The Megacities Are Cooking

Guest Post by Willis Eschenbach

[OK, had to start over, had bad numbers for the areas. Graphics have been replaced. I was using “core area” but I should have been using “greater metropolitan area”. All conclusions are unchanged.]

I got to thinking about the phenomenon known as the “Urban Heat Island” effect, or UHI. Cities tend to trap heat due to the amount of black pavement and concrete sidewalks, the narrow canyons between buildings that slow down the wind, and the sides of the buildings reflecting sunlight downwards.

As a result, cities are often warmer than the surrounding countryside. In some cities, it’s hot enough that it affects the local weather. Here’s a simplified diagram:

Figure 1. A simple sketch of typical increases in temperature due to the Urban Heat Island effect.

What I was curious about, however, was another kind of urban heat effect. This is the heat from all of the energy used within the city—electricity, fuel for transport, fuel for heating buildings, all of it. Eventually, almost all energy ends up as heat. So I went and got the energy usage for 27 huge “megacities”, along with the area of the city itself. I then combined the two to give me a measure of citywide energy usage in watts per square metre (W/m2). As a measure for comparison with Figure 2 below, a doubling of CO2 is said to increase the “forcing”, the total radiant energy impinging on the surface, by 3.7 W/m2.

Figure 2. Additional forcing from direct energy use. The energy data is paywalled. The link is to SciHub’s copy of the paper. It may have a “CAPTCHA” that asks you in Russian to type in a word to prove you’re actually a humanoid. Just type it in, it’s not Putin in disguise.

This was surprising to me. I hadn’t expected the effect to be so large.

Finally, I converted the forcing to an equivalent warming. The Intergovernmental Panel on Climate Change (IPCC) fifth assessment report, completed in 2014, gave a likely “Transient Climate Response” of about 1°C to 2.5°C for each additional 3.7 W/m2 of forcing. I’ve used 1.5°C because the heat generation persists over time. As a result, the cities have had time to equilibrate to the additional heating. Figure 3 shows that result.

Figure 3. Nominal warming from the additional forcing due to direct energy use. Colors indicate that I don’t like boring graphs.

Not much more to say about all of that. Note that this is a “first cut” analysis, I make no overarching claims about the accuracy of the results. I’ve used conservative assumptions and the best data I could find. It looks to be a significant additional heating source due to direct energy usage in the densest of the largest cities, one that is not generally included in the calculations of the Urban Heat Island.


Here, I’m in the Forest Cool Island, life is good. I spent my morning crawling around under my house successfully putting a new “generator” into my floor furnace so we now have a warm house again, a less than pleasant job that came complete with a veritable plethora of bad words. Then I got out the pumice stone and scrubbed a toilet bowl until it sparkled, and this has been my afternoon project … do I know how to have fun, or what?

My very best wishes to each of you,

w.

[UPDATE] In the comments below, someone asked about human body heat and how that affects the forcing in megacities. Humans on average put out on the order of 120 watts continuously. Here’s how that plays out.

Figure 4. Additional forcing from the heat emitted 24/7 by the human body.

You can see how densely populated Seoul, South Korea is …

DATA: I’ve appended the data below, in comma-delimited form. PJ is petajoules, 10^15 joules.

City,                PJ,    km2,Population
Beijing,            952,   6562,  21516000
Buenos Aires,       702,  10888,   3054000
Cairo,              282,   1600,  10230000
Delhi,              316,   3182,  11034000
Dhaka,              350,   1353,   8906000
Guangzhou,         1474,   7711,  14043000
Istanbul,           464,   5500,  14025000
Jakarta,            589,   5100,  10075000
Karachi,            339,   1100,  14910000
Kolkata,             78,   1785,   4486000
Lagos,              350,   1535,    861000
London,            1065,  11391,   8825000
Los Angeles,       1848,  10780,   3884000
Manila,             918,   2521,   1780000
Mexico City,       1099,   7346,   9041000
Moscow,            1984,  14925,  12197000
Mumbai,             191,   2350,  12478000
New York,          2824,  17884,   8622000
Osaka,             1258,   6930,   2691000
Paris,              657,  17174,   2229000
Rio De Janeiro,     384,   4540,   6718000
Sao Paulo,          589,   8479,  12252000
Seoul,             1848,   5076,  10197000
Shanghai,          1644,   5177,  24256000
Shenzhen,           350,   3051,   8378000
Tehran,            1145,   9500,   8154000
Tokyo,             2438,   8014,  13839000

204 thoughts on “The Megacities Are Cooking

  1. Yeah, they’re currently trying to sell us that ‘urban living ‘ is better for the environment, while they destroy the suburbs and rural-areas.

    • We’re dealing with Agenda 21 in my city. They desperately want to tear down iconic structures built 50 years ago that will last for centuries if maintained so that they can be replaced with “sustainable development”. It’s all just intended to bankrupt cities and force more and more people into the communist -style apartments through ever increasing property taxes.

      • I feel ya’. I live in for-God’s-sake Portland Oregon. We’re about to have another fight over forcing Cap and Trade on us – trying to sneak it in real quick after the new year.

        The Oregon legislature has nothing but screw citizens over with every move they made in recent memory.

        But hey, they legalized weed, so that’s enough for the brain dead morons that keep voting them in.

  2. It’s a strange coincidence that you posted this today. For the last couple days I’ve been pondering whether all of the heat that is released in the usage of energy/fuel has any impact on temperature and, if so. how much.

      • I am never forget the day I first meet the great Lobachevsky
        In one word he told me secret of success in mathematics:
        Plagiarize

        Plagiarize!
        Let no one else’s work evade your eyes
        Remember why the good Lord made your eyes
        So don’t shade your eyes
        But plagiarize, plagiarize, plagiarize
        Only be sure always to call it please “research”

        —Tom Lehrer

          • That story appears to be a confabulation or a conscious lie by Lehrer. It’s unreliable at best and is sourced in personal envy one presumes.
            Even the NYT appears to admit this. Best not to spread fictional slanders like this, though I am happy to stand corrected:

            https://www.nytimes.com/2002/03/09/books/connections-plagiarism-that-doesn-t-add-up.html

            “Mr. Lehrer imagined an unscrupulous acolyte following in Lobachevsky’s footsteps* by writing a math book in which every chapter is stolen from somewhere else and the index is copied from an ”old Vladivostok telephone directory.”

            ”Plagiarize, plagiarize, plagiarize,” Mr. Lehrer sang. ”Only be sure always to call it please — ‘research.’ ”

            *Lobachevsky was actually cleared of all wrongdoing* — similar ideas developed simultaneously in different countries — but plagiarism lives on. “

          • Michael, Lehrer was JOKING. It was merely another in the long list of people coincidentally making simultaneous discoveries.

            w.

        • Reminds me of the programmer’s credo.
          “Plagiarize like hell, claim nothing!”

          Far too many dilettante programmers plagiarize other’s programs than claim the plagiarized program code as theirs without giving credit where it is due.
          Much like Al Gore and the internet.

      • “I got out the pumice stone and scrubbed a toilet bowl until it sparkled, and this has been my afternoon project … do I know how to have fun, or what?”

        Ha ha

        I read every article with “Eschenbach” on the byline because they are consistently good.

        I didn’t get the purpose of this article.

        The first issue is that oceans cover 71% of our planet, so THOSE temperature measurements are most important.

        Repeated changes in ocean measurement methodology make those data questionable.

        And there’s a lack of Southern Hemisphere ocean coverage before WWII.

        The next step is to consider the other 29% — land surface temperature data.

        I believe cities / urban areas cover only about 3% of the land surface.

        Your article seems to focus on that 3%.

        I don’t get it.

        With only 3%, UHI, land use changes, and economic growth of urban areas could not be that important.

        The UHI effect is ignored by most surface temperature calculations, and abused by one organization.

        Of course a city is warmer than surrounding suburbs and countryside.

        But over time, with population growth, anyplace could get warmer, not only a city.

        But:
        What if an urban weather station located near buildings was moved to the middle of a large park? Negative UHI ?

        What if a city loses population — Detroit used to have two million people, and lots of manufacturing — now 675,000 people, and very little manufacturing. Negative UHI ?

        The real issue is how much does nearby economic growth & land use changes affect the warming or cooling measured by each weather station.

        And why do we need weather stations located where they WILL be affected by nearby economic growth?

        UHI affects rural weather station too:
        A rural station, over time, could gradually become a station in a village, then in a town, then in a larger town, and eventually in a city, with a century of economic growth.

        And then there are local changes to individual weather stations, such as the green weeds around a weather station being killed with RoundUp, leaving bare brown soil, changing the albedo.

        It is also a well known fact that climate alarmists park their cars right next to some accessible weather stations so their hot engine exhaust causes local warming, or maybe that was jet planes idling near airport weather stations, located between runways. I forget which.
        You just can’t trust those smarmy leftists.

        My bottom line is that surface temperature measurements are so haphazard, and non- global, with excessive infilling and “adjustments”, that they belonged in the toilet bowl in the 1990s … replaced by satellite data, that at least is close to being global, and is measured in a stable environment.

