Measuring the Phoenix Urban Heat Island

Note Updates at the Bottom.  Could we please agree to actually read the whole post and the updates before commenting?  All commenters welcome, and I never delete comments except in the case of outright advertisement spam

This is a project my son did for Science Fair to measure the urban heat island effect in Phoenix.  The project could also be called "Disproving the IPCC is so easy, a child could do it."  The IPCC claims that the urban heat island effect has a negligible impact, even on surface temperature stations located within urban areas.  After seeing our data, this claim will be very hard to believe.

In doing the test, we tried to follow as closely as possible the process used in the Nyuk Hien Wong and Chen Yu study of Singapore as published in Habitat International, Volume 29, Issue 3 , September 2005, Pages 547-558.  We used a LogTag temperature data logger.  My son used a map and a watch to mark our times, after synchronizing clocks with the data logger, so he could match times to get temperature at each location.  I called out intersections as we passed them and he wrote down the times.  At the same time, I actually had a GPS data logger where I gathered GPS data for location vs. time, but I did not share this with him because he wanted to track locations himself on the map.  My data below uses the GPS data, which was matched with the temperature data in an Excel spreadsheet using simple Vlookup calls.

To protect the data logger from the 60mph wind  (we tried to drive at exactly 60 so my son could interpolate distances between intersections) we put the datalogger in a PVC Tee:


We added some insulation to reduce the effect of heat from the car’s roof, and then strapped the assembly to the roof with the closed part of the Tee facing forward (the nose of the car is to the left in this picture).


We drove transects two nights in a row.  Both nights were cloudless with winds below 5 mph.  Ideally, we would have driven between midnight and 6 AM, but this was my kid’s science project and he needs to get to bed so we did it from about 9PM to 11PM.  We were concerned that the air might still be cooling during the test, such that as we drove out from town, it might be easy to mix up cooling with time and cooling with location.  Our idea for correcting this was to drive and gather data on an entire loop, starting in the center of town, going about 30 miles out, and then returning to the starting point.  That way, with data taken in both directions, the results could be averaged and the cooling rate would cancel out.  As it turned out, we didn’t even bother to do the averaging.  The two trips can be seen in the plots, but the urban heat island shows through pretty clearly in the data and the slope of the line between temperature and distance was about the same on the inbound and outbound legs.

I used the GPS lat/long points to calculate the distance (as the crow flies) from the center of town (My son did it the hard way, using a tool on Google maps).

The first night we went north (click to enlarge):


The second night we went south.  The urban profile going south is a little squirrellier, as the highway we were traveling tends to dip in and out of the urbanization.


Here is the total route over the two nights.  I’m still trying to figure out the best way to plot the temperatures on the map (again, click to enlarge)


You can see the results.  Even at the too-early time of 9-11PM, the temperature fell pretty linearly by about 0.2-0.3 degrees F per mile from the city center (as the crow flies).

I would really love to do is to go down to Tucson and run this same test starting at the USHCN weather station there and driving outwards.  That may have to wait a few weeks until my job calms down a bit.

Update:  Per some emails I have received, it is theoretically possible for the urban heat island effect to be real and to have integrity in the surface temperature record.  The first way this could happen is if the official measurement stations are well sited and outside of growing urban heat islands.  I know for a fact by direct observation that this is not the case.  A second way this might be the case is if one argues that urban heat islands exist but their effect is static over time, so that they may bias temperatures but not the warming signal.  I also don’t think this is very credible, give growth of urban areas over the last 50 years.

A better argument might be that because most US temperature stations are arriving at daily temperature averages from just measuring daily min and max temperatures.  It might be arguable that while urban temperatures cool more slowly at night, they still reach the same Tmin in the early morning as the surrounding countryside.  Unfortunately, I do not think this is the case — studies like this one taken at 5AM have seen the same results.  But this is something I may pursue later, redoing the results at whatever time of day Phoenix usually hits its minimum temperature.

A good argument for the integrity of the surface temperature measurement system is NOT that scientists blind to local station installation details can use statistical tools to correct for urban biases.  After looking at two stations in the Arizona area, one urban (Tucson) and one rural (Grand Canyon) it appears the GISS statistical method, whatever this double-secret process may be [insert rant about government-funded research by government employees being kept secret] it actually tends to average biased sites with non-biased sites, which does nothing to get the urban bias out of the measured surface warming signal – it just spreads it around a little.  It reminds me a lot of my kids spreading the food they don’t like in a thin layer all over the plate, hoping that it will be less noticeable than when it sits in one place in a big pile. 

