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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. 201
    ray ladbury says:

    Steven Mosher, I mean no disrespect by this, but your responses give an impression that you have never worked with very large datasets or with a very large geosciences information network. Among others, the assertion that useful data cannot be gleaned from the extra stations in an oversampled network–even if tossed off flippantly–is so far off the mark that it indicates that you don’t have a lot of experience in data analysis. You seem to completely discount the validity of algorithmic and statistical filtering, leading me to wonder whether you have seen what it can do. If I am not too far off the mark, then why should we have confidence that you will be able to competently assess the implications of any siting irregularities that you find? Would your time not be better spent first learning something about the analyses that use the data you seek to improve? After all, how can you improve the product when you do not understand the needs of your customer? I have no objection in principle to what you are doing. It may be particularly valuable as we move from global to regional climate modeling (where the oversampling is a lot less). What I object to is effort wasted in an attempt to “help” when you don’t understand what help is truly helpful.

  2. 202
    Chuck Booth says:

    Re 188 Responses by steven mosher

    You seem to be making one very fundamental mistake here: No offense to Ray or Timothy, but neither is a climatologist (as they frequently point out in their posts), so what they write on this blog carries no weight in field of climatology. So, it really doesn’t matter whether they agree or contradict one another – you can choose to believe one, or the other, or both, or neither, and it makes no difference; the reality of anthropogenic global warming does not hinge on their ability to explain or defend the measurement of temperature.
    What you should be reading and trying to understand is the peer-reviewed literature that underlies the conclusions in the ICPP reports. If there are serious problems with the raw data, report this in a venue that will be read or heard by the scientists making the temperature measurements and using those data in their analyses – your criticsms are falling on deaf ears here, as far as I can tell (I’ve seen no evidence that anyone is taking your concerns seriously, as you seem to be saying that which scientists who study climate already know, and have known for a long time).

  3. 203
    matt says:

    #176: Ray Ladbury: I do not care about Al Gore. The impetus to deal with this issue is not coming from him, but from what the science is telling us. Listen to the scientists–they are very nearly all on the same side on this one. I have nothing against someone making money if they do so honestly. I deplore those who lie to make a buck or to preserve their privileged status–and that is what the denialist disinformation machine is doing in this case.

    Hi Ray. I didn’t ask if you cared about Al Gore, I asserted that there are those on both sides driven by an agenda. Do you disagree?

    When something isn’t completely understood, it doesn’t matter if 100% of scientists believe it is true. H Pylori. Nobel Prize. It’s a very good example of how modern peer review stumbled for 40+ years. Even the IPCC agrees there are major components of our climate that are poorly understood. And like particles in the mid 90’s, these misunderstanding could indeed have a substantial impact on long-term estimates. Please state if you disagree and I’d be keen to adjust my mindset.

    Again, I don’t think either side is lying here. I think both sides aren’t being completely transparent with data. And when I hear of lost data, secret source codes and hidden techniques, I get suspicious. And you should too!

    We have a very interesting article for our discussion here: http://www.climateaudit.org/?p=1798#comments

    Are you interested in making this a case study for the discussion as a whole? From my perspective, folks here are arguing this stuff has been vetted multiple times. I look at another set of folks that can’t find original data or techniques, and their conclusions are that somebody just decided to add 3 degrees of warming to NYC during the last 20 years.

    If you are correct, then there’s an answer here and a few minutes with Dr. Karl et al will clear things up. If the other team is correct, then yes, things look fishy and unvetted and we should be suspicious.

    [edit]

  4. 204
    Marion Delgado says:

    dan hughes realclimate is losing credibility only with dead-enders out in the far standard deviations of the Bell curve. You need to own your statements. there IS no balance. the people calling mainstream science alarmists are mostly liars. Some of them are fools. The rest are simply of a contrary opinion by happenstance.

    On the other hand, the mainstream scientists and average people calling the denialists denialists are correct. There is an observable running from science – attacks on the very concept of peer review, of a consensus developing on what evidence means, on wanting more funds for gathering more data, on the stations that gather data, and so on.

    Since the less than 1% is mostly paid Exxonists, what has gained or lost credibility (and frankly, that’s a falsehood, you’ll ALWAYS claim RealClimate is “losing credibility”, implying that it had any with dead-enders) among them is irrelevant. Don’t waste people’s time with such boilerplate. If you ever have a point to make, now would be a good time to make one.

