Emanuel Article

A thoughtful article by Kerry Emanuel on overall AGW issues here.

60 Comments

  1. Steve McIntyre
    Posted Jan 27, 2007 at 10:47 AM | Permalink

    TAC says:
    January 27th, 2007 at 5:51 am
    edit

    Kerry Emanuel has an interesting and pleasantly readable article which attempts to make sense of the whole climate debate. I don’t agree with everything he writes, but it does offer much to think about.

    Incidentally, the article has already received some attention at RC.

    #363

    Interesting article.

    Some comments:

    Plotting the global mean temperature derived from actual measurements and from proxies going back a thousand years or more reveals that the recent upturn in global temperature is truly unprecedented: the graph of temperature with time shows a characteristic hockey-stick shape, with the business end of the stick representing the upswing of the last 50 years or so.

    I wish I could reproduce the hockey stick

    Computer modeling of global climate is perhaps the most complex endeavor ever undertaken by mankind.

    Not even close. Or maybe I misunderstood the sentence.

    This exercise has been repeated using many different climate models, with the same qualitative result: one cannot simulate the evolution of the climate over last 30 years without including in the simulations mankind’s influence on sulfate aerosols and greenhouse gases. This, in a nutshell, is why almost all climate scientists today believe that man’s influence on climate has emerged from the background noise of natural variability.

    I can simulate the evolution of the climate over last 150 years just by using AR1 p=0.93 process. Including more regressor variables makes the fit better, spurious correlation or not.

    Were the entire Greenland ice cap to melt, sea level would increase by around 22 feet”¢’‚¬?flooding many coastal regions including much of southern Florida and lower Manhattan.

    + 3 degrees from now for 2000 years, would Greenland ice cap melt then?

    In the first category are findings that are not in dispute, not even by les refusards
    The year 2005 was the warmest in the instrumental record.

    Is this true?

    366
    David Smith says:
    January 27th, 2007 at 10:26 am
    edit

    RE #363 Likewise, I find Emanuel’s article interesting and worth a read by people of all persuasions. It may even be worth its own thread here at CA.

    There’s something in it for everyone. For example,

    Scientists are most effective when they provide sound, impartial advice, but their reputation for impartiality is severely compromised by the shocking lack of political diversity among American academics, who suffer from the kind of group-think that develops in cloistered cultures. Until this profound and well documented intellectual homogeneity changes, scientists will be suspected of constituting a leftist think tank.

    I would have used the word ideology rather than politics, but the point stands.

    Another paragraph is

    many of the critical uncertainties about climate change are slowly being whittled down. The extremists are being exposed and relegated to the sidelines, and when the media stop amplifying their views, their political counterparts will have nothing left to stand on.

    I think he misses a key consideration. As the conversation grows, it includes increasing numbers of technically-trained people. Some of these are visible at CA and include mathematicians, geologists, physicists, engineers, chemists, medical professionals and so forth.

    While we lack knowledge of some specifics, we are not stupid people. We learn, we question, as we would learn and question any topic. We are not going to accept things based on “trust me”: any persuasion will need to be based on “show me”, especially on the extraordinary claims. We are not impressed by scareplots, including Emanuel’s famous pin-the-end plot.

    To the chagrin of some, technically-oriented people tend to be influential in their own small parts of the world. This influence extends beyond other technical people to include parts of the general public. It spreads not so much via the internet but rather by the coffee (tea) pot. In our way, we’re a factor in the public debate.

    Don’t dismiss the mathematicians, geologists, engineers and so forth as extremists but rather work to convince us, using science that stands up to intense auditing, as other fields of science use and do.

  2. Posted Jan 27, 2007 at 2:14 PM | Permalink

    If there’s a problem it’s not James Inhofe (and I am no supporter of him, for the record), it’s Kerry Emmanuel’s own analysis of global warming that is deeply flawed. It’s difficult to reason with a man who didn’t reason himself into his current beliefs.

    Kerry is still a Mann-made Hockey Stick believer:

    Plotting the global mean temperature derived from actual measurements and from proxies going back a thousand years or more reveals that the recent upturn in global temperature is truly unprecedented: the graph of temperature with time shows a characteristic hockey-stick shape, with the business end of the stick representing the upswing of the last 50 years or so. But the proxies are imperfect and associated with large margins of error, so any hockey-stick trends of the past may be masked, though the recent upturn stands above even a liberal estimate of such errors.

  3. David H
    Posted Jan 27, 2007 at 3:08 PM | Permalink

    Kerry Emanuel’s essay is skilfully written and not a little seductive. But he is still attributing by exclusion, relies entirely on models and once again asserts without any evidence that recent decades are exceptional. One might ask which part of the NRC report he did not understand.

    Having said that we have little knowledge of aerosols he readily falls in line with the high CO2 sensitivity scenarios whereas as has been pointed out previously here by Ferdinand Engelbeen, a lower CO2 and aerosol forcing can have similar results.

  4. David Archibald
    Posted Jan 27, 2007 at 4:03 PM | Permalink

    You have all been too kind. Emanuel’s essay is a pack of lies. Earth’s early atmosphere was 20% carbon dioxide, buy the way that is 200,000 ppm. The greenhouse effectd due to CO2 would have been exhausted at one hundredth of that level, so the early atmoshphere was not what saved Earth from being an ice ball. A big one is his saying that runaway greenhouse could boil the oceans into the atmosphere. One could go on and refute individual assertions, but that is missing the point of the article, which is to provide a belief system for the AGW rank and file.

  5. TAC
    Posted Jan 27, 2007 at 4:07 PM | Permalink

    #3 I, too, was surprised to see Emanuel refer to the hockey stick. However, I wonder if this constitutes an endorsement of the HS, or — and I think this is likely — just an outdated opinion based on an early (and insufficiently rigorous) assessment of Mann’s work.

