Guest Post by Willis Eschenbach
I’ve been thinking about the idea of the urban heat island (UHI) as a result of my post on the bogus temperature “record” at Heathrow. The “urban heat island” refers to the fact that cities generally run warmer than the surrounding countryside. This is from some combination of the direct heat generated by fuel use, and the land surface change (more buildings, more asphalt, less grass and trees). In this regard, I ran across a very interesting interactive map today from a professor named Modi. It shows the energy used by buildings in New York, block by block. It was run on ZDNet under the subhead of “Midtown Manhattan uses more energy than Kenya”, which is an interesting statistic in itself. Here is a view of the map:
Figure 1. Energy use in downtown Manhattan, along with some of the boroughs. Click for a larger version.
This is just one view of an interactive map of NYC energy use by buildings, produced at Columbia University. So why was this map interesting to me? Well, it’s because of the values in the legend. Let me translate them into units that we are more familiar with, watts per square metre (W/m2) of land area …
Figure 2. Energy use in downtown Manhattan, along with some of the boroughs, expressed in W/m2. Click for a larger version.
Dang … just … dang.
Finally, please note that authors point out that this is NOT the total block-by-block energy consumption in NYC. It is only the energy used in buildings for heating, cooling electricity, and hot water. It does NOT include such things as fuel for the vehicles used in the areas, nor electricity to run the subway system, the street lighting, the traffic signals, or the pumps to supply water to the buildings and take away the sewage. The article says:
Still, Modi [the developer of the map] said he hoped city residents would see his map as a call to cool their behavior at home. Across the city, 75% of all energy comes from buildings, according to the study, whereas nationwide buildings only account for 40%. (The main reason for the difference: fewer New Yorkers drive.)
So for the full energy use in Manhattan, you could jack all of those energy use numbers up by about 1/3 …
Finally, are Dr. Modi’s numbers right? I have no idea … but if they are, then UHI is no mystery …
w.
[UPDATE] WUWT reader usurbrain commented below:
And do not forget to add the human heat load, ~100 watts per hour emitted by each human working in the building. …
To which I replied as follows:
Human heat load … good thought, usurbrain. For the population I get the following:
<blockquote>… approximately 4 million people on a typical weekday, 2.9 million on a weekend day, and a weekday night population of 2.05 million.</blockquote>
Assuming I’ve not made some arithmetical error, this gives a weighted 24/7 average of 3E+6 humans on the island. Manhattan is 87.5 square km, or 8.7E+7 square metres. In other words, we have 0.03 humanoids per square metre.
I fear, however, that you’ve underestimated the energy production of your average American heat generating unit, we’re world champion caliber in that regard. The average American heat generating unit has a fuel consumption given by the USDA as 2,640 calories for men and 1,785 for women, an average of 2212 calories of fuel per generating unit. And since in the longer term humans are 100% efficient at turning fuel into heat, that converts to about 107 watts continuous.
Put that together and we get 0.03 heat producing units per square metre times 107 watts per unit gives us just over 3 W/m2 of extra ground-level energy to add to the UHI mix …
Not insignificant, to be sure.
So where there are high rise towers on a site there is greater energy use per square metre (foot) of land surface. How about normalising the data by population density then see what happens.
More trivialisation of ‘science’ by someone who wants to get some sort of netgonition it seems to me. A scientific selfie.
I agree that it would be interesting to see these stats per capita also, but is that really relevant to the topic of urban heat islands?
Are you suggesting that the degree of heating in urban settings is a function of population, independent of energy usage? All those bodies radiating heat?
No. I was just commenting on Professor Modi’s comments about Manhattan energy usage etc. In that context per capita ‘UHI’ effect would seem more relevant. As Willis points out there are other components to the UHI that the maps reproduced reflect and for a proper analysis they need to be accounted for.
That said it may well be that population density is a material parameter but it might be that high population density has a lower per capita energy footprint than low density, eg suburbia with all its car use. I don’t know the numbers but I bet they can be improved by better building design etc.
I believe that has been shown to be the case . Certainly urban heating is more efficient because living and work surface area per capita is much less . Transportation tends to be more efficient too , despite the summer hell of the subway whose tubes add the heat of each train’s AC to the already insufferable street .
Thanks, M, but I’m not sure what your point is. I’m trying to estimate the energy used in Manhattan, in W/m2, in order to see what kind of effect that has on local temperature measurements. Why would you want to divide that by the population?
As to your accusation that this is a “trivialization of science”, my suggestion would be to emulate the rooster, and wait until it’s actually sunrise before you start preening, strutting, and crowing …
w.
Willis: You are too kind to an ass. He probably considers himself a climate “scientist”.