  5. 205
    Philippe Chantreau says:

    Dave Blair (190). Geology with economics and psychology? That’s non-sense. Geology maybe more of an integrative discipline that uses physics, chemistry, biology, mathematics, but it is far from the approximation of the others you mention.

  6. 206
    Timothy Chase says:

    Chuck Booth (#188) wrote:

    You seem to be making one very fundamental mistake here: No offense to Ray or Timothy, but neither is a climatologist (as they frequently point out in their posts), so what they write on this blog carries no weight in field of climatology.

    None taken.

    I am here principally to learn. I also enjoy participating in the discussion – much like those who never let their qualifications stand in the way of criticizing that which they do not understand, but with the objective of understanding that which I do not understand. Oh, and I would like to be helpful, if possible.

    I am quite satisfied with that.

    *

    “I could be bounded in a nut shell and count myself a king of infinite space, were it not that I had bad dreams.”

    Hamlet, Act II, scene ii

  7. 207
    Paul G says:

    == Re: Post #189 by Eli Rabett: ==
    =”Eli thinks that a lot of people don’t have a clue about how stations are run and calibrated and checked. There is literature out there folks, go read it before running off telling everyone that you are going to save the world by taking pictures.”=

    That old saying keeps coming to mind: “A picture is worth a thousand words.” From some of the embarassing photos seen, I would say those photos trump every single word posted on this thread in defense of the current surface site situation.

    == Eli goes on to say: ==
    Hint: One picture says nothing about the HISTORY of the station.==

    I don’t understand your point. A picture of a bad site speaks of professional neglect. That there have not been regular photos taken of core sites speaks of neglect too as the history of the site becomes suspect also.

    That people do not “understand” how sites have been run/calibrated/checked is understandable. One needs proper documentation to understand something.

  8. 208
    nicolas L. says:

    re 203

    “We have a very interesting article for our discussion here: http://www.climateaudit.org/?p=1798#comments

    Fascinating indeed…

    – About what people can lose their time at (determine the position of the station to the centimetre was a great achievement). So one presumably bad measurement station in NY and the whole data is to throw in the garbage? Just one thing about this analysis, it would have been smarter I think to compare the adjustments made with the energy consumption of the city, for exemple, rather than to the population (unless one thinks body heat has a great role in UHI…)

    I’m also astonished by the local dimension of the debate. Some people apparently don’t want to rely on the American meteorological data. I still don’t get why, but whatever… The fact is, America is only a small part of the world, and many other countries have pretty darn good meteorological networks.

    If I take my own country, France, we have at our disposal one of the best and most complete (specially for our relatively small territory) meteorological data network. This network is run by a public office named Meteo France, whose only agenda is to predict as accurately as possible national weather. Their data collections are then reused for climate studies.
    For those you are keen on French , here is the link to their site, and the link to the maps that show the French meteorological data collection network:
    http://www.meteofrance.com/
    http://climatheque.meteo.fr/aide/climatheque/reseauPostes/

    So, what does Meteo France has to say about temperature variations in France during the 20th century?

    http://secours-meteo-fr.axime.com/FR/climat/img/tempminimaxi.gif

    If you know France a bit, you’ll notice that the regions that experienced the highest warming trends are rural areas… Could there be a Rural Heat Island?
    Of course this is all local data, but I guess one could find the same kinds of results when looking at other meteorological networks around the world. But wait a minuteâ?¦ isn’t it precisely what climate scientists are doing when collecting global data?

  9. 209
    Ray Ladbury says:

    Matt,
    First, what do you mean “lost data, secret source codes and hidden techniques”–the techniques are published. The code has been peer reviewed and the data are available to any fool with a high-speed internet connection–as illustrated by your climateaudit post, which makes a reconstruction for a single station and uses it to draw ridiculous conclusions about the network as a whole.
    And do you really equate the state of medical science–which really still isn’t all that scientific–and physical science? In any case, you will note that as soon as there was any evidence of the link between H. Pylori and ulcers, it was accepted almost immediately. This shows that peer review works, not that it fails. And in the case of climate change, ALL the evidence is on the side of the consensus–which is precisely why it is so strong. The denialists have no evidence and no coherent theory to back up their position.
    You emphasize the “uncertainties” in the model, but completely ignore the likely effect of these uncertainties–which is that they are extremely unlikely to significantly change the conclusions of the analysis. Likewise you emphasize the siting errors without a thorough understanding of their likely effect in light of analysis procedurss–namely, the effect of removing “bad” stations on the conclusions will be butkis.