    Emanuel would not be alone in making this mistake. This past week I heard reference to the HS in a colleague’s talk — this came from a smart, diligent, scientist with a background similar to Emanuel’s (MIT-educated, among other things). When it was pointed out that, post NAS and Wegman, the HS is no longer intellectually defensible, the colleague simply backed down, admitted that he hadn’t really followed the HS debate, and said he’d stop referring to the HS in his talks; no big deal.

    Readers of CA may not want to hear this, but a large part of climate science research does not depend on whether the HS is valid (though the HS did provide graphical drama for the introductory slide).

    It is possible that I am wrong about Emanuel. Perhaps he has carefully reviewed all the evidence and has concluded that the HS is valid. However, given what I know of him, that hardly seems plausible.

  6. Ken Fritsch
    Posted Jan 27, 2007 at 4:28 PM | Permalink

    I believe I have somewhat the same take on Emanuel’s piece as David Smith. It appears as a great soft sell and as a lead into the IPCC 4R report. It makes you image that it was written by a polite and considered gentleman which I assume it was. You want to think that in general terms he has essentially got it right and would I ever like to agree with him. It has been hotter in the past than now. Nature packs a wallop. Computer models have resolution problems and there is that uncertainty due to the effect of clouds. He sets you up (perhaps not intentionally) by these general statements when he gets to what I now see as his subtle punch lines (perhaps not so intended).

    He throws out a disclaimer line which seems in line with his piece to this point:

    But the proxies are imperfect and associated with large margins of error, so any hockey-stick trends of the past may be masked,..

    Then he turns what he said on its head with:

    .. though the recent upturn stands above even a liberal estimate of such errors.

    In the next paragraph he simply hits the reader with this one and without a lead in:

    My own work has shown that hurricanes are responding to warming sea surface temperatures faster than we originally expected, especially in the North Atlantic, where the total power output by tropical cyclones has increased by around 60 percent since the 1970s.

    I am thinking: well, he continues to sound like a nice man, but I have some background information that might shed some doubt and uncertainty on the proxies and hurricanes issues, but this nice man is talking as though they are givens.

    Finally he adds some nice soft sell touches including:

    Although far from perfect, the IPCC involves serious climate scientists from many countries and has largely withstood political attack and influence.

    The IPCC reports are fairly candid about what we collectively know and where the uncertainties probably lie.

    And this one is particularly nice:

    But we are by no means certain about what kind of changes are in store, and we must be wary of climate surprises. Even if we believed that the projected climate changes would be mostly beneficial, we might be inclined to make sacrifices as an insurance policy against potentially harmful surprises.

    What his piece misses, in my mind, is the whole discussion about the uncertainties of climate results that he chooses to state as though they were givens.

  7. McCall
    Posted Jan 27, 2007 at 6:54 PM | Permalink

    Given the highly politicized background and timing behind AR4, I’m troubled by what may be a carefully wordsmithed “remarkable” fact (this 3rd “remarkable” was found only 30% thru the article): “As a result, the surface of the earth receives radiation from the atmosphere as well as the sun. It is a remarkable fact that, averaged over the planet, the surface receives more radiation from the atmosphere than directly from the sun!”

    I would hope that there is a non-tortured methodology for concluding such? For example, these qualifying phrases strike me as suspicious: 1) “the surface of the earth” 2) “receives radiation” and “receives more radiation”, and 3) “averaged over the planet” — other more physics appropriate terms could have been used, and were used in the article.

    What “truthiness” of the statement is forfeited if these phrases are omitted/modified? For instance, since much solar radiation incident on clear water passes through the “earth’s surface” to be progressively absorbed at depths reaching ~100 meters — is still counted as “received radiation” at the earth surface in Dr Emanuel’s point, or was a significant amount of the direct solar energy contribution forfeited in passing through the earth’s surface that is water? Another line of questioning might be how scattering was handled in this nugget.

    Given the level of suspicion on both sides, we can expect this article deserves parsing — and it will get it here, RC and other blogs, though probably only in select areas consistent with suspicion.

  8. TAC
    Posted Jan 27, 2007 at 10:11 PM | Permalink

    #7

    I’m troubled by what may be a carefully wordsmithed “remarkable” fact (this 3rd “remarkable” was found only 30% thru the article): “As a result, the surface of the earth receives radiation from the atmosphere as well as the sun. It is a remarkable fact that, averaged over the planet, the surface receives more radiation from the atmosphere than directly from the sun!”

    This has been addressed over at RC (see comment #16 and particularly the linked document).

  9. Dave Dardinger
    Posted Jan 27, 2007 at 11:39 PM | Permalink

    re: #7

    I don’t see where your problem is. It’s true that the downwelling back-radiation (IR) from the atmosphere is greater than the amount directly from the sun; and the amount of IR from the surface is correspondingly greater too. I’m not sure I’d use the word “remarkable” except in the sense that the layman might find this fact remarkable.

    Let’s see if we can do a simple back of the envelope example. Say the surface of the earth would be at 240 K without an atmosphere but is 273 with it; I think I see 33 deg C of greenhouse warming bandied about a lot. Now I also hear that the energy emitted by a blackbody is proportional to the fourth power of the temperature. so I get 3.3 x 10^9 for 240^4 and 5.6 x 10^9 for 273^4. This isn’t quite double, but it makes the point. Since the amount of energy leaving the system must equal what comes in, it must be the case that the extra energy that the surface emits is sent back in the form of backradiation. Plug in better figures and I suspect you might easily have more backradiation than incoming solar radiation.

  10. David Brewer
    Posted Jan 28, 2007 at 5:28 AM | Permalink

    Can anyone tell me whether Emanuel has made a basic error about atmospheric composition?

    He says: “…CO2, or carbon dioxide (presently about 380 tons for each million tons of air), and CH4, or methane (around 1.7 tons for each million tons of air).”