Sorry folks, I just thought it was a rather pointless exercise to map the energy use of high rise buildings. What would you expect other than the big buildings are big users? It may well be that tall apartments are the least energy intensive per capita, i.e efficient per capita, yet the original paper apparently talks about getting people to moderate their energy usage. I wasn’t having a go at Willis’s article but at the mapped data and comments like the one about more energy used than Kenya. Manhattan is a global city, one of the great metropolis’s and densely populated, why wouldn’t it have a high energy density and a stinking hot UHI effect? It may well be that energy efficiency is to be found in concentrated urban environments which maximise public transport and minimise car usage etc. Again, going back to the original paper referred to the author of that seems to imply something different.
As for UHI, apart from it contaminating the surface temperature record and giving an excuse for all those ‘adjustments’ what else do you expect to happen in such an environment.?
Methinks some of you are all a bit prickly. Go bite your bums.
And JF I am about as skeptical as they come.
M Seward July 21, 2015 at 6:57 am
Seriously? You accuse me of “trivialization of science”, you say I only want “netgonition”, you call my post a “scientific selfie” … and now you want to whine that in response I am “prickly”?
Really?
Here’s a secret for you, M—”prickly” is what you get back when you act like a pri … never mind, it’ll just get beeped out by the censor, but you know what I mean. If this seems complex to you, let me put it more simply:
“Karma” is like hitting a golf ball in a tiled bathroom …
To your more substantive issue. You seem to think that mapping the total energy usage of New York is “pointless”. Why? Because high rise buildings …
In that regard you say:
You do understand that some folks claim that there is no discernible UHI effect in the data? You do know that some folks think that the UHI is trivial, a few W/m2? You do recall that the size and nature of the UHI is a matter of debate and discussion?
Finally, you may not realize it, but there is a huge difference between M Simon waving his hands and saying that Manhattan has a “stinking hot UHI effect”, and a scientist who actually measures the size of the effect. What is “pointless” is you waving your hands. In my experience, accurate measurements of significant physical phenomena are rarely pointless.
M, I can do the research for you, but I can’t do the thinking for you. If you find something pointless, my advice would be to ask what the point is before slipping into attack mode and telling people to bite their bums … it’s free advice and you are free to ignore it, it’s just that I can’t see you driving your reputation off of a cliff without saying something.
Best regards,
w.
PS—Somewhere in head post I figured out the population density of New York, which is 0.03 people/m2. We know the energy used. I leave it as an exercise for you to figure out what you seem to think is so important, which you claim is the per capita energy usage. For comparison, average energy usage per capita in the US is about 9.3 kilowatts on a 24/7 basis …
I understood M Seward’s disparagement to be directed at Professor Modi.
Not that I agree it is an appropriate criticism of the Professor’s work. That has provided us all with seriously more information than we had before. But if I understood correctly, it’s fair for M Seward to observe that we’re prickly if we take his criticism of the Professor as being a shot at you, Willis. Especially since he later explicitly said he wasn’t taking a shot at Willis’s article.
Can someone who knows the answer, tell me how figures like this affected by the fact the energy is released to the outside world, where heat rises, rather than inside a greenhouse or indoors? (Yes, some of it’s in a building, but the building is not in a dome… I hope people can infer my meaning because I’m not expressing it well.)
Now I’ve been troubled recently myself by the whole issue of UHI. Here on WUWT recently I addressed a standard explanation of it to a defender of the orthodoxy. This was in response to his assertion that ‘(UHI) has little effect on the temperature of the Globe, and is often near airports where it’s cooler than in the city’, or words to that effect. I later saw that Richard Muller had used almost exactly the same words when describing BEST’s consideration of UHI. I inferred him to mean that the changes (increases) in anomalies of cities and urban areas are barely distinguishable. On the other hand, there’s this work of yours Willis, and I’ve seen a chart Anthony posted showing distinctly different large trends between city and country. Indeed, what you’re reporting here seems to me to be a quantitative assessment of a paradigm my common sense already assumed.
So I have conflicting claims as to what the data actually says. I’ll go off and do my own reading, but it’s possible some informed reader can already clarify the discrepancy.
Help would be much appreciated.
Leo Morgan July 21, 2015 at 10:41 am
I see that you are right about M Simon, Leo, and this is precise why I insist that people quote what they object to. What M Seward said was:
Now, obviously M Simon is addressing me directly with that statement. He is not talking to the mapmakers.
The other half of his comment was:
Since the first half of his comment was directed to me, I assumed (incorrectly as it turns out) that he was continuing to address me. But you gotta admit, that’s the logical assumption. Please, folks, let us know who you are talking about.