  10. 210

    [[I remain skeptical that CO2 is the primary culprit or even that a warmer earth is a bad thing (by the way, can anyone tell me what the temperature or climate should be?)]]

    No doubt better climates are possible. But our agriculture and our economy are adapted to THIS climate. That’s why changing it is a bad idea. Where the hypothetical optimum lies is completely irrelevant to the actual threat.

  11. 211

    [[First in line at the cash register is Al Gore with his clean energy fund. If folks don’t believe in warming, his fund tanks. If they are scared to death of warming, his fund soars. ]]

    Global warming theory existed long before Al Gore was born and if he disappeared tomorrow it would still be happening. Ad hominem attacks on Gore do nothing to disprove the very clear scientific evidence that the world is warming, that we’re doing it, and that it’s a serious problem.

  12. 212

    [[Climatology is a soft science (much like economics, archaeology or geology are) so it’s difficult to prove theories and is open to interpretation. ]]

    Climatology is a “soft science?” Geology is a “soft science?” What in the world are you talking about? Have you ever studied either?

  13. 213

    [[Maybe it is just me, but the way to combat this is to not take the Timothy Chase route and devine what’s in their souls to decide if a response is necessary, but rather to make sure that everything is documented so that these questions won’t come up in the future. ]]

    You just don’t get it. It HAS BEEN documented, over and over again. Temperature stations are checked a number of ways. The urban heat island effect has been studied a number of times. The things the denialists keep screaming that we should do have already been done. The point is, no evidence would be good enough for them. They don’t have the intelligence to look at what has already been published on the subject, so they keep saying the climatologists don’t check their data, which is wrong. Not an interesting new point of view, just flat-out dumbass wrong.

  14. 214

    [[When something isn’t completely understood, it doesn’t matter if 100% of scientists believe it is true. H Pylori. Nobel Prize. It’s a very good example of how modern peer review stumbled for 40+ years. Even the IPCC agrees there are major components of our climate that are poorly understood.]]

    There are. But the reality of global warming and its cause is not one of those components. We know enough to understand what’s going on and why it’s going on, and not anything you say about the consensus is going to change that. Sure, the consensus has been wrong in the past. But it’s been right a lot more often, and that’s the way smart people will continue to bet. See if you can look up Isaac Asimov’s 1961 article, “My Built-In Doubter,” to understand why.

  15. 215
    pete best says:

    Al Gore is the political face of climate change, after all climate change is about burning fossil fuels, stop that and you can stop some climate change, the worst bits hopefully but we have already signed up to 1 to 1.5 degrees I believe with 2 degrees getting more and more likely each year.

    Economic and politics will dictate how far AGW goes, at the moment 3 degrees is getting more likely by the year and 2 degrees seemingly a certainty.

    There is plenty that politicians can do to mitigate climate change but the laws of physics seem to be against us otherwise we would not be burning all of the available coal, gas and oil. Thanks nature for the free prosperity and progress but we might just cause a bit of a issue whilst using it all.

    ironic isn’t a big enough word for it.

  16. 216
    Ray Ladbury says:

    Paul G.–your contention that a bad site speaks of professional neglect is absolutely unsupportable. In many cases, the site was fine, but a city grew up around it. So, do you throw out a long data history and make do with only pristine, brand new stations? Hell no. You learn about the errors introduced by the changed circumstances and find a way to use the data.
    Your post illustrates the reason why this technique raises concerns: It is because the photos give no context to how the data are used. And most who see the photos will lack any knowledge of this context (as you do) and draw conclusions based on that ignorance. Context is everything when dealing with a complicated network and if you don’t understand context, your efforts are likely to generate more heat than light.

  17. 217
    Jeffrey Davis says:

    H. pylori isn’t a good example for the denialists since it isn’t the cause of all stomach ulcers that the popular press has made it out to be.

    Misrepresentation of the science. Where have we heard that before?

