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No man is an (Urban Heat) Island

Filed under: — gavin @ 2 July 2007

Observant readers will have noticed a renewed assault upon the meteorological station data that underpin some conclusions about recent warming trends. Curiously enough, it comes just as the IPCC AR4 report declared that the recent warming trends are “unequivocal”, and when even Richard Lindzen has accepted that globe has in fact warmed over the last century.

The new focus of attention is the placement of the temperature sensors and other potential ‘micro-site’ effects that might influence the readings. There is a possibility that these effects may change over time, putting in artifacts or jumps in the record. This is slightly different from the more often discussed ‘Urban Heat Island’ effect which is a function of the wider area (and so could be present even in a perfectly set up urban station). UHI effects will generally lead to long term trends in an affected station (relative to a rural counterpart), whereas micro-site changes could lead to jumps in the record (of any sign) – some of which can be very difficult to detect in the data after the fact.

There is nothing wrong with increasing the meta-data for observing stations (unless it leads to harassment of volunteers). However, in the new found enthusiasm for digital photography, many of the participants in this effort seem to have leaped to some very dubious conclusions that appear to be rooted in fundamental misunderstandings of the state of the science. Let’s examine some of those apparent assumptions:

Mistaken Assumption No. 1: Mainstream science doesn’t believe there are urban heat islands….

This is simply false. UHI effects have been documented in city environments worldwide and show that as cities become increasingly urbanised, increasing energy use, reductions in surface water (and evaporation) and increased concrete etc. tend to lead to warmer conditions than in nearby more rural areas. This is uncontroversial. However, the actual claim of IPCC is that the effects of urban heat islands effects are likely small in the gridded temperature products (such as produced by GISS and Climate Research Unit (CRU)) because of efforts to correct for those biases. For instance, GISTEMP uses satellite-derived night light observations to classify stations as rural and urban and corrects the urban stations so that they match the trends from the rural stations before gridding the data. Other techniques (such as correcting for population growth) have also been used.

How much UHI contamination remains in the global mean temperatures has been tested in papers such as Parker (2005, 2006) which found there was no effective difference in global trends if one segregates the data between windy and calm days. This makes sense because UHI effects are stronger on calm days (where there is less mixing with the wider environment), and so if an increasing UHI effect was changing the trend, one would expect stronger trends on calm days and that is not seen. Another convincing argument is that the regional trends seen simply do not resemble patterns of urbanisation, with the largest trends in the sparsely populated higher latitudes.

Mistaken Assumption No. 2: … and thinks that all station data are perfect.

This too is wrong. Since scientists started thinking about climate trends, concerns have been raised about the continuity of records – whether they are met. stations, satellites or ocean probes. The danger of mistakenly interpreting jumps due to measurement discontinuities as climate trends is well known. Some of the discontinuities (which can be of either sign) in weather records can be detected using jump point analyses (for instance in the new version of the NOAA product), others can be adjusted using known information (such as biases introduced because changes in the time of observations or moving a station). However, there are undoubtedly undetected jumps remaining in the records but without the meta-data or an overlap with a nearby unaffected station to compare to, these changes are unlikely to be fixable. To assess how much of a difference they make though, NCDC has set up a reference network which is much more closely monitored than the volunteer network, to see whether the large scale changes from this network and from the other stations match. Any mismatch will indicate the likely magnitude of differences due to undetected changes.

It’s worth noting that these kinds of comparisons work because of large distance over which the monthly temperature anomalies correlate. That is to say, that if a station in Tennessee has a particular warm or cool month, it is likely that temperatures in New Jersey say, also had a similar anomaly. You can see this clearly in the monthly anomaly plots or by looking at how well individual stations correlate. It is also worth reading “The Elusive Absolute Surface Temperature” to understand why we care about the anomalies rather than the absolute values.

Mistaken Assumption No. 3: CRU and GISS have something to do with the collection of data by the National Weather Services (NWSs)

Two of the global mean surface temperature products are produced outside of any National Weather Service. These are the products from CRU in the UK and NASA GISS in New York. Both CRU and GISS produce gridded products, using different methodologies, starting from raw data from NWSs around the world. CRU has direct links with many of them, while GISS gets the data from NOAA (who also produce their own gridded product). There are about three people involved in doing the GISTEMP analysis and they spend a couple of days a month on it. The idea that they are in any position to personally monitor the health of the observing network is laughable. That is, quite rightly, the responsibility of the National Weather Services who generally treat this duty very seriously. The purpose of the CRU and GISS efforts is to produce large scale data as best they can from the imperfect source material.

Mistaken Assumption No. 4: Global mean trends are simple averages of all weather stations

As discussed above, each of the groups making gridded products goes to a lot of trouble to eliminate problems (such as UHI) or jumps in the records, so the global means you see are not simple means of all data (this NCDC page explains some of the issues in their analysis). The methodology of the GISS effort is described in a number of papers – particularly Hansen et al 1999 and 2001.

Mistaken Assumption No. 5: Finding problems with individual station data somehow affects climate model projections.

The idea apparently persists that climate models are somehow built on the surface temperature records, and that any adjustment to those records will change the model projections for the future. This probably stems from a misunderstanding of the notion of a physical model as opposed to statistical model. A statistical model of temperature might for instance calculate a match between known forcings and the station data and then attempt to make a forecast based on the change in projected forcings. In such a case, the projection would be affected by any adjustment to the training data. However, the climate models used in the IPCC forecasts are not statistical, but are physical in nature. They are self-consistent descriptions of the whole system whose inputs are only the boundary conditions and the changes in external forces (such as the solar constant, the orbit, or greenhouse gases). They do not assimilate the surface data, nor are they initiallised from it. Instead, the model results for, say, the mean climate, or the change in recent decades or the seasonal cycle or response to El Niño events, are compared to the equivalent analyses in the gridded observations. Mismatches can help identify problems in the models, and are used to track improvements to the model physics. However, it is generally not possible to ‘tune’ the models to fit very specific bits of the surface data and the evidence for that is the remaining (significant) offsets in average surface temperatures in the observations and the models. There is also no attempt to tweak the models in order to get better matches to regional trends in temperature.

