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Richard Tol on UHI

May 30, 2017
tags:

By Paul Homewood

 

h/t AC Osborn

 

Richard Tol has a new paper out about urban warming:

 

 

image

The effects of global warming on cities could be reduced by painting roofs white, a study suggests.

Planting trees, and replacing dark coloured roads and pavements in towns and cities would lower the temperature in towns and and cities by as much as 2°C.

Switching building materials and increasing the amount of plants in our cities could significantly cool them down – making them more pleasant places to be if the earth starts overheating, the study claims.

The effects of global warming on cities could be reduced by painting roofs white, a study suggests. Planting trees, and replacing dark coloured roads and pavements in towns and cities would lower the temperature in towns and and cities by as much as 2°C  

The effects of global warming on cities could be reduced by painting roofs white, a study suggests. Planting trees, and replacing dark coloured roads and pavements in towns and cities would lower the temperature in towns and and cities by as much as 2C.

  

The authors of the study, published in Nature Climate change said towns and cities will bear the brunt of global warming, because they are much hotter than the surrounding countryside or sea.

This is because of the ‘urban heat island effect’ – dark, hard surfaces such as black tarmac soak up heat, making the area hotter, while white and lighter coloured ones reflect it away, so less heat is absorbed.

But because cities generate vastly more wealth than the countryside, the impact of global warming will be much more significant unless measures are taken such as greening cities and using surfaces that reflect away heat and light. 

http://www.dailymail.co.uk/sciencetech/article-4551986/Cities-paint-building-roofs-WHITE.html

There is nothing new in any of this of course. But what is interesting is this comment:

In the journal Nature Climate Change, the researchers, from Sussex University, Mexico and The Netherlands, wrote: “Between 1950 and 2015, 27 per cent of cities and 65 per cent of the urban population warmed more than the world average (about 0.6C).

“Moreover, during this period, about 60 per cent of the urban population experienced warming twice as large as the world.

 

In other words, not only is the UHI effect real, it has been increasing since 1950.

Urban and Intermediate stations dominate the GHCN, and there are less rural stations than there were a few decades ago.

It has also been found that most rural stations tend to have short/broken records.

 

xGHCN_urban_ratio

http://oprj.net/articles/climate-science/34

Berkeley Earth come to similar conclusions, finding that 27% of the Global Historical Climatology Network Monthly stations are located in cities with a population greater than 50000.

Given the domination of urban records, how confident can we be that the effect of UHI is being properly accounted for?

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24 Comments
  1. May 30, 2017 7:30 pm

    No doubt that the urban heat island effect is in play in downtown Los Angeles. Curious, following a piece in the LAT’s on the subject of cooling LA as presented here (but seemingly shrilling that the main culprit was climate change (I suspect they mean man-made) and their presentation of how many more days of extreme heat during the summer months would be experienced by certain future time frames, I took a look at the standing records for Los Angeles – for June – August. Interestingly, 25 of the high temperature records still standing are from the late 1800’s – that’s out of 92 days – 27% of them. Records have been kept since 1877, so those 25 days of records, only represent 18% of years in the record. Still standing strong.

    More to my point. There would have been no urban heat island effect in the 1800’s in downtown Los Angeles; so in order to tie those records today, with easily 4-6 F on the table because of the effect during our summer months here, would not the measured temps today have to come in 4-6 degrees warmer than the established records?

    For example, to break the record of 106, set on Aug 19, 1885, would not we’d have to hit, say 110-112, just to tie it? And, another one to break it. That 106 is still the record high for the entire month of August, BTW.

    Should not the temps be adjusted to accommodate what is given as a scientific understanding, even by the EPA?

  2. tom0mason permalink
    May 30, 2017 9:09 pm

    This sound like a rehash of John Holdren’s pet theory that excessive power usage in big cities would eventually overheat the world.
    .

    Roy Spencer covered the subject in https://www.drroyspencer.com/2014/01/john-holdren-pseudoscience-czar-predicted-waste-heat-would-doom-humanity/

    Holdren co-authored a book chapter with Paul Ehrlich (the honorary Failed Forecast Czar) back in 1971 entitled Overpopulation and the Potential for Ecocide. In that chapter, they forecast both a human-caused ice age and human-caused warming, with the latter being the biggest threat.

    What is astounding from a science perspective is that Holdren blamed warming on waste heat, the result of humans and their energy use, rather than a slowly increasing greenhouse effect. He predicted that the localized nature of this waste heat would eventually spread to be a global problem.

    But a little research and few minutes of math (which I assume Holdren learned at some point) would have revealed that humanity’s waste heat generation is, from a global perspective, trivial…

    Are the urban temperature records adjusted just as much as all others?
    Surely even through we now have more devices using more power overall power consumption (within cities) may be rising but waste heat is probably not rising as fast.