    The ratios (380 ppm for CO2, 1.7 ppm for methane) appear correct for volume, but not for mass. Adjusting for the specific gravity of each gas, I make the correct figures roughly 580 tons of CO2 and 0.95 tonnes of methane per million tons of air.

    Am I missing something?

  11. TAC
    Posted Jan 28, 2007 at 5:52 AM | Permalink

    #10 David Brewer: I agree with you. The standard unit for reporting atmospheric CO2 concentration is µL/L, with a corresponding current level somewhere below 400.

    FWIW, this sort of error could be due to a mistake by Emanuel, by a grad student, or — most likely — from an editor at Boston Review who tried to improve the writing. I would not make much of it.

  12. David Smith
    Posted Jan 28, 2007 at 8:12 AM | Permalink

    RE #10, #11 I agree, too, that the amounts are in error. It’s an error of no particular consequence but it is a touch sloppy for a published article.

  13. Roger Bell
    Posted Jan 28, 2007 at 9:22 AM | Permalink

    I wonder if the “linked document” of 1997 could/should be improved. For example, Jonathan Tennyson and his group at University College, London, have made extensive additional calculations of water vapour lines in more recent years and I would not be surprised if there have been improvements in the CO2 data. Using these better data probably wouldn’t affect the basic ideas of the document but might well affect the details.
    Roger Bell

  14. Francois Ouellette
    Posted Jan 28, 2007 at 11:24 AM | Permalink

    One observes that the two sets of simulations diverge during the 1970s and have no overlap at all today, and that the observed global temperature also starts to fall outside the envelope of the all-natural simulations in the 1970s. This exercise has been repeated using many different climate models, with the same qualitative result: one cannot simulate the evolution of the climate over last 30 years without including in the simulations mankind’s influence on sulfate aerosols and greenhouse gases. This, in a nutshell, is why almost all climate scientists today believe that man’s influence on climate has emerged from the background noise of natural variability.

    This single paragraph is at the crux of AGW. Forget the rest: the hockey stick, UHI or anything else. The sole reason that scientists believe that GHG’s are the culprit is because the models can’t simulate the past without them. But for me, this is precisely the weakest link in the chain!

    Just take this simple point: from the sunspot data that I have downloaded, and despite whatever “Jim Barrett” might say, the sun HAS been more active since 1960 than in all the previous instrumental record (not 1000 years, but a full 100). How come, then, that in the aforementioned simulation, temperatures actually start to go DOWN in 1960?! Well, it can only be so if we assign a very small influence to the Sun, based on the very small changes in TSO (total solar irradiance).

    But then, I have just finished reading papers on what we know about the glacial cycles. And for all we know, despite the fact that Milankovitch’s cycles match the glacial ages, all the calculations of the solar irradiance modulation due to such cycles give a VERY SMALL NUMBER, much too small to explain the huge temperature modulation of the glacial ages (10-20C). So people explain it with nonlinearities and threshold effects, in other words, the Sun DOES have a much larger effect on climate that what we get from just the irradiance changes.

    So, as a trained scientist, I just can’t get myself to fully trust simulations that are based on a small solar forcing, when some clear evidence tells me otherwise. It’s really not a matter of ideology. I would love to believe that GHG’s ARE the main culprit. But it’s not simulations like that that will convince me. If AGW is solely based on that, then they’ll have to count me out.

  15. TAC
    Posted Jan 28, 2007 at 12:22 PM | Permalink

    #14 Francois, I share your view. AFAICT, the AGW argument amounts to little more than this:

    We cannot explain what we see any other way.

    OK. Maybe that’s true. However, one hears the same argument from the Intelligent Design proponents ;-)

  16. David Smith
    Posted Jan 28, 2007 at 12:40 PM | Permalink

    Emanuel makes this statement in his irrefutable section:

    “‚⠠The annual mean geographical extent of arctic sea ice has decreased by 15 to 20 percent since satellite measurements of this began in 1978.

    I’ve tried to replicate this but without success. My sources are this chart, which ends in 2004 from Cryosphere Today and the NSIDC .

    One note is that satellite measurement began in late 1978, so that 1979, not 1978, is the first full year of satellite determination.

    I can get 10 to maybe 15% but not 15 to 20%.

    It has no bearing on the point he’s making but it does seem like a stretch of the data, like his 2005 PDI plot.

  17. McCall
    Posted Jan 28, 2007 at 1:04 PM | Permalink

    re: #8 thanks for the energy flow diagram — his intension now evident. I misinterpreted his language switch to “received etc” when he’d been using “absorbed/emitted etc” black-body language elsewhere — it shouldn’t have thrown me.

    re: #9 thanks. Similarly, I thought an incremental black-body argument was being made that
    earth+atmosphere – earth-alone > earth-alone.
    Even with the Stefan’s T^4 factor, I knew no way that was true with just ~33 incremental T with atmosphere (need ~45.5); so I guessed he was using strange surface/other definitions to reduce the earth-only baseline and get the difference he wanted. Again my fundamental misread and error.

  18. Posted Jan 28, 2007 at 1:33 PM | Permalink

    Re;4

    Nir Shaviv has a theory to expalain the ‘faint sun paradox:’

    Cosmic Rays and the Faint Sun Paradox:

    The sun, like other stars of its type, is slowly increasing its energy output as it converts its Hydrogen into Helium. 4.5 Billion years ago, the sun was 30% fainter than it is today and Earth should have been frozen solid, but it wasn’t. This problem was coined as the “Faint Sun Paradox” by Carl Sagan.

    If the Cosmic Ray Flux climate link is real, it significantly extenuates this discrepancy. This is because the young sun, which was rotating much faster, necessarily had a much stronger solar wind. This implies that less cosmic rays from the galaxy could have reached Earth because cosmic rays lose energy in the solar wind as they propagate from the interstellar medium to Earth. Since less cosmic rays implies a higher temperature, this effect will tend to compensate for the fainter sun.