        • The actual city of Detroit lost a lot of population, but that’s mainly because people moved to the nearby suburbs where it’s generally safer (among other factors). The Metropolitan area still has millions of people, and most areas (outside of Detroit ghettos) are growing in population and development.

          I assume the UHI is now greater in the suburbs of Detroit, while most of the city itself (outside of downtown) resembles a post-apocalyptic scenario with plant-life overgrown on top of crumbling infastructure and collapsed homes.

        • “With only 3%, UHI, land use changes, and economic growth of urban areas could not be that important.”
          Question: What percentage of the thermometers are in that 3%? Are they only 3% or are they closer to 10 %?
          Clearly remember an analysis here on WUWT that shows that for the State of California alone the temperature increase is shown to be essentially, completely, due to UHI.
          I am very familiar with a weather station that was right across the fence from the parking lot for the local municipal airport 60 years ago. Back then there were only three or four commercial flights a day and about a dozen private flights. Today those numbers are orders of magnitude greater and many are small jets. Weather station is still in the same place. Its location would easily qualify for the web page showing sites that should not have weather stations. Also back then there was no AC at that airport terminal.
          The objective of weather stations should be to collect the data of the area temperature and not the temperature of the local airport, airport parking lot and HVAC exhaust]t temperature.

        • Weather stations’ primary purpose is not the production of data for climate scientists. Weather stations gain info on the local weather for those who need that info: especially pilots at airports…..just as sea level tidal gauges are most important for those who skipper boats in a harbor.

          And, people want to know how hot or cold it is so that they may plan their clothing and outdoor activities.

          So weather stations are where they belong. Scientists (or government agencies) who want non-UHI contaminated measurements can set up their own stations for that purpose.

        • While urban (or otherwise developed) areas cover only a negligible fraction of Earth’s surface, they account for the bulk of available historical data. Met stations are rarely located at pristine, undeveloped sites. Such highly unrepresentative siting is what makes UHI so pernicious when compiling regional or global averages. The sheer preponderance of UHI-corrupted data in most the world makes a travesty out of “homogenization.” Don’t drink the Mosher kool-aid!

    • Such coincidences are strange aren’t they? Nearly twenty years ago I was conversing with a Dutch colleague about this same topic — our other colleagues couldn’t believe we were worrying about such an insignificant factor when — CO2!. Then two nights ago I was reading an old Scientific American article where the author was worrying that with a mere 10 more doublings of energy demand (a factor of 1024!) we would be dumping a heat load onto the entire planet equivalent to solar isolation.

      • You should check the numbers. I think you are out by a factor of 10. Current global annual primary energy consumption is 5.4E20J. Annual insolation is 5.4E24J. That gives insolation 10,000 times greater than all primary energy consumption.

    • I’ve been thinking about this for years. Roy Spencer did a post on it a couple of years ago with pictures of buildings taken with an infrared camera.

  3. Willis

    Is this apples to apples since this forcing would be 24/7 and CO2 forcing would be only during daytime?

    • Don’t your figures represent perfect thermal efficiency of all energy used?

      Since a large portion of electrical loads power mechanical devices, the actual heat produced is substantially less than’ (for example) a furnace.

      • RobR January 16, 2020 at 10:40 am Edit

        Don’t your figures represent perfect thermal efficiency of all energy used?

        Since a large portion of electrical loads power mechanical devices, the actual heat produced is substantially less than’ (for example) a furnace.

        A car drives down a level road. In a perfect world, that wouldn’t take any energy once the car got going, and that energy would be recouped by regenerative braking when the car slowed down.

        But in fact, like most mechanical work, the car is operating against friction. Mechanical friction of the engine. Air friction of the car moving through the air. Rolling friction of the tires on the road. Friction of the brake pads against the brake disks.

        And although it’s generally invisible, all of that mechanical energy used to overcome friction ends up as heat. It’s most apparent in brakes—they convert mechanical energy directly into heat energy. But it’s invisible in terms of air friction—the air is warmed by the passing car, but you wouldn’t know it from observation.

        Remember, energy can’t be destroyed. All that can happen is that it changes form … and eventually, with small exceptions, at the end of the day it ends up as heat. It’s the nature of entropy.

        Regards,

        w.

        • Willis,

          The portion of energy converted to useful work equates to a devices mechanical efficiency.

          I’ve no quarrel with your thesis, I just believe that additional calculations are required. If all of the energy consumed by a blender were converted to heat, there would be no energy left to chop the ice.

          Put another way: a heater consuming the same load as a blender, will produce more heat.

          • “Put another way: a heater consuming the same load as a blender, will produce more heat.”

            Think about what would happen if you operate the blender inside one freezer and the heater inside an identical freezer. The extra energy that the freezers consume to maintain internal temperatures is likely to be the same. But the freezer containing the heater will cut in sooner because its load is promptly transferred to the air instead of being transferred to the ice.

          • It’s interesting to note how much of the mechanical “work” done in a city is only fleeting.

            Consider a bus that drives around town for 16 hours or so, taking people to work in the morning, returning them home in the evening, and parking in the same spot where it began the day. The only net “movement” is all the air molecules that got pushed out of the way along the route. Nearly all of the energy has been converted to heat.

            Elevators take people up, then back down again.

            Willis’ approximation is probably very close to accurate, and sure simplifies things.

          • RobR, what you fail to understand is that you are neglecting the fact that the energy used to stir your drink will also result in heat.

            If the watts are the same, the heat is the same. The only difference is where the heat comes out.

          • Negative Entropy delay appears to be ignored in the calculations. But perhaps over a relevant (60 years?) timeframe that becomes irrelevant as that entrpoic relaxtion will release the heat.

            So you are both right, just tempirally talking about different timeframes.

            Just musing.

          • Precisely the example I was thinking of. I’ve observed it numerous times: Commuting to work on a cold morning, frost on everything, but after only several minutes of traffic the highway is clear and dry.

        • Which Mod. deleted additional responses from Old Engineer and I.

          If WUWT. Doesn’t stand for truth, where exactly does it stand?

          My point was valid, and anyone with a basic understanding of machinery would agree.

      • RobR-

        Actually, Willis’ figures represent the opposite- zero percent efficiency- all the energy being turned into heat rejected to the atmosphere, no useful work being done. For example, most gasoline fueled, IC engine powered, cars are about 33% efficient. One third of the fuel energy is used to propel the car down the road, one third of the energy goes out the exhaust pipe, and one third goes to the radiator. Note that some of the energy used to propel the car down the road is rejected to the atmosphere when the car is brought to a stop and the brakes heat up.

        Cold fired, stream turbine powered electrical generation plants have about the same 33% efficiency, with one third of the fuel energy converted to electricity and rest going up the stack or to other heat losses.

        So Willis’ estimate of temperature maybe somewhat on the high side. But given the uncertainty in all the input data, it’s probably a good first cut.

        • Old Engineer,

          You’re correct regarding mechanical efficiency. My first post specifically mentioned thermal efficiency.

          Best,

          Rob

          • “…Therefore, the mechanical work a blender performs, will generate heat at a rate substantially less than a device designed to convert power into heat.”

            RobR: You have solved (inadvertently I guess) the conundrum for yourself. You are confusing the rate at which something happens with the end result.

        • old engineer:

          No, Willis is correct that it all ends up as “heat” (thermal energy). To take your car example, with 33% of the gasoline’s thermal energy generating useful mechanical power, so 67% directly expelled as waste heat.

          But that 33% useful mechanical power is almost immediately turned into thermal energy as well, through air friction, surface friction of the tires, and internal friction (bearings, etc.). That is why you need to expend some power at constant speed.

          The interesting issue is thermal electric generation, where the initial waste heat generated at the power plant is not co-located with the dissipation from the actual use of the electricity. I haven’t figured out what is included in the statistics Willis uses.

          Often the power plant is located outside the urban area where the electrical power is used (and dissipated into thermal energy). In this case, only the electrical power itself should be included. But if the power plant itself is inside the urban area under consideration, its waste heat should be included.

          • One of the rare examples where the energy input does not all end up as heat is endothermic reactions. For example, electrolysis. But it is rare to find aluminium smelters or chlorine plants in urban areas.

            Photosynthesis is also endothermic meaning trees are sucking energy from their environment and growing themselves with that energy.

          • Ed Bo,

            I beg to differ. A simple thermograph of a blender and a hair dryer consuming 100 watts of energy will yield vastly different results.

            A machine cannot create more energy than it consumes. Therefore, the mechanical work a blender performs, will generate heat at a rate substantially less than a device designed to convert power into heat.

          • Rob, this is very basic thermodynamics. Conservation of energy. What the heck happens to that 100 watts of mechanical power in the blender? Where does it go?

            In fact, some of the very first experiments that established the science of thermodynamics involved a “blender” of sorts, spinning a paddlewheel in a liquid, and measuring the increase in temperature of the liquid, equating the increase in thermal energy of the liquid to the mechanical energy input of the paddlewheel.

          • Ed Bo, Willis, et al.,

            I stand corrected in my previous assertions and appreciate the cordial responses.

