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Mind the Gap!

Filed under: — rasmus @ 18 November 2008 - (Italian)

Mean temperature difference between the periods  2004-2008 and 1999-2003
Confusion has continued regarding trends in global temperatures. The misconception ‘the global warming has stopped’ still lives on in some minds. We have already discussed why this argument is flawed. So why have we failed to convince ;-) ?

The confused argument hinges on one data set – the HadCRUT 3V – which is only one of several estimates, and it is the global temperature record that exhibits the least change over the last decade. Other temperature analyses suggest greater change (warming). Thus, one could argue that the HadCRUT 3V represents the lower estimate, if a warming could be defined for such a short interval.

Global mean temperature estimates: CRU, NASA-GISS data and the NCEP and ERA40 re-analyses
A comparison with other temperature analyses, such as the NASA/GISS (pink in the figure on the left), reveals differences. We can also compare with model-generated data (re-analyses), keeping in mind that one must be very careful with these data since they are not appropriate for studying long-term climate change (they give a misrepresentation of trends – at least on a local scale). Nevertheless, information from independent data suggest an increase in global mean temperatures even over the last decade.

All scientific questions involve some degree of uncertainties (error bars), and these can only be reduced if one can prove that they are influenced by an external factor (‘contamination’) or if some of the data are not representative for the study. Hence, if some of the data are incorrect, then it’s fair to exclude these to reduce the error bars. But this requires solid and convincing evidence of misrepresentation, and one cannot just pick the low values and claim that these describe the upper limit without proving that all the data with higher values are wrong. In other words, arguing that a lower limit is the upper bound is utter nonsense (even some who claim they are ‘statisticians’ have made this mistake!).

Another issue is that some of the data – i.e. the data from the Climate Research Unit (CRU) – have incomplete coverage, with large gaps in the Arctic where other data suggest the greatest increases in temperature. The figure below reveals the holes in the data knowledge. The figure compares the HadCRUT 3V data with the NCEP re-analysis.

Temperature measurements over the Arctic: CRU data and the NCEP re-analysis
Figure caption: The difference between Oct. 2007 – Sep. 2008 temperature average and the 1961-1990 mean temperature for HadCRUT 3V (upper left) and NCEP re-analysis (upper right). Below is a comparison between the 12-month 60N-90N mean temperature evolution (red=NCEP, black = HadCRUT 3v)). (click on figures for PDF-version)

Re-analysis data are results from atmospheric models where observed data have been fed into the models and used to correct the simulation in order to try to get a best possible description of the real atmosphere. But it’s important to note that the NCEP re-analysis and other re-analyses (e.g. ERA40) are not regarded as being appropriate for trend studies due to changes in observational systems (new satellites coming in etc). Nevertheless, a comparison between the re-analyses and observations can highlight differences, which may suggest where to look for problems.

Mean temperature difference between the periods  2004-2008 and 1999-2003
The animated figure shows the temperature difference between the two 5-year periods 1999-2003 and 2004-2008. Such results do not show the long-term trends, but it’s a fact that there have been high temperatures in the Arctic during the recent years.

The recent Arctic warming is visible in the animated plot on the right showing the NCEP re-analysis mean temperature difference between the periods 2004-2008 and 1999-2003.

The NOAA report card on the Arctic was based on the CRUTEM 3v data set (see figure below) which excludes temperatures over the ocean – thus showing an even less complete picture of the Arctic temperatures. The numbers I get suggest that more than 80% of the grid-boxes north of 60N contain missing values over the most recent decade.

Temperature measurements over the Arctic: CRU data and the NCEP re-analysis
Figure caption: The difference between Nov. 2007 – Oct. 2008 temperature average and the 1961-1990 mean temperature for CRUTEM 3v (upper left) and NCEP re-analysis (upper right). Below is a comparison between the 12-month 60N-90N mean temperature evolution. (click on figures for PDF-version)

The funny thing, however, is that the last decade of the Arctic CRUTEM 3v temperatures are closer to the corresponding estimates from NCEP re-analysis than the more complete HadCRUT 3v data. This may be a coincidence. The re-analyses use additional data to fill in the voids – e.g. satellite measurements and predictions based on the laws of physics. Thus, the temperature in areas with no observations is in principle physically consistent with surrounding temperatures and the state of the atmosphere (circulation).

Below is a figure showing a similar comparison between HadCRUT 3v and GISTEMP (from NASA/GISS). The latter provides a more complete representation of the Arctic by taking spatial correlation into account through an extrapolating/interpolating in space. But GISTEMP does not really have a better empirical basis in the Arctic, but the effect from the extrapolation (the filling in of values where there is missing data) gives the recent high Arctic temperatures more weight.

GISS-CRU warming difference over 1996-2004
Figure caption: The 2007 mean temperature anomaly wrt to 1961-90: (upper left) HadCRUT 3V, (upper right) GISTEMP, and (lower) temperature evolution for the Arctic (red=GISTEMP, black = HadCRUT 3v).

A comparison between temperatures over the most recent available 30-year period (1978-2007) shows high temperatures over parts of Russia (Figure below – upper left panel), and the difference between the GISTEMP and HadCRUT 3v shows a good agreement apart from around the Arctic rim and in some maritime sectors (upper right panel). The time evolution of the Northern Hemisphere mean for the two data sets is shown in the lower panel, showing a good agreement over most of the record, but with slightly higher GISTEMP estimates over the last 10 years (the global mean was not shown because my computer didn’t have sufficient memory for the complete analysis, but the two data sets also show similar evolution in e.g. the IPCC AR4).