Mistaken Assumption No. 6: If only enough problems can be found, global warming will go away

This is really two mistaken assumptions in one. That there is so little redundancy that throwing out a few dodgy met. stations will seriously affect the mean, and that evidence for global warming is exclusively tied to the land station data. Neither of those things are true. It has been estimated that the mean anomaly in the Northern hemisphere at the monthly scale only has around 60 degrees of freedom – that is, 60 well-place stations would be sufficient to give a reasonable estimate of the large scale month to month changes. Currently, although they are not necessarily ideally placed, there are thousands of stations – many times more than would be theoretically necessary. The second error is obvious from the fact that the recent warming is seen in the oceans, the atmosphere, in Arctic sea ice retreat, in glacier recession, earlier springs, reduced snow cover etc., so even if all met stations were contaminated (which they aren’t), global warming would still be “unequivocal”. Since many of the participants in the latest effort appear to really want this assumption to be true, pointing out that it doesn’t really follow might be a disincentive, but hopefully they won’t let that detail damp their enthusiasm…

What then is the benefit then of this effort? As stated above, more information is always useful, but knowing what to do about potentially problematic sitings is tricky. One would really like to know when a problem first arose for instance – something that isn’t clear from a photograph from today. If the station is moved now, there will be another potential artifact in the record. An argument could certainly be made that continuity of a series is more important for long term monitoring. A more convincing comparison though will be of the existing network with the (since 2001) Climate Reference Network from NCDC. However, that probably isn’t as much fun as driving around the country taking snapshots.

510 Responses to “No man is an (Urban Heat) Island”

  1. 451
    sidd says:

    Re:Comment by Vernon 15 Jul 2007 9:48 am

    “The satellite data shows no change in trend.”
    In this comment a reference is made to
    http://sealevel.jpl.nasa.gov/science/invest-cazenave.html

    The data in the reference extend to 2000. Abdalati cites data through 2007 and finds an increase in the rate of sea level rise. So i take it you do not believe Abdalati ?

  2. 452
    Rod B says:

    re 438: How in the hell does anyone know, to the mm, what the sea level rise was, per year or even century, since 1000BC, 1000AD, 1500AD or even 1800?? What scientific magic/speculation/ guesswork is involved?

  3. 453
    John Mashey says:

    re: #451
    I ask once again, here: does anyone have any independent evidence that Ponder the Maunder is actually being written by a 15-year-old girl, i.e., that this whole story is actually true? I have serious reservations. Just as an example

    http://www.physicsforums.com/showthread.php?t=163888&page=6
    Search for Kirsten-B (yes, Kirsten, she explains in later post that someone in another country set it up for her and mis-spelled it), and she asys (about a poll on global warming):

    “If I can offer an inside view on how this poll would look if scientists were responding, my guess is that it would look like this:

    Yes 10%
    No 10%
    Leaning yes: 25%
    Leaning no: 10%
    The other 45% would not answer the poll due to fear of being bothered by one side or the other.
    Government scientists such as those with NASA JPL or GISS gave me the okay to acknowledge them in my paper that would be turned in to my teacher, but would not approve of the same in the on-line version.”

    Does anyone think that makes *any* sense?
    [Somehow, I’d be surprised if she talked to Gavin. :-)]

  4. 454
    David B. Benson says:

    Re #452: Rod B — In some locations the relative sea stand is measureable to +/- 2 mm or so, at least since about 1750. The location I am thinking of is the French-built fortress at Louisbourg in Nova Scotia. There is an iron ring, for securing boats, set in the wall of the dock. Everything is built directly on bedrock. The height of the iron ring above mean sea stand is easily measured, and has been, although I don’t know when these measurements began.

    However, at this location there are vertical changes in the land stand, due to isostatic rebound, which must be compensated for. Similarly for sites in Britian and France, where again there is good relative sea stand data for several hundred years.

  5. 455
    Dan says:

    re: 452. From the IPPC report, specifically, http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Pub_Ch05.pdf, tide gauge data date from ~ 1870s. It really is not all that difficult to look these things up when there is a direct link to the IPCC reports on this page.

  6. 456
    Timothy Chase says:

    John Mashey (#453) wrote:

    I ask once again, here: does anyone have any independent evidence that Ponder the Maunder is actually being written by a 15-year-old girl, i.e., that this whole story is actually true? I have serious reservations. Just as an example

    http://www.physicsforums.com/showthread.php?t=163888&page=6
    Search for Kirsten-B (yes, Kirsten, she explains in later post that someone in another country set it up for her and mis-spelled it), and she asys (about a poll on global warming):…

    I seriously doubt she is anything more than a sock-puppet – but don’t try yanking the sock off to find out who the hand belongs to. It won’t work.

    Essentially, she is playing the role of a conservative “honest child” to the “global warming emperor” who is wearing no clothes. Propaganda. And just the sort that will warm the hearts of those who are stuck forever in the valley of denial – if I may mix metaphors a bit.

    I remember a few weeks back running across a “news article” in one of the “news sites” for people who are on the far right. This is where I first learned of “her” and how she had predicted the “end” of the Australian drought whereas mainstream scientists had expected the drought to never end – presumably. At that point I figured that she might be a precocious, yet brainwashed fifteen year old, but looking at what is in that paper now I would have to say “sock-puppet.”

    However, if people were to try to “get her to come forward,” that would look bad. If people were to call “her” various bits of dishonesty, that would look bad. Either way, it looks like you are picking on a kid. You won’t be able to figure out “who she is,” so it is probably just better to leave it be. The only people who will fall for that sort of thing are too far gone for you or anyone else to be able to do anything about anyway.

    So I would keep to the facts and to criticizing the real people who really abuse them. She really abuses the facts, but she’s not real and it is not much use trying to fight a ghost – particularly one that won’t respond back unless it suits the puppet master’s needs. And if you try fighting a “cute” ghost, that will just make you look mean, bullying, silly or all of the above.

    So I would ignore the sock.

  7. 457

    [[Yes, we are in between ice ages so the sea’s rise.]]

    Seas. No. By the Milankovic cycles which govern ice ages, the world should now be cooling and sea level dropping. We passed the peak of the interglacial 6000 years ago. For the matrix math needed to calculate the changes, check a textbook on celestial mechanics.

  8. 458

    [[re 438: How in the hell does anyone know, to the mm, what the sea level rise was, per year or even century, since 1000BC, 1000AD, 1500AD or even 1800?? What scientific magic/speculation/ guesswork is involved?]]