    So is Tol just hyping-up the UHI effect in order to justify CO2 restrictions on burning fuel?
    If so is he fully cognizant of the facts, or is he just a stooge for Malthusians like Holdren and Ehrlich?
    Or maybe it is all true, and the city dwellers be cooked faster in the summer.

    • May 30, 2017 9:18 pm

      The waste heat thing is interesting, Tom

      HH Lamb wrote in the 1970s how this was seen to be a problem at the time as well

    • tom0mason permalink
      May 30, 2017 9:30 pm

      Grrr…

      No proof-reading skill, no matter how long I take to write it.

      Remove —
      “Surely even through we now have more devices using more power overall power…” with

      Insert —
      Modern devices are becoming more power efficient. So even though now we have more devices using more power, overall power consumption (within cities) may be rising but waste heat is probably not rising as fast.

      Remove —
      “…and the city dwellers be cooked faster in the summer.”

      Insert —
      and the city dwellers will be cooked faster in the summer.

      There are probably more I’ve missed. 😦

    • dennisambler permalink
      May 31, 2017 10:05 am

      Richard Tol is an economist and IPCC author and on that basis, assumed to be a climate scientist.

      • May 31, 2017 11:20 am

        Wait just a minute. Did not that unimpeachable source, Th e Washington Post, in their recent rant denigrate our very own Paul Homewood as “an accountant?” Paul, you just became a “climate scientist.”

      • Jack Broughton permalink
        June 2, 2017 11:31 am

        Note to Joan, IMHO Paul is actually a leading climate scientist: he has actually read HH Lamb, whose knowledge shows the present lot of modellers as primitives. Climate science = knowledge of the climate, not being a rogue programmer.

  3. May 30, 2017 9:21 pm

    I used to fly into Panama City on business. As we flew over i noticed that all of the roofs were made of black or dark coloured asbestos type materials. In the office, it was very hot, but the a/c took good care of that, except the a/c was working flat out all of the time, and failures where commonplace. When there was a power outage when it quickly reverted to external ambient, AKA “hot and humid as hell”. I talked the staff of our office about painting their roof white. No one believed me when i told them about the reflectivity of white. OK they knew about that, but didn’t see why that would make it cooler. In the end I made such a nuisance of myself that they agreed to do it. On my next visit the splendid white roof of our office stood out like a sore thumb. Inside the office the difference was immediately apparent. It was cool and the a/c units where operating at reduced outputs. The human atmosphere in the office was transformed. People I’d never spoken to, just a brief nod going in and out, came over to me and shook my hand. Why? For improving their work environment. My office management where ever the top. They had a new problem, which was explaining to managers of adjacent offices what they had done. In fact I had to meet them and give an impromptu lecture on thermal insulation and it’s cost benefits.

  4. May 30, 2017 9:28 pm

    (continued) …as time went on, in my arrivals noticed that more and more Panama roofs where becoming white!
    Now of course, it’s normal.
    So I was responsible for turning Panama’s roofs from dark to white, with huge economic savings for the community.
    This was in the days of the fascist dictator Noriega, who used to have a patriotic anthem played on loudspeakers all over the city, and all traffic had to stop, switch off engines, and listen to it patriotically. I know this since I’ve sat in many a stationary taxi at midday in Panama City. Oh this good ole days!

    • May 31, 2017 11:55 am

      Congratulations. Air-con is now commonplace even in the UK, rather than open the windows and use fans the windows are closed and the air-con goes on. I ended up wearing a sweater on hot days at work in a shared office, because there was always someone who wanted what to me was an uncomfortably low temperature.

  5. Graeme No.3 permalink
    May 30, 2017 10:28 pm

    The old black arabs v white arabs problem springs to mind. Back in the days when scientists made measurements not computer models, the question came up as to why some arab tribes wore white and other black.
    Neither set seemed to be dying like flies so the intrepid scientists inserted thermometers beneath the robes, along with making surface measurements. It came out to the black robes absorbing more heat but radiating more as well. then someone pointed out that the robes were thick enough to be insulating, and that air circulation was more important.

    I worked for a firm which had 2 tanks (containing the same water based paint) installed where they received solar heating from early morning until early afternoon. In the west of Sydney where it gets hotter than the (ocean influenced) city. They painted one tank white, and the other white but with a small percentage of hollow ceramic spheres, which added some insulation. This reduced the temperature of the contents by 0.5-1.0℃. I believe this idea is in use by those selling “paint that cool”.

  6. Gerry, England permalink
    May 30, 2017 10:29 pm

    It is a shame to see Richard Tol involved in this sort of rubbish but then he does believe in global warming despite shredding Stern’s report. From reading The Deniers, Tol is one of those who is happy to point out when rubbish is published in their field but believes that those in other fields are competent and honest.

  7. Athelstan permalink
    May 31, 2017 6:55 am

    Mr. Ross McKitrick wrote the best, a definitive deconstruction of T data sets, imho. I’ll synopsize, GHCN figures aren’t worth spit.