Again, I have not inspected their procedure, but looking at the results there seems to be a built-in assumption in the GISS algorithms that they expect an equal chance of a site being biased upwards vs. downwards.  In fact, I seem to see more GISS corrections fixing imagined downwards biases than upwards biases.  I just don’t see how this is a valid assumption.  The reality is that biases in outdoor temperature measurement are much more likely to be upwards than downwards, particularly over the last 50 years of urbanization and even more particularly given the fact that the preferred measuremnt technology, the MMTS station, has a very very short cable length that nearly gaurantees an installation near buildings, pavement, etc.

Update #2:  To this last point, consider this situation:  Thermometer one in the city shows 2 degrees of warming.  Thermometer two a few hundred kilometers away shows no warming.  Someone aware of urban biases without a dog in the hunt would, without other data to guide them, likely put their money on the rural site being correct and the urban site exaggerated or biased.  The urban site should be thrown out, not averaged in.  However, the folks putting the GISS numbers together are strong global warming believers.  They EXPECT to find warming, so when looking at the same situation, absolutely sure in their hearts there should be warming, the site with the 2 degrees of warming looks correct to them and the no warming site looks anomalous.  It is for this reason that the GISS methodology should be as public as possible, subject to full criticism by everyone.

Update #3:  I know that many commenters see one line or even a title to a post and jump to the comment section to bang out their rebuttal without reading the post. I typcally do not respond to such folks, but there are just so many here I feel the need to say:  Yes, the IPCC knows urban heat islands exist.  What I said, and I think it is true, is that the IPCC does not believe urban heat islands substantially bias the surface temperature record, and, if they do, their effect can be statistically corrected by approaches like that used by the GISS and discussed above in Update #1.  I admit that this experiment alone, even if the quality was perfect, would not disprove that notion, but it has to make one suspicious (skeptical, even?)  By the way, if you want to yell "Peterson!" at this point, see here.  The volume of interest, pro and con, on this post I think is going to motivate me to go down to Tucson and run the same test with this USHCN station as the urban starting point, and then we’ll see.

By the way, my point is clearly not, as some skeptical supporters might make out, that urban heat biases in surface temperature measurement account for all historical warming.  Clearly that is not true, as satellites, which do not have this urban bias problem, have measured real global warming, though at a lower rate than the surface temperature record.

Update #4:  To some of you commenters:  give me a break.  This is a junior high school science project funded with a $65 temperature logger and a half tank of gas.  I am sure the error bars are enormous and the R-squared probably has little meaning  (to tell the truth, Excel just put it there when I asked it to draw a trend line through the data).  Some of the data on the second run in particular looks weird to me and I would want to do a lot more work with it before I presented it to my PhD review board.  That being said, I would be happy to put it in front of said board next to the typical junior high baking soda and vinegar volcano project.

Given our constraints, I think we did a moderately thoughtful job of structuring the project– better, in fact, than the published Singapore study we emulated.  In particular, the fact that we did the run both ways tends to help us weed out the evening cooling effect as well as any progressive heating effect from the car itself.  I honestly had zero idea what we would find when we downloaded the data to the computer.  I kind of thought it would be a mess — remember, we were not really doing this at the right time of day.   It was not until my son did the charts using his position log he took by hand that I thoughy, "wow, there is a big effect here."   That is when I decanted the data from my GPS logger to check his results using a little more accurate position vs. time data and produced the charts here.  As I said, I really should have averaged position data for the forward and reverse runs, but I think the charts were fairly compelling.

Update #5:  The other half of my son’s project was to participate in the survey of USHCN temperature stations.  He did a photo survey of two sites.  Below is a picture from the USHCN station at Miami, AZ.  Left as an exercise to the commenters who are defending the virtue of the US surface temperature netork:  Explain how siting the temperature instrument within six feet of a reflective metal building that is perfectly positioned to reflect the afternoon sun from the SW onto the instrument does not introduce any measurement biases.  As extra credit, explain why the black gravel and asphalt road and the concrete building 6 feet away don’t store heat in the day to then to warm up the air around the instrument at night as the heat re-radiates.


50 thoughts on “Measuring the Phoenix Urban Heat Island”

  1. Seems to me that to “close the loop,” you would need to dig up the GISS data for stations in your area and find out how much they have been “corrected” for UHI.