        • old engr says:
          with one third of the fuel energy converted to electricity and rest going up the stack or to other heat losses.

          Greatest loss by far is the condenser condensing the steam to water (and that heat having to be rejected to the ambient environment) and then the necessity of re-heating it back to steam. That’s the disadvantage of using water as the working fluid (but water remains the most practical fluid).

        • Basically Willis is right, but some energy can be stored for a long time. If you drive your car to the top floor of the airport parkade, some of the chemical energy of the fuel (or the electrical energy) is converted into gravitational potential energy. If you then fly to Arutanga for a 6 month vacation, that potential energy does not get changed into heat (of your car’s brakes) for 6 months.
          If you build a very tall building, potential energy of the materials in the upper floors may be stored for centuries.
          But all of this is niggling – effectively all of the energy we consume is transformed into heat somewhere and sometime.
          But Willis is not saying that all the energy “ends up” as heat – his Figure 3 is based on the understanding that all the energy “ends up” as radiation out to space. The city is radiating energy out to space.

        • Not all of it, some can end up as entropy. In the cited example of a blender take a liquid with large pieces of a solid in it and break up the solid into very small particles. Some of that energy ends up as entropy (disorder).

        • I understand that CO2″back radiation” happens at night but is it still 3.7 w/m2 through the entire cycle, maybe true but does seem right to me.

          • Bob, The 3.7 W/m2 is not the downwelling radiation. It’s the estimated average change in downwelling LW radiation from a doubling of CO2.

            w.

          • I was thinking more along the lines of the warming effect, rather than the forcing. Enhanced greenhouse warming is more significant at night, in winter and in cold air masses because it retards cooling. Most of the rise in average daily temperatures is due to higher low temperatures, not higher high temperatures.

          • The amount of back radiation depends on the level of IR at the time.
            While this level goes up by a bit when the sun out (the ground gets hotter), the total amount of IR doesn’t change by that much on a percentage basis from day to night.

          • Like any global figure, it’s going to be specific depending on time and place. I can imagine a scenario where lower atmosphere CO2 prevents some long wave infrared radiation from reaching the ground. I envision heat reradiating off the bottom of clouds as the source.

            Clouds absorb all longwave IR radiation well (and hence are capable of emitting longwave IR well). link

            In that case presumably, the forcing due to lower atmosphere CO2 would be a negative number.

        • It could be, I have seen change as large cooling as 7 F just going 12 miles north of Pasco, to see darker skies for teaching my Daughter stars and stuff. When I come home after 11/2 hours later it warms back up 6 F. This was last November when there was a clear sky night.

          284,000 residents in the region.

          • You didn’t feel the toasty CO2 radiation in the cloudless sky? Me neither! Just because we have down-welling radiation doesn’t mean the the surface, or near-surface air warms. It doesn’t if the surface and air is already radiating at a higher equivalent temperature, i.e. warmer. The radiation just gets reflected, or you can say absorbed and re-radiated, which is the same thing.

          • @John Francis

            Put your helmet on, while you await the inevitable “but it slows the rate of cooling” argument. Which the Climate Fascists, of course, equate to “heating.”

          • And Pasco is a desert environment (though the surrounding area has been “modified” a bit by farming using irrigation and chemical fertilizers), where the supposed “effect” of CO2 should be the largest, due to the relatively smaller amount of water vapor present.

            Which tells you that the supposed “effect” of CO2 is a complete non-issue.

      • Still seems wonky to me, having something slowing heat loss vs a direct heat source doesn’t seem equal to me, but hey what do I know.

        • And CO2 has higher emissivity than air so I’m not sure how it actually “slows” heat loss.

          • Robert – Absorptivity equals emissivity for any and all wavelengths. So if CO2 “has higher emissivity than [most of the other constituents of] air”, which it does, it also has higher absorptivity.

            An atmosphere without emissive/absorptive gases would allow radiation (and the energy it carries) from the warm surface to pass directly to space. By absorbing some of that radiation before it reaches space, these gases reduce the direct flux to space. They do also emit radiation at the same wavelengths, but because the temperature is (generally) lower than the surface, the intensity is less.

        • Temperature is determined by the amount of energy in an object.
          Whether you increase the amount of energy going in, or reduce the amount of energy going out doesn’t matter. They both result in the object having more energy and hence getting hotter.

          • You need to add heat capacity to that statement. Bake a pie in your oven. Put your hand in the oven. Now put your hand in the pie. The pie burned your hand but the air in the oven did not. Why? Same temperature, but big difference in heat capacity.

        • Only someone with ZERO understanding of radiative heat transfer would write that.

          It’s not a good idea to get your science from the pink unicorn brigade at PSI. The only interesting thing there is how many different ways they get things completely wrong.

          Hint: That’s not what Wien’s Displacement Law means at all.

        • Hey Ed Bo,

          Previous comment on WUWT stated the following:

          “*I’m a professional infrared astronomer who spent his life trying to observe space through the atmosphere’s back-radiation that the environmental activists claim is caused by CO2 and guess what?* In *all the bands that are responsible for back radiation in the brightness temperatures (color temperatures) related to earth’s surface temperature (between 9 microns and 13 microns for temps of 220K to 320 K) there is no absorption or radiation by CO2 at all.* In all the bands between 9 and 9.5 there is *mild absorption by H2O,* from 9.5 to 10 microns (300 K) the atmosphere is perfectly clear *except around 9.6 is a big ozone band that the warmists never mention for some reason.* From 10 to 13 microns there is more absorption *by H2O*. Starting at *13 we get CO2 absorption but that wavelength corresponds to temperatures below even that of the south pole.* Nowhere from 9 to 13 microns do we see appreciable absorption/radiation bands of CO2. *This means the greenhouse effect is way over 95% caused by water vapor and probably less than 3% from CO2*. I would say *even ozone is more important* due to the 9.6 band, but it’s so high in the atmosphere that it probably serves more to radiate heat into space than for back-radiation to the surface. *The whole theory of a CO2 greenhouse effect is wrong*, yet the halls of academia have gone to great lengths trying to prove it with one lie and false study after another. *I’m retired so I don’t need to keep my mouth shut anymore. Kept my mouth shut for 40 years, now I will tell you, not one single IR astronomer gives a rats arse about CO2.* *Just to let you know how stupid the global warming activists are, I’ve been to the south pole 3 times and even there, where the water vapor is under 0.2 mm precipitable, it’s still the H2O that is the main concern in our field and nobody even talks about CO2 because CO2 doesn’t absorb or radiate in the portion of the spectrum corresponding with earth’s surface temps of 220 to 320 K.* Not at all. Therefore, for *Earth as a black body radiator IT’S THE WATER VAPOR STUPID and not the CO2”

          How is this in violation of Wien’s Displacement Law?

          Not hostile comment, just trying to understand, as this IR Astronomer & Macha’s comment (and other experiments i have seen) appear cohere on this.

          Apologies if it’s a silly question.

          • First, here’s the absorption with both CO2 and water. This shows what gets through the atmosphere, so notches mean absorption.

            Now, lets remove the CO2. This is just water.

            Note the lack of the notch between about 550 and 700 or so. That’s the absorption by CO2.

            Finally, here’s the absorption with no water, just CO2.

            The difference between the first one and this one is the absorption due to water.

            So … both CO2 and water are responsible for significant absorption. The bands overlap, but CO2 still absorbs.

            The astronomer is talking in terms of wavelength, while the graphs are in wavenumber. They are related as follows: wavelength = 10000/wavenumber.

            w.

          • ” IT’S THE WATER VAPOR STUPID and not the CO2””

            Yep, its right there in all those sciency papers that get ignore by the MSM when they’re quoting some low-IQ teenage “influencer” going on about how we’re all gonna die if we don’t DO SOMETHING RIGHT NOW about coal and oil and gas.

            Like, say, close down Niagara Falls? I mean, all that water vapour pouring down every second is KILLING US.

          • Michael – Macha’s assertion that “CO2 IR will only slow cooling at -80C” is just plain wrong. I see this mistake made commonly on climate blogs, and it does come from a complete misunderstanding of Wien’s Displacement Law.

            Wien’s Law states that the peak wavelength for idealized blackbody radiation is inversely proportional to the temperature of the radiating body. The equation is:

            Amax (um) = 2898 (um*K) / T (K)

            For a blackbody at 193K (-80C), the peak wavelength is 15 um, the center of gaseous CO2’s main absorption/emission band.

            But this in NO WAY means that radiation with 15 um wavelength “has a temperature” of -80C, and cannot affect anything above that temperature. Objects of many different temperatures emit 15 um radiation, and there is NO mechanism for a receiving object to discern the source of this radiation.

            Most solid and liquid objects are close to perfect blackbodies in the longwave IR range, with absorptivities/emissivities of 0.95 or so. (Polished metals are the significant exception.) They can be considered “graybodies” having almost ideal absorption and emission over a wide range of wavelengths.

            The astronomer’s comment is just plain wrong as it pertains to the relevance of CO2 absorption/emission band of ~14-16um to heat transfer. This is because he does not consider the broadband nature of thermal emission and absorption.