  18. 218
    pat n says:

    That political face of climate change (Al Gore) was used in year 2000 to stop my research and communication efforts on climate and hydrologic change in the Upper Midwest and global warming at the NOAA National Weather Service (NWS) North Central River Forecast Center (NCRFC) in Chanhassen, MN. I continued my efforts from 2002-2005 until I was removed by NWS. It was important to me that I act as I believe concerning climate change and public service. I would be surprised to learn that anyone here at realclimate has spent more time and effort evaluating climate and hydrologic data in the US than I did in my career in runoff modeling and river forecasting from 1976-2005. Less weight should be given to number crunching statistics and more weight to manual evaluation of data would help. More effort should go into tracking regional changes in temperatures which has been shown to be following the course of rapid greenhouse global warming.

  19. 219
    Gary says:

    I’m sorry but I am still not clear on this. First, I suspect that if weather sations are examined that most willl be found to be accepable. BUT, NOAA tells us that NON URBANIZING land use changes can cause changes in station temperature measurements. And when theses changes occur 95% result in warmer temperatures http://www.agu.org/pubs/crossref/2006/2006GL026358.shtml And Dr Hansen tells us that staions may have a 5 standard deviation from the average monthly mean and still be considered accurate. http://pubs.giss.nasa.gov/abstracts/1999/Hansen_etal.html So it does seem that there could be a potential warm bias in the raw data. Since National and international policies are being formed based on the rate of global warming isn’t it very important to assure that you instraments are not giving us biased data? Since some one appears to be willing to get at least visual information on these sites for free I don’t see how this is not a good idea. Alternatively the government could instruct people who maintain the sites to take a couple of pictures for annalysis by whom ever is interested. Isn’t it better for people to be concerned about global warming than Paris Hilton?

    [Response: You misinterpret both papers you cite. In any situation where there is a real increasing trend in temperatures, trends before any particular point will be smaller than trends after. Thus you cannot use the Hale et al result to claim causality – and in fact the authors specifically state that. Similarly, the Hansen et al exclusions are to get rid of obviously flawed data, not to certify that everything remaining is perfect. -gavin]

  20. 220
    Vernon says:

    I am most likely wrong but over sampling to reduce errors in the data would only work if the errors were random. I don’t have a back ground in climatology or statistics but I do in telecommunications and electronics. My back ground says that you can over sample to pull a signal out of RANDOM back ground noise, but if there is a bias, then the bias comes though with the wanted signal.

    I from what I have read so far, the problem with surface stations is not that they be in the shade, but that man-made structures and activities are too close… this would indicate a temperature increase bias and I don’t understand how over sampling with remove a bias.

  21. 221
    Jim Cripwell says:

    Ref 211. As I tried to ask in #118, where is the evidence, here in 2007, that the world is still warming up? There is quite clearly lots of evidence that in the last 30 years or so, global temperatures have been rising. (Why is in dispute). But where is the evidence that this warming trend is continuing as we sit here and now in July 2007? The latest NSIDC data for June 2007 shows that there is more ice in the arctic than there was at the same time last year. This is almost certainly not significant as the data is extremely noisy, but it is still a fact. The Hadley/CRU data shows that the average annual temperature for 2007 is unlikely to set a record, as forecast by the UK Met. Office. The average temperature anomaly for the first 5 months of the year is 0.476 C, third highest on an annual basis. Not all glaciers are retreating. There is contradicatory evidence as the whether sea levels are rising, and no clear data that they are, in fact, rising. We have not seen the first hurricane of 2007 in the North Atlantic. I am not talking about the predictions of GCMs. I am talking hard measured data. To repeat, where is the hard measured data, here in July 2007, that the warming trend is continuing?

    [Response: Well in my location, temperatures have gone up by about 10 deg C in the last few hours. But possibly that’s too short a period to be matched to long term climate model trends? Indeed…. – gavin]

  22. 222
    Dave Blair says:

    #190
    Soft science is usually controversial, subjective and have hypothesis that can’t be tested. Global Warming is very controversial and political.

    Even Physics has some soft aspects to it to – for example String Theory. However, most physics hypothesis can be test and are not controversial.

    #205
    There are aspect of all those science areas that are certainly “hard science” but relatively speaking they fall on “soft” side of the spectrum as does climatology.

    #212
    Geology has many hypothesis that cannot be directly tested.

  23. 223
    Ray Ladbury says:

    #221 Jim, Ice is still melting and the mass balance is still negative–that’s a pretty good indication we are still warming. Winters are still starting later and ending earlier. Again a pretty good indication. And temperatures, while not as high as 2005 or 1998 are still historically high. Just because every year is not warmer then the one before doesn’t meant he trend has reversed.
    And if you were so inclined, you could look at the physics, but you do not seem to be so inclined.