  2. Fantastic. Run a regression analysis and see if those two slopes are statistically significant (though by their looks, they probably are). Also, though you did add insulation, it might not be enough to shield the logger fully from the heat island of the car. In fact, the car may, with time, be cooling down or heating up slightly. A vacillating car temperature could definitely affect your results. To be certain that what you note can be fully attributed to the urban heat island, you should attach a thermometer to the roof of the car to measure its temperature at every point at which you take the temperature with the logger. Then simply subtract Troof from Tair at every point and plot the points again. (Yes, I know that temperature probably can’t be subtracted like that — still, even if the actual temperatures are thus made flawed, the trends, at least, will be more accurate.)

  3. As far as controlling for car effects, surely a better way would be to make some sort of pylon and mount it near the front of the roof. A foot or so should be enough to keep the sensor clear of any car bias.
    Good job anyway, I hope he got an award for the efforts. Come to that, you should as well.

  4. As far as controlling for car effects, surely a better way would be to make some sort of pylon and mount it near the front of the roof. A foot or so should be enough to keep the sensor clear of any car bias.
    Good job anyway, I hope he got an award for the efforts. Come to that, you should as well.

  5. Wow, you really think the IPCC has said that heat islands don’t exist? Please, try reading any IPCC document. You have proved nothing that is not already extremely well known.

  6. How about time? Do you have to correct for time? I would think that if you wait 2 hrs in the evening it would cool too.

    You did ride out of the city and back in, so that should give you some correction.

  7. Good work! Since the weanies at the IPCC deny the significance of UHIs, when the reality gets rubbed in their faces they may have some splainin to do.

    Here’s a question: When the reality of global cooling hits the awareness of earth’s billions, what do you think they are going to do to the obscurantists and would-be climate dictators? What happened to Mussolini and Ceausescu will be nothing compared to what happens to “Eli Rabbett” and the other rodents, I fear.

  8. Nice work – your son deserves an A+++! I would, however, suggest that you do a multiple regression using both distance and elevation vs temp. Temps vary with elevation (higher = cooler usually, and nighttime air drainage can make lower = cooler sometimes) Also beware of irrigated areas (evaporation from them can create local cool spots).

  9. Scientist,

    I usually go out of my way to be as polite as possible, but… you’re an idiot.


    The IPCC says that UHIs are adjusted for and their impact is small. We’re not sure about that. They say that they adjust for it (and I’m sure they do try), we’re just not sure that they’re doing it right. The primitive code they use to do this has recently been released and people are working to reverse engineer the adjustments they make. It would help the government employees that collect this data would be more forthcoming with their methods.

    By making the claim that we are saying that the IPCC denies the existence of UHIs, you’re either dense or intentionally obfuscating.

  10. scientist-

    Fourth Assessment Report from the IPCC (2007: p.244) says the following.

    Studies that have looked at hemispheric and global scales conclude that any urban-related trend is an order of magnitude smaller than decadal and longer time-scale trends evident in the series (e.g., Jones et al., 1990; Peterson et al., 1999). This result could partly be attributed to the omission from the gridded data set of a small number of sites (<1%) with clear urban-related warming trends. In a worldwide set of about 270 stations, Parker (2004, 2006) noted that warming trends in night minimum temperatures over the period 1950 to 2000 were not enhanced on calm nights, which would be the time most likely to be affected by urban warming. Thus, the global land warming trend discussed is very unlikely to be influenced significantly by increasing urbanisation (Parker, 2006). ... Accordingly, this assessment adds the same level of urban warming uncertainty as in the TAR: 0.006°C per decade since 1900 for land, and 0.002°C per decade since 1900 for blended land with ocean, as ocean UHI is zero.

    as you can see, the ipcc does in fact make the claim that the UHI effect is exceedingly small and need not be considered “significant”. worse, they base the bulk of this opinion on min temps. what about max temps? look at a weather map around a city in the summer. where do the highest highs occur? asphalt can hold an awful lot more heat than grass. your straw man argument is a nice try, but holds no water.

  11. Wow. This is the first story on your home page? I hope that anyone visiting this website sees how ridiculous your pseudo-science is.

    If you ask me, you are doing a terrible thing by trying to confuse everyone, even your own son. The real scientists have spoken. There is no “scientific” debate. The only debate right now regarding the science of the issue is between those who hold degrees in applicable fields, and idiots like yourself who have nothing better to do than to try to disprove a report that took thousands of people months and months of hard work.

  12. Some of these people a scary!

    Seems like the teenagers are the ones getting to the truth with open minds.