            For example, your body at 310K (37C) has a peak emission wavelength of 9.5 um, but its radiation intensity at 15 um is over half that of the peak. This is significant for heat transfer considerations.

            Because real substances are broadband emitters at earth ambient temperatures, they emit significant radiation in CO2’s 14-16 um absorption band. The diagrams Willis posted above show the large “bite” CO2 takes out of surface radiation. It is significant.

            Yes, water vapor (and clouds) are more significant. But the interesting question is how much difference increasing CO2 concentration, which induces a slight broadening of the 14-16 um band, makes, given all the other things going on in the atmosphere.

          • Also thanks to Ed Bo for the good explanation. Radiant utility boilers have long been necessarily designed w/the radiation-absorbing characteristics of both CO2 and H2O in mind (both which are abundant in flames & flue gas).

          • beng: I have directed the dragon slayers at PSI to good on-line engineering heat transfer textbooks regarding the nature of radiative heat transfer. Their response? Those textbooks are completely wrong!

            I have then asked them why they are wasting their time on blogs when, if they really believe that our engineers who design potentially very dangerous thermal systems have been taught completely bogus science, they should be out trying to shut down these systems to avert catastrophe…

          • Thanks heaps Willis and Ed Bo. I genuinely appreciate the time you both took to disabuse me (and no doubt others) of common misunderstandings

          • Yes Willis, I’ve posted those same graphs multiple times.

            Ed Bo January 17, 2020 at 10:37 am
            Michael – Macha’s assertion that “CO2 IR will only slow cooling at -80C” is just plain wrong. I see this mistake made commonly on climate blogs, and it does come from a complete misunderstanding of Wien’s Displacement Law.

            I’ve lost count how many times I’ve rebutted that fallacious Wien’s Law argument (as recently as two days ago).

            But this in NO WAY means that radiation with 15 um wavelength “has a temperature” of -80C, and cannot affect anything above that temperature. Objects of many different temperatures emit 15 um radiation, and there is NO mechanism for a receiving object to discern the source of this radiation.

            Some examples: an object at 193K has a peak spectral radiance of ~1.1 W/m2/sr/µm at 15microns whereas the same object at 288K has a peak spectral radiance of ~5.8 W/m2/sr/µm.

            Because real substances are broadband emitters at earth ambient temperatures, they emit significant radiation in CO2’s 14-16 um absorption band. The diagrams Willis posted above show the large “bite” CO2 takes out of surface radiation. It is significant.

            Indeed!

    • No, as most of the warming seen, is seen as higher minimum temperatures, which, of course, occur at night.

  4. Every time an electrical appliance is switched on … be it a light, refrigerator, vacuum cleaner, washing machine, Tesla car, etc., heat is generated and since there are more electrical appliances in cities than in rural communities, it all adds up. It doesn’t matter a tinker’s cuss where and how that electricity was generated: use of electric energy will contribute to the UHI effect. So even the beloved solar, wind & biomass ‘green energy’ generators are contributing to this UHI effect.

    • Are there still any cities with generating plants within the city limits? If so, does the energy used to create the electricity get counted?

      • MarkW

        Ah!…My particular grouse.

        Our city dwelling cousins are delighted to use energy, just as long as it’s NIMBY.

        The Greater London area, generally recognised as that delineated from its rural surroundings by the M25 motorway system which entirely circles the area, with a 20 mile radius, has not one single source of meaningful electricity production within it.

        Not a single large wind turbine to be seen.

        • Same thing happened here in Toronto, Canada:

          The Liberal government of the day actually listened to the engineers and planners and was going to put allow some gas plants in the GTA (Greater Toronto Area).

          Of course, the green hit the (voting) fan, the plants were cancelled (to a cost of a billion dollars in cancellation fees), THEN the bastards built plants a hundred clicks from Toronto.

          I’ve said that I wished we could somehow route the black and brown outs through the Liberal ridings…

      • Bridgeport, CT has three, a coal-fired plant to be decommissioned within a couple of years, its recently completed/started replacement (gas fired) and a waste-to-energy plant.

        NIMBYs can only keep them out of their back yards when they’re rich, after all.

    • It isn’t clear to me that a rural household automatically uses less electricity.
      In particular, farms: irrigation systems, lighting & heating for animals, electrically powered machinery etc.
      The UHI is much more likely a function of density and concrete coverage as opposed to electricity consumption.

      • @c1ue – This is “forcing” per square meter. Back of the envelope calculation (literally, on the back of the electric bill envelope) says that my household generates an average of 2.02 Watts per square meter (of my suburban lot and halfway across the street). In the ballpark of what Willis comes up with, although a full figure would have to include our heat generated for transportation, a share of the heat generated by the places we shop, etc. (I might be able to figure transport heat, given a couple of hours, mostly to figure out average fuel use, but have no way to get numbers for the “overhead” heat.)

        The average farm size (US) this year is 434 acres – call it 1.8 million square meters. That average farm would have to be using about 1,500 – 1,700 times my energy consumption to match the “forcing” per square meter.

        I don’t think so. Even less do I think that the rural household generates as much “forcing” per square meter as even a modest apartment building.

      • c1ue,
        This is about density of energy usage. Because the population density is so much higher than in the country, the effect on the surrounding area is much greater.

      • c1ue, if you’ll recheck, Willis took total energy used and divided it by surface area.
        Hence he did what you asked, calculated energy density.
        In this post, he didn’t talk about concrete holding in heat.

    • And lets not forget the energy all those rechargeable gadgets we all have now use. Just counting my wife and I: 1 cellphone, 2 tablets, 1 iPod, 1 cordless headphones, 1 FibBit for the daily stuff…cordless screwdrivers, drills, etc.

      (Of course, in the Good Old Days, we simply threw out batteries, Seriously Not Good, but I do have to remind the Krazy Klimate Kiddies (of all ages) that, yes, you have to do ALL the math and add everything up if you are actually “sciencing” stuff.

  5. It’s not surprising that the global terrestrial weather station data shows continuing warming that differs significantly from the satellite data. The urban heat island effect explains the difference.

    The U.S. has a climate reference network (USCRN) of properly-sited weather stations that is a small subset of all U.S. stations (USHCN), but the GISTEMP and HadCRUT data that is cited most often for “warmest year ever” (gee, I wonder why?) comes from thousands of global stations, of which a large number are poorly sited and biased by the urban heat island. Fake “global” warming.

  6. I routinely see a 10 degree F difference between morning temps (after clear nights) from the multiple thermometers at my house 14 miles from the city and in the city when I get to work. The biggest thermal change is at about 7 miles when I get on the interstate. Spring trees also bloom 2 weeks earlier in the city.
    Two years ago we had two days in a row at 11 below and my multi-year rosemary garden died out. The local airport only recorded down to zero. Noticing heat island effect is a part of my daily routine.

    • The mangos in Miami are in full bloom…
      …at our house outside the city, they have not come out of dormant yet

      • I live in a suburban part of Sarasota County and my mango tree is also in full bloom. It is positioned in the middle of my back yard which consists of Florida native vegetation. Of course we have had higher than normal temps the last few weeks, around 80F daily.

  7. UHI likely accounts for a large portion of the “observed” land heating. It really is a lot hotter in the city than outside it. I have measured this many times from my truck. In the winter you can literally predict the temperature over the river and then inside the city (Fort Worth, Texas) by knowing the temperature at my house. The temperature drops as one approaches the river (-1 to -2), and then increases as one gets inside the city (+1 to +2 as compared to my house). So a delta of up to 4 degrees from the river to inside the city. This measurement assumes there is little wind – if the wind is up the differences are less but still observable.

    And it isn’t just the energy transformed into heat, it’s also the energy stored in the pavement and building walls as heat. It would be interesting if a city albedo was available – I am betting those cities that are darker are also hotter. The most common building materials will effect it as well – those with greater mass like brick and stone should be able to store more heat, and therefore radiate heat longer in the night. For example, I am willing to bet that 1^2 meter of airport tarmac radiates heat longer than 1^2 meter of a simple road (its thicker) – assuming they are made of similar materials.

    Another contributing factor (I think) is a reduced amount of evaporation within the big cities. Without water to transmit heat upwards, any air convection will be much less efficient. With storm drains to convey rain away from the city, the water is simply not available to be evaporated.

    • Robert
      Back when I lived in San Jose (CA), I frequently drove to Sacramento and beyond. Neither of my cars had air conditioning. Therefore, when I drove in the summertime, I drove with the windows down (unless it got over 110). There was an area of irrigated alfalfa alongside Highway 50, near Davis, that was distinctly cooler than the typical 100 deg F. It was surprising how much just a few acres of transpiring greenery could impact the air temperature.

  8. Thanks, Willis. Your Figures 2 and 3 are enlightening. Just imagine the last 3 to 5 decades with time-series graphs, especially the Asian megacities. Oy!

    Regards,
    Bob

      • Well that’s the IPCC for you.