    Plugging in the numbers reveals that about 2/3’s of the temperature increase required to warm the young Earth to above today’s temperature, can be explained with this effect. The remaining 1/3 or so, can be explained with moderate amounts of greenhouse gases, such as 0.01 bar of CO2 (amounts which are consistent with geological constraints), or some NH3 or CH4.

    http://www.sciencebits.com/ice-ages

  19. McCall
    Posted Jan 28, 2007 at 1:39 PM | Permalink

    Correction “need ~45.5″: observing the accepted 255 degrees K earth-only baseline and 255+33=288 K for earth+atmosphere, one really needs an incrementally increased temperature of 255+48.3=303.3 K raised T^4 to get to what I thought was Dr Emanuel’s black-body fact.

  20. Douglas Hoyt
    Posted Jan 28, 2007 at 1:46 PM | Permalink

    One observes that the two sets of simulations diverge during the 1970s and have no overlap at all today, and that the observed global temperature also starts to fall outside the envelope of the all-natural simulations in the 1970s. This exercise has been repeated using many different climate models, with the same qualitative result: one cannot simulate the evolution of the climate over last 30 years without including in the simulations mankind’s influence on sulfate aerosols and greenhouse gases. This, in a nutshell, is why almost all climate scientists today believe that man’s influence on climate has emerged from the background noise of natural variability.

    There is a lack of imagination in the above as well as a lack of knowledge of how clouds are behaving. From 1985 to 2000, cloud cover decreased and the Earth warmed. Evidence for the cloud cover decrease comes from Palle’s observations and the ISCCP observations. The climate models do not simulate the large cloud variations that are observed.

    It is likely the models constrain clouds and hence climate tightly and assume the large scale decadal drifts in temperature are externally forced. The alternative explanation is that cloud cover drifts up and down over a wide range and is not tightly constrained. It is like a thermostat with a wide dead band.

    An Earth thermostat with a wide dead band and corresponding low climate sensitivity is consistent with observations. The climate models with their assumed narrow dead bands and corresponding high climate sensitivities can only be forced to agree with observations with great difficulty.

  21. Erkel
    Posted Jan 28, 2007 at 2:50 PM | Permalink

    A question:

    Emanuel makes a point of discussing the water vapor feedback as a crucial point for the expectation of a large (>1 deg C) response to CO2 forcing. He also says that H2O is fundamentally different from other greenhouse gases because of its short residence time.

    If the competing hypotheses are 1. natural warming, with some small or negligible anthropogenic effect, and 2. unnatural warming with a large anthropogenic effect, how does the residence time of H20 matter at all in distinguishing between these scenarios?

    Shouldn’t we expect H20 amplification in response to temperature changes of any kind, regardless of forcing? No matter the rates of evap and precip, I would expect a warmer atmosphere would assume a state of greater absolute humidity, with the timescale of absolute humidity variations driven by the temperature changes (of any sort), and presumably amplified by H20.

    Has anyone come across scientific work addressing the natural variability of greenhouse forcing by H20? Broecker has suggested that H20 greenhouse reductions during glacial times were large in his 1997 paper ‘Mountain Glaciers, recorders of atmospheric water vapor content?’ There just seems to be some disconnect between the presumption of a large H20 greenhouse amplification with regard to CO2 forcing, but not with regard to natural forcing during the Holocene. The stability of the Holocene would seem to indicate that H20 amplification of natural temperature swings is rather minor, yet we expect H20 amplification with regard to CO2 to be large. If I am missing something here, please advise…

  22. David Smith
    Posted Jan 28, 2007 at 3:01 PM | Permalink

    RE my #16

    I found this quote from the NSIDC:

    Satellite data indicate that during the past 30 years, annual snow cover in the Northern Hemisphere and Arctic sea ice extent have decreased at a rate of about 3 percent per decade.

    The document is here .

    3% per decade times 3 decades is about 10%, not 15 to 20%.

    Does this difference indicate a problem with Emanuel’s theme? No. Is it an exaggeration, to help sway an audience? You decide.

  23. Safin Blum
    Posted Jan 28, 2007 at 7:31 PM | Permalink

    3% drop per decade over three decades is an overall decrease of about 8.75%

  24. David Smith
    Posted Jan 28, 2007 at 9:22 PM | Permalink

    Re #14, #20

    My main problem with attributing the warming of the last 30 years to GHG is illustrated by this graph:

    Tropospheric thickness

    This plot (500mb geopotential height) may be hard to grasp at first, especially in this unsmoothed form. It is a time series (1950-present) of the thickness of the troposphere (bottom half). The warmer the air, the thinner it becomes, and the higher the red line on the chart rises.

    It reveals a lot. Much of the year-to-year variation can be tied to volcanoes and El Nino / La Nina, for instance the warm El Nino spike in 1998 and the cool depression (volcano- Pinatubo?) circa 1992.

    The really interesting part is the sudden rise about 1976. The troposphere suddenly warmed and stayed warm, with a secondary jump around 2001.

    To me, that indicates that, circa 1976, something shifted in the atmosphere/ocean and as a result it became slightly less efficient at removing heat, and warmed. A second, smaller shift occurred circa 2001. The atmosphere/ocean shifted mode, or modes, of some kind in those timeframes.

    As I see it, there is a lag before the oceans warm to match the reduced heat removal. So, the surface temperature took some years to fully respond.

    (It’s also interesting that Antarctica (60S-90S) did not show the same atmospheric expansion (see this plot of 500mb heights . The atmospheric warming was mainly in the tropics and the Northern Hemisphere.)

    So, my questions are, how does the CO2/sulfate model offered by Emanuel square with this non-homogeneous sudden warming in the 1970s, and again circa 2001? Do the computer models show this?

    My mental picture of GHG warming is of a slow-motion, ever-building event. Sudden jumps, like those in this atmospheric thickness record, look more like something from Mother Nature’s playbook.

    (The nice thing about the records of geopotential height is that no one has monkeyed with them – they are, within their limitations, a truth, convenient or otherwise.)