    Start here:

    http://www.ncdc.noaa.gov/paleo/primer.html

  9. 459
    Dylan says:

    Re: 443, Laurence I have no idea what you are saying. I’m not disputing that anthropogenic greenhouse gasses are the primary contributor to global warming, I’m asking whether direct “thermal pollution” or anthropogenic heat flux is even having a measurable effect globally? Clearly it has a significant effect in urban/high-population areas, which presumably actually ments that most of us are directly experiencing far more warming than is actually occurring on a global scale, due to the UHI effect.

  10. 460
    tamino says:

    Re: #459 (Dylan)

    The rate at which earth absorbs energy from the sun is about 4 x 10^16 watts. This is (average solar insolation = 342 W/m^2) x (1 – albedo = 0.7) = about 240 W/m^2, which is the “climate forcing” due to the sun. This applies to the entire earth surface (1.7 x 10^14 m^2).

    I believe (correction please) the power generated by humans is on the order of 10^13 watts. This amounts to an average climate forcing of a mere 0.06 W/m^2.

    The sensitivity of climate to forcing is about 0.75 deg.C/(W/m^2). So the 0.06 W/m^2 antrhopogenic-heat-flux forcing will cause about 0.045 deg.C global temperature rise. This is insignificant compared to the 4 W/m^2 (leading to 3 deg.C temperature increase) forcing from doubling CO2.

    I believe most of the UHI is *not* due to anthropogenic heat flux, but due to changes in absorption/loss of energy of earth’s surface from land-use change (asphalt and concrete absorp and radiate much differently than soil and plants, and buildings block both radiation and wind).

  11. 461
    Dick Veldkamp says:

    Re #459 Human generated power (Tamino)

    Human generated power is around 2 kW per head, or 6e9 * 2e3 = 1.2e13 W = order of 10^13 W as you state.

  12. 462
    Rod B says:

    re 454,8 Sea Levels. While I don’t dispute the interesting nature of looking at what we think the sea level was, viz-a-viz GW, the responses did nothing to alleviate my contention that measuring sea levels to +/- 1 or 2mm is at best a SWAG (scientific wild-assed guess). When they put their little stick in the water back in 1750 (or whenever) did they read it at the crest or trough of the 2mm waves during still waters? And how much did the land stand change? Anywhere?

    Barton, I didn’t read every word of your reference link, but I found no mention of sea level in centuries past in all of their proxy accolades.

  13. 463
    Hank Roberts says:

    Dylan — in brief — the simple heat energy added from all human fuel burning and power producing activity is tiny compared to the extra solar heat energy that is retained with the increase in CO2 in the atmosphere. Note the heat we produce by burning fossil fuel and running nuclear plants is added when the activity happens. The heat capturing ability of the atmosphere with the increasing CO2 doesn’t happen just at the time, it continues for centuries (til the total amount of CO2 we added gets taken out of the atmosphere again by biology and geology).

    Imagine sitting in a hot bath, and partly blocking the drain, while the hot water keeps pouring in (say with no more variation than 3 parts in 1300 or so in how much is pouring in moment by moment). The hot water around us rises. Yes, we may also start to sweat a bit, or spill a bit of water out of our drinking glass, or weep at our plight, but that’s a trivial addition to the incoming total amount, and has nothing to do with our blocking the drain, which is what’s making the level rise.

  14. 464
    Chuck Booth says:

    Re 462 sea level measurements

    The seemingly precise measurements of sea level over long time periods are made by looking at bench marks (e.g., geological formations) at known time intervals, then dividing the change in sea level by the time period (e.g., http://www.sciencedaily.com/releases/2003/01/030122072142.htm).
    There are plenty of good sources of information on the web regarding the measurement of current sea level:
    http://www.pol.ac.uk/psmsl/manuals/
    http://unesdoc.unesco.org/images/0012/001251/125129e.pdf
    (these two links take you to the same source: Intergovernmental Oceanographic Commission MANUAL ON SEA LEVEL MEASUREMENT AND INTERPRETATION)

    The following also have valuable information:
    http://medgloss.ocean.org.il/
    http://science.howstuffworks.com/question356.htm
    http://en.wikipedia.org/wiki/Sea_level

    Finally, these might be of interest;
    http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=1160322
    http://www.agu.org/pubs/crossref/1994/93JC03355.shtml
    http://neptune.gsfc.nasa.gov/publications/pdf/pubs2002/4_Direct_estimation_sea.pdf

  15. 465
    Dick Veldkamp says:

    #462 Sea levels long ago (Rod B)

    It’s an interesting question: how DO we know what the sea level was long ago? I would like to see on the post on the subject. I found some information in the TAR: http://www.grida.no/climate/ipcc_tar/wg1/423.htm#1131

    “The geological indicators of past sea level are usually not sufficiently precise to enable fluctuations of sub-metre amplitude to be observed. In some circumstances high quality records do exist. These are from tectonically stable areas where the tidal range is small and has remained little changed through time, where no barriers or other shoreline features formed to change the local conditions, and where there are biological indicators that bear a precise and consistent relationship to sea level.”

    There’s some general info here: http://www.science.org.au/events/npc2006.htm

    There are some detailed publications on the web, but usually behind a pay wall. From what I gather the trick is to look at stable rock formations (which used to be) in coastal areas + common sense calculations (say if you know the extent of the ice sheets 10,000 years ago, you know how much water was left for the oceans).

    Although looking at past climate and sea level helps us with the general picture, in a way it is academic. If Greenland melts, the water cannot magically disappear. Hence the sea level has to go up by 7 m (or whatever the exact figure is).

  16. 466
    Steve Reynolds says:

    456 Timothy Chase> And if you try fighting a “cute” ghost, that will just make you look mean, bullying, silly or all of the above.

    Yes, you do.

    Interesting that Judith Curry has invited your ghost to go to her school:

    Kristen, you are doing an amazing job. Some of your interpretations are not correct, but that is almost beside the point. I am very impressed by the thoroughness of your efforts and your ability to handle yourself in a fairly hostile environment. When you are ready to start thinking about where you want to go to university, please consider Georgia Tech, my contact information can be found on my web page http://www.eas.gatech.edu/people/faculty/curry.htm

    I could provide a link for this (gavin, would it be censored?).

