon says:

    #182 Kevin McKinney, #183 Ray Ladbury. I was interested not so much in the forcing effect of clouds themselves so much as the change in albedo which might result from a change in the overall extent of global cloud cover.

  39. 189
    Anonymous says:

    (I may have double-posted this again. If I did, please feel free to delete the duplicate.)

    t_p_hamilton @173 and MARodger @181 – Many thanks for the clarification. If I understand MARodger and the the Myhrvold-Caldiera paper correctly, approximately 1 TW of coal is used globally to generate electricity, which if continued to be used unabated, will be responsible for approximately 0.325 deg C in 100 years. (The remainder of coal’s contribution is attributable to its use for non-electricity generating purposes.)

    I guess that I am just somewhat surprised, because I thought that it would be larger.

    How does this square with the goal to reduce carbon emissions by 80% by 2050? If I understand the above calculation correctly, it would seem that, in the electricity sector, we could mostly concentrate on meeting additional demand with efficiency and carbon neutral generation (and avoid some of the fights associated with replacing existing coal generation plants); but if we need to reduce emissions by 80% by 2050, then I am not sure whether this makes sense.

    In sum, I am confused by how to think of the contribution of current global coal electricity generation to global warming.

  40. 190
    Ray Ladbury says:

    [edit - please stay substantive]

  41. 191
    Ray Ladbury says:

    Dan H.,
    I notice you conveniently forget that clouds keep things warmer at night. Now why would that be?

  42. 192
    Jim Eager says:

    Dan H @185:

    The increased water vapor will almost certainly result in increased cloud formation

    Well, that is Lindzen’s assertion, but so far his evidence is, shall we say, rather unconvincing.

    And where will this increase in clouds take place, Dan?

    As the lower atmosphere warms what will happen to the mean altitude of nucleation and condensation?

    And what will be the net change in radiative forcing at the surface beneath those clouds?

    If the answers to these questions is uncertain, then “almost certainly” is a very poor choice of words indeed.

  43. 193
  44. 194
    simon abingdon says:

    #190 Ray Ladbury. “clouds keep things warmer at night”. We disagreed over this before. Clouds absolutely don’t “keep” things warmer at night, because everything cools inexorably at night, albeit at a slower rate if there is cloud cover. You can’t keep a corpse warm with a blanket.

    [Response: Please leave the semantic arguments at home. Clouds at night lead to warmer temperatures than if there were no clouds - i.e. they warm. Move on. - gavin]

  45. 195

    #187–”I was interested not so much in the forcing effect of clouds themselves so much as the change in albedo which might result from a change in the overall extent of global cloud cover.”

    And yet, Simon, you were responding to a set of comments which were about climate sensitivity, for which radiative forcing would be a much more relevant metric–and you responded in a fashion which gave no suggestion that you were changing the topic. It seems odd (and confusing!) to ask ‘how someone knew’ something if you weren’t interested in the point they were discussing in the first place.

    #185–”The increased water vapor will almost certainly result in increased cloud formation…” I’d be very interested in your source for this suggestion, Dan. I didn’t find much to support it–or contravene it, for that matter. So a cite would be very welcome.

    I did find one paper saying that Arctic clouds increase during summer and fall as the 21st century continues, according to a particular selection of GCM runs studied. That does not, of course, imply a global increase. Nor, as I indicated in my reply to Simon, does that imply that the cloud feedback will necessarily be negative.

  46. 196
    simon abingdon says:

    #193 Kevin McKinney “And yet, Simon, you were responding to a set of comments which were about climate sensitivity, for which radiative forcing would be a much more relevant metric–and you responded in a fashion which gave no suggestion that you were changing the topic.”

    Sorry, I had no idea I was “responding”. I was just interested in the earth’s albedo.

  47. 197
    Hank Roberts says:

    > aerosols

    The best lack all conviction, while the worst
    Are full of passionate intensity.

  48. 198
    Dan H. says:

    Kevin,
    Here is one citation for increased cloud cover.

    http://cgcs.mit.edu/research/focus-areas/convection-atmospheric-water-vapor-and-cloud-formation/

    Ray,
    Yes, clouds help keep nights warmer. They also help to keep days cooler. These are separate from the albedo effect.

  49. 199
    Hank Roberts says:

    > clouds … warmer
    You can get an infrared thermometer for $15 now from Amazon.
    No excuse for not checking this stuff out yourself.

    Measuring the Temperature of the Sky and Clouds – My NASA Data …
    http://mynasadata.larc.nasa.gov/P18.html

    Why does it get colder on clear nights than on cloudy nights?
    http://littleshop.physics.colostate.edu/tenthings/IRThermometer.pdf
    The crucial piece is the infrared thermometer. … You will see a much higher temperature—the cloud is warmer, …

  50. 200
    Hank Roberts says:

    > one citation for increased cloud cover

    What do you suppose they mean?

    “… CGCS researchers have constructed a new and significantly improved representation of cumulus convection. A comprehensive and systematic series of tests of this new scheme are now being performed …. Sensitivity of atmospheric water vapor content to the parameters of this new representation of convection is also being evaluated through use of the so-called adjoint of the scheme.”

    No “will almost certainly result in” claim; Dan’s pointed to a press release about some research they have started doing, looks like.

    Fail. Try again?


Switch to our mobile site