GISS-CRU mean difference over 1976-2005
Figure caption: (upper left) HadCRUT 3V mean T(2m) anomaly over 1976-2005 (wrt to 1950-1980) ; (upper right) The GISS – HadCRUT 3V difference in mean T(2m) over 1976-2005; and (lower) the Northern Hemisphere mean temperature variations (red=GISTEMP, black=HadCRUT 3v).

Note, the low Arctic sea-ice extent over the last summers are independent evidence of high Arctic temperatures.

The insufficient observational coverage has also been noted by the IPCC AR4 and by Gillett et al. (Nature Geoscience, 2008), who argue that the observed warming in the Arctic and Antarctic are not consistent with internal climate variability and natural forcings alone, but are directly attributable to increased GHG levels.

They also suggested that the polar warming is likely to have discernable impacts on ecology and society (e.g.).

In their study, there are at least 15 grid boxes with valid data (usually representing one measurement) over 1900-2008 period. Furthermore, the only valid observations they used from the Northern Hemisphere were from the Arctic rim, as opposed to in the high Arctic itself. The situation is slightly better for the Antarctic (with one observation near the South Pole). Nevertheless, the title ‘Attribution of polar warming to human influence’ [my emphasis] is a bit misleading. Parts of the high-latitudes yes, polar no.

The attribution study was based on series of 5-yr-mean temperatures and spatial averages of 90 degree sectors (i.e. to four different sectors), where sectors and periods with no valid data were excluded.

There are some caveats with their study: The global climate models (GCMs) do not reproduce the 1930-1940 Arctic warm event very well, and the geographical differences in a limited number of grid-boxes in the observations and the GCMs may have been erased through taking the average value over the 90-degree sectors.

The 1930-1940 Arctic warming was probably not externally forced, but one could also argue that the models do not capture all of the internal variations because few reproduce similar features. Furthermore, the present GCMs have problems reproducing the Arctic sea-ice characteristics (which tends to be too extensive), ocean heat content, and fail to capture the ongoing decrease in Arctic sea-ice area. Most of these problems are seen in the gap with no CRUTEM 3v data, but there are also some uncertainties associated with the lack of data in the Polar regions.

The optimal fingerprint analysis hinges on the assumption that control simulations with the GCMs realistically reproduce the climate noise. I think that the GCMs do a good job for most of the planet, but independent work suggest local problems in the Arctic associated with a misrepresentation of the sea-ice extent. This may not have affected the analysis much, if the problem is limited to the high Arctic. Furthermore, the results suggested a one-to-one correspondence in trends between simulations and observations, but the analysis also gave a regression coefficient of 2-4 for natural forcings. The latter suggests to me that there may be some problems with the analysis or the GCMs.

Thus, this is probably not the final word on the matter. At least, I’m not convinced about the attribution yet. The whole boils down to insufficient amounts of empirical data (i.e. observations), GCM limitations at the high-latitudes, and too large data gaps. But the pronounced changes in the Arctic are consistent with AGW. The irony seems to be that the real world shows signs of more dramatic changes than the GCMs project, especially if you look at the sea-ice extent.

The lack of data in the polar region is a problem, and the ongoing International Polar Year (IPY) campaign is a huge concerted international effort to improve the data. Data is irreplaceable, regardless of the modelling capability, as science requires the theory to be tested against independent empirical data. The re-analyses provide a physically consistent description of the atmosphere – suggesting high temperatures in the Arctic – but we can only be sure about this when we actually have been there and made the real measurements (some can be done by satellites too)

A glimpse into the technical details
More technically, the complicated analysis involved a technique called ‘optimal fingerprinting‘ or ‘optimal detection’, looking for best signal in the noisy data and puts emphasis on regions where the GCMs give most realistic description of the climate variations. Basically, the optimal fingerprint techniques involved linear least-squares regression, which is familiar to many analysts.

The analysis of Gillett et al. involved ‘time-space’ orthogonal empirical functions (EOF) with truncation of 28 (and up to 78 modes for the Arctic, where the maximum truncation was the number of sectors multiplied with the number of 5-yr means – see supplementary material Fig. S3). These come into the equation through the estimation of the noise (covariance matrix), i.e. the internal variations and their magnitude. The clever thing is that they let each EOFs describe a set of 20 maps of 5-year-mean temperatures, thus representing both the spatial features as well as their chronology.

For the mathematically inclined, EOFs are similar to eigenvectors, and are mainly used to prepare data before further analysis. The purpose of using EOFs is often either to (i) compress the information or (ii) to make the data more ‘well-behaved’ (in mathematical terms: orthogonal). While one typically only use a few of the first EOFs, Gillett et al. experimented with just one up to the whole set because they took advantage of their orthogonal properties to allow the calculation of the inverse of the noise co-variance matrix. This is a neat mathematical trick. But this doesn’t help if the GCMs do not provide a good description of the internal variations.


419 Responses to “Mind the Gap!”

  1. 201
    Geoff Beacon says:

    189. Lawrence. Thanks. It’s good to find someone able to say it as they see it.

    Are there any others?

  2. 202
    Mark says:

    Kevin, diplomacy doesn’t stop wars.

    It’s strange but once it requires a lot of dead before one side starts thinking “Hey, maybe we ought to talk”. They don’t think of doing the talking before.

    Can anyone think of a time when diplomacy stopped a war? The only ones that come close were just grandstanding attempts and were unlikely to turn into real war (except *maybe* by proxy, cf Afghanistan vs USSR).