  17. 467
    Gary says:

    Re: 452,455,458 etc., NASA satellites (Jason/Topax) estimate sea level rise to be pretty stable at 2mm/year. BUT NASA says accuracy is 2-3 CM. Real Climate has commented previously on reports from EU satillites that the level of the Arctic Sea is falling

    [Response: You confuse single retrieval error with errors in the global mean (much smaller). And the recent trend in the Jason/Topex records are closer to 4mm/yr (from what I remember from a recent presentation). – gavin]

  18. 468
    Hank Roberts says:

    Gary, that’s accuracy for each individual measurement.

    You understand it’s possible to detect a trend in millimeters, with instruments that have accuracy in centimeters, right? Not with ONE instrument but with _many_ of them —-same issue as with weather stations — to detect a small trend with large variability in the measurements, you need a whole lot of measurements.

    tamino.wordpress.com/2007/07/05/the-power-of-large-numbers/

    Satellites allow those repeated measurements.

  19. 469

    [[re 454,8 Sea Levels. While I don’t dispute the interesting nature of looking at what we think the sea level was, viz-a-viz GW, the responses did nothing to alleviate my contention that measuring sea levels to +/- 1 or 2mm is at best a SWAG (scientific wild-assed guess). When they put their little stick in the water back in 1750 (or whenever) did they read it at the crest or trough of the 2mm waves during still waters? And how much did the land stand change? Anywhere?

    Barton, I didn’t read every word of your reference link, but I found no mention of sea level in centuries past in all of their proxy accolades.]]

    http://www.springerlink.com/content/5lqjuxh4amlte1kh/

    http://cat.inist.fr/?aModele=afficheN&cpsidt=5254620

    http://pubs.nrc-cnrc.gc.ca/cgi-bin/rp/rp2_abst_f?cjes_e99-091_37_ns_nf_cjes

    I believe sediments and corals are the main proxies.

  20. 470
    Marion Delgado says:

    Rod B #236

    What I posted speaks directly to the falsehood that RealClimate is losing credibility. Not only is that demonstrably untrue in general, even the sites and people who would say that, the ones Dan Hughes is promoting, have always said RealClimate and anyone else supporting peer review and the scientific consensus have no credibility. You can’t “lose” credibility with such people.

    You seem uninterested in whether such claims are true or false. I think a “skeptic” would be, but a “denialist” would not.

  21. 471
    Timothy Chase says:

    Re Steve (#466)

    If she is a real person, my sympathies to her.

    She is going to see a fair amount more than I am of what is to come.

  22. 472
    Dan Hughes says:

    re: #470

    I challenge you to cite a single reference in which I have stated that peer-review and the scientific consensus have no creditibility. I also challenge you to provide a citation in which I have ‘promoted’ any site other than my own.

    Absence these citations, I will consider your statements proved false.

    I additionally interpret your remarks to mean that I am a “denialist”. First tell me of what I am a “denialist” and then I again challenge you to cite a single reference in which I have stated denial of that.

    Absense these citations, I will consider your statements that I am a “denialist” false.

  23. 473
    Hank Roberts says:

    Q’n’Answers from Parker on his study, here:
    http://www.climateaudit.org/?p=1718#comment-119294

    Starting around #387 as currently numbered, though numbers can change if responses are interleaved or excised later.

    Seems climatologists are starting to participate more at CA, because people write asking them for more information. Panta rhei.

  24. 474
    Rod B says:

    re 470 Well, you could’ve fooled me. Somehow it sounded like you were giving skeptics (questioners) a bad name by calling them all denialists, and them a worse name by calling them all Exxonists! I don’t agree with much (some, actually) of the postings here by the moderators. But they are credible and have my highest respect.

  25. 475
    Hank Roberts says:

    Why let yourself be tempted to snap at anyone’s rhetorical flourishes, when the whole world of science is spread out before you waiting to be understood? The rhetorical stuff is — in fifty years — going to look as silly to those remembering us as anything in history looks to us now. Cavaliers v. Roundheads, who do you think was right? Doesn’t matter, any more than it matters which group dressed better or had better hair. Dustbin o’ history. We inherit the consequences of their wasting time on politics instead of making public health and education happen a few centuries earlier than it did.

    Look at the Parker answers. There’s real wonderful information about how the world works and how the tools work.
    Sure there are people trying to fill up the space with FUD. There are some trying to figure out how the world works.

    Parker wrote, answering a question about his paper:

    “The selections of stations made for GSN by Peterson, T.C., Daan, H. and Jones, P.D (1997), and for global monitoring and trend estimation by Jones and Moberg (2003) cited above were carefully made to avoid severe urban biases. I never challenged the reality of urban heat islands, and merely assert that the station selection has largely succeeded in avoiding locations with increasing urban effects.”

    And answering a question about the confidence level in the statistics:

    “From the standard errors in Table 1 of my J Climate paper, the calm-night trends and windy-night trends for the globe have 95% confidence limits (± 2 standard deviations) of 0.05 and 0.06 deg C per decade. So the difference between calm trends and windy trends for the globe can be estimated with 95% confidence within â��(0.052+0.062) ~ 0.078 deg C per decade. If we then assume that nearly all of any urban effect will be concentrated in the calm nights, which were defined as the calmest third of nights, then overall urbanisation trends of about 0.03 deg C per decade (a bit more than a third of 0.078 deg C per decade) in minimum temperature should be readily detectable. If more conservatively we assume that not much more than half the urban warming effect is concentrated in the calm nights with the rest in the intermediate-wind-strength nights, then urbanisation trends of about 0.05 deg C per decade in minimum temperature should be readily detectable. As urbanisation is felt in minimum temperatures much more than in maximum temperatures â�� which may even be reduced – an urbanisation trend of 0.025 deg C per decade in mean temperature should be detectable using the more conservative assumption. This is about 10 times smaller than the rates of global warming over land since the late 1970s reported in the IPCC 4th Assessment. The more conservative assumption allows for some stations to be affected by large heat islands which persist to some extent even in windy weather (Morris et al. (J. Applied Meteorology, 40, 169-182 (2001))); but GSN stations will almost always be in smaller settlements than Melbourne, with smaller heat islands easily reduced by any wind, or with no heat island at all. None of the US stations used in my J Climate paper is in a city with a population approaching that of Melbourne (3.8 million)….”