        CO2 up by what, 50% and bitumen, concrete, roofs up by what 1000% in the same time so of course its all about ‘carbon pollution’. Not even the Nazis would have tried such an absurd propaganda line. The communists, well that’s a different story.

        • You mean the political organization that ignores the sun, clouds and history also ignores UHI?

          Hard to believe.

          Basically, the same professional liars who ignore the Little Ice Age (then downplay when they can’t do that any longer) ignore (then downplay) UHI.

        • The sensors aren’t located all over the earth. For the most part they are located in areas contaminated by UHI.

        • Global averages are a good way to hide a herd of elephants. When Willis begins to break it down a lot of interesting things appear. The UHI effect is included in the global averaging of temps as if it hardly exists.

          His post a couple of days ago using buoy data showed nearly 800 w/m2 at the peak of day while 240 avg is the usual global average solar gain quoted. Global averaging is the backdoor for fraud and misdirection. The global average of fires vs land mass should show that Australia doesn’t have any fires recently!

          • We live in a innumerate society.

            People used to almost brag about how bad their math skills were: couldn’t balance a check book (remember those), couldn’t do math in your head. They would NEVER brag about being illiterate, of course.

            Here in Toronto our usual MSM are all over the provincial government using “average” class sizes in negotiating with the teacher’s unions. Apparently, its BAD to use averages there.

            I posted a comment about “now, use the same train of thought about how useful an average global temperature would be…”

            Never got published, for some reason…

        • Actually the said that they didn’t need to adjust the global numbers since UHI had only increased by 0.1C, so there was no significant contamination of urban and suburban sites.

    • Paul S January 16, 2020 at 10:41 am

      Can the calculated temperature increase be checked with actual temperate records?

      Difficult, because we’re looking at two factors with the same outcome—UHI from concrete, buildings, and asphalt, and direct heating from energy use. Disentangling them wouldn’t be easy.

      w.

        • At least those cities are energized just look at the traffic lights…
          My guess is that China is ramping up their CO2 output early and unnecessarily so they can claim to reach Peak CO2 early.

    • I did this about ten years ago. A small college nearby has its campus located out in the countryside. During an extreme cold snap I began to take reading around and within the campus at night. There was an obvious effect of warmer air within the campus throughout the night and I could only assume that heat dissipated from buildings and equipment was the causative factor.

      In one extreme case a set of doors at the lowest end of the campus would pop open in response to HVAC going on up campus (there is a long hallway connecting the entire campus for student comfort and safety during the winter). Lots of conditioned air being pumped into the environment at -10F or so.

  9. Going from my office in a typical commercial environment to my home right next to the Atlantic Ocean, it is not unusual to experience a temperature differential of as much as 8 degrees in the summer and slightly less in the winter.

  10. Most eco-fanatics *are* from major cities. That’s where they live, not in the country. So, yes, their brains are cooking in the UHI heat, which is fine with me. A 2012 paper about Anatolia found that there was no observable “warming” in the country. However, Anatolian cities got progressively hotter[1]. In 2016 Murray and Heggie [2] looked exactly at what the above article is about, viz., the contribution to warming made by the actual heat generation as opposed to CO2. They found that heat output fluctuations explain observed warming better than CMIP5 models.

    [1] https://doi.org/10.1007/s00704-011-0515-8
    [2] https://doi.org/10.1002/2016EF000352

  11. Manilla (2018 pop. 12,946,263) releases over 3 times the heat from energy usage than Tokyo (pop. 38,001,000) ??? I seem to recall from somewhere recently that Tokyo consumes 2 gigawatts at times. Hard to believe Manilla is anywhere close to Tokyo in energy usage.

    • I second Alan. Manila in the first place? Surprising. I don’t know your sources, the numbers are worth double-checking.

  12. is there a global rural temperature record for high quality Stevenson screens? That would eliminate UHI.

    • Mosher will be along soon to tell you it doesn’t matter. Problem is, he’s still averaging different rural locations together, which is a no-no.

  13. There is also an impact on rainfall. Here in Raleigh during the summer approaching convective rain storms tend to disappear as they approach the city from the southwest to west, then reform on the other side.

    We stay hot and dry where I live which is near downtown Raleigh. The major weather station here is RDU airport, which is northwest of the main city of Raleigh and southeast of Durham. RDU gets significantly more rain than I get on my weather station (not calibrated to NWS standards, but is equivalent to other personal weather stations in the neighborhood). Rain cools.

    It’s also interesting that this area is heavily wooded but there are enough hard surfaces to evidently make a difference.

    This doesn’t seem to be as much influence during the six colder months (Oct-Mar) when the Sun angle is less.

    • It’s fascinating to use weather radar to watch approaching ice and snow storms. For the first 10 to 20 minutes after transitioning from water to ice or snow, the area above our local city stays with water, leaving a big dot in the middle of all the wintry weather.

  14. It isn’t just those, too. Consider that each human radiates 50 W. I am not sure about the pets and even the flora and fauna that also live there. Cities are naturally warmer than their surroundings just as ant hills and bee hives are, the other energy is more cake.

  15. I’m sorry, but this is just impossible! Haven’t we been warned repeatedly that if the climate warms by 3 C over X number of years (where X is less than 100), it will be the end of civilization on Earth as we know it? It’s the AGW rallying cry, don’t you know.

    Now you’re telling us that major metropolitan areas around the world, particularly in energy-rich countries, have experienced UHI warming of 3-6 C, most of which likely has occurred since WWII. How is it possible that humans can live, work and prosper in such metropolitan “hothouse” conditions?

    /sarc

    • And it gets worse. The average temperature of Maine is 46F. That of Florida is 72F. How is it possible for anybody to live in Florida?

  16. They also consume electrical and fuel energy at nearly twice the rate of an average interstate highway of the same surface area with much less efficiency.

    And are full of people who sweat.

    That’s the problem. UHI has little to do with the building materials and lots to do with the power consumption being concentrated so heavily that many buildings have to run cooling systems in the midst of winter storms.

  17. My professor at University in the early 1970’s (Civil Engineering, Hydrology) published many papers (and achieved tenure from that effort) on showing the definitive effect of increased severe weather (mainly thunder storms) down wind of big cities.

    • rms
      NASA has studied this also. Atlanta (GA) was the first city looked at. Precipitation and temperature are affected for tens of miles downwind. That’s why any analysis of UHI impact has to examine meteorological parameters downwind, and not average it with the upwind areas.

  18. Wouldn’t there also be effects from back radiation? Generally, the assumption is that CO2 (not to mention water vapor) is well mixed but is that valid on a mesoscale in cities? Also the wind blocking by tall structures and temp inversions would contribute to retention of heat just as they do pollution.

  19. Corresponds with my casual observations from the car thermometer in the U.K. also. The effect around and in smaller towns is most pronounced on winter nights and can often be 2C. It is also noticeable when moving from rural areas onto a motorway (ok highway!)

  20. Willis Eschenbach:
    Your calculation is in two dimensions. Height is not factored in. Maybe it should be. But the CO2 impact of 3.7 watts per square meter might be only two dimensions as well. The heat you’re talking about is IR. And the CO2 warming is IR going up but slowed. I could be wrong about whether three dimensions instead of two changes anything.

  21. Interesting analysis. What caught my eye was the supersizes at which cities had the highest impact per area and which were lower on the list. I coul;dn’t have predicted the outcome and then my next thought was why/ Best guess I came come up with is population density and some aspect of the energy use mix. It does appear some of the highest energy density use is in areas where cooling might be more common than heating and where efficiency may be less due to lower economic achievement. The population density might be the key driver. Would love to see analysis I of that.

  22. “the total radiant energy impinging on the surface, by 3.7 W/m^2”

    This is only valid for 255K. For the surface you need to take 5.4W/m^2. Better still to take average temperature for each city and calculate the first derivation of Stefan-Boltzmann equation for this temperature.

  23. …”it’s not Putin in disguise.”
    ==========
    Funny Willis, of course it is not him personally.
    Then again, how would you know ??

  24. Willis, please don’t forget that cities collect, funnel and channel rainwater away, preventing much of the surface heat from evaporating water that in would have otherwise evaporated, switching off much convective transfer by water, and generally drying the area, setting a preference over the storm-drainage parts of urban areas, for energy transfer by direct radiation over transfers by convection and the potential energy held in water vapor (which is released later during condensation). And I now notice that Robert of Texas just made this same point.

  25. Notice that it is axiomatic when we are told from On High, by our Wise Superiors that High Density STACK -N-PACK is “The Future”, that it is “Most Efficient” and “Better for The Environment”…. that THEY always keep their second homes, vacation homes and cabins well outside the Urban crab-buckets that they prescribe for the rest of us…

  26. Headline “The Megacities Are Cooking” should read “The Megacities Are Cooking with microwaves”

    “Electrosmog” describes the electromagnetic waves surrounding us in our environment. According to NASA [1]:

    “As you sit watching TV, not only are there visible light waves from the TV striking your eyes, but also radio waves, transmitting from a nearby station, and microwaves carrying cellphone calls and text messages, and waves from your neighbor’s WiFi, and GPS units in the cars driving by. There is a chaos of waves from all across the spectrum passing through your room right now.”