  24. 224
    stephan harrison says:

    Any comments on the recent Science paper about evidence for a stable Greenland ice sheet?

  25. 225
    pete best says:

    Re #218, the rapid pace of climate change is not rapid enough for many humans to take notice. For rapid can mean many things, geologically rapid is still millenia whilst humanly rapid is in decades at the most or a life time.

    I personally believe what the scientists are saying just like a believe Astronomers, cosmologists, biologists, chemists and physicists in general. I feel sorry for climate scientists as they are being accused of many things that other scientists simply are not being accused of, cooking their data, misinterpreting their findings, getting it wrong.

    I believe in the scientific method more than any other human endeavour and as far as that goes there is no reason not to believe the climate scientists, their science is as scientific as anyone elses. Maybe its becuase a large number of the lay public (bless them) take an interest in climate science as well as the detractors and obfuscators that the web is full on spurious results and conjecture, all of it wrong in the main.

    I for one feel that realclimate was necessary and is needed and I bet that even Al Gore comes here once in a while.

    One other good site to vist politically is George Monbiots turnuptheheat.org for the UK listeners. Seems that big business wants to lie to us about climate change to and their green credentials.

  26. 226
    caerbannog says:

    #225

    Here’s a little excerpt from an interview of one of the authors:

    “We should remain very worried about rising sea levels,” he [Willerslev] said. “We know that during the last interglacial, sea levels rose by 5 meters or more. But this must have come from sources additional to Greenland, such as Antarctic ice. It does not appear the whole [Greenland] sheet will melt.”

    (Taken from an article at http://www.boston.com)

  27. 227
    Eli Rabett says:

    Vernon, the way that temperature records are made subtracts out the monthly mean over a thirty year period at a station (or a collection of nearby stations). This is called the temperature anomaly and is what GISS and Hadley look at (it would be hard to put temperatures in Washington, DC and Moscow on the same scale otherwise. The second principal virtue of this is that is gets rid of the annumal cycle, so you can compare the anomaly at one location in January with that in June, e.g. how much higher or lower the temperature was than the average. The method also gets rid of any offsets. For the offsets to produce a trend, they too must vary over time in one direction. A much more stringent condition. If the barbeque is sitting out there for 20 years, there will be no effect over 20 years.

  28. 228
    Paul G says:

    == Post #216 by Ray Ladbury: ==
    =”your contention that a bad site speaks of professional neglect is absolutely unsupportable. In many cases, the site was fine, but a city grew up around it.”=

    If some of the photographs do not speak of professional neglect, I do not know what does. Sure, cities grow up around sites, but that does not explain BBQ’s, AC units, etc.. And since many of these site have not been properly documented over the years, the neglect possibly goes back a long time.

    =”So, do you throw out a long data history and make do with only pristine, brand new stations? Hell no. You learn about the errors introduced by the changed circumstances and find a way to use the data.”=

    That is the point that is being made and so strenuously avoided by posters here. Do a thorough, professional review of all sites, or at least core ones, and IMPROVE the data’s integrity.

    =”Your post illustrates the reason why this technique raises concerns: It is because the photos give no context to how the data are used. And most who see the photos will lack any knowledge of this context (as you do) and draw conclusions based on that ignorance.”=

    As a layman, I have not heard a single solid post that reassures me that some of these sites have been properly QCed or that the data, with adjustments made, is actually of good quality. Clever obfuscations yes, commonsense explanations, no.

    Lastly, I would suggest making photographic documentation is not a “technique”, but one of the fundamental steps in documenting, identifying, and validating the data any particular site provides.

  29. 229
    Jeffrey Davis says:

    Statistics aren’t the phenomenon, and “natural variability” is not an actual force. There are variations in forcings that can produce variations in world wide climate, and the source of that change can be identified and measured. Sceptics can’t simply expect “variability” to produce a change. There has to be a diminution of some actual force to produce a halt in the increase in global temps.

    That seems obvious, but I keep seeing people ascribe a power to “variability” as if there’s an actual missing ingredient out there called “variability”.

  30. 230
    Chris O'Neill says:

    “Any comments on the recent Science paper about evidence for a stable Greenland ice sheet?”

    aka evidence for an unstable West Antactic ice sheet.