    Wonderful. Worth understanding.

    Ya know, the problem with education these days isn’t the kids who _want_ to learn. It’s the ones who would rather squabble. Let’s not.
    Reality’s out there somewhere, and we are in it, whether we know it or not.

  26. 476

    One thing I have to say for Kristen — she reached the same conclusion in the end that I’ve reached. Either way, AGW or not, sooner or later we’re going to run out of the fossil fuels that are creating the controversy. Whichever way this goes, reducing fossil fuel use is the only long term strategy that makes sense.

  27. 477
    Hank Roberts says:

    Don’t answer trolls, no matter what spoke of the political wheel they’re coming from.
    Leave Gavin time to notice when personal remarks aren’t appropriate or someone reposts old PR points.
    He’ll delete the inappropriate stuff. We help — by not taking the bait, feeding the trolls, or falling into bad behavior.

  28. 478
    Gary says:

    RE 467,452,455 etc. Actually the NASA Jason site says global sea level accuracy is 3.3 cm http://sealevel.jpl.nasa.gov/newsroom/features/200612-1.html and as of Dec. 06 average sea level rise between 1993 and 2006 is slightly less than 3 mm per year.

  29. 479
    Rich says:

    Many years ago in college, my Geology Professor (Dr. Miller) explained the climate as a sine wave. During the Ice Age, we were at the bottom (or top) of the sine wave and now, we are coming out of the Ice Age. It will continue to get warmer to a point. That point would be the top of the sine wave then we will start a downward trend again. He was also a professional meteorologists and said that most meteorologist do not believe in global warming. I have talked to a couple over the years and they confirmed what the Dr. Miller stated. How can you explain this? I cannot find anything that refutes his explanation of the sine wave. The climate cannot just stop. We must be going into or coming out of an Ice Age.

  30. 480
    Hank Roberts says:

    Rich, try this to begin, that’s one of the basic questions frequently asked and answered: http://www.realclimate.org/index.php/archives/2007/05/start-here/

  31. 481
    Timothy Chase says:

    Many years ago in college, my Geology Professor (Dr. Miller) explained the climate as a sine wave. During the Ice Age, we were at the bottom (or top) of the sine wave and now, we are coming out of the Ice Age. It will continue to get warmer to a point. That point would be the top of the sine wave then we will start a downward trend again.

    Not quite a sine wave:

    Ice Age Temperature Changes
    http://www.globalwarmingart.com/wiki/Image:Ice_Age_Temperature_Rev_png

    Not quite a sine wave.

    The temperature tends to go up fairly quickly on geologic timescales, but it takes a long time to come down. The reason why it takes such a long time to come down? It takes a while to clear the carbon dioxide from the atmosphere once its in there. A fair amount longer than it takes to put it in there.

  32. 482
    Philippe Chantreau says:

    Rich, you need to do a little (very little in fact) research. It took me only a few sessions of reading about GW to learn about Milankovitch cycles. Don’t rely only on what one individual told you many years ago, regardless how much he impressed you.

  33. 483

    [[Many years ago in college, my Geology Professor (Dr. Miller) explained the climate as a sine wave. During the Ice Age, we were at the bottom (or top) of the sine wave and now, we are coming out of the Ice Age. It will continue to get warmer to a point. That point would be the top of the sine wave then we will start a downward trend again. He was also a professional meteorologists and said that most meteorologist do not believe in global warming. I have talked to a couple over the years and they confirmed what the Dr. Miller stated. How can you explain this? I cannot find anything that refutes his explanation of the sine wave. The climate cannot just stop. We must be going into or coming out of an Ice Age. ]]

    The ice ages are governed by the “Milankovic cycles” — periodic changes in the distribution of sunlight over Earth’s surface, due to cycles in the Earth’s orbital eccentricity, axial tilt, and precession. The changes are amplified by the effect of greenhouse gases.

    Following the calculations of these cycles, the Earth passed the peak of the current interglacial period about 6,000 years ago and should now be cooling. And it was — until the last 150 years or so. Since then it has been warming, because of the steadily increasing production of atmospheric greenhouse gases by human technology.

    Earth’s temperature history is not a simple sine wave. Your geology professor didn’t know what he was talking about. That’s the danger of pontificating outside your field of expertise.

  34. 484
    SteveF says:

    Here’s the Pielke Sr paper on dodgy temperature stations, if anyone is interested. It’s an interesting read:

    http://climatesci.colorado.edu/publications/pdf/R-318.pdf

  35. 485
    caerbannog says:

    Over at http://www.surfacestations.org, I noticed that the folks who run things there have highlighted two USHCN stations: one (Orland, CA) that they consider to be “well-sited” and the other (Marysville, CA) that they consider to be “poorly sited”. Low-resolution temperature history plots are displayed for
    both sites.

    Of interest is the fact that surfacestation.org’s low-res Orland plot shows general cooling, while surfacestation low-res Marysville plot shows general warming. To see what was up here, I decided to wander on over to http://cdiac.ornl.gov/epubs/ndp/ushcn/state_CA_mon.html to have a look at the two stations’ data myself.

    What I found is that mean temperature data for both stations go back to the late 1800’s. And the data for both stations show anomalously high temp readings in the late 1800’s. But the surfacestation.org folks show the anomalously high pre-1900 readings only for the Orland station (it’s pretty clear that they are using the “mean-temp” data here). But they truncate the Marysville mean data at 1905 or so (thereby eliminating the big pre-1900 temperature “spike”). That, in conjunction with plot-autoscaling, gives a casual viewer a very misleading (and very exaggerated) impression of the differences between the two stations.

    In fact, the differences in the temperature trends for the “poorly sited” Marysville and the “well-sited” Orland stations diminish greatly post-1950 or so. And both stations show a consistent warming trend over the past few decades (with the Marysville site showing a bit more warming, according to my eyeball estimate).

    The largest discrepancies in the data for the two stations appear to predate urban-encroachment on the Marysville site.

    If the surfacestation folks are highlighting these USHCN stations to support their thesis that air-conditioning vents, parking lots, etc. are responsible for increasing temperature readings, then it’s pretty obvious that they have not looked at the actual data very carefully.