  3. 203
    Anne van der Bom says:

    simon abingdon #200:

    Didn’t you forget some:
    6) Cosmic rays
    7) Natural variability
    8 ) Urban heat island
    9) The oceans
    10) Medieval Warm Period
    11) CO2 lags temperature
    12) Little Ice Age
    13) Saturated absorption bands
    14) Cooling since 1998
    15) Eco-left conspiracy

  4. 204
    Hank Roberts says:

    Sidetrack, Mark. http://www.gwu.edu/~nsarchiv/nsa/cuba_mis_cri/
    Wrong metaphor; look at teaching evolution or epidemiology or public health — the people describing that as war are claiming they’re victims of persecution. Don’t feed.

    Simon, Fermi’s question has corollaries:
    – “How long will we be viable?”
    – “What could possibly go wrong?”

    David Brin’s good on this topic, with frequent recommendations at http://davidbrin.blogspot.com/ Picking just two that say something about teaching science and how people learn:

    http://thesciencenetwork.org/programs/beyond-belief-candles-in-the-dark
    http://www.edge.org/documents/archive/edge261.html#3

  5. 205
    Hank Roberts says:

    P.S., Brin also notes work relevant to the Fermi Paradox, just in this past week. Still no joy. http://arxiv.org/abs/0811.2376

  6. 206
    Arch Stanton says:

    Anne van der Bom (203), (perhaps you are being facetious, if so you left out “hockey stick”) none the less 5-15 all fall under 1-4, and have been discussed here repeatedly.

  7. 207
    jcbmack says:

    The averaging of the grid boxes and identifying anomalies, spatial averaging, time averaging and the utilization of both larger and smaller boxes has led to many methods to reducing sampling, bias, and large number related errors. Several issues do remain which are mentioned straightforward in the HADCRUT3 literature and the potential discrepancies over the deviation in temp C, from the actual monthly, decade, and century temperature changes recorded are also well discussed. The utilization of statistics, the standard deviation, (sigma and so forth) are all to put a play on the word: standard. The cross analysis of the temperature data from the oceans and land leave some questions unanswered, but again the further applications of error analysis and averaging smooths out figures enough to get a reading that one can be confident indicates a global warming trend. The improvements in sensitivity to nuances is incredible, but again over time these nuances play less of an integral role than one might think and chaotic weather patterns (or other global events) not only must be considered in relationship to sharp deviations or discrepancies, but global climate system coupling and potential climate change and actual warming must be understood as having a cyclic relationship with ongoing changes in weather patterns and feed backs resulting from not just the green house gases, but from the affects of such greenhouse gases after a positive and feedback; the magnitude is still not clearly shown nor is the reason for the positive feedback being a net factor, but it quite cleat that it is. Still, as models are modified, paramaterized, and made more sensitive with existing technology and utilization of data and statistical techniques, there should be a more compelling presentation of immense accuracy for the skeptical mathematicians, meteorologists, etc… (and hopefully the trickle down for the lay people)

  8. 208
    jcbmack says:

    Bullocks

  9. 209
    Francois Marchand says:

    I watched a CNN special, financed by Shell, I believe, featuring “seawater rivers”, which would both pump CO2 out of the atmosphere, and take care of the rising level of the oceans. The proponent seems to be an American. I thought it a bit odd; any clues?

  10. 210
    Guenter Hess says:

    Mark (#186),
    There is no war and there are no fence sitters, there are tax payers. A lot of countries acting right now and spending a lot of money into climate simulation and related research as well as new technologies.
    I guess all the people in our countries pay their taxes and are entitled to voice their opinion. Therefore I think they are also entitled to be treated with respect.
    Best regards
    Guenter Hess

  11. 211
    Francois Marchand says:

    (re 117, belatedly). Ms Anna Loftin has been writing that the European leaders reneged on their commitment to lower emissions of CO2 by 30%, down to 20% only, by 2020. Where did she ever get that figure of 30? As far as I know, continental Europe is -give or take haolf a percentage point- more or less on track regarding its goals, so what is she driving at? Any other country in the world she has in mind, which would be doing better?

  12. 212
    Mark says:

    Hank, how about we use “Stop persecuting us”? We’ve got a lot more proof that we’re being picked on.

    PS you’re wrong that not calling them denialists will stop them bleating about how they’re being jobbed.

  13. 213
    Ray Ladbury says:

    Simon Abingdon,
    The Sun–I think we understand that pretty well. If it shines brighter, we get warmer. It’s output has been remarkably stable, and more to the point is measurable.

    Water vapor–We also understand that better. It’s a greenhouse gas with a short residence time in the atmosphere.

    Neither explains a long-term rising trend of rising temperatures. I would suggest that the fact that you didn’t include clouds and aerosols is a pretty good indication that you don’t know what you are talking about. That is where most of the uncertainty resides.

    I also find it interesting that you utterly ignore the fact that CO2 is a greenhouse gas and propose no mechanism by which it ceases to act as one once its concentration rises above 280 ppmv.

    Might I suggest that rather than trying to justify your own skepticism, your time could be better spent learning the science that is already known about climate. Your criticisms might then at least be relevant and informed.

  14. 214

    Mark, (#202) diplomacy has stopped a lot of wars, though as you point out, generally a lot of people have to die first–indicative is the prevalence of the words “treaty of—” and “status quo ante bellum” in modern European history. I dare say diplomacy has stopped a goodly number of wars before they got started–possibly the last India-Pakistan crisis was a example, though of course there is an inherent “attribution problem” as to why they didn’t actually go to war.

    But as Hank’s post indicates, we can quibble about war and diplomacy all we want, but we are quibbling about a metaphor; we are not literally at war regarding climate change. The question remains open as to whether this is a metaphor that will serve us well. It certainly captures the urgency and vital significance of the issue, but are we likely to prevail through sheer force or sheer resolve? Or do we need primarily to persuade? If that is the case, then obviously we need to keep our eyes on what is persuasive–and that may not be the crushing argument or the devastating putdown.