  31. 231
    Sam says:

    Gavin – you didn’t post my last entry, so I don’t expect this one to be posted either. But at least I know you are reading this so here goes. News comes out, potentially good news. The article you are quoted in is titled “Greenland Ice Yields Hope on Climate.” The Globe asks you, the climate expert, to comment. Now granted, god knows you may have been misquoted or taken out of context, but your response does its best to put as negative a spin on the information as possible. Why? It would appear because the data do not support your beliefs. It does not help your credibility when you appear to be less than open regarding new information.

    [Response: Things sometimes wait around for responses…. anyway see above. – gavin]

  32. 232
    mankoff says:

    Re: #61

    But it would also be nice if all the KMLs relevant to climate change were gathered in the same place – or at least links to the sites where they are available. Somebody may already be doing that. I will have to check.

    Google is making a library, here:
    http://earth.google.com/outreach/showcase.html

    And http://earth.google.com/gallery/

    -k.

  33. 233
    Sam says:

    Gavin in the news! It seems a new study http://www.boston.com/news/local/articles/2007/07/06/greenland_ice_yields_hope_on_climate/?page=2
    indicates that the Greenland ice did not melt in the previous interglacial about 125,000 years ago. The temperature then was higher than predicted by current models and higher than temperatures current models associate with the total loss of the Greenland ice. In the Boston Globe article, Gavin weighs in, saying well at least the ice melted 450,000 years ago, and hey maybe the ice 125,000 years ago was really thin.

    [Response: I was simply pointing out that evidence for an unglaciated Greenland sometime in the last half a million years indicates that the ice sheet is in fact unstable. Other than the fact that some ice must have remained during the last interglacial, this data point provides no information on the size of the Greenland ice sheet at that time – and you still need to explain 4 to 6 m of sea level rise. It is almost inconceivable that this could have happened without a substantial Greenland component. – gavin]

  34. 234
    tamino says:

    Re: #228 (Paul G)

    That is the point that is being made and so strenuously avoided by posters here. Do a thorough, professional review of all sites, or at least core ones, and IMPROVE the data’s integrity.

    Sounds like a fine idea. Here’s the catch: absolutely NONE of the people claiming problems with the data are doing that. They’re taking pictures of sites for the sole purpose of discrediting the data, not improving it. And contrary to their claims, they are definitely implying that the global surface temperature record is corrupt and the indicated trends are way overblown.

    GISS and HadCRU have worked *very hard* to identify bad data, correct them when possible, discard them when not. They apply objective, sound statistical procedures which do not favor warming or cooling, do not credit or discredit the data reputation, just bring us closer to the ever-elusive truth. They have applied their methodology consistently and comprehensively, publishing their results and methodology in the peer-reviwed literature, and their analysis applies to, and can be taken in the context of, the whole network.

    The skeptics you seem so enamored of have worked very hard to identify bad sites, without analyzing or even *considering* quantitatively the effect on the data of the siting problems, only making generally snide remarks about the unreliability of the surface temperature record. From what I’ve seen, they’ve photographed fewer than 100 of 1221 stations in the USHCN, have done absolutely no investigation of the many thousands of stations outside the U.S. But they gleefully post pictures of a few dozen or so sites they proclaim to be “proof” the surface temperature record is invalid, on blog sites under such titles as “how not to measure temperature.” Not exactly science at work — yet they’re already convinced they know the answer. I’m convinced that they decided what the answer was, even before they looked.

    As a scientist, I have not seen a shred of solid evidence indicating that micrositing problems are anywhere near of enough magnitude to invalidate the present analysis of the surface temperature record. If someone chooses to undertake an objective, statistically sound study of the impact of siting problems on the surface temperature data, great! So far, none of the skeptics has even tried. A smear campaign is not a valid reason to doubt the quality of the data or analysis.

  35. 235
    SomeBeans says:

    I’d like to commend mankoff’s GISTEMP Google Earth thingummy:
    http://edgcm.columbia.edu/~mankoff/GISTEMP/
    Colour coded balloons taking you to temperature records.

    Perhaps combine it with a perusal of images of Indiana State Climate Office’s site – with added photos:
    http://www.agry.purdue.edu/climate//hcn.asp

    A lengthy browse of surfacestations.org does get a bit dull, you quickly realise that not many of the stations are very interestingly located.