  36. 486
    Timothy Chase says:

    caerbannog (#485) wrote:

    If the surfacestation folks are highlighting these USHCN stations to support their thesis that air-conditioning vents, parking lots, etc. are responsible for increasing temperature readings, then it’s pretty obvious that they have not looked at the actual data very carefully.

    Either that, or judging from the graphing techniques you’ve outlined, they saw one thing, but decided to show something else because it suited their purposes.

    The nice thing is that Mankoff in #26 has made available a Google Earth KML file which points the program to a server which makes available all the data for every station across the US and it would appear, throughout the world. We you use it, you can bring up graphs for each station, you have an easy indicator of how close stations are to urbanized areas, and he is even trying to get photos of the stations into the server so that those can be delivered to your Google Earth app as well.

    Sure, there might be a “Surface Stations” organization trying to make climatologists look bad, but we are getting to the point that anyone with Google Earth on their computer, an internet connection and the KML pointer to the server can be an “army-of-one Real Surface Stations.”

    When you get right down to it, though, the surface stations do little more than add a chunk of data (one of many, actually) which confirms or disconfirms the results being given by the models. The models themselves aren’t based upon surface station data – but upon the principles of physics, chemistry and even systematic empirical studies being performed in various labs. But the people at Surface Stations want to change the subject, create the appearance that the network is doing a bad job due to incompetance, neglect or questionable motives on the part of climatologists – since they obviously don’t want the topic of conversation to be the rising temperatures.

    Anyway, thank you for pointing this out. Your post is well-worth reading in its entirety by anyone concerned with this sort of thing.

  37. 487
    dhogaza says:

    If the surfacestation folks are highlighting these USHCN stations to support their thesis that air-conditioning vents, parking lots, etc. are responsible for increasing temperature readings, then it’s pretty obvious that they have not looked at the actual data very carefully.

    I disagree, I imagine they’ve looked VERY carefully before cherry-picking …

  38. 488
    dhogaza says:

    Q: Why are you doing this? Isn’t all the data discontinuity and urban biases accounted for by all the adjustments made to the climate data sets as described in the USHCN home page?

    A: Yes adjustments have been made to account for measurable and predictable data biases, such as Time of Observation and station moves, but the National Climatic Data Center (NCDC) and NASA’s Goddard Institute of Space Flight (GISS) who are the main collectors, analyzers, and modelers of climatic data have not done a site by site hands on photographic survey to account for microsite influences near the thermometer. To date all such studies conducted have been data analysis and data manipulations used to spot and/or minimize data inconsistencies.

    Note the subtle misdirection from the surfacestations.org FAQ.

    1. adjustments have been made to account for measurable and predictable data biases, such as Time of Observation and station moves

    2. To date all such studies conducted have been data analysis and data manipulations used to spot and/or minimize data inconsistencies.

    The two together leads one to believe that the only analysis done has been to remove “predictable data biases … such as Time of Observation and station moves” when, of course, the actual data analysis done is much more sophisticated than that and is designed to remove distortions due to siting problems, etc.

    Intentional dishonesty, subtle or not, makes one wonder about their objectivity, motivation, etc.

    And, oh yeah, we have that cherry-picking data distortion example posted just above by caerbannog, as well.

    There seems to be a pattern emerging from the data available on the site, and it has nothing to do with station siting …

  39. 489
    dhogaza says:

    Sheesh, it gets better and better …

    Yes NOAA is responsible for the operation, documentation and upkeep of the USHCN set of weather stations. In fact in 1997 there were concerns expressed by a National Research Council panel about the state of the climate measuring network.

    In 1999, a U.S. National Research Council panel was commissioned to study the state of the U.S. climate observing systems and issued a report entitled: “Adequacy of Climate Observing Systems. National Academy Press”, online here The panel was chaired by Dr. Tom Karl, director of the National Climatic Center, and Dr. James Hansen, lead climate researcher at NASA GISS. That panel concluded:

    “The 1997 Conference on the World Climate Research Programme to the Third Conference of the Parties of the United Nations Framework Convention on Climate Change concluded that the ability to monitor the global climate was inadequate and deteriorating.”

    Yet, ten years later, even the most basic beginning of a recovery program has not been started.

    Their quote in no way supports their contention that problems mentioned by Karl and Hansen are due to siting issues. Nothing in that quote supports their premised, yet they wave it around authoritatively. The fact that it’s Hansen being quoted is a nice touch, making it seem as though the (arguably) most famous name in climate science doesn’t trust the data.

    The paper being referenced costs $20 to download, but I’ll bet my sweet bippy that they’re talking about the need for more money for more data collection, not any mistrust of the data being collected. “inadequate” does NOT mean “biased”.

    And, in fact, the quote above doesn’t even mention monitoring in the US. It could be as easily interpreted to mean that the two are satisfied with monitoring in the first world and are calling for improved data collection in the developing world, for instance.

    Or any number of things.

    Taken out of context, it’s useless.

  40. 490
    dhogaza says:

    Check out the first seven sites on their “odd sites” page.

    All are in OR, CA, WA and all are “badly sited” for a variety of reasons ranging from their being a nearby BBQ to their being nearby pavement, air conditioning exhaust, etc.

    Yet – look at the temperature trends for each. Despite the variety of “biases” that are “polluting” the record, the trend plots for each correlate nicely.

    So apparently each air conditioner was installed at the same time, each parking lot paved at the same time, and each of the varying sources of “bias” apparently have roughly the same effect.

    Interesting!

  41. 491
    Hank Roberts says:

    I noticed listening to the local NOAA Weather Radio over this past weekend that they now broadcast a “Climate Summary” comparison along with the local weather report and forecast. The text info has far more than that. Most of it’s laid out as tables, and I think the web software here would remove all the spaces and lose the columns so won’t try copying; your NOAA Weather summary will have it all.
    …THE UKIAH CLIMATE SUMMARY FOR JULY 29 2007…
    CLIMATE NORMAL PERIOD 1971 TO 2000
    CLIMATE RECORD PERIOD 1906 TO 2007
    This is what’s now included in the automated weather radio broadcast:
    THE UKIAH CLIMATE NORMALS FOR TODAY
    NORMAL RECORD YEAR
    MAXIMUM TEMPERATURE (F) 92 109 1977
    MINIMUM TEMPERATURE (F) 56 40 1924

    Not sure why NOAA considers record temperatures to be “climate” information rather than natural variation. I suppose the spin is that until we have new records being set regularly the climate hasn’t changed. But maybe not.