    Keep the good work and don’t let them grind you down.

    I don’t know what got me to thinking about it, but last night I got to thinking about aqn uncle that died of modern medicine.

    He had stomach ulcers and the settled science of the time was that the only treatment was surgery, so they kept cutting him up until they killed him.

  13. Mr X, given that he’s done a pretty good job of poking a pretty big hole in a pretty significant part of the report, it is those “thousands” of people who should be ashamed of themselves.

    And you fail so badly at “real” science it’s not even worth making fun of. Just a hint, though – “real” science is skepticism. It’s not blindly following what those in positions of authority say. Science isn’t consensus, it isn’t what “scientists” say, it is, in whole, the act of testing ideas. That’s it. Science = Testing. If you aren’t testing, you aren’t doing science.

  14. “Wow. This is the first story on your home page?”

    Gentlemen, I think we’re found a rare specimen of Neverheardofblogus.

  15. “Wow. This is the first story on your home page?”

    Got to love it, when a puedoscience believer proudly asserts his stupidity.

  16. I’m thinking maybe “X” isn’t a pseudonym, it’s how he really writes his name. Or, it’s TCO again, too ashamed to show himself under his “real” name now that he’s sobered up.

  17. It’s a wonderful science experiment. It just doesn’t show bias over time. It shows heat islands. That’s NOT CONTESTED.

  18. If you think that the amount of UHI is larger than known in the literature, you should write a paper on it. I think you will find that the magnitude of the UHI has been well studied. It is a trickier issue to say how it is corrected for, how it changes over decades, the impact on the overall trend (which is some average of posited contaminated and uncontaminated sites). However, just showing “Phoenix has a big UHI” is not new, not contested.

  19. It’s really sad with all the interesting things to think about in this world, that we have to deal with someone who thinks that he can argue a conclusion (requiring mutual on states of A and B), by citing evidence for A being on, and ASSUMING B on, when his opponents concede A, but not B.

    It’s just really sad. Is this lack of intelligence? Lack of honesty? Self deception?

  20. I mean it’s really bumming me out. Are skeptics stupid? I thought we were supposed to be smarter and more honest. More willing to let the chips fall how they may, than the professionals. But instead we get game playing and citing of earrly data, without final results, we get crap “pulbickation” in echo-chamber filled blogs. We get lack of statistical testing. We get Johnny lies too, so I will arguments.

    It’s just really, really sad. This is not the ethic that I learned in school. This is not cricial thinking. This is not how scientists should be. Dick Feynman would rip you all up the belly, for your self-serving ways.

  21. I mean it’s really bumming me out. Are skeptics stupid? I thought we were supposed to be smarter and more honest. More willing to let the chips fall how they may, than the professionals. But instead we get game playing and citing of earrly data, without final results, we get crap “pulbickation” in echo-chamber filled blogs. We get lack of statistical testing. We get Johnny lies too, so I will arguments.

    It’s just really, really sad. This is not the ethic that I learned in school. This is not cricial thinking. This is not how scientists should be. Dick Feynman would rip you all up the belly, for your self-serving ways.

  22. In your update #2, you site a couple interesting issues.
    A. Biases of the data analyzers.
    B. Whether potentially biased thermometers should be included (with correction) or omitted.

    On A: yes, perhaps your “opponents” could have the bias, you ascribe. However, even in your words themselves, you show your bias: you have an implicit assumption that the trending up station must be contaminated. But you never cited it as a predicate. I’ve seen a similar thing from Watts where he shows a station with an up trend and says that it must be classic urbanization or station micro-site: he doesn’t even include as a possibility, that the station MIGHT be accurate and just be recording an up trend. Of course, it’s easy to find your opponents wrong, if you can’t even encompass a world view that maybe they are right.

    On B: This is the more interesting question. Very poorly addressed by the users of these adjustments or by the sniping critics. I honestly don’t know what the statistical meaning of including such adjusted data to a trend is. How does it change the degrees of freedom and are we properly accounting for it? What is the meaning wrt long term trends of the geo average?

  23. BillBodell – are you illiterate or something? The man has clearly stated that he thinks that the IPCC doesn’t believe in heat islands. He thinks that by measuring the urban heat island in Phoenix that he’s ‘disproved’ the IPCC. Unfortunately he is making a fool of himself and also his son. He’s got it into his head that GISS is evil, and nothing could possibly change his mind, even if GISS has specifically mentioned Phoenix as a good example of a strong urban heat island.