  15. 215
    simon abingdon says:

    Hank #205 “Still no joy” Perhaps 10^22 stars just isn’t enough for evolution to come up with an encore. Needs far more than a chain of twenty-two 1 in 10 chances, no? (Sorry OT)

  16. 216
    Lawrence Coleman says:

    What the denyalists are saying I believe is that they want 100% proof that humans are the main reason for Climate change. The problem here is that we will never have 100% proof. There is no definative proof that smoking causes cancer either and that’s because mammalian biochemistry is so terribly complex with countless cascading chains and sequences and complex interactions with internal chemicals and external ones and then there’s the dna which tells each gene how much of a certian type of amino acid to produce and when. However you would be seriously ignorant if you did not find striking correlations between what we are doing to our bodies and the onset of cancer. It’s like the more we know the less we actually know. Climate science is the same I would guess. The interactions at play are endless, they spiral off into smaller and smaller subsets ad-infinitum. Laypeople have to be content when the members of the IPCC say CC is 90% caused by anthopogenic means..that’s as good as we are going to get!..ok..maybe in another 5 years it’ll be “we are 92% sure..”. You will never ever get 100%. Dave Andrews says in 198..”well Lawrence how do you know that?” Dave..90% is good enough for me to take action. I don’t need our boat to be completely undewater before you say “man the bilge pumps”. I just read an article on the impact of nitrates from cities and car engines being deposited in arctic snow turning to N20 again when the spring thaw begins and contributing 1/3 to the N20 in the arctic atmosphere thus forcing decay of the ozone hole. Gavin would be the first to say there is a hell of a lot we dont understand yet. That’s why adequate funding is so critical at this time. We know it’s happening..what we dont have a good handle on yet is the time frame we have.

  17. 217
    Julius St Swithin says:

    If you compare CRU, NOAA and satellite estimates from 1979 they are marked by periods with little or no increase (79 to 82, 87 to 91 and 02 to 06), periods with falls (83 to 83, 91 to 93 and 05 to 08) and periods with increases (85 to 87, 94 to 99 and 00 to 02). Overall there has been an increase of around 0.3 C. Unfortunately in the debate on climate change too many people read too much into short term changes in temperature. So the only sensible reply to the question “Has global warming stopped?” is one Mao Tse Tung gave when asked “What are the consequences of the French Revolution?” – “It is too early to tell.”

  18. 218
    Hank Roberts says:

    It’s amazing how many giants there are to stand on. A bit excerpted from this is relevant to the topic:

    Criticism in a Mass Society
    by W H Auden

    Published in 1941 in a book of essays titled The Intent of the Critic, ed D A Stauffer, Princeton University Press.

    Found somewhere on the Web. You know how.

    _______excerpt______

    … It will not take us long to discover that in a modern society, whatever its political form, the great majority prefer opinion to knowledge, and passively allow the former to be imposed upon them by a centralized few—I need only mention as in example the influence of the Sunday book supplements of the newspapers upon our public libraries.

    If we are concerned, as I think we should be, at this trend, we shall accomplish nothing by cries of lamentation or superior sneers; we cannot hope to effect any reform unless we can discover, firstly, what it is in the structure of our society that makes for this state of affairs, secondly; how far the molding of the opinions of the few by the many is inevitable, and then what steps it is possible to take within the inevitable to minimize its dangers and take advantage of its possibilities.

    … the only check on authoritarian control by the few, whether in matters of esthetic taste or political choice, is the knowledge of the many. We cannot of course all be experts in everything; we are always governed, and I hope willingly, by those whom we believe to be expert; but our society has already reached a point in its development where the expert can be recognized only by an educated judgment. The standard demanded of the man in the street (and outside our own special field, we are all men in the street) rises with every generation.

    This cannot be emphasized too strongly. …

    … Our differences, and they are vital, are as to the essential nature of that unity and the form which it should take. The cohesion of a society is secured by a mixture of three factors, community of actions, community of faith and beliefs, and coercion by those who possess the means of exercising it. In a differentiated society like our own, the first factor has in large measure disappeared. If we are agreed that the third should be as small an influence as possible, we must examine the second very carefully.

    I have used two words, faith and belief, to describe two different forms of assent: assent to presuppositions which cannot be immediately proved true or false, as, for example, science presupposes that the world of nature exists; and assent to propositions that can be experimentally tested, e.g., the proposition that water boils at one hundred degrees centigrade. In proportion as a society is closed and traditional it tends to regard all propositions as presuppositions and so to discourage initiative and research because it fears the destruction of its fundamental assumptions.

    … False beliefs in fact lead to bad poetry, and bad poetry leads to a falsification of belief. …

  19. 219
    Ray Ladbury says:

    Simon Abingdon, Again off topic, but relevant to the type of misunderstanding one often sees in scientific matters. To say that a mere 22 one in ten chances would preclude development of life ignores many things. Chief among them:
    1)Genetics is changing continually with billions of copies of what are nominally the same instructions.
    2)The events in question are not independent, so multiplication of probabilities is not appropriate.
    3)Evolution is shaped by the environment, which is brutally efficient.

    I suspect that the answer to Fermi’s paradox is that any intelligent lifeforms simply haven’t seen anthing promising enough from our edge of the galazy to justify the investment needed to come and say “howdy”. People seem to forget that there’s a cosmological speed limit that will limit interstellar tourism pretty severly.

  20. 220
    Ray Ladbury says:

    #210, Guenter, By all means, the tax payers are entitled to their opinion and to respect of that opinion. They are not, however, entitled to their own set of facts independent of physical reality. If people seek to influence policy, they must first acknowledge the science. If not, they leave empty their seat at the negotiating table where we decide what to do about the threat we face from climate change

  21. 221
    John Lang says:

    I read Dessler’s water vapour paper linked above.