  25. Jaye Bass
    Posted Jan 28, 2007 at 10:20 PM | Permalink

    One way to tell the difference is to make use of the fact that the increase in greenhouse gases and sulfate aerosols dates back only to the industrial revolution of the 19th century: before that, the human influence is probably small. If we can estimate how climate changed before this time, we will have some idea of how the system varies naturally. Unfortunately, detailed measurements of climate did not themselves really begin in earnest until the 19th century; but there are “proxies” for quantities like temperature, recorded in, for example, tree rings, ocean and lake plankton, pollen, and corals.

    Plotting the global mean temperature derived from actual measurements and from proxies going back a thousand years or more reveals that the recent upturn in global temperature is truly unprecedented: the graph of temperature with time shows a characteristic hockey-stick shape, with the business end of the stick representing the upswing of the last 50 years or so. But the proxies are imperfect and associated with large margins of error, so any hockey-stick trends of the past may be masked, though the recent upturn stands above even a liberal estimate of such errors.

    Quotes like this bring the “thoughtfulness” of the essay into considerable doubt.

  26. Willis Eschenbach
    Posted Jan 29, 2007 at 12:00 AM | Permalink

    David Smith, thanks for your interesting post, in which you raise salient points. One clarification. You say:

    (The nice thing about the records of geopotential height is that no one has monkeyed with them – they are, within their limitations, a truth, convenient or otherwise.)

    The data you are using is from the NCEP/NCAR Reanalysis of global data. To do the “reanalysis”, they have created a best fit to the data using a computer model. While it is useful for certain purposes, at the end of the day it is computer model results, not “truth convenient or otherwise”. Unfortunately, in common with far too much climate “science”, they don’t indicate the error estimate. This makes their information much less useful, for example we can’t determine the significance of the “jumps” in the data which you have noted.

    In particular, there are many areas of the world for which there are no data, good, bad, or otherwise. The computer fills these areas in with the best computerized guesses … which leaves questions:

    1) How good is that guess?

    2) What is the worldwide data density variation in space and time?

    3) How much of the world has a data density of 0 at any given time?

    An excellent example of this, from a different perspective, involves the shrinking summer Arctic ice area. If we used that ice change as out “best guess” for the Antarctic, we’d be way, way out. The Antarctic ice is expanding at about the same rate as the Arctic ice is shrinking, globally we are neither gaining nor losing.

    The rude truth is that the world is neither homogeneous nor are the transitions smooth. I use the NCEP/NCAR data myself if I need global coverage, it’s the best we have … but I don’t trust it or mistake it for observational data.

    w.

  27. The Big Fish
    Posted Jan 29, 2007 at 6:02 AM | Permalink

    Being new to this, I am wondering if the sun was 30% dimmer billions of year ago would that be compensated with the Earth being closer. Just like the moon has moved away from the Earth, hasn’t the earth moved away from the sun over time?

  28. Posted Jan 29, 2007 at 6:19 AM | Permalink

    Re #27

    I don’t know about the Earth’s orbit changing but certainly the rotation speed has slowed. See http://www.talkorigins.org/indexcc/CE/CE011.html

    1. The earth’s rotation is slowing at a rate of about 0.005 seconds per year per year. This extrapolates to the earth having a fourteen-hour day 4.6 billion years ago, which is entirely possible.

    The rate at which the earth is slowing today is higher than average because the present rate of spin is in resonance with the back-and-forth movement of the oceans.

    Fossil rugose corals preserve daily and yearly growth patterns and show that the day was about 22 hours long 370 million years ago, in rough agreement with the 22.7 hours predicted from a constant rate of slowing (Scrutton 1964; Wells 1963).

    1. Scrutton, C. T., 1964. Periodicity in Devonian coral growth. Palaeontology 7(4): 552-558.
    2. Wells, J. W., 1963. Coral growth and geochronometry. Nature 197: 948-950.

  29. MarkW
    Posted Jan 29, 2007 at 6:49 AM | Permalink

    #18,

    A couple of other points.
    4.5 billion years ago;
    1) The earth was closer to the sun. (the same tidal effect that is causing the moon to spiral
    outwards from the earth.)
    2) The earth was more radioactive. Resulting in a higher heat flux from below.
    3) Being 4.5 billion years closer to the big bang, the cosmic background radiation would have
    been a few degrees warmer.

  30. fFreddy
    Posted Jan 29, 2007 at 7:02 AM | Permalink

    Re #29, MarkW

    the same tidal effect that is causing the moon to spiral
    outwards from the earth

    I don’t understand that. I would have thought that tidal effects would take energy out of the system (i.e., convert to heat or whatever) which would imply that the moon would drop to a lower orbit, and eventually bash into the earth. Where am I being stupid ?

  31. MarkW
    Posted Jan 29, 2007 at 7:02 AM | Permalink

    The reason the earth’s rotation has slowed is because energy is being transfered to the moon, causing it’s
    orbit to increase in diameter.

    In extreme thumbnail, the moon’s pull causes the tides. One facing the moon, a smaller one on the other
    side of the earth. Since the earth is rotating faster than the moon is orbiting, these tidal bulges are
    dragged out from under the moon. The larger, closer bulge leads the moon, the smaller further bulge
    trails the moon. This results in a net, small acceleration on the moon.

    This same affect should be in play between the earth and the sun.

  32. fFreddy
    Posted Jan 29, 2007 at 7:17 AM | Permalink

    Excellent, thank you.

  33. beng
    Posted Jan 29, 2007 at 9:57 AM | Permalink

    RE 16: David Smith says:

    I can get 10 to maybe 15% but not 15 to 20%.

    I wonder how much of the total occurred in the Spitzenbergen Island area of the far N Atlantic? This is the one area that has experienced recent ice-extent decreases (Mann & Hansen made a big deal about this area in a paper, I think). Perhaps most of the northern sea-ice decrease is rather localized.