    Every year, the quantity and nature of radio and microwaves contained in this Electrosmog increases. However, research into whether they might interact with human biology, and exactly how they might interact, is a field clouded by the jargon and complexity of each technology and hampered by inadequate experimental guidelines.”
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5406447/

    • yes it’s a beautiful area.
      Imagine cool zones in cities.

      Now who would have thought that cities could have cool islands?

      Science of course.

  27. Here is another way of coming at it, which gives a slightly improbable answer, so suggestions for refinement welcome. (Decane used as a handy example hydrocarbon.)

    Taking London as example. (Data from wiki.)
    Population density (people/m2): 0.0057
    Per capita CO2 emissions (UK, t CO2/person): 5.6
    Per capita C emissions (t C/person): 1.53
    Expressed as moles of decane (divide mass in grammes by 12): 12727
    Combustion enthalpy decane: -6778 kJ mol-1
    kJ/person/year: 86,300,000
    kW/person: 2.73
    kW/square metre: 0.015
    W/square metre: 15
    Expressed as doublings CO2 (divide by 3.7): 4.2
    Temperature increase locally (1.5 C/doubling): 6.3 C

    Pleased to receive opinions on getting a better number. I suppose an obvious point is that not all the carbon footprint comes from within the city.

    j

  28. Someone up above commented on the energy in the food eaten by the population … humans on general emit an average of about 120 watts of thermal energy. Here are the results per city, I’ve added this to the top post as well.

    w.

  29. Another reason for UHI, and a concept that most climatologists seem to not understand in general, is the increased surface area from buildings and other structures. You see, when you type in a search engine “surface area of Earth”, the number given is an abstract number based on conceptualizing the Earth as a perfectly smooth marble, when in reality we know that is far from true.

    The abstract number is the figure used to derive the erroneous +33 C of the Earth’s surface. Using the real surface area would bring the real surface temperature much closer to that estimated. Climatologists should understand elementary concepts before trying to destroy the world’s economy on account of their dogmatic beliefs.

  30. Please note that I had bad data, so I had to recalculate and replace the graphics. Conclusions are unchanged, city rankings are different.

    w.

  31. Seem to remember that Leif Svalgaard said that all of our energy usage on Earth, when spread out across the globe, is the same as the energy the Earth gets from the reflection of the Moon. ie: not a lot.

    Not sure how true that is.

    Ralph

  32. Willis, there is an underground effect, too. After a light snow or frost when the paved streets are white, there will be melted circles above the manhole covers. Room temperature and hot water sewage heats the pipes, ground, manhole shafts, and the cast iron covers. Helpful hint – if your community has paved over manhole covers, this effect allows the public works staff to locate hidden manholes.

    • In a similar vein, at my last house, the sewer line ran along the foundation underneath the driveway. Always was the last part of the driveway to accumulate frozen precipitation, and the first spot where frozen precipitation melted.

      Gives a whole new connotation to the phrase “Hot Shit,” eh? 😀

  33. Interesting analysis Willis. Of course, the impact on global temperature is relatively small since only a small proportion of our planet’s surface has been intensively developed into large cities.

    However, the localized effect is, as you have shown, potentially very large.

    We also know that a significant proportion of our temperature measuring stations are located in or close to areas of significant human development. So believe the impact of UHI on global temperatures as commonly reported is indeed significant (albeit hard to quantify).

  34. I checked Willis’s LA numbers just for fun. It seems his PetaJoule numbers are annual totals.

    1,848,000,000,000,000,000 Joules
    ÷ 3,600 Joules per watt-hour
    ÷ 365 days per year
    ÷ 24 hours per day
    ÷ 10,780 square kilometers
    ÷ 1,000,000 square meters per square kilometer
    = ~ 5.436 W/m2, as shown in the graph

    A similar calculation shows that the average Los Angeleno uses about 11,000 kwh of energy from all sources, which is higher than I’d expect, but certainly plausible given that all commercial and industrial energy consumption is included.

  35. Minor quibble: how do “sides of the buildings reflecting sunlight downwards” trap heat citywide?

    • Forced additional heating of the concrete/ground. Much like all those mirrors at Ivanpah power station outside of Las Vegas. Reflect some sun on a surface that already gets sun, and you increase the amount of heating of that surface (more power radiated on it).

      • Thanks, but still not buying the argument. With a building in the way, heat that would have landed on First Street now lands on Second Street. No net change to city’s heat.

        • You seem to be neglecting the increased surface are of the building vs. a flat piece of ground with no building on it.

          Including the roof, which is the same size, give or take, as the “footprint” of the building anyway.

  36. Add the data in figure 2 and 4, take observed values of the urban heat effect, the temperature that is, and you can calculate what the true forcing is, the temperature rise for 1.0W/sqm?

  37. The measurement of rising temperatures in the centre of large cities was an invaluable source for the Warmistas in search of any evidence that CO2 was causing catastrophic heating on the Earth.

  38. To me it seems that the factor used for conversion to temperature change is too high.

    I had thought that forcing is the transient imbalance at the top of the atmosphere. To me that suggests that the increased back-radiation at the surface needed to redress the imbalance is greater than that imbalance. So the conversion factor should be lower. No?

  39. “Finally, I converted the forcing to an equivalent warming. “
    That would work if the cities have a glass cover. But in fact most of the extra heat is blown away in the wind.

    • If you hunt around the US EPA website and pursue Urban Heat Island effects there is plenty of data to show the expected temperature rises from Willis’ calculations are well below those measured.
      There are also lots of built environment effects raising the temperature even more.
      Some places are even trying to paint the dark streets white to reduce that.

    • Do you have any evidence to support that claim?
      The fact that UHI is huge and growing is already documented. Don’t ya just hate it when real world data refutes what you are paid to believe?

    • As someone who rode a Triumph Bonneville back in the 60’s there was definitely a temperature difference as one left the city and went into the suburbs and country. You got colder.

  40. Willis,

    Really interesting piece, I know in my CBD suburb you can walk down the street, turn a corner and suddenly get +2C because of the layout. So even within the center of big cities there will be significant effects.

    From my understanding, if this is accurate, then it should have serious implications for the temperature homogenisation processes currently being used. Would you agree?

    It would also be good to see how this effect scales with city size…

  41. Why just cities. Look at global total energy production and add that to the earth’s heat balance.

  42. Willis,

    Since you appreciate constructive criticism : it’s not only under your home you may crawl around and use strong words :

    Your numbers for Paris are not consistant : a population of 2,3 million is for the “inner city” which is 105 sq km .

    The “greater Paris” reaching as far as you find contiguous buildings is about 2845 sq km and about 12 million people, more or less organized in 412 “communes (boroughs ?). And the whole “région Ile – de – France” grouping 1281 “communes” is only 12000 sq km wide.

    All numbers according to the french Larousse encyclopedia.

    I hope it will make us parisiens and banlieusards look a li’l bit more like hot peoples…

    Keep on surprising and enlightening us !
    Cheers !

  43. If this amount of heat is subtracted from the temperature record, little or no warming remains; and, as urban weather stations now comprise most of the data for the average global surface temperature there is a major uncertainty in that as well.

  44. Back about 1950 a paper was published about the down-wind weather from South Bend, IN. By 1950, more than half of all employment was in the manufacturing sector. (Wiki)
    The paper was republished in a book of readings used in university ‘urban geography’ classes. On of my instructors knew the authors of the paper and the editors of the book.
    This was my first exposure to a study of the effects of cities on local weather.

  45. Nice work, Willis,
    This fits comfortably with a boring, lengthy review of UHI that I posted on WUWT a year or so ago. My strong conclusion was that UHI is an effect that probably distorts land surface records unacceptably, but those in paid research that should research and correct it at trying to avoid it. Mostly, Though I did reference a few papers worth reading. Geoff S

  46. Nice work, Willis,
    This fits comfortably with a boring, lengthy review of UHI that I posted on WUWT a year or so ago. My strong conclusion was that UHI is an effect that probably distorts land surface records unacceptably, but those in paid research that should research and correct it at trying to avoid it. Mostly, Though I did reference a few papers worth reading. Geoff S

  47. Auckland city is the largest in NZ. Assuming that it is powered by NZ’s largest hydro power plant, I have always assumed that the city is warmed by the amount of power used. I have asked a number of people what would happen if the power to Auckland was cut and the water was allowed to run down the spillway. Would the river heat up? I reckon it would, and electrical engineers agree with me. Everybody else disagreed. Everybody else is wrong!

  48. “As a measure for comparison with Figure 2 below, a doubling of CO2 is said to increase the “forcing”, the total radiant energy impinging on the surface, by 3.7 W/m2.”

    err no. That’s TOA

    As for anthropogenic heating?

    why guess when there is science?

    data I have discussed before

    http://www.cgd.ucar.edu/tss/ahf/

    other stuff

    https://www.nature.com/articles/sdata2017116

    one of my favorite authors

    https://www.sciencedirect.com/science/article/pii/S1352231015302156

    The great thing is the vast vast major of GHCNV4 stations are not in urban areas.