  24. Scientist,

    Let’s try an exercise in communication. In the second sentence of his post, the author says “The IPCC claims that the urban heat island effect has a negligible impact”. This makes it clear that the author knows that the IPCC is aware of urban heat islands. The author thinks that the IPCC believes that the UHI effect has a negligible impact. If you want to try and make a rational arguement you can debate whether the IPCC believes the UHI effect is negligible. But, since the author never said that the IPCC denies the existence of UHIs, it is not constructve to claim that he did. The author is arguing that the UHI effect is greater than the IPCC claims. Debate that, and then we’ll have something to discuss.

  25. Interesting, a little pack of Al Gore zombies that suddenly converged here. Time after time they have to shout down any challenges to their cash cow of global warming.

    Here are my thoughts about the science:
    A few years ago, I drove out of my town and watched a thermometer. I saw similar data.

    At 60 mph, I’d be very surprised if any car body temperature affected the air temperature readings.

    Who wants to set up a site like to document this effect?

    First, let me say: good work. Impressive.

    You are measuring over an asphalt road. You probably should measure an open field at the end of the run out of the city to see if there is an asphalt heat effect form the road in the country.

    Perhaps one should drive all major roads away from all of the weather stations. Some will go though the city center and some will go directly towards rural. All will add to the data.

    If someone decides to do this on a national scale, how do you do it this using CHEAP instrumentation? (Some new cars have thermometers.)

    Or, maybe, we just need to collect all of those area temperatures that TV news provides every day?


  26. TCO, let’s put it simply: The conclusion of the runaway AGW proponents depends upon A, B, C, D, and E. A depends in turn upon F and G. The challenge here is to G – no, it doesn’t disprove anything. It doesn’t disprove the runaway AGW hypothesis. BUT it does poke a big hole in the assumptions that produced that hypothesis, in this case, that the UHI effect is negligible. (This is important because virtually all historic surface temperature readings have been situated in urban environments, particularly outside the United States.)

    Does it prove that the data record is bad? No. But it does indicate some serious potential faults, and provides a reason for further study. It is, in essence, evidence for the claim that the science is not settled.

    The skeptic questions the conclusion – skepticism is not arriving at another conclusion by the way.

  27. Adrian: The existence of large UHIs is NOT CONTESTED. So how does demonstrating that they exist contribute to the examination of the trend lines? It’s already accepted by your opponents that they exist. The question is if their changes over time have affected the overall record: to what extent has the factor changed with time and how well are time trends adjusted to deal with this. One can easily imagine that the UHIs are NOT being adequately adjusted for, but you have to look at that aspect. Just showing that they exist does nothing, because our opponents ALREADY agree that they exist.


    I mean this is child-like!!!

  28. TCO – the IPCC refers to the effect of UHI as negligible. The demonstration is not that they exist – can’t YOU get THAT – but that they are significant. Yes, the argument is precisely that the UHIs aren’t being adequately adjusted for – the opposition calls them negligible, and given that the UHI measured in this case is larger than the total change in temperature over the past century, I think we can agree they are anything but.

    That is, the noise of the UHI is MUCH larger than the perceived signal of AGW. It’s not the only noise that is being put forward as a problem, but it’s one for which the evidence is readily presentable.

    And the significant part of the efforts being discussed here are the examination of local CHANGES – that is, things which make differences to the trend, which obviously are not being well handled. For example, the measuring station being discussed in the other thread I’m arguing with you in. That’s sort of the point of Watts’ efforts – to show that the measuring stations, however well they may have originally been positioned, have with time been developed around, leading to a TREND of greater UHI noise.

    And coming from the least polite individual on the forum, I can’t take the accusation of child-like behavior seriously.

  29. Well all that was done in this exercise was to show existence! You need to actually do some math, look at the whole network, look at the corrections, look at the nightlights, all that crap to make a call as to whether IPCC or GISS is citing a too high number because of UHI growth. I honestly don’t know if they are or not. I have to see numbers and such to tell the difference.

    P.s. I was just reading how the brighter someone was on a subject, the more likely he was to have a low certitude on an issue. And the less knowledgeable, the more certain and convinced of his foundation for said certainty. Listen to Rumsfeld…appreciate the philosophy of uncertainty.