    The number of weather stations providing data to GHCN plunged in 1990 and again in 2005. The sample size has fallen by over 75% from its peak in the early 1970s, and is now smaller than at any time since 1919. The collapse in sample size has increased the relative fraction of data coming from airports to about 50 percent (up from about 30 percent in the 1970s). It has also reduced the average latitude of source data and removed relatively more high-altitude monitoring sites.

    It’s a very good read, PDF in detail here.

    After reading that, it is difficult to set store in aught the alarmists utter, not that I ever believed their warmist man made blurb – in the first place. Indeed, it always was [man made CO2 = runaway warming] a crock, a poltically inspired myth, it goes something like this; “just lend us your ears and all that you own and tomorrow will be a brighter day + don’t forget the children – we promise blah, blah, cake tomorrow blah, blah, blah…………..!”

    The Wet office are so very fond of quoting Temperature measurements from just beside Heathrow airport runway and are fond of the refrain “It’ll be warmer in the cities and towns”……………..

    no s**t?

    • May 31, 2017 11:27 am

      I believe it was Ross McKitrick along with Steve McIntyre who broke open the little “Climategate” escapade at UEA.

      • Athelstan permalink
        May 31, 2017 11:47 am

        The very same.

  8. 2hmp permalink
    May 31, 2017 11:00 am

    OK, but in winter more fuel will be used for heating. So the the net balance is what matters.

  9. Jack Broughton permalink
    May 31, 2017 12:01 pm

    The effect of white coating is a well-known effect resulting from simple use of the Stefan Bolzmann laws.
    However, is not the important matter here that the UHI effect is causing present temperature measurements to be over-estimated relative to historical values? This means that the corrections, so beloved by NOAA etc. are in the wrong direction. Correction downwards of ”recently” measured data would seem to be justified, rather than reduction in historical data. This looks like a double whammy of errors to me.
    Incidentally, the 2 deg K warming in towns is a good rule of thumb, I have often observed this rise when travelling through the (surprisingly accurate) thermometer in my car. It also applies on busy motorways.

  10. CheshireRed permalink
    May 31, 2017 12:12 pm

    Don’t the IPCC add a pathetic amount to global temps to allow for UHI? They can’t have it both ways, either there’s no impact (which we know is not correct) or there is, in which case it should be properly allowed for. Any sort of uplift to allow for UHI would taint the already dubious data.

    PS Reports say Trump is withdrawing from Paris.

  11. Jack Broughton permalink
    May 31, 2017 1:05 pm

    Is not the important matter here that the UHI effect is causing present temperature measurements to be over-estimated relative to historical values? This means that the corrections, so beloved by NOAA etc. are in the wrong direction. Correction downwards of ”recently” measured data would seem to be justified, rather than reduction in historical data. This looks like a double whammy of errors to me.

  12. May 31, 2017 1:44 pm

    ” …………… global warming on cities could be reduced by painting roofs white …….”

    Would white tarmac help?

  13. John Peter permalink
    May 31, 2017 4:13 pm

    I am confounded. Looks to me as if the number of fully urban stations have greatly decreased. Maybe it is the heat today getting to me.

  14. JasG permalink
    June 1, 2017 4:10 am

    The minimal observed extra warmth comes from Winters getting less cold. Summer temps are the same. Ergo painting your roof white makes sod all difference.

  15. June 1, 2017 5:17 pm

    Much of what is said about the urban heat island effect reflects a misunderstanding of its effect.

    Essentially, the climatological significance of the UHI effect is that it heats the meteorological instruments that climatologists use. And the effects are becoming worse over time as the number of weather stations declines, by closing of rural stations, and the expansion of cities, which makes rural and semi-rural weather station sites more urban.

    So the small rise in urban temperature is not itself especially relevant to global temperature.

    What is relevant is that the data that is collected give a distorted picture of global temperature change.

    We know that climate has changed since the Little Ice Age, but about half the increase in temperature occurred before 1950. Since 1950, climate has fluctuated up and down. Temperature dropped from about 1960 to 1970. The 20 years between about 1975 to 1995 saw global temperature rise back to the levels reached early in the 20th century.

    Not much change in global temperature has occurred since 1995, apart from super El Ninos and almost equally, super La Ninas.

    So, apart from data contamination caused by the UHI effect, there were 20 years since 1950 with a measurable rise in temperature (1975-1995).

    That’s what we are expected to be alarmed about, 20 years of warming that ended more than 20 years ago.

    The alarm is based on an extraordinary delusion and the madness of crowds.

  16. Bartemis permalink
    June 3, 2017 12:43 am

    The downside is it would cool you in winter, too.

    What would be really nice would be some kind of coating that was temperature sensitive, so it would turn pale with warmth, and dark with cold.

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