  42. 492
    tamino says:

    Re: surfacestations.org

    I’ve posted about these graphs on my blog.

  43. 493

    The graphs on surfacestations.org front page for Orland and Marysvills are directly from NASA GISS, unedited, except for presentation size.

    There are links under the pictures to take you directly to those graphs at the GISTEMP website. If you are unhappy with how they look, GISS is the source.

  44. 494
    steven mosher says:

    for your reading pleasure:

    A technique to detect microclimatic inhomogeneities in historical records of screen-level air temperature

    Runnalls K. E. and T. R. Oke

    JOURNAL OF CLIMATE 19 (6): 959-978 MAR 15 2006

    Abstract: A new method to detect errors or biases in screen-level air temperature records at standard climate stations is developed and applied. It differs from other methods by being able to detect microclimatic inhomogeneities in time series. Such effects, often quite subtle, are due to alterations in the immediate environment of the station such as change,, of vegetation, development (buildings, paving), irrigation, cropping, and even in the maintenance of the site and its instruments. In essence, the technique recognizes two facts: differences of thermal microclimate are enhanced at night, and taking the ratio of the nocturnal cooling at a pair of neighboring stations nullifies thermal changes that occur at larger-than-microclimatic scales. Such ratios are shown to be relatively insensitive to weather conditions. After transforming the time series using Hurst resealing, which identifies long-term persistence in geophysical phenomena, cooling ratio records show distinct discontinuities, which, when compared against detailed station metadata records, are found to correspond to even minor changes in the station environment. Effects detected by this method are shown to escape detection by Current generally accepted techniques. The existence of these microclimatic effects ire a source of uncertainty in long-term temperature records, which is in addition to those presently recognized such as local and mesoscale urban development, deforestation, and irrigation.

    Now, if think the current methods do a fine job, Consider
    Oke’s conclusion.

    Gradual changes in the immediate environment over time, such as vegetation growth, or encroachment by built features such as paths, roads, runways, fences, parking lots, and buildings into the vicinity of the instrument site typically lead to trends in the cooling ratio series. Distinct régime transitions can be caused by seemingly minor instrument relocations (such as from one side of the airport to another, or even within the same instrument enclosure) or due to vegetation clearance. This contradicts the view that only substantial station moves, involving significant changes in elevationand/or exposure are detectable in temperature data. It is not surprising that small station moves, even without changes of elevation or exposure, are capable of introducing inhomogeneities into the record,because there are often several confounding changes occurring at the same time. For example, a stationmove often coincides with screens being repainted, cleaned, or replaced, new instruments installed, and observers being reinstructed about their practices. Further, it is common for the new instrument site to bewithout grass for a few years, and there are many indications of muddy conditions around the instruments until grass is both planted and properly maintained. These factors, combined with subtle changes in the immediate surroundings (such as moving away from a parking lot or building), appear to be a significant causeof inhomogeneities in temperature records As isolated occurrences, activities such as painting, cleaning, or releveling screens or instruments do not frequentlycause significant changes to cooling régimes.”

    “We suggest these effects are possibly underappreciated by many agencies responsible for maintaining the qualityof climatological records. Whether such small thermal effects amount to a significant concern largely dependsupon whether by their nature they are biased. That is, ifthe majority of the anomalies tend toward net warmingor net cooling. If they do, even tenths of a degree in onedirection take on real significance in the global climate change debate. Intuition, experience, and review of classic microclimatic case studies (e.g., Geiger 1965)suggests to us that the net impact of the most commonchanges (compaction due to trampling, increased paving,tree growth, removal or soiling of snow cover, construction of buildings and introduction of irrigation)lead to alteration of nocturnal controls on the surface heat balance (thermal admittance, sky view factor androughness and shelter) in ways that reduce nocturnal cooling and consequently increase the minimum temperature.Removal of trees and desiccation will act in the opposite direction. Are the environments of climatestations preferentially modified during the inexorableprocess of development in a way that leads to net thermalimpacts? We suspect they are, but the question deserves attention and objective analysis.”

    “This study suggests that it might be beneficial to reexamine stations that passed previous homogeneity analyses and to consider the implications of the concerns raised by the work here for the large databases ofair temperature data that are assumed to be homogeneous and unbiased.”

  45. 495
    J. Althauser says:

    Perhaps this is the sort of thing Mr. Watts is trying hap-hazardly to show –
    “Heat waves in Europe nearly twice as long –
    Study adds to evidence that Europe’s climate has become more extreme”

    http://www.msnbc.msn.com/id/20108935/from/RS.2/

    “Researchers compiled temperature records from 54 high-quality recording stations from Sweden to Croatia and found that heat waves last an average of three days now (with some lasting up to 13 days), while they lasted only 1.5 days on average in 1880.”
    and . . .
    “The trend was found only after Della-Marta and his colleagues realized that many historical records overestimated past temperatures because sensors were not shielded from the sun as they now are. The researchers corrected for this warm bias of the historical records.”

  46. 496
    Timothy Chase says:

    A technique to detect microclimatic inhomogeneities in historical records of screen-level air temperature
    Runnalls K. E. and T. R. Oke
    JOURNAL OF CLIMATE 19 (6): 959-978 MAR 15 2006

    A few quotes and comments…

    While these kinds of bias are assumed to be too small to obscure true climate signals in regional- or global-scale averages, their undoubted continued presence in the global database is still cause for concern (Davey and Pielke 2005).

    pg.959

    Note: interesting choice of references for the first page.

    *

    Regime transitions are easily identified as inflection points in the normalized series. For example, a persistent period of above-average conditions transforms into an ascending trace, because positive differences from the mean are accumulating. A transition to below-average values is marked by an inflection point (i.e., a change from a positive to a negative slope). Steeper slopes result from larger deviations from the mean. Hence, changes in either the magnitude or sign of the slope signal régime transitions.

    pg 961

    However, if H exceeds 0.5, the rescaled trace should be inspected for inflections in the trace. There is no simple indication as to what deviation from 0.5 constitutes evidence of persistence only that its strength increases as H approaches unity.

    pg 961

    Note: any deviation from “no trend at all” might be regarded as a reason for considering a site as suspect.