  30. Hey, everyone; sorry to intrude on your verbal bar-brawl, but I have a question, for warming skeptics and true believers, alike:

    As I see it, there are three ways to pooh-pooh the heat-island effect which may be adopted. You can either say…

    (a.) Heat island effect has no possibility of affecting the warming conclusions of IPCC, no matter how big it is;

    (b.) Heat islands would change the conclusions of IPCC if it were big enough, but it has been measured, and it actually isn’t that big, so the conclusions are left unchanged;

    (c.) Heat island effect was big enough to influence the IPCC data, but the IPCC data has used some method of adjusting the data to “correct” for its influence, which was sufficient to prevent it from skewing the results.

    Now, it seems to me that one really can’t argue (a.), and IPCC doesn’t even try to. The quote given by Morganovich, above (Fourth Assessment Report from the IPCC, 2007, p.244) states, “…any urban-related trend is an order of magnitude smaller than decadal and longer time-scale trends….Thus, the global land warming trend discussed is very unlikely to be influenced significantly by increasing urbanisation.” In short: If the urban heat island effect were big enough, it would make a difference, but it’s “an order of magnitude” too small.

    So, IPCC is arguing (b.), right?

    Well, apparently not: To quote another post above: “The IPCC says that UHIs are adjusted for and their impact is small. We’re not sure about that. They say that they adjust for it (and I’m sure they do try), we’re just not sure that they’re doing it right.”

    Okay, that sounds like option (c.): “The effect is there, it’s big enough to make a difference, but we’ve corrected for it.”

    Which is it, (b.) or (c.)? Does IPCC correct for the heat-island effect, or just dismiss it as being too small to bother with?

    If IPCC is actively adjusting for the effect, then they must have measured the effect in order to determine by how much to adjust, right? So, what was their methodology to measure it? Was it a better methodology than Climate Skeptic’s little field trip described above?

    Thanks for any clarification you folks can give.

  31. I think their take is c, albiet your division into b and c is mildly confusing (partly me being tired).

    To further complicate things: One of the points that the IPCC comment is trying to address is that they AGREE with skeptics that the impact of UHI growth is more likely to overstate temp in aggregate than to reflect total temp increase due to changed land use. Let me explain that.* If you could TRULY measure the temp at every point over land (and water) and integrate them, then the issue of UHI growth would be irrelevant. That is because land use itself is a cause of global warming. Pave the planet and it will warm. Everyone, warmer and skeptic agrees. But the issue is that only a very small portion of the planet is currently paved or increasingly being paved. Most of it really isn’t. However temp instruments tend to be concentrated more towards areas where paving is going on (or exists already). So the potential problem is that localized paving could be falsely inflating the temps of the network imputed to be over all land (note that UHI has no appreciable impact on water temps).

    There are various ways of dealing with this problem: essentially they mostly boil down to trying to use the parts of the network that are constantly rural (either by correction to all records, or just by using only rural records). In theory, what’s really needed is to avoid records that are urbanIZING. However, that’s not how they do it. One can easily imagine that this might be done properly or improperly. One has to dig into the details to see if the methods make sense. There are some interesting things for instance, like JohnV’s charts where he shows similar temp patterns with all “best in class” stations as with the whole network. But bottom line, you have to dig into the details to make a call. Sorry Meyer, going with the ED’s day one hypothesis is not good enough. You actually have to think this one through.

    *sheesh, I feel like GAvin or something but I’m not. I’m a right to bear arms Republican…although pretty sick of Bush who is a Democrat when it comes to domestic policy. Rather have a Clinton in there and just have Congress stall than the crap…but I divert.

  32. TCO, I think you’re more clear when you’re tired.

    Look at the experiment being described here as one item in two sets. The further experiments of this set should be to continue measuring the UHI effect of large cities, or even just Phoenix – the second set of experiments would be to measure the UHI effect of cities of approximate size to Phoenix at various points in time. This experiment demonstrates a non-negligible UHI effect, making the paired set of experiments worth doing, to establish exactly how much of the warming in Phoenix over the past, say, half century, have been due to urbanization.

    Building materials have changed over the past half-century, so it’s not going to be perfect, but we can get an idea. The population of the Phoenix area is ~4 million; I’ve found figures ranging from 100k to 270k in 1950 for the city itself (figures for the general area are harder to locate), but let’s assume, say, 400k for the same geographic area. The next step would be for a reader who lives in a similar-environment and isolated 400k city to engage in the same experiment on a day with roughly similar temperatures (since UHI won’t be linear with respect to “natural” temperature increases), and to take the difference, to find out approximately how much change the UHI effect has had in Phoenix, at least, over the past half century.