    That doesn’t seem to indicate any slowdown of the N Atlantic thermocline circulation. Perhaps the surface-sinking can occur along much of the ocean ice-sheet edge, instead of just localized spots (near Greenland & Iceland?) like the standard explanations seem to indicate.

  34. Ian
    Posted Jan 29, 2007 at 10:38 AM | Permalink

    #31
    Wow, that’s a really interesting theory (it is difficult to tell tone, with text — I’m serious not sarcastic)! I have never heard that theory before but it sounds like a good one. Very interesting. Another theory (much more speculative) that I read about recently was this one (http://riofriospacetime.blogspot.com/2006/12/hot-young-solution-to-faint-sun.html). It just goes to show how little we really know. Many scientists speak with such confidence (arrogance) that you would swear the history of the universe and even its future had been completely determined except for a few minor details. This is completely false of course. We still know almost nothing.

  35. Posted Jan 29, 2007 at 11:03 AM | Permalink

    #31 That is an very interesting theory that I had not heard before. Here is another I read recently — http://riofriospacetime.blogspot.com/2006/12/hot-young-solution-to-faint-sun.html
    Just goes to show how little we really know. I hope this is not a duel post. Site is slow this morning and timed out on me.

  36. Posted Jan 29, 2007 at 11:54 AM | Permalink

    One observes that the two sets of simulations diverge during the 1970s and have no overlap at all today, and that the observed global temperature also starts to fall outside the envelope of the all-natural simulations in the 1970s. This exercise has been repeated using many different climate models, with the same qualitative result: one cannot simulate the evolution of the climate over last 30 years without including in the simulations mankind’s influence on sulfate aerosols and greenhouse gases. This, in a nutshell, is why almost all climate scientists today believe that man’s influence on climate has emerged from the background noise of natural variability

    Indeed, this seems to be the main reason most climate scientists find to support the notion of catastrophic AGW.

    It should be stressed, once again, that we are thus talking about a theory, still not validated by empirical observations. These are not facts, as the media and some scientists like to present them. From this point of view, there is an abysmal difference between the AGHGs – global warming link and, for example, the HIV virus — AIDS one. Still we are urged to spend trillions of dollars on the former hypothetical problem now and we are told that this is the biggest threat to humanity…

    Besides, my humble opinion is that this scientific theory is not a particularly robust one. In order to defend itself from the much more economical account of the observations offered by Lindzen and others it needs to resort to unconvincing aerosol hypotheses and other “masking effects’, even though the IPCC TAR itself declared the current scientific knowledge of the former to be “very low”.

    Plotting the global mean temperature derived from actual measurements and from proxies going back a thousand years or more reveals that the recent upturn in global temperature is truly unprecedented: the graph of temperature with time shows a characteristic hockey-stick shape, with the business end of the stick representing the upswing of the last 50 years or so. But the proxies are imperfect and associated with large margins of error, so any hockey-stick trends of the past may be masked, though the recent upturn stands above even a liberal estimate of such errors.

    I believe that Emanuel, as a climate scientist must surely have read the NAS and the Wegman reports. But if he hasn’t, his statements on the hockey stick and probably other aspects of climate science are obviously not very relevant.

    Still, I enjoyed reading his essay.

  37. jae
    Posted Jan 29, 2007 at 12:21 PM | Permalink

    Yes, thoughtful essay, but I’ve got some problems with it. For example:

    1.)There is much evidence that the MWP was hotter than now, so kill the “unprecedented” bit. We can’t say for sure that modern warming is unprecedented. The climate scientists are evidently still trying to ignore or minimize the MWP.
    2.)I’ll bet that the instrumental record is biased strongly by land use changes (UHI, e.g.). Why doesn’t he mention that nobody can audit the “global average mean temperature.”
    3.)I think it is simply naàƒÆ’à‚⮶e to say that the only possible explanation for warming is GHGs, and especially naàƒÆ’à‚⮶e to try to demonstrate this with computer model results. They could easily insert more solar forcing or cloud effects into the models to explain the rise in temperature. Why are these guys so enamored of computer models?
    4.)He says we cannot predict weather with a computer model beyond two weeks and probably never will be able to. Then he invokes a computer model to predict climate for years. Is climate easier to predict than weather? I doubt it.

  38. Posted Jan 29, 2007 at 12:33 PM | Permalink

    #29

    And every second, the Sun looses some 4 million tons of weight (should I say millll-yun ? ). It should have small effect in distance 5 billion years ago vs. today. (relatively not a big thing, less than permille of mass per 10 billion years)

  39. David Smith
    Posted Jan 29, 2007 at 12:45 PM | Permalink

    RE #33

    A website that can generate sea ice anomaly for any area, by month and year, is here . The pink line is the typical ice extent.

    Heatwise, there was a sudden rise in Arctic air temperature about 1976 (change in the PDO?) and the start of a warming of the Atlantic portion of the Arctic region in the early 1990s (change in the AMO?). Both of those put heat into the Arctic, so sea ice loss in recent decades is not surprising. What’s unknown is the extent to which the ice loss is natural and part of an oscillation.

  40. MarkW
    Posted Jan 29, 2007 at 1:06 PM | Permalink

    Emmanuel points out that the proxies are imperfect and have large margins of error.

    I would like to point out that the instrument record is also far from perfect and also has
    a non-trivial margin of error as well.

  41. Greg F
    Posted Jan 29, 2007 at 6:26 PM | Permalink

    In the article it states:

    Most scientists were deeply skeptical of Hansen’s claims; I certainly was. It is important to interpret the word “skeptical” literally here: it was not that we were sure of the opposite, merely that we thought the jury was out.

    At roughly this time, radical environmental groups and a handful of scientists influenced by them leapt into the fray with rather obvious ulterior motives. This jump-started the politicization of the issue, and conservative groups, financed by auto makers and big oil, responded with counterattacks. This also marked the onset of an interesting and disturbing phenomenon that continues to this day. A very small number of climate scientists adopted dogmatic positions and in so doing lost credibility among the vast majority who remained committed to an unbiased search for answers.