    There is large literature on this issue. No envelope backs required.

    In fact if you read the primary literature on UHI, as any good researcher should do, you will find references in things called footnotes!

    • The temperature meters don’t have to be *in* the urban areas, just down wind of them, in order to suffer from UHI.

  49. “It looks to be a significant additional heating source due to direct energy usage in the densest of the largest cities, one that is not generally included in the calculations of the Urban Heat Island.”

    huh

    The urban heat island is typically measured in one of two ways.

    1. A comparison of an urban station with a nearby rural station.
    2. A transect run across the city.

    The Difficult job is ACCOUNTING FOR THE SOURCES OF THE EXCESS HEAT.

    http://meteora.ucsd.edu/cap/docs/sailorandlu.pdf

    One of the sources is from Anthropogenic heating.

    So you want to know about Seoul? Well go study the science!!

    https://link.springer.com/article/10.1007/s13143-015-0065-6

    Willis: “It looks to be a significant additional heating source due to direct energy usage in the densest of the largest cities, one that is not generally included in the calculations of the Urban Heat Island.”

    Science: “Anthropogenic heating by human activity is one of the key contributing factors in forming urban heat islands, thus inclusion of the heat source plays an important role in urban meteorological and environmental modeling. In this study, gridded anthropogenic heat flux (AHF) with high spatial (1-km) and temporal (1-hr) resolution is estimated for the whole South Korea region in year 2010 using a statistical regression method which derives based on similarity of anthropogenic air pollutant emissions and AHF in their emission inventories. The bottom-up anthropogenic pollutant emissions required for the regression method are produced using the intensive Korean air pollutants emission inventories. The calculated regression-based AHF compares well with the inventory-based AHF estimation for the Gyeong-In region, demonstrating that the statistical regression method can reasonably represent spatio-temporal variation of the AHF within the region. The estimated AHF shows that for major Korean cities (Seoul, Busan, Daegu, Gwangju, Daejeon, and Ulsan) the annual mean AHF range 10–50 Wm−2 on a grid scale and 20–30W m−2 on a city-scale. The winter AHF are larger by about 22% than that in summer, while the weekday AHF are larger by 4–5% than the weekend AHF in the major Korean cities. The gridded AHF data estimated in this study can be used in mesoscale meteorological and environmental modeling for the South Korea region.”

    Willis: “It looks to be a significant additional heating source due to direct energy usage in the densest of the largest cities, one that is not generally included in the calculations of the Urban Heat Island.”

    the science
    http://www.meteo.fr/icuc9/LongAbstracts/gd5-1-2961311_a.pdf

    “All cities emit heat into the planetary boundary layer. A small but important source of this heat is human
    activity and its associated burning of fossil fuels for urban transport, industrial processing, and domestic
    heating and cooling (Oke, 1982). Combustion processes in cities set the anthropogenic heat flux, which is
    an important forcing term in models of the urban heat island effect and global climate change (Allen et al.,
    2011; Flanner, 2009). In perhaps the earliest study to quantify the thermal effects of human activity on
    urban climate, Eaton (1877) calculated the heat released from coal combustion in the Metropolitan District
    of London in the late nineteenth century. Accounting also for the ‘vital heat’ of the city’s 3.5 million
    inhabitants, Eaton predicted these sources to raise the air temperature in London by 1.4 K (cited in Garnett
    and Bach, 1965). In a more detailed study, Ichinose et al. (1999) used numerical models to simulate air
    temperature changes of > 2 K by these same effects during winter nights in central Tokyo.
    Published estimates of anthropogenic heat release originate mostly from wealthy, mid-latitude cities such
    as Tokyo and London, with few comparable estimates from cities of tropical or low-income regions. The
    literature could therefore profit from a universal set of anthropogenic heat flux densities representing cities
    of diverse geography, and having consistent methods of derivation. Herewith, we initiate the development
    of such a dataset. Using an inventory approach, we calculate heat flux densities at metropolitan scale for
    the world’s 27 megacities, i.e., urban agglomerations of more than 10 million people. The global distribution
    of these cities—and our use of a common methodology—allows for regional insight into the economic,
    climatic, and demographic influences on anthropogenic heat release in urban environments.”

    • “The urban heat island is typically measured in one of two ways.

      1. A comparison of an urban station with a nearby rural station.”

      It’s not just sufficient to use a nearby rural station. The rural station has to be located outside the impact zone of the UHI.

      • Tim
        You said, “The rural station has to be located outside the impact zone of the UHI.” That means it has to be upwind, or orthogonal to the wind direction.

    • Thanks, Mosh. You keep saying that you know all about UHI, and how Berkeley Earth has removed the UHI from their data. Perhaps you’d explain this, then.

      The “WORLD AVG” is the global average temperature trend per Berkeley Earth … and of all of the datasets, Berkeley Earth has the highest trend.

      Regards,

      w.

    • I see you’ve provided a clone to repeat your talking point – I’d say the propaganda is way ahead.

    • To quote the given reference on its methodology:

      The inventory approach equates sensible heat release with energy consumption

      The bald assumption that ALL energy consumed produces ONLY heat–and no work or light–is symptomatic of Mosher’s grasp of “way ahead” science.

  50. Not sure what you are using for city areas.

    city area can be defined two ways.

    1. ADMINISTRATIVELY. the land the government defines as belonging to the city
    2. BY LAND COVER. the land that actually represents the urban cover and not, for example, the
    bordering regions which may or may not be administratively defined as being part of the city.

    • Mosh, thanks for all of that, always good to hear from you. You say “the science is way ahead” of me and that this is all well known. But the link you provided with the claim that science is way ahead has a total of 9 citations. The UCAR paper is about country-level energy use, not cities. And the “new global anthropogenic heat estimation based on high-resolution …” paper has 10 citations.

      The 2015 Elsevier paper is the only one that’s on point and has gotten traction. I was surprised to see that the Elsevier paper gives values much, much higher than the ones that I calculated. For example, they say that anthropogenic heating in NY City is 63 W/m2 … this is about 40% of annual average absorbed sunshine in NYC. And in the winter, anthropogenic heat is given as 97 W/m2, which is larger than absorbed sunshine at 80 W/m2 for DJF. That seems awfully high.

      Meanwhile, here’s a paper with some guy called “Mosher” as one of the authors … it says:

      The UHI effect can be attributed to many physical differences between urban and rural areas, including absorption of sunlight, increased heat storage of artificial surfaces, obstruction of re-radiation by buildings, absence of plant transpiration, differences in air circulation, and other phenomena [7].

      Notice what’s missing in your description? The guy busting me didn’t consider anthropogenic heat important enough to even mention. To make sure I wasn’t missing anything I followed the reference [7], which is to the seminal Oke paper that says:

      The UCL energy balances considered have not explicitly included anthropogenic heat releases due to space heating, industrial operations or automobile use. If such heat releases enter the UCL (e.g. walls, windows, doors, vehicle exhausts, etc.) they may form an important, even dominant, component of the local energy balance but in general they are small (see the following section).

      So Oke is not considering anthropogenic heat, and even when he does he only includes direct heating of the air, and then only what escapes through doors, windows, etc.

      Finally, you’ve busted me for saying:

      “It looks to be a significant additional heating source due to direct energy usage in the densest of the largest cities, one that is not generally included in the calculations of the Urban Heat Island.”

      Since neither Oke nor you included anthropogenic heat in your discussion of UHI, I’d say I was not too far wrong … I’d say we’re both half right on that one.

      In any case, thanks for the interesting links.

      My best to you as always,

      w.

      • I also note that in the paper by the Mosher fellow it says (emphasis mine):

        Time series of the Earth’s average land temperature are estimated using using
        the Berkeley Earth methodology applied to the full dataset and the rural subset; the difference of these is consistent with no urban heating effect over the period 1950 to 2010

        Now Mosh, I assume that this is the real finding from the real data. You’re too good a scientist to do otherwise. But I gotta ask … with the huge anthropogenic heat effect in the papers you cite, plus the effect from asphalt and concrete, and the large number of temperature stations in urban areas (10% or more), what’s your explanation for y’all finding “no urban heating effect”?

        One possibility is that it is an artifact of the “scalpel method” used by Berkeley Earth. I’ve asked you and Zeke a couple of times about this, for example in my post “Problems With The Scalpel Method“. The nearest thing to an answer I got was that you’d analyzed this and dismissed it. I asked where I could find that analysis … crickets.

        Finally, theres an interesting and informative post about UHI by Mosher here on WUWT, worth reading. No mention of anthropogenic heat in it, but fascinating otherwise.

        w.

        • As an engineer, if the readings before and after up to the next significant digit and go from there. That would truly be all the accuracy you could expect from that measurement device if aging has an impact on the readings.

          The problem that causes for the CAGW alarmists is that this would make it impossible to see the heat increases they say we are having on a global basis. It’s why taking temperature measurements only accurate to the nearest degree or the nearest tenth of a degree and averaging them to produce a figure supposedly accurate to the nearest hundredth of a degree is such a joke! You simply cannot increase accuracy by implementing averages. 2+2 is not equal to 4.0!