    The data shows there was a 1.5% (percentage points) decline in relative humidity in the lower troposphere and a 1.5% increase in relative humidity in the upper troposhere (no real change in the middle.)

    I’m not sure that supports the contention that relative humidity remains broadly constant with changes in temperature (or warming in particular).

    There is obviously much more water vapour in the lower troposphere than the upper troposphere given the decrease in pressure.

    This would signal a decline in the overall level of relative humidity as the temperatures declined in the study period (which itself might indicate the feedback effect is larger than predicted but it at least indicates that it is not stable across the weighted average of the troposphere).

    [Response: Actually it pretty much does. As temperature increases, the saturation specific humidity goes up by 7% per deg C. If Relative humidity is roughly the same (within a percent or two), then the actual water vapour is still increasing at pretty close to 7% per deg C - giving a significant water vapour feedback. You can see the kinds of predicted changes in RH (on the order of a percent or two) in the GISS model results (available here). - gavin]

  22. 222
    simon abingdon says:

    Ray #213 “you didn’t include clouds” (H2O?) “The Sun–I think we understand that pretty well” (pretty?)

  23. 223
    simon abingdon says:

    Ray #218 Well how about these for starters?
    (1) a nearly circular orbit stable for billions of years,
    (2) an abundance of (liquid) water,
    (3) significant land masses amid the oceans,
    (4) an appropriate tilt to the planet’s axis,
    (5) benign influences of nearby bodies (moon and Jupiter),
    (6) gravity sufficient to contain an atmosphere,
    (7) an ecology enabling this atmosphere to be breathable,
    (8) the fortuitous extinction of the dinosaurs,
    (9) appearance of the opposable thumb,
    (10) the development of bipedalism,
    (11) availability of materials for toolmaking,
    (12) a physiology enabling the evolution of language

  24. 224
    Ray Ladbury says:

    Simon, That is what I mean. Your reference to “H20″ and “The Sun” is vague–not at all the way one would talk if he had a good understanding of the science. Why not at least learn what you are opposing?

    ReCaptcha says: knowing of

  25. 225
    Steve Reynolds says:

    Ray: “…suspect that the answer to Fermi’s paradox is that any intelligent lifeforms simply haven’t seen anthing promising enough from our edge of the galazy to justify the investment needed to come and say “howdy”.

    Depending on the density of civilizations, it may also involve someone enforcing non-interference in a ‘nature preserve’.

  26. 226
    Brian Klappstein says:

    “…So why have we failed to convince ;-) ?…”

    For a start comparing 2 clunker data sets to prove warming is still possibly happening isn’t very persuasive. More objective temperature datasets are derived from the satellite MSU sources.

    MSU data have “holes at poles” but the empirical surface data north/south of 82.5 is pretty slim also. Outside of these zones the MSU datasets have much better coverage of the globe for recent climate history.

  27. 227
    simon abingdon says:

    Ray #223 I added to your somewhat overconfident (“can only be explained by 4 hypotheses”) list of reasons why people might not accept AGW (#185) the comment “the Sun and H2O. More research needed” (#200).

    Your lukewarm assertion (#213) “The Sun–I think we understand that pretty well” and your admission (also #213) that “clouds [H2O] and aerosols … is where most of the uncertainty resides” are really quite shocking given the momentous importance of AGW theory.

    Here are three questions:

    (1) Is solar magnetic flux variability and its consequent effects on cosmic ray shielding well understood?
    (2) Is the involvement of cosmic rays in cloud production well understood?
    (3) Are the feedback mechanisms of clouds well understood?

    By “well understood” I mean understood to a level where earth-shaking policy decisions could be made with confidence. “Pretty well” obviously falls short of this criterion as would all admissions of uncertainty.

  28. 228
    Mark says:

    Brian, #225.

    Isn’t it you who are using two clunker datasets to prove warming is no longer happening?

    90 stations got recorded incorrectly.

    Why do they make correction fluid?

  29. 229
    Mark says:

    simon #222. What about

    a worm that lives inside a childs eye, eating the eye and making the child blind
    mlaria protection giving people sickle cell anaemia
    human physiology changes for speech mean we can’t breathe while drinking
    playground in amongst the sewers

    If there’s a reason, it’s not from a benign source. Or even that competent a one.

    Or there’s no source and things just happen.

  30. 230
    Barton Paul Levenson says:

    FurryCatHerder writes:

    Perhaps instead of saying “10 years isn’t long enough” the pro-AGW crowd will start to recognize that the giant ball of fire has an influence?

    They never said it didn’t. What they said, correctly, was that since solar output has shown no trend for the past 50 years, it can’t have caused the sharp upturn in global warming of the last 30. Period.

  31. 231
    Barton Paul Levenson says:

    simon abington writes:

    Hank #205 “Still no joy” Perhaps 10^22 stars just isn’t enough for evolution to come up with an encore. Needs far more than a chain of twenty-two 1 in 10 chances, no? (Sorry OT)

    The combinatorial argument against abiogenesis does not stand up to analysis. See (remove the hyphen before copying and pasting into your browser’s address window):

    http://www.geocities.com/bpl1960/Combo.html

  32. 232
    Barton Paul Levenson says:

    simon abington writes:

    Ray #218 Well how about these for starters?
    (1) a nearly circular orbit stable for billions of years,

    In the Solar system, no planet has eccentricity exceeding about 0.25, and most are well under. And they’ve all been about where they have been for the past 4.5 billion years, Velikovsky notwithstanding. A lot of exosolar planets have high eccentricity, but this may be an observation bias since we’re just starting to detect them (first reliable exoplanet detection was in 1992).