    *

    Changes in the physical controls of the microclimatic environment of a site should affect nocturnal cooling, and become evident as régime transitions when the normalized transformed series is plotted. Station history files, or metadata (Aguilar et al. 2003), can be used to see if inflection points correspond to documented physical changes to the microenvironment, of either station in the pair. If metadata records are not available to help identify the cause of the inflection point, it is still reasonable to interpret change points in R time series as inhomogeneities capable of biasing the record.

    pg 961

    Note: apparently any “regime change” or “inflection point” is reason for regarding a site as suspect – even when it is not possible to identify the cause of the change. As such, it would seem that the default assumption is that until proven otherwise, rising trends in measured temperatures are to be assumed to be a defect in how those temperatures are being measured rather than as reflecting a rise in temperatures.

    *

    This paper is purposely restricted in its scope.

    pg 976

    Note: This sort of statement is usually not the sort of thing one should take at face value.

    *

    Whether such small thermal effects amount to a significant concern largely depends upon whether by their nature they are biased. That is, if the majority of the anomalies tend toward net warming or net cooling. If they do, even tenths of a degree in one direction take on real significance in the global climate change debate.

    pg 977

    Note: The authors are clearly aware of the political implications – and give no consideration to the mountains of evidence which exist independently of land sites demonstrating the phenomena of global warming.

    *

    Intuition, experience, and review of classic microclimatic case studies (e.g., Geiger 1965) suggests to us that the net impact of the most common changes (compaction due to trampling, increased paving, tree growth, removal or soiling of snow cover, construction of buildings and introduction of irrigation) lead to alteration of nocturnal controls on the surface heat balance (thermal admittance, sky view factor and roughness and shelter) in ways that reduce nocturnal cooling and consequently increase the minimum temperature.

    pg.977

    Note: The sort of pattern they expect to find will have the same pattern as global warming – temperatures rising more quickly at night than during the day.

  47. 497
    Chuck Booth says:

    Re 496 Timothy Chase’s analysis of the Runnalls and Oke paper:

    “even tenths of a degree in one direction take on real significance in the global climate change debate”

    Translation: If we gived them (AGW proponents) a tenth, they’ll take a degree.

  48. 498
    Hank Roberts says:

    Has anyone followed up on that paper in the refereed journals, anyone looked for any subsequent citation to it? I didn’t find one, but didn’t look hard.

  49. 499
    dhogaza says:

    Runnalls K. E. and T. R. Oke

    JOURNAL OF CLIMATE 19 (6): 959-978 MAR 15 2006

    Abstract: A new method to detect errors or biases in screen-level air temperature records at standard climate stations is developed and applied.

    Strange, I thought their new method was going to be “photography”, with profuse citing of surfacestations.org.

    (just joking)

    Perhaps this is the sort of thing Mr. Watts is trying hap-hazardly to show –

    “The trend was found only after Della-Marta and his colleagues realized that many historical records overestimated past temperatures because sensors were not shielded from the sun as they now are.”

    I know you’re joking, but Watts’ photographs would likely lead to such stations being classified as “good stations”, because the thermometers are now shielded from direct sunlight.

    Just another example of the bogosity of the effort.

  50. 500
    Timothy Chase says:

    Hank Roberts (#498) wrote:

    Has anyone followed up on that paper in the refereed journals, anyone looked for any subsequent citation to it? I didn’t find one, but didn’t look hard.

    I found one paper that actually appears technical and would appear to reference it:

    Mesoscale and macroscale aspects of the morning Urban Heat Island around Athens, Greece
    Kassomenos, P. A.; Katsoulis, B. D.
    Meteorology and Atmospheric Physics, Volume 94, Numbers 1-4, November 2006 , pp. 209-218(10)

    … but I couldn’t actually see the article, so I have no idea what they said.

    Beyond this, about the only people who refer to it from what I can tell are those associated with Pielke, the “Frontiers of Freedom” site which I believe sees their political agenda in anything they choose to discuss, the AGW-denialist “The New Zealand Climate Science Coalition,” the Idsos and Idsos and Idsos “CO2 Science,” and of course Steve McIntyre at his “Climate Audit” blog.

    For example, from the Pielke group, you get:

    Runnalls and Oke (2006) also present a methodology for the detection of inhomogeneities in temperature records associated with changes in LULC (e.g., “vegetation growth, or encroachment by built features such as paths, roads, runways,” etc.), and related factors that can be “microscale and subtle.”

    Documentation of Uncertainties and Biases Associated with Surface Temperature Measurement Sites for Climate Change Assessment
    BY ROGER PIELKE SR., et al
    Bulletin of the American Meteorological Society, June 2007
    http://climatesci*colorado*edu/publications/pdf/R-318.pdf

    I don’t believe that is peer-reviewed.

    The Frontiers of Freedom has the page:

    Continued bias at the American Meteorological Society?
    http://ff*org/centers/csspp/library/co2weekly/20060906/20060906_05.html

    I doubt the CO2 Weekly is a peer-reviewed journal.

    “The New Zealand Climate Science Coalition” mentions the article as one of the references to the piece:

    Climate Science Coalition response to comments by Dr. David Wratt
    Discussion Document
    http://members*iinet*net*au/~glrmc/Wratt%20&%20RSNZ%20-%20compiled.rtf

    However, other than the citation, I see nothing to indicate that the author of that document had ever read it. But John Daly is mentioned in the main text as someone authoritative at a couple of points.

    There is a reference to it without the title in:

    TEMPERATURE VARIABILITY: GLOBAL, REGIONAL AND LOCAL
    Dr Vincent Gray, June 2007
    http://www*climatescience*org*nz/assets/2007641323570.TempVariability607.pdf

    He maintains that there is no such thing as average temperature. I am not sure that the authors would care to have Dr. Gray’s glowing recommendation.

    But that doesn’t appear to be peer-reviewed, so no matter.

    Oh, and I ran across mention of it in:

    Media Matters – NY Times article on Gore leaves out inconvenient truths
    Global Warming Misinformation
    http://globalwarmingmisinformation*org/items/200703130003

    At least the website appears appropriately named.

    I could keep digging…

    Oh, joy!

    … but it probably wouldn’t be good for my mental health.