    It’s rather interesting that the Pielke group managed to visit far flung corners of Colorado for their photos but failed to photo the one at Boulder, on their doorstep: I wonder why that might be…

  36. 236
    Rod B says:

    very good, Marion (204). You got most of the ad hominems and protagonists talking points and sound bites into only three concisely and well written paragraphs.

  37. 237
    caerbannog says:

    This dustup over monitoring sites reminds me of the “Mann’s PC method mines for hockey sticks” claim. Mann’s critics generate “hockey-stick” leading PC’s from random noise and claim that they are somehow equivalent to Mann’s data-derived “hockey-stick”, all the while neglecting to look at the dynamic ranges of their noise-only hockey-stick PC’s vs. Mann’s PC’s.

    Things like Y-axis magnitudes count for something, you know….

  38. 238
    mankoff says:

    Re #235:

    I’d love to include photographs of each station in the popup bubble in Google Earth. I (hesitantly) contacted SurfaceStations.org about this but I have not heard back. I fear they will simply use the GE data to find blue stations near cities and photograph those. Oh well…

    If you know of other station photograph data sets, I’d be pleased to contact their maintainers and try to add it to GE. I can’t figure out how to link into that Purdue page, and it would be nice to have a U.S. or global location, rather than having to do 50 times the work for each state…

  39. 239
    Jim Cripwell says:

    Re 223 I have looked at the physics, on both sides; I participated in the NERC debate. Hence my status as a denier, and my concentration on hard data. To quote William Wordsworth “To the solid ground on Nature, trusts the mind that builds for aye.” When you comment on the winters, I assume you are referring specifically to the northern hemisphere. A dichotomy has developed between the temperature anomalies of the northern and southern hemispheres; no-one seems to know why. I assume you have no explanation. The south is cold, and the north warm; and we are supposed to be talking *GLOBAL* effects. Argentinia is having some of the most brutally cold weather on record this year, and it is only just winter. The government has been forced to ration natural gas. Of course temperatures are at historically high levels. Assuming the world is now cooling, when we look back with 20/20 hindsight from the year 2020, we will observe that the the cooling trend started at the maximum of the warming trend. I am sorry, but I do not understand what is meant by “the mass balance is still negative”. If you mean that the trend still shows that ice is disappearing from the arctic, I agree with you. However, again assuming that a cooling trend is upon us, one of these years the amount of ice in the arctic will start increasing. And the harbinger of this trend will probably be precisely what is now being observed.

  40. 240
    caerbannog says:

    re #239

    When making claims about *global* effects, one must resist the urge to “cherry pick”. Notwithstanding the selected weather snapshots in Argentina, the southern hemisphere is warming along with the rest of the globe, even if it is lagging the northern hemisphere a bit (think Southern Ocean heat-sink).

    http://cdiac.ornl.gov/trends/temp/jonescru/graphics/nhshgl.jpg

  41. 241
    Sam says:

    Re: 239. The southern hemisphere has warmed, just not as much as the NH. the answer may be in the sea surface temperatures. The northern oceans have been in a hot phase for the past few decades, perhaps warming the land masses more than occurs in the south. By the way, the northern Pacific appears to be flipping over to a cooler regime. Check out the sea surface data. It is posted three times a week. The data base goes back over ten years. The ’98 el nino was amazing relative to SSTs. Here is the link:
    http://www.osdpd.noaa.gov/PSB/EPS/SST/climo.html

  42. 242
    SomeBeans says:

    #238
    I found the Indiana link on surfacestations.org. Pictures of well-sited stations are particularly dull – which perhaps explains why no-one has collected them together in one place!

    #239
    I’m really struggling to see the cooling trend you’re so confidently talking about in these GISTEMP plots for the northern hemisphere, equatorial regions and southern hemisphere:
    http://data.giss.nasa.gov/gistemp/graphs/Fig.B.lrg.gif

  43. 243
    tamino says:

    Re: #239 (Jim Cripwell)

    Hence my status as a denier, and my concentration on hard data… A dichotomy has developed between the temperature anomalies of the northern and southern hemispheres; no-one seems to know why. I assume you have no explanation. The south is cold, and the north warm; and we are supposed to be talking *GLOBAL* effects.