    (2) an abundance of (liquid) water,

    Any planet with the right size and temperatures should have plenty of liquid water. Hydrogen is the most common element in the universe and oxygen isn’t far behind.

    (3) significant land masses amid the oceans,

    A planet would have to be extremely large to be entirely ocean. Earth is about 70.8% ocean, Mars has about 36% if you count both polar caps. I’ve seen one estimate that early Mars had about 15% ocean coverage.

    (4) an appropriate tilt to the planet’s axis,

    According to Dole (1964, 88), axial inclination of up to 54 degrees is compatible with habitability.

    (5) benign influences of nearby bodies (moon and Jupiter),

    We probably do need the Moon to stabilize our axial tilt. Ditto Jupiter for diverting outer-system comets. I’d guess about 1-10% of otherwise suitable planets have the right setup.

    (6) gravity sufficient to contain an atmosphere,

    True for Venus, Earth and Mars. The thin atmosphere of Mars is probably due to early impact ablation.

    (7) an ecology enabling this atmosphere to be breathable,

    Any old enough planet with liquid water and organic chemicals should.

    (8) the fortuitous extinction of the dinosaurs,

    Why is this a requirement? If the big impactor hadn’t hit, perhaps there would now be intelligent dinosaurs on the planet, probably descended from the coelurosaurs or other bipeds.

    (9) appearance of the opposable thumb,

    True, this was very useful. It has shown up a few times, e.g. in primates and raccoons. Cephalopods make do with tentacles.

    (10) the development of bipedalism,

    Yes, useful to free the hands. Again, no reason to think it wouldn’t arise. Allosaurs, coelurosaurs, primates, birds, and occasional bipeds like bears, raccoons and meerkats.

    (11) availability of materials for toolmaking,

    Unlikely to be a problem. Stone is going to be pretty much universal on a terrestrial planet, and probably metal as well. And any planet with an ecology will probably have an equivalent of wood.

    (12) a physiology enabling the evolution of language

    A good point. As far as we know only humans have developed language per se (I am not impressed with ape language experiments). Is a nonverbal intelligence possible? There used to be a theory that Neanderthal man was nonverbal, due to an apparent lack of Broca’s and Wernicke’s area in skull casts, but I think someone may have disproved it. Does anybody know?

  33. 233
    Barton Paul Levenson says:

    Brian Klappstein writes:

    For a start comparing 2 clunker data sets to prove warming is still possibly happening isn’t very persuasive.

    Global warming is shown by land surface temperature station readings, sea surface temperature readings, balloon radiosonde temp. readings, satellite temp. readings, borehole temp. readings, melting glaciers, sea level rise, treelines moving toward poles, mammal, bird and insect migration toward poles, increase in spread of tropical diseases, increasing atmospheric water burden, etc., etc., etc. It’s happening. Deal with it.

  34. 234
    Ray Ladbury says:

    Simon Abingdon, Re: your 3 questions.

    (1) Is solar magnetic flux variability and its consequent effects on cosmic ray shielding well understood?
    Again, you must define what you mean by “well understood”. We understand it quite well wrt the solar cycle. We also know that GCR flux hasn’t changed much in the 50 years we’ve been measuring it. So, yes, we understand it well enough to know that’s not behind the current warming epoch.
    (2) Is the involvement of cosmic rays in cloud production well understood?
    We understand it well enough to see that since GCR fluxes aren’t changing, it’s not a driver of current climate change.
    (3) Are the feedback mechanisms of clouds well understood?
    I said that clouds remain a big uncertainty for climate models. However, they can provide both positive and negative forcing.

    What you left out is that we understand very well how CO2 acts as a greenhouse gas. We understand the major feedbacks and we know that we need a sensitivity around 3 degrees per doubling for our models of climate to work. If that is wrong, then everything we know about climate is wrong, and the success of the models does not support that conclusion.

  35. 235

    Re 232–Barton, thanks for a concise list of some of the corroborating observations; I’ll only add that these are documented in in peer-reviewed published work, and are thus not merely anecdotal. One of the frustrating constants is the tendency of some to disregard this information, apparently because it is “inconvenient.”

    Re 231–since the whole “Fermi paradox” discussion is a bit OT, I’ll only add a personal opinion that the view of (sophisticated) cognition being exclusively language-dependent is being seriously undercut by neurological research, which reveals that cognition draws upon a much larger suite of underlying perceptual and reality-modelling/processing capabilities. (Of course, language does still remain a tool of great significance.) No specific cites to support that, I’m afraid!

  36. 236
    PHE says:

    BPL. And how about these, all from recent newspaper headlines:
    - increase in kidney stone occurence due to warmer climate
    - Dormice forced to take bird food because of climage change
    - Lemming populations ravaged by climate change
    - Climate change keeps swans in Siberia
    - Salt levels in the oceans
    - Common seal population in sharp decline due to CC
    - Black widows in UK
    - Butterflies fight losing battled against CC
    - Whales lose blubber due to CC
    - CC hits minorities hardest

  37. 237
    Alexandre says:

    Barton: about the lack of speech of Neanderthals. I think Jared Diamond covers that subject on The Third Chimpanzee. If I remember right, he claims that Neanderthals had the limited speech we probably had some 35.000 years ago: just simple words, no complex syntax. It was not enough to trigger the steady development of technology we had from then on.

    (I know, this is drifting away from the topic…)

  38. 238
    Alexandre says:

    Barton: about the lack of speech of Neanderthals. I think Jared Diamond covers that subject on The Third Chimpanzee. If I remember right, he claims that Neanderthals had the same ability of speech we had some 35,000 years ago: just simple words, no complex syntax. It was not enough to trigger the steady development of technology we had from then on.