    Who are these scientists that “lost credibility”?

  42. John Baltutis
    Posted Jan 29, 2007 at 7:33 PM | Permalink

    Any of those radicals that questioned the consensus A in AGW?

  43. jae
    Posted Jan 29, 2007 at 9:28 PM | Permalink

    LOL. This is ENRON II, Science Version. It’s fun watching the ENRON of science!

  44. Jaye
    Posted Jan 29, 2007 at 10:08 PM | Permalink

    Sad but true Climate Correct

  45. Greg F
    Posted Jan 30, 2007 at 10:12 AM | Permalink

    One other thing strikes me about this article. Emanuel engages in the “truth is somewhere in the middle” fallacy to justify his position.

  46. jae
    Posted Jan 30, 2007 at 10:17 AM | Permalink

    No, he tries to make it look like the middle, but he’s no where near in the middle.

  47. W.R.Newberry
    Posted Jan 30, 2007 at 11:10 AM | Permalink

    I guess the professor, being one of the 100 most influential people, gets a free pass concerning his absurd remarks on hurricanes. In this day and age where the first wisps of dust off the African coast are recorded and followed 24/7 he makes the inference that we have a reliable and comparable record of Atlantic hurricane activity streatching back 150 years. Bunk! We (humanity) don’t know what activity occurred over 100 years ago and we never will (unless someone invents a time machine and corrects the record).
    His use of the term “scientific illiterate” to describe Senator Inhofe could just as well be applied to that hero of clear scientific thinking – AL Gore. While Emanuel’s article starts well, it deteriorates rapidly toward the end and reveals itself as nothing more than agenda driven
    propaganda.

  48. Steve McIntyre
    Posted Jan 30, 2007 at 12:27 PM | Permalink

    I thought that the shot at Inhofe was self-indulgent but that the closing section had some good points. I was surprised by the following comment by Emanuel:

    Scientists are most effective when they provide sound, impartial advice, but their reputation for impartiality is severely compromised by the shocking lack of political diversity among American academics, who suffer from the kind of group-think that develops in cloistered cultures. Until this profound and well documented intellectual homogeneity changes, scientists will be suspected of constituting a leftist think tank.

  49. Posted Jan 30, 2007 at 1:02 PM | Permalink

    Dear Steve #48, this is probably the first time when you promote the same article as Real Climate (January 23rd), isn’t it? ;-) They must have missed the particular paragraph you mentioned, among others.

  50. Steve McIntyre
    Posted Jan 30, 2007 at 1:06 PM | Permalink

    Actually we’ve often discussed the same articles. A year ago, I often had parallel discussions of some of their topics e.g. Cohn and Lins, Koutsoyannis. There are lots of things in the Emanuel article that I disagree with but I was too tired to write a comment on it (I’ve had a nasty flu/cold for about a week.)

  51. Posted Jan 30, 2007 at 2:08 PM | Permalink

    Dear Steve, sorry to disagree but I don’t think that you have falsified my assertion – that this was the first time when you promote (positively) the same article as RealClimate.

    If you search for ClimateAudit Cohn-Lins

    http://www.google.com/search?q=climateaudit+cohn-lins

    it shows “Motls” ;-) and leads you to the RC blog by Rasmus

    http://motls.blogspot.com/2005/12/temperatures-autocorrelation.html

    http://www.realclimate.org/index.php?p=228

    who is negative because the climate is “stable” and the LTP could be misused by the skeptics: Cohn Lins were pitching statistics against physics, and you remember all these things. Koutsoyannis is the same thing:

    http://www.climateaudit.org/?p=483

    It was never an article where you gave the same sign as RC. I said that Kerry Emanuel was the first time when RC and CA rated a thing both by a positive sign. ;-)

  52. Greg F
    Posted Jan 30, 2007 at 3:28 PM | Permalink

    Steve,

    Not surprising to me. He says “shocking lack of political diversity among American academics“, not ‘American scientists’. He seems to be concerned that the average person will lump all those scientists with the dominant ideology in academia in general. Although academics in science and engineering tend to be to the right of other academic fields, they still are to the left of the average American.

  53. Peter D. Tillman
    Posted Jan 30, 2007 at 6:31 PM | Permalink

    Re: #27 et seq.

    The place to to start for the geological evolution of climate is still Nance, R. D., T. R. Worsley and J. B. Moody. 1988. The supercontinent cycle, Scientific American, 259(1):72-79

    –which is the “greenhouse-icehouse” cycle, fueled by supercontinent creation /destruction and the long-term secular decline in atmospheric CO2.

    There’s a half-decent Wikipedia summary at http://en.wikipedia.org/wiki/Supercontinent_cycle

    and a precis of the supercontinent argument at http://scienceweek.com/2004/sa040730-5.htm

    Worsley’s elegant CO2 vs. geological time plots don’t seem to be online.

    Cheers — Pete Tillman
    Consulting Geologist, Arizona and New Mexico (USA)

  54. John Baltutis
    Posted Jan 30, 2007 at 7:36 PM | Permalink

    Re: #48

    Not surprising at all. What’s surprising is that he made that comment. It’s a prevalent problem within all “cloistered” cultures, especially academia. If one doesn’t embrace and espouse the consensus viewpoint, he’ll never get a position or tenure within that culture. I’m currently perusing The Trouble with Physics, Lee Smolin, 2006, wherein are many references to that problem within the physics community.

  55. Posted Jan 31, 2007 at 8:09 AM | Permalink

    Dear John #54,

    you shouldn’t get confused by the postmodern book you’re just reading. The isomorphism between the two fields is just the opposite than you indicate. The author of the book you’re reading is a bubble of hot air created by the media whose influence has nothing to do with actual science.