However, his assigning his comment to the people who made the map is even more strange. I could kinda understand him busting me, I get that all the time. But to me, the makers of that map have worked long and hard to produce hard estimates of actual energy use, and have mapped it in a form that is valuable to our understanding of the UHI, as well as being both clear and strikingly presented.
For me, to characterize the making of that most fascinating map as “trivialization of science” and “a scientific selfie” is truly strange, and it’s one of the reasons I assumed he was talking about me.
But perhaps he meant something different entirely … don’t know.
It’s a question I’ve been giving some thought to since I came across the map. Energy consumption in the heart of Manhattan is on the order of half a kilowatt per square metre. This is about the same as the total downwelling radiation at the surface (longwave plus shortwave). Part of the answer is that a good chunk of the heat is released at the tops of the buildings. It’s unclear what effect that might have, when combined with street-level releases. Certainly to some extent releasing heat at the tops of buildings will cause rising air and cooler air will be drawn in.
On the other hand, with any kind of wind some of the heat will assuredly be mixed downwards to street level, where it will join the heat radiating up from the streets and the steam grates and the like.
What the net effect of all of it will be is an unanswered question.
My main reason for posting this was that I was quite surprised by the size of the heat flux, of over half a kilowatt per square metre.
w.
Willis Eschenbach July 21, 2015 at 5:40 pm
I am sorry you took it that way but as I read the map the units were W/sq m and I assume they are the units used by Professor Modi not you. You quote Professor Modi as commenting about more energy than Kenya which is a per capita reference by implication and then referring to how residents ( of Manhattan) should “cool their behaviour”, again a per capita reference by implication.
I was not saying anything about your narrative or about what interested you in Professor Modi’s work, I get what your interest is and have no issue with it. I ONLY commented on some matters where you quoted Professor Modi.
I suggest you go read my post again. I could perhaps have been more explicit in my turn of phrase but there you go, it was late (AEST) and I commented on my initial takeout from your post. The thing that first struck me which was the map, the units and the quotes in italics, i.e. the things that the eye is drawn to in a graphical sense when you first view the post.
Sorry Willis but you and some others seem to have jumped to an incorrect conclusion and gosh haven’t you arced up at length. Loosen up, do some yoga perhaps, and if you are still feeling ‘prickly’ then you will be able to bite your bum with ease. I hope it is therapeutic because Houston YOU seem to have a problem.
The topic is heat island affect. Such the only figure that matters is energy per unit area.
One would think that someone such as your self that sets himself up as a critic of others, would bother to get something that basic correct.
Sorry Mark but Professor Modi’s comments were what I took issue with.
They seemed like the usual warmist thumbprint on what was at its core solid science. Why mention more energy than Kenya or that residents should cool it re their UHI effect. Yes the gross UHI effect is made up of the sum of the local energy per unit area but so what? On what basis does he make such unscientific comments about Manhattan? He may be right or he may be wrong but to be right he would at least need to look at the per capita numbers. Besides are the resideents of Manhattan responsible for the UHI of all the office space? Although the data ( map) presented was in energy per unit area units, Modi seemed to be making some sort of energy profligacy per capita point which I thought was crap.
Yes, where’s there’s lots of energy use, energy usage is high. Well done. And you have claim Willis is trivialising science?
Read the follow up comment, he was referring to the original paper that Willis was quoting, which does boil down to a complexity barely over “water is wet”
Normalising the data by population density??? What a joke. Can’t believe how stupid some of the paid shills are.
Read Modi’s quoted comments, Tim. He is making calls that relate to per capita energy use that are at best
simplistic extrapolations of the basic per unit area data. Others seem to get what I am getting at but hey maybe we are all stupid.
Just for the record, by happenstance I was the first to post on Willis’s article so seem to have got some extra attention.
As I opened the post my eye was drawn to the maps and it did not even register who had written the post. I was referring to Professor Modi’s comments about ‘more energy than Kenya’ and the implication that Manhattan people should be shamed by the UHI effect of the city. That was the trivialisation of science I was referring to, not Willi’s article. I get it that Willis was interested in the data. Willis loves data as we all know and just loves graphing it to all our benefits.
I apologise for the unintended perceived slight.
Leo Morgan seems to have got it but some of you probably needed another coffee before posting. Willis, no need to be so territorial. You did what you and others accused me of doing.
Thanks, M, for the apology. I regret my misunderstanding and my harsh words.
I was misled by the fact that your first paragraph was obviously addressed to me, viz …
From my reading of that, you were asking me that question, not the map-makers. And so I responded to that question.