      • yes the science is STILL way ahead of you

        http://www.meteo.fr/icuc9/LongAbstracts/gd5-1-2961311_a.pdf

        You still dont get it.

        We measure the UHI as a temperature differential.

        say its 5C worst case.

        PARTITIONING THAT into various causes has been worked on for ages

        “All cities emit heat into the planetary boundary layer. A small but important source of this heat is human
        activity and its associated burning of fossil fuels for urban transport, industrial processing, and domestic
        heating and cooling (Oke, 1982). Combustion processes in cities set the anthropogenic heat flux, which is
        an important forcing term in models of the urban heat island effect and global climate change (Allen et al.,
        2011; Flanner, 2009). In perhaps the earliest study to quantify the thermal effects of human activity on
        urban climate, Eaton (1877) calculated the heat released from coal combustion in the Metropolitan District
        of London in the late nineteenth century. Accounting also for the ‘vital heat’ of the city’s 3.5 million
        inhabitants, Eaton predicted these sources to raise the air temperature in London by 1.4 K (cited in Garnett
        and Bach, 1965). In a more detailed study, Ichinose et al. (1999) used numerical models to simulate air
        temperature changes of > 2 K by these same effects during winter nights in central Tokyo.
        Published estimates of anthropogenic heat release originate mostly from wealthy, mid-latitude cities such
        as Tokyo and London, with few comparable estimates from cities of tropical or low-income regions. The
        literature could therefore profit from a universal set of anthropogenic heat flux densities representing cities
        of diverse geography, and having consistent methods of derivation. Herewith, we initiate the development
        of such a dataset. Using an inventory approach, we calculate heat flux densities at metropolitan scale for
        the world’s 27 megacities, i.e., urban agglomerations of more than 10 million people. The global distribution
        of these cities—and our use of a common methodology—allows for regional insight into the economic,
        climatic, and demographic influences on anthropogenic heat release in urban environments.”

        lastly read my words.

        Do you understand what I MEANT by
        “INCLUDING”
        and what I MEANT by
        “OTHER PHENOMENA.”

        Anthropogenic heat flux is typically a small percentage of the cause of UHI.

        So you are still behind on the science. do keep up

        • Still no answer to the scalpel question?

          And could you cut down on the snark? It makes you look like a dickhead, and I know you aren’t one.

          w.

        • Ah yes, I see that steve is still trying to pull out the “you just don’t understand how science” works BS. It’s easier than actually trying to come up with an explanation that holds together mathematically.

        • “and domestic heating and cooling (Oke, 1982)”

          Raise your hands those of you who believe we use significantly more energy now than in 1982 for heating and cooling… I assume of course that all those power plants built in the mean time was built for a reason.

  51. Willy, you have been tricked with BA’s. The Federal Capital of Buenos Aires has 3 million people.
    But this is just the small central area. But the much larger entire mega city of BA’s has over 13 million people.
    And there is a major heat island effect happening.I know because I lived there for 3 months in 2014 to learn & dance Tango,

  52. “We measure the UHI as a temperature differential.”

    What temperature differentials? Between urban thermometers and rural thermometers within the UHI impact zone? I.e. “nearby rural staitions”?

    • Or rural stations that are well within the UHI zones of smaller cities outside the big cities.

      Just because a station is listed as rural (or was listed in the data base 10 to 15 years ago as being rural) does not mean that the station is pure (nor does it mean that the station is still rural today).

  53. I grew up in the Austrian countryside. Winters were snowy and cold. The landscape was the same as Vienna which was only 60km away. We went to the capital often to see family. Every time we went there we could see a pretty obvious change. Less snow and not as freezing as it was at home. The urban heat island at work. My father explained it to be in absolutely unscientific terms. It was a thing during his childhood as well and my father is pushing 85. Only now we seem to have forgotten about it and think the globe warms. Get out of the city …

  54. Again, it looks to me as though Mr. Eschenbach didn’t treat “forcing” correctly. I’ll provide an undoubtedly oversimplified, radiation-only analysis to explain why I think he may have erred. Executive summary: I think forcing takes its value from the top of the atmosphere, not from the surface.

    So what do I think forcing is? Consider the usual case: forcing from CO2.

    If from an equilibrium state the CO2 concentration somehow makes an abrupt quantum jump and the atmosphere’s infrared opacity therefore does, too, the effective radiation altitude will abruptly increase. Because of the lapse rate the new radiation altitude has a lower temperature than the old one, so outgoing radiation falls abruptly, changing an erstwhile radiation balance to an imbalance.

    It’s that initial imbalance’s value that I think is the forcing value associated with the CO2-concentration increase. The imbalance would decay, of course, but it’s the initial imbalance value that remains as the value of the concentration change’s forcing; even though a new equilibrium is established for the new concentration, its forcing value remains the value of that initial imbalance.

    How is the imbalance redressed? The imbalance causes the surface temperature to rise and (modulo any lapse-rate change) thereby increase the radiation-altitude temperature by the same amount until the radiation out returns to the radiation-in value. The value of that top-of-the-atmosphere initial imbalance is associated with the surface-temperature change needed to redress it.

    However, the surface temperature changes from a value higher than that of the radiation-altitude temperature, so the surface-radiation increase that attends the surface-temperature increase exceeds radiation-altitude’s increase: it exceeds the initial radiation-altitude imbalance, i.e., the forcing. The surface-radiation increase may be, say, half again the forcing value.

    It’s not clear to me that Mr. Eschenbach took this into account; I got the impression that he was going by surface, not top-of-the-atmosphere values. But if anyone has a different understanding, I’d love to hear it.

  55. What is this “degrees C” you’re going on about? What’s is it in atom bombs / sec (the correct measure of AGW)?

  56. “Cities tend to trap heat due to the amount of black pavement and concrete sidewalks, the narrow canyons between buildings that slow down the wind, and the sides of the buildings reflecting sunlight downwards.”

    As a guy who remembers going barefoot and feeling cool grass versus hot sidewalks. I have to ask. Doesn’t the moisture of grass and soil play a role in making dry things hot and wet things cool? Cities with storm sewers tend to dry themselves quicker than most places.
    “They paved paradise and put in a parking lot.”
    I do know that technically minded people working on farm scale irrigation systems will tell you that wet soil equals cool and dry soil equals hot.

  57. In the 2000’s I was working in Crawley, Uk, the day the highest uk temperature record was set there. For those that don’t know Crawley is where Gatwick airport is. In the evening set off for my drive home around the m25 motorway, 6-10 lanes of carnage. Thermometer dropped from 32 to 30 to 27 deg C. Off the M25 up the M3 temperature dropped to 25. The m3 motorway in to london is bordered by rivers, lakes (old gravel pits) and reservoirs. Once into the suburbs where i lived temperature went up to 30C. That was 4 miles from heathrow where frequent annual records are set.

    Thinking on the comments above about solar irradiance dwarfing human energy release and heat island effects, in an ideal stable climate wouldn’t energy emitted be less than incident energy?

    From a thermodynamic perspective negative entropy should be observed by photosynthesis, other life forms and chemical and geological processes building higher order.

    That would also suggest our global energy release is more significant than any forcing CO2 may cause.

  58. It looks to me that there is an error regarding the area and population data of Los Angeles. You have an area of 10,780 km2 with a population of 3.884 million. The 10,780 km2 is very close to a Wikipedia value of 10,510 km2 that represents the land area of Los Angeles County. However, the population of Los Angeles County is 9.8 million (est 2018 ). The 3.884 million might be an older City of Los Angeles value as the 2018 amount is 3.99 million with an area of 1,210 km2. The official Greater Los Angles area consists of 5 counties. I wouldn’t use this grouping as it is made up of large relatively sparsely populated areas of mountains and deserts. I think the more appropriate grouping would be the Los Angeles Metropolitan Area as it consists of just 2 counties, Los Angeles and Orange that are mainly urban, adjacent to one another, and consist of 12,362 km2 and 13,310,447 people.

  59. Willis, really enjoyed this article as it helped with a longstanding question I had about how much heat is produced by human civilization and how that compares to what we receive from the sun. I’m not there yet, but I think this helps validate that we are heating up locally, but not globally.

    A couple of years ago, I was re-reading a science fiction novel that postulated an earth-like planet inhabited by trillions of human-sized beings. It further postulated that the heat generated by the beings, along with their industrial heat by-products was so great that they had to up move the planet away from the sun to maintain their lovely tropical climate. Since I first read this in maybe the 70’s, I wondered if it was possible for our leaking heat to cause this catastrophe.

    With these numbers, it’s obvious that UHI contributes to local temperature reporting, which in turn inflates the models, which in turn inflates the rhetoric. I’m a bit disappointed, and correct me if I’m wrong, to see that the UHI contribution to heat, when spread across the entire planet (i.e. dive by planetary meters squared), is not significant.

    On the other hand, if I extrapolate Seoul out to a 100x or 1000x globe-spanning megacity, the waste heat alone will make any GHG contribution meaningless.

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