    (I know, this is drifting away from the topic…)

  39. 239
    Ike Solem says:

    Regarding “natural cycles”, let’s remember that ENSO, the PDO, and the AMO are nothing at all like other natural cycles – such as the daily tidal cycle, or the monthly orbit of the Moon around the Earth.

    A natural cycle implies predictability, and this is where ENSO diverges. Let’s look at the 20th century ENSO index: http://www.cdc.noaa.gov/ENSO/enso.mei_index.html

    For an example of more predictable cyclical behavior, see the solar neutron output/sunspot cycle, 1950-2002: http://www.ngdc.noaa.gov/stp/SOLAR/COSMIC_RAYS/image/cr_ssn.gif That cycle is very clear, but has a negligible effect on climate, and in any case – the solar output has been flat, hasn’t it?

    In the case of ENSO, there is no simple cyclical trend, though the index wobbles between positive (El Nino) and negative (La Nina) conditions. Keep in mind that no climate model has ever come close to reproducing this “clear cyclical trend”, either. The AMO and PDO are not nearly as well understood – there is little if any mechanistic explanation for the PDO or the AMO, unlike the case with ENSO (where it is still controversial). The PDO and AMO were detected using time series analysis as well, which makes the a priori assumption that cyclical behavior is there in the data, waiting to be discovered.

    [Response: Not quite true. We do indeed understand ENSO better, but models do in fact produce internal modes that are quite 'PDO' and 'AMO' like, and their are a multitude of mechanisms that have been imputed to explain them. The dynamics underlying the AMO in the GFDL model simulations are explored in some detail in Delworth and Mann (2000) linked above. -mike]

    That’s an important point. Climate models don’t reproduce the 20th century warming trend if anthropogenic increases in CO2 are not included. Those increases are due to burning fossil fuels, mostly, as measured by radioactive dating experiments – fossil fuel has no 14C, unlike biomass. However, no climate model reproduces the details of the best-understood climatic oscillation – El Nino. This indicates there is a good deal of randomness to this oscillation – hardly a clear cycle.

    Second, we need to remember that most of the warming from CO2 so far has gone into the oceans, not the atmosphere. The heat capacity of water is far greater than that of air, so the oceans don’t warm nearly as much – but the heat is still there.

    A large El Nino represents a surface ocean-to-atmosphere heat transfer, which is why 1998 surface temperatures were high (and that’s why the fossil fuel industry PR folks like to start all their climate trends in 1998). Still, this is just a redistribution of energy – if it was the only factor, you would see net cooling of the oceans.

    Thus, if we take Jared’s claim that the atmosphere is warming because of AMO and PDO and ENSO related heat transfers from the ocean, we should see an equivalent ocean cooling (1) and we should also see no energy imbalance at the top of the atmosphere (2), meaning that the Earth is shedding as much energy as it is absorbing. Neither of these is true.

    [Response: This is true to first order, but there are 2nd order impacts that can actually change the TOA radiation budget. For example, changes in type and extent of cloud. This is seen w/ ENSO. Harder to say if its seen w/ these putative lower frequency internal modes, since they are not well sampled over the satellite interval. -mike]

    In fact, there is a clear measured energy imbalance at the top of the atmosphere, though Triana/DSCVR would make that measurement more accurate. There is also a steady trend of ocean warming, as well as a steady trend of melting ice. Melting ice doesn’t change the temperature, but it does represent energy storage by the Earth, and it accounts for some portion of that top-of-the-atmosphere imbalance. Therefore, there is no way that ENSO or AMO or PDO or MJO type oscillations can be responsible for the observed warming.

    Also, remember that the water vapor increase is an amplification of the warming brought on by CO2 and methane and N2O. I don’t see how that helps any denialist arguments, re #81.

    As far as why fossil fuel producers are funding huge efforts to prevent action on global warming, that should be obvious – loss of market share. A 95% reduction in fossil fuel use is not going to make them very happy, is it?

    There are plenty of viable replacements for fossil fuels, some safer than others, but there is no technological problem that is preventing the widespread adoption of renewables. The problem is one of emerging and disruptive technology.

    For example, in 1980 there were no cell phones or cell phone networks – and now there are. There was no pre-existing mobile communication technology to compete with. However, fossil fuel use has increased quite a bit since 1980, even though solar and wind were well developed in the 1970s. We don’t all have electric cars and solar panels on our roofs, but we all have cell phones. Electric cars and solar panels are disruptive technologies, while cell phones are emerging technologies, which is the difference.

    Maybe RodB has some other explanation for the American Petroleum Institute, Exxon’s funding of denialist climate groups and tobacco institute scientists, or the $100 million contract delivered to Edelman PR services to “clean up oil’s image?”? Then there is the Edison Electric Institute, so named because “American Coal Insitute” doesn’t sound so good. The coal-fired utilities and the petroleum industry have armies of PR flacks, lobbyists, politicians, government employees and internet bloggers – all working to keep the status quo intact. It’s called market share – they’re worried about losing 95% of it – and that includes everyone from Chevron to Peabody Coal to Saudi Arabia, Russia and Venezuela.

  40. 240
    simon abingdon says:

    Ray #233 Ray, I posed three questions: thank you for responding. Your answers included the following, and I quote:

    1) “We understand it quite well”
    2) “We understand it well enough”
    3) “clouds remain a big uncertainty for climate models”

    Clouds cover half the surface of the planet.

    Whither AGW theory?

  41. 241
    Brian Klappstein says:

    “…It’s happening. Deal with it….”