Since your first paragraph was addressed to me, when you went from the previous quote directly to …
… perhaps I can be forgiven for assuming that you were still talking to me.
All the best, no hard feelings, no harm, no foul, play on …
w.
Willis Eschenbach
July 21, 2015 at 6:59 pm
Sorry Willis, it was my rushed post that set this off but I though I was just being succint at the time. I had no issue with the map maker’s efforts rather the comments by Professor Modi you quote which placed some apparent moral/ethical construction on the numbers.
Re quantifying UHI, I get your interest, but UHI per se is not evidence of energy profligacy as Professor Modi’s comments might suggest. 5 million neanderthals living in caves and piles of rocks would produce a significant UHI effect but we would hardly accuse them of contributing to ‘destroying the planet’. Actually we might suggest they stop cutting down trees for firewood and switch to coal.
PS I am not a rooster. I am more of a bear.
The area of Kenya is 582,650 m^2: the area of Manhattan is 87.46 km^2 – so the energy use per m^2 is over 6,660 times as great. The per capita comparison is irrelevant in this context (there are many rather more dramatic comparisons that could be made on that basis), although perhaps it might be fairer to compare with Nairobi and Mombasa, rather than the whole of Kenya. Of course, these numbers don’t reflect energy used by Con Ed in providing electricity to Manhattan, whereas the comparison is with Kenya’s primary energy consumption.
Have I missed something here? 500 watts per metre sq PER YEAR is trivial surely?
500Kw, not 500w. Read twice, reply once
Apologies, Heading is in Kw, side bar is W, confusing to say the least
Yeah,you missed something. Units are 5000 kWh per year.
Got your units screwed up. Watt is a unit of power – energy per unit of time. If you put a PER YEAR on it, it would be Energy per unit of time squared per square meter and I don’t know what that would be.
5000 KWh is 570 Watts per sq M continuously all year. That is more than solar insolation. Some escapes as light. The rest is heat.
5000 x 1000 x 3600 / 365.25 days / 86,400 seconds = 570 Watts
Thank you Willis. I had often wondered how much of UHI was due to energy use, petrol, electricity, and how much due to just concrete and bitumen. This has gone some way to informing that curiosity.
There is a ton of literature on this that is happily being ignored.
but to get an idea you can look at the weekend effect in Tokyo.
thankfully the world isnt NYC.
Thankfully.
Ecomods I assume would like all people to form new-york-sized cities. I don’t.
About the literature. Yes, maybe, but newspapers a la ordinary theguardian do not really like to bring this kind of stuff to the knowledge of the wide public.
Mosher, I have read some of the UHI literature and it seems pretty straightforward. The bigger picture however is something I find fascinating and sorely lacking in published research (at least recently).
Gavin S. says to divided total energy consumption (15TW back then – its probably 18.5 now) by the earths surface area (510mm km2) to give the relative value of direct energy on global warming – a small 0.03W/m2. And so its been generally ignored. But I’ve always thought thats too simple – cities are basically point energy sources that emit steadily and are concentrated in the northern hemisphere. 92% of the worlds energy is consumed in the northern hemisphere (which has about 17% of the earths land area). Just that simple math and accounting for higher energy consumption bumps that to a non trivial 0.2 W/m2 . Remove land north of 65degrees latitude where few people live, 0.35 to 0.4 W/m2 comes into play. In another 30 years these numbers will be on the same order of magnitude as theoretical feedback global warming in the northern hemisphere.
There always seems to be an assumption that this heat diffuses via the heat equation equally globally which makes little sense. Indicatively global warming is much stronger in the northern hemisphere, with the southern hemisphere barely warming in 35 years. Global energy consumptions has roughly doubled since 1980 which coincides well with satellite era measurements. With the notable exception of the arctic, warming is concentrated on land and at latitudes where the most energy is consumed. This is never explained well and is appears to be more than coincidence. Both the arctic and antarctic are areas I generally dislike with any levels of accuracy because of ice, general volatility, bad measurements spatially/quality (which is much worse with time).
Basically I have always wondered why no research has been done into a “latitude” or “hemispheric” heat island effect, especially from a modeling perspective. There would have to be some constraints on heat distribution to make it meaningful. Is heat produced partially reflected back created a non CO2 feedback effect? Is heat being stored and released slowly so net heat is being added to the system? Does wind or coriolis effect constrained heat flow across the equator?
I would appreciate any research you could direct my way on the subject. I think its meaningful but as a semi-retired mathematician I need to read a little more…
Steven Mosher July 20, 2015 at 9:25 pm
Mosh, I can’t tell you how much I dislike this kind of vague drive-by mudslinging that you seem to alternate with your thoughtful, insightful comments.