    Anyone here live in a city whose general area houses ~400k people, with a roughly similar environment to Phoenix? New Mexico, Nevada, Arizona, and possibly Utah seem like likely states.

  33. I fucking GET that this experiment shows evidence on point A. But point A is agreed to by both sides. Shit man, pull the dick out of your brain.

  34. I’m almost physically sick with the butt-ass stupidity here.

    There are so many important things to be done. Problems to be solved. Experiments to run. Analyses to do. And we end up having to explain and re-explain the most idiotic points like this. If this is skepticism, it needs a fucking enema. It needs soapy water rammed up its ass.

  35. Is the ‘climate skeptic’ aware that his ‘update 2’ is pure fiction? As is very well documented, urban sites showing a different trend to nearby rural sites are corrected to match the rural trend. Why does he think it’s the other way around?

    BillBodell – Don’t you think it’s a bit strange to appoint yourself as the interpreter of what the ‘climate skeptic’ is saying? Why do you think you know exactly what he means, when he himself refuses to clarify? If you think that somehow the difference between ‘non-existent’ and ‘negligible’ is important then I’m not much impressed at all. It’s clear that the ‘climate skeptic’ has not read the many published papers on how GISS derives their surface temperature record. It’s also very clear that he really does believe that he has shown something new and hasn’t realised (although it has been pointed out to him) that Phoenix is a textbook example of an urban heat island. Why does he think he is ‘disproving’ the IPCC?

    R.C. – you seem to think that the IPCC carries out scientific research. It does not. It describes the results of the scientific research carried out in the field of climate science regarding anthropogenic global warming. To find out which of your suppositions about urban heat islands is closest to the truth, try reading the literature. Don’t rely on wilfully ignorant ‘climate skeptics’ to inform you – you might as well ask an Arsenal fan to commentate on a Tottenham game and expect to get an unbiased description.

  36. Everyone knows that greenhouse gas concentrations increase at about 1% per year.

    Although the exact sensitivity of global temperature to greehouse gasses is in dispute, it seems prudent to worry a bit over a phenomenon that is growing at 1% per year.

    Consider then that in the US asphalt production is growing at 2% per year.

    What is the effect of all this asphalt? No one denies that a blacktop parking lot has a surface temperature higher than a grass field. There is twice as much asphalt around today’s temperature sensors as there was just a few years ago. When I look at Anthony Watts’ pictures I don’t see a lot of dirt roads.

    Asphalt grows at twice the rate of CO2. Surface temperature sensors are increasingly likely to be mounted near asphalt. Even without this experiment or any other study, we should expect surface thermometers to show higher temperatures today than they did in the past.

    the Urban Heat Island effect is prima facie plausible. Furthermore it can be directly experienced by almost anyone who drives into a city or just looks at a TV weather report. What is surprising is that the UN’s IPPC has seemed to discount and minimalize UHI as an explanation for warming measurement trends.

    The IPPC argues that adjusting for the small UHI effect is easy and they say they have already done so. Yet those who have looked closely at those adjustments are not encouraged. The adjusters don’t keep very good records. In many cases their adjustments seem to be arbitrary and ad hoc. There is also a suspicion that the record has been “adjusted” to promote a warming agenda.

    It is in the best spirit of science and freedom of inquiry to test the opinions of politiical authority. This kid is lucky to have a dad who encourages him to think for himself and test his ideas.

  37. I think that several of you, in the heat of calling each other names, have forgotten one very important point. Not global warming, climate change or any of the science of adjustments, but the very simple fact that this whole effort was a schoolboy’s science project. It may or may not have been suggested by his father, who, incidentally, has obviously gone a long way in helping his son, and as such, should be judged. School science projects are emphatically not Nobel prize candidates and are very often quite simple in form, design and objective and certainly not ground-breaking, nor are they expected to be.
    So, just this once, leave off the mud-slinging, behave yourselves like gentlemen and apologise to the young man concerned for your behaviour. If you really want to act like… don’t know, can’t think of a descriptive word at the moment, but anyway go to some of the serious rough and tumble blogs.

  38. R.C.

    The answer is C.

    Hansen at NASA (GISS) is responsible for putting out one of the two primary versions of the Surface Temperature record (the other is HADCru). He most definitely believes that there is such a thing as Urban Heat Islands. He adjusts the historical temperature to account for UHIs. What’s his method? He describes it in several places. Is this method accurate? Could it be better? What does his program actually do? These are all good questions. Hansen is not cooperating with efforts to address these questions. He was forced in September 2007 into releasing his code. There is a major effort underway at ClimateAudit to dig into this matter. If you want to know more, give it a visit.