    (Comment by Barton Paul Levenson)

    Or maybe not. We appear to be looking at a state change in the PDO based on the when the last one occurred plus the current “cool spell”. Also the lack of heat content increase in the ocean depths since 2003 also point to a possible state change in a major climate driver. If so we’re about to find out what influence the cool phase of the PDO has relative to GHG forcing.

    In any case my point was that MSU data are a better place to look for possible changes in the warming rate in the last 30 years, compared to the surface data set (at least the land part). Hopefully we can agree on that point.

    Regards, BRK

  42. 242
    simon abingdon says:

    #231 Barton Thank you for your unnecessarily considered response to my would-be aliens’ shopping list! I put it together basically because of Hank’s throwaway reference to the Fermi paradox in #182. But delighted that you agreed with even a few of my “evolutionary requirements”. I think the problem with discussions like this is that however much we try, we can’t get rid of the idea of intelligence being somehow the “crowning glory” of evolution, rather than just another run-of-the-mill survival trick like the elephant’s trunk. So, while I’m not holding my breath I’ll say “keep looking, and good luck”.

  43. 243
    Hank Roberts says:

    For a lively tour of the “can’t be” opinions ites google: “La Nina of 2008″ +GISS +divergence
    Nobody’s published that I can find.

    Gavin, you wrote earlier that you’d be happy to talk about the uncertainties.

    May I suggest a _far_more_moderated_ topic and plead that you do, conversing but firmly held to the subject?

    There’s a lot I’d love to learn about the areas you could teach about.

    You could create a parallel thread for failed postings for that particular topic — if you prefer not to just discard them.

    PS — I realize you are already over-busy. I’m thinking a slow topic with responses by scientists. It’d be a chance many people don’t have to understand how argument, even ‘hard argument,’ gets done.

  44. 244
    SecularAnimist says:

    Barton Paul Levenson wrote: “As far as we know only humans have developed language per se (I am not impressed with ape language experiments).”

    Note that “ape language experiments” in which gorillas and chimpanzees have been taught to communicate using American Sign Language, and experiments in which African Grey Parrots (e.g. Dr. Irene Pepperberg’s Alex) have been taught to communicate in spoken English, address the ability of non-human animals to acquire and use human languages. They do not address the ability of non-human animals to develop their own languages. There is ample evidence that a number of non-human species, including dolphins, whales, various primates and birds, communicate with each other in their own complex languages, which humans have so far, for the most part, been unable to understand.

  45. 245
    Pekka Kostamo says:

    Jonathan 112: Terminology was changed by the Bush administration, on advice from Mr. Luntz, a consultant on communications.

    Based on his target audience testing, “climate warming” is perceived (felt) as more threatening than “climate change”, so the latter should be used.

    Such testing of words and phrases on selected audiences is commonplace in the political arena. A speechmaker’s usual tool of trade.

    Besides, it provides a far stronger base for the “climate has always been changing” theme we see every day.

    Here is Mr. Luntz himself (as well as Dr. Singer, by the way):
    http://video.google.com/videoplay?docid=-8012901811669462665&q=denial+machine

  46. 246
    Martin Vermeer says:

    BPL #231

    There used to be a theory that Neanderthal man was nonverbal, due to an apparent lack of Broca’s and Wernicke’s area in skull casts, but I think someone may have disproved it. Does anybody know?

    The Neanderthal buried their dead, which appears to indicate the power of reflection and foresight. Of course this power could be non-verbal, but language would make it a power of a community rather than of individuals — much more useful.

    No, I don’t know ;-)

  47. 247
    Mark says:

    re #240

    Clouds do not cover half the planet, so point one against you. If you’re so badly off already, what chance you have anything useful to add?

    Now clouds can increase insulation and thereby increase temperatures. They can reduce insolation and thereby reduce temperatures.

    This tends to cancel out the differences.

    Then again, the clouds by themselves will be unable to change the climate outcome enough to matter in any case, unless there’s a gigantic change in the world (e.g. supervolcanoes erupting, nuclear holocaust or ELE impact).

    So, whither your point?

  48. 248
    Mark says:

    Ike: “A natural cycle implies predictability, and this is where ENSO diverges. Let’s look at the 20th century ENSO index: http://www.cdc.noaa.gov/ENSO/enso.mei_index.html

    Nope, fallen at the first hurdle again.

    A natural cycle implies a natural production.

    Predictability? No. Unless you’re thinking about the foxes/rabbits that you did in school in your teens.

    If you want a real one, here’s two for you to investigate:

    1) Cicada eruptions.
    2) Locust swarming.

    Both vary around a nominal period (13-year for the case of one species of Cicada) but the external influences can and will change this if they happen to make a year too bad for eruption/swarm or make an early year much better for it.

  49. 249
    Phil Scadden says:

    #241

    Can you please explain to me how you can get oceans cycles like PDO being responsible for temperature record and yet have the oceans continuing to warm? If oceans cooled then you could call heat exchange but they arent.

    “In any case my point was that MSU data are a better place to look for possible changes in the warming rate in the last 30 years, compared to the surface data set (at least the land part). Hopefully we can agree on that point.”

    You believe that analysis and interpretation of MSU data is easily than surface records? Perhaps you should look at Tamino’s analysis of differences between RSS and UAH. In any case, we are still warming.

  50. 250
    Hank Roberts says:

    > cloud cover … percent

    Cite please? This may help:

    http://www.astrobio.net/news/article2683.html

    (Yes, it’s a news article; yes, they did misspell “Cretaceous” — but note the cloud cover number in it. Just saying, check for what’s possible.)

    > Cicada … locust

    Context helps in these discussions.

    “This is climatology. Argument is down the hall.”


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