    It’s pure politics. If you read the book carefully, you will see that he’s been using and he is still planning to use the same methods as the warming alarmists, such as reliance on philosophical preconceptions, imposing language of political correctness, affirmative action for authors of convenient things etc.

    You may perhaps get some philosophical message right after all but be sure that in the physics details, the book is a constant flow of nonsense that is quantitatively unjustifiable. Thanks.

    All the best
    Lubos

  56. John Baltutis
    Posted Jan 31, 2007 at 6:59 PM | Permalink

    Re: #55

    Notwithstanding your opinion on the referenced book, do you disagree with this?

    It’s a prevalent problem within all “cloistered” cultures, especially academia. If one doesn’t embrace and espouse the consensus viewpoint, he’ll never get a position or tenure within that culture.

  57. jae
    Posted Feb 1, 2007 at 10:30 AM | Permalink

    56: I agree with it. I’ve experienced it.

  58. William Wallace
    Posted Feb 1, 2007 at 1:43 PM | Permalink

    I am very glad you posted this article, because until now I have not been able to figure out why climate scientists (well some of them) are so adament that anthropogenic CO2 will cause the world-to-end-as-we-know-it.

    And it shows the metamorphoris from a reasonable explanation of the science and uncertainties to name calling and ridiculous predictions. All in the same article.

    There is a good explanation of chaotic processes, why weather can’t be predicted even in theory, climate models cannot model clouds, clouds are the largest uncertainty in the models, etc. The text “uncertain” is used eleven times in the article.

    The money quote is below:

    “Scientists are most effective when they provide sound, impartial advice, but their reputation for impartiality is severely compromised by the shocking lack of political diversity among American academics, who suffer from the kind of group-think that develops in cloistered cultures. Until this profound and well documented intellectual homogeneity changes, scientists will be suspected of constituting a leftist think tank.”

    Kerry Emanuel is not a moron, he knows the climate models are nonsense, Senator Kennedy is a hypocrite, and nuclear is the only immediate solution, but he can’t come out and say it, otherwise he will end up an outcast.

  59. Posted Feb 1, 2007 at 4:11 PM | Permalink

    Dear John #56,

    It’s a prevalent problem within all “cloistered” cultures, especially academia. If one doesn’t embrace and espouse the consensus viewpoint, he’ll never get a position or tenure within that culture.

    I would agree that this is a mechanism that sometimes plays a role. I disagree that it is universal and I disagree that this behavior is always unjustified or counterproductive. There is a lot of “consensus” in cases where the underlying opinion is indeed correct. For example, most physicists think that the people who want to revise Einstein’s relativity and return before 1905 are crackpots. I think so, too. The “alternative physicists” don’t get jobs, and I personally think that it is very correct. The fact that most people in physics departments believe that they’re wrong is not a social construct. It is a result of their independent analysis of facts. I was never brainwashed by relativity – on the contrary, learned it despite the environment that didn’t care. This is true for many physicists – all of us have to re-discover old things all the time and only sometimes we find really new important insights – and even those who learned all these things at school can have the right to view their conclusion as a legitimate conclusion of people with independent brains.

    The previous paragraph explained why it’s not always a wrong thing that people happen to agree at the end – because the agreement simply has objective pillars underlying it in cases when it’s not doctored. And be sure that there are many cases in science where it’s not doctored by hysteria and intimidation – where it’s simply a state of our current knowledge. Even if you’re suspicious about the scientific statements, it’s still true that the crackpots are less intelligent and intellectually powerful, according to many objective criteria. We can learn their stuff but they can’t learn ours. The situation is not symmetric.

    Finally, I also want to point out that the mechanism is not always present, and sometimes it’s working in the reverse direction. Many of the things that are dominant today used to be fringe subjects. Surely, academic feminism used to be a fringe subject in the past, and I hope that it will become one in the future, again. There are both positive as well as negative theories and ideologies and frameworks that are both dominant as well as marginal. These things are uncorrelated and they must be expected to be uncorrelated, and everyone who is building some policies on the assumption that they are correlated is politicizing science, adding irrationality to it, whatever is the sign of his or her contribution.

    Lee Smolin is politicizing science in yet another direction. At a political level, it is really the same direction as in climate science. It is about artificial amplification of some “oprressed” people’s ideas. In the world of AGW, these oppressed people who are used to push some ideology are those who can’t produce too much CO2. In the world of quantum gravity, they’re people who are not intellectually powerful enough to learn modern QFT and string theory. Of course, in both cases, the usage of the “poor” people as an argument is a fraud because where the outcome is that some pretty rich biased climate scientists and their political allies earn millions or billions of dollars, and Lee Smolin earns hundreds of thousands of dollars on his unjustified alarmism, too. Once again, it is always wrong if someone starts to push political arguments as the main ones, whatever is the color of these political arguments. You can’t determine the truth in science in this way. And that’s the memo. ;-)

    Incidentally, I’ve written dozens of things about Lee’s methods to “find a new Einstein”. Some of them are cited in his book, e.g.

    http://motls.blogspot.com/2005/06/why-no-new-einstein.html

    http://motls.blogspot.com/2005/09/why-no-new-einstein-ii.html

    The main point of these texts is the free market of ideas that decides as optimally as reality allows as long as people behave rationally.

    Best
    Lubos

  60. John Baltutis
    Posted Feb 1, 2007 at 7:56 PM | Permalink

    Re: #59

    Thanks for the links. I’ll peruse your and the responder’s viewpoints after I finish the book and Peter Woit’sNot Even Wrong. I’m only half way through and haven’t encountered what you refer to as his “politicizing science in yet another direction” bent.

    Given that, I do contend that “cloistered” cultures is a major problem within academia and that “tenure” and the prevalent “political correctness” and “postmodernism” movements are it main faults.

    Since this is grossly off-topic, I’ll refrain from further comments on the subject until I complete my readings.

    Cheers

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