    It is the policy of this blog’s author not to respond in the comment threads. I’m not sure that’s a good policy, but that’s what it is. How do I know? I read it on the blog. The difference between non-existent and negligible is significant. Non-existent means it DOESN”T EXIST. Negligible means that IT DOES EXIST, but has little effect. If you want to argue about how much effect UHIs have on the surface temp record or argue that the IPCC believes the effect of UHIs are more than negligible, then we’ll have something to discuss.

  39. Even if I agreed with “TCO” (I don’t even understand most of what it says), I would still make this request:

    Please ban “TCO” and its morphs for foul language. We want children to read this stuff.

  40. Sigh. We get rid of RW, and this “Scientist” individual appears following the exact same argument pattern – claim the post said something it didn’t, then argue with everyone about the meaning of the word “is.” Scientist, your pseudonym is laughable, and your argumentative technique makes your side look ridiculous.

    And I think TCO has a good idea, basically, but his approach is acidic and therefore renders the effort useless. TCO, if you want people to listen to you, be polite and reasonable, and offer constructive criticism, rather than swearing wildly and making sullen comments about other people’s uselessness.

    The only use of acidity is to make somebody angry, which can on occasion be a useful approach – angry people tend to abandon facades of rationality, but only if they were only pretending at rationality to begin with; switching to rational modes of argument will then completely throw them off. (RW is a good case in point, as I utilized exactly that technique on him.) When arguing with rational people, it accomplishes little except to make you look bad.

  41. If I recall, there was a couple of papers by some scientist named Parker who tried to prove that UHI does not exist.

    I just Googled UHI and Parker together and found this story on Real Climate –

    “There are quite a few reasons to believe that the surface temperature record – which shows a warming of approximately 0.6°-0.8°C over the last century (depending on precisely how the warming trend is defined) – is essentially uncontaminated by the effects of urban growth and the Urban Heat Island (UHI) effect.”

    Seems like the RC scientists don’t think it exists, yet here we have a student who can measure it. Maybe they never leave the office up there at RC.

    Funny how stuff works out sometimes. No need to spread foul language, just give the kid an atta-boy and move along there TCO person.

    TCO? What does that mean? Talking Completely Obtusely maybe?

  42. Adirian – you must not be fully understanding the claims made by the ‘climate skeptic’. He thinks that by measuring an urban heat island effect, he has proved the IPCC wrong. The experiment carried out only shows things which have been known for decades. And remember, the claim was that this would ‘contribute something to science’.

    The lack of ability of most people commenting here to understand the difference between the statements ‘urban heat islands do not exist’ and ‘urban heat islands do not bias the temperature record’ makes them all look ridiculous. And with your infantile talk of ‘sides’ I think you look rather ridiculous as well. Do you define your views according to which ‘side’ you see yourself as belonging to? Which ‘side’ do you think I am on? What are the ‘sides’? How many ‘sides’ are there?

    BillBodell – I can see that you are aware of the difference between the existence of urban heat islands and their effect on the surface temperature record. I think you can see that an experiment which shows that they exist says absolutely nothing about their effect on the temperature record. But the ‘climate skeptic’ cannot see that; how can you think that he can if you read what he says? For example: The IPCC claims that the urban heat island effect has a negligible impact, even on surface temperature stations located within urban areas. After seeing our data, this claim will be very hard to believe.


    Even if you compare the “best” temperature stations with the most contaminated ones you’ll get very small differences in averages. And also note this:

    “Since NASA uses satellite photos to remove stations that are near bright lights I will try and figure out which of these stations (if any) are a part of NASA’s official temperature record.”


  44. Speaking as a real scientists with the real degrees and all, and as a bit of a scientific method expert. I have to say wonderful work. People like morganovich are either entirely clueless about what science is or are pulling your leg.

  45. Want to know how stable these temps are for determining min/max? Let’s do some science, a little experiment.

    How about measurements in Phoenix at the same time spanning 9 F ? There’s your science buddy.

    Sunnyslope (KAZSCOTT10) for yesterday:
    44.8 F 85% y ~7 PM
    73.2 F 34% ~ 3 PM
    59 F

    Woopdeedo. What’s that tell us?

    Personal Weather Stations in Arizona.

Comments are closed.