    I suspect you don’t concentrate as much on “hard data” as you claim. The southern hemisphere is hot, the northern is hotter. The hemispheric temperature trends 1975 to present are: northern hemisphere 3.1 +/- 0.5 deg.C/century; southern hemisphere 1.2 +/- 0.4 deg.C/century.

    Your claim that “no-one seems to know why” indicates you haven’t really researched the question. The southern hemisphere has a much greater fraction of ocean (as opposed to land) than the northern. Due to the thermal inertia of the oceans, it has been expected for some time that the northern hemisphere would warm faster.

    I am sorry, but I do not understand what is meant by “the mass balance is still negative”.

    It means that the net change in ice mass is negative, i.e., Greenland is still losing ice, not gaining it.

  44. 244
    J Edwards says:

    Re #235
    Recommend following that link to the Purdue Univ Climate page. The review of the Indiana HCN sites was done as part of a Master’s thesis by a Purdue grad student. Her paper is available from the site in pdf format, and reliably answers many of the questions on why a survey is helpful.

  45. 245
    Vernon says:

    Re: 228 I fail to see how that will remove biased data. I could see if the the nosie was random but the bias would not be removed as noise in the over-sampling. I dont think you understand bias… a biased signal would vary over time, it just would be either higher or low that it should be due to the bias. What your saying works fine for ramdom noise but this sounds just like signal processing and you cannot eliminate a bias that you have not identifed. That is why identing the surface stations so to determine the bias is needed.

  46. 246
    Hank Roberts says:

    >> “Any comments on the recent Science paper about evidence for a stable Greenland ice sheet?”
    > aka evidence for an unstable West Antactic ice sheet.

    Yep — the author interviewed on NPR (Ira Flatow, ‘Science Friday’) made the same point.
    Previous sea level rise we thought came from melting Greenland — didn’t.

    Think: Where else was there ice? Yep. That’s an uh-oh for the ‘no problem’ people, not good news.

  47. 247
    Jim Cripwell says:

    Re 243. You are absolutely right, though I could argue minor points. But as happens in this sort of discussion, we have strayed from the main point. The claim was made that “Winters are still starting later and ending earlier”, in my search for what the trend of temperatures is in July 2007. My point, which I should have restricted my comments to, is that this statement is true for the northern hemisphere in 2007, but not the southern. As to Greenland, my comments referred only to the floating ice mass in the Arctic Ocean. Again I should have been more specific.

  48. 248
    ray ladbury says:

    Vernon and Paul G., OK, let’s say that somebody fires up the ol’ barby right under the thermometer just as it is taking a measurement. It registers a high temperature. But the last reading was much cooler, and the reading after that one was also much cooler, and lo and behold none of the several nearby stations shows anything like the temperature of our fricaseed thermometer. Now do you suppose I’m going to blindly include this in my dataset, or am I going to develop techniques that identify and remove that data point? This is true even if somebody sets up a hotdog stand and has the barby going 24/7/365.25. Same thing goes for the air conditioning unit or pretty much any anomaly you care to choose.
    That is the point that is being made and so strenuously avoided by denialists here. Before you can do a thorough, professional review of all sites, or at least core ones, and IMPROVE the data’s integrity, you have to UNDERSTAND how the data are being used, what kinds of errors you may encounter, how often and what the likely effect of those errors will be. Understanding before action–what’s so hard to comprehend about that. You’ve been saying it to climate scientists for years when it comes to action on climate change. Now you seem to be deaf to the phrase once climate scientist have incontrovertible evidence that they do understand the climate.

  49. 249
    Tim McDermott says:

    re 225:
    Analysis of the insect mitochondria, cellular components that contain genomes that can be used to date DNA, as well as amino acids, indicate d that the creatures were at least 450,000 years old. Uncertainties with dating, however, leave the possibility that the DNA dated only as far back as the last interglacial period. (from the boston.com article)

    It looks to me like this isn’t enough to start talking about overturning climate models.

  50. 250
    James says:

    Err… On the question of weather station data integrity and whether documenting them with (single) photographs is a worthwhile project, I get a little worried when I read that some of the alleged problems are due to things like barbecue grills or SUVs parked next to the station. Now maybe I have a nasty suspicious mind, but – naming no names, you understand – just how hard would it be for someone, or some group, with a vested interest in casting doubt on temperature records, to stuff their old grill in the back of their SUV, and drive around setting up photos of such problems?