You have not identified anything that I or anyone else has said that you disagree with, or anything that I have done wrong. You have not said what it is that you think I am ignoring that is covered by the literature. You have not given a link to a single piece of the ignored literature and explained how it is so important.
Finally, you don’t seem to understand that simply because a man doesn’t mention or discuss what you think is important, it doesn’t mean he is “ignoring” it … he may simply be writing about something else.
For example, the interactive map I was discussing only covers New York City … does that mean that the authors of the map were “ignoring” Los Angeles? No, it just means that they made a map of New York.
Similarly, when I discuss the map of New York, it doesn’t mean that I am “ignoring” Tokyo. It just means I’m discussing the map of New York.
Sorry, I don’t go on a snipe hunt for any man. If there is something about the weekends in Tokyo that you think is important, spit it out, give us a link, divulge the details, show us the data. This hand-waving is garbage … and the most frustrating part is, there is likely something interesting about weekends in Tokyo, but I can’t waste time looking for it.
Did I say the world was NYC? I don’t recall saying that … did anyone say the world is NYC?
Steven, if you can find something actually wrong with my analysis, please quote what I said that you think is wrong and tell us all what is wrong with it. I’m happy to discuss most anything, and I do value your insights.
And if you think that I’ve omitted something important, please have the common courtesy to identify it and tell us why it is important, and we can discuss that as well.
But if you don’t have specific issues, let me invite you to forego these comments full of vague allegations of unspecified errors and omissions. Such mud-slinging makes it look like you are out of ammunition. I doubt greatly that you are … but it sure makes you appear that way.
w.
Willis, I couldn’t respond to your comment below. There is nothing wrong with your analysis; as usual its quite entertaining and thoughtful. I think Mosher is referring to a bunch of papers on anthropogenic heat flux (AHF), and there are tons of them that go about attempting quantify UHI using various measurements. Some even go so far to look at potential regional effects in dense areas (Europe, China, US East Coast) which are pretty dramatic. This effect is not modelled in GCM’s though there are some new attempts to add it.
I think there might be some secondary effects of AHF to consider that contribute warming in the northern hemisphere on land and its been mistaken for positive feedback CO2. Very little, if any, research beyond UHI on cities has been done – its simply dismissed as too small.
ToA is 340 W/m^2. CO2 RF between 1750 & 2011 = 2.0 W/m^2. Cloud feedback = – 20 W/m^2. Just a few perspective values.
Impossible, don’t you know the UHI doesn’t exist? They proved it using Chinese data, but, er, the dog ate the list of stations and data so you’ll just have to take CRUs word for it.
No worries, all the heat is hiding in the Deep Hudson.
Hilarious …
w.
And do not forget to add the human heat load, ~100 watts per hour emitted by each human working in the building. That is 800 watts per day X 200 days or 160 kW per year per person. That heat plus all of the heat generated in the building from electrical equipment is pumped out the evaporative heat exchangers on the roofs of those buildings (or dumped into whatever heat sink the HVAC uses as some might use river water. Many buildings are now making ice at night, as the electricity is cheaper, and then using that ice to help cool in the day. This goes on winter and summer. How many people are working each day in each block.
Human heat load … good thought, usurbrain. For the population I get the following:
Assuming I’ve not made some arithmetical error, this gives a weighted 24/7 average of 3E+6 humans on the island. Manhattan is 87.5 square km, or 8.7E+7 square metres. In other words, we have 0.03 humanoids per square metre.
I fear, however, that you’ve underestimated the energy production of your average American heat generating unit, we’re world champion caliber in that regard. The average American heat generating unit has a fuel consumption given by the USDA as 2,640 calories for men and 1,785 for women, an average of 2212 calories of fuel per generating unit. And since humans are 100% efficient at turning fuel into heat, that converts to about 107 watts continuous.
Put that together and we get 0.03 heat producing units per square metre times 107 watts per unit gives us just over 3 W/m2 of extra ground-level energy to add to the UHI mix …
Not insignificant, to be sure. I’ll add this to the head post.
w.
That’s, what, 5 times greater than the estimated TOA radiative imbalance? Anthropogenic global warming, indeed.
” since humans are 100% efficient at turning fuel into heat”???
Surely some of that fuel energy is converted to mechanical energy, like pumping blood, breathing, evapo/transporation, walking, lifting, etc., whereas the heat loss is only the residual that remains after all useful work is accounted for.
Willis,
A friend of mine corrected me when I used food calories to make similar calculations years ago. As I recall a calorie in the medical world is not the same as the engineering calorie by some order of magniude. Did you consider the difference or was my friend wrong?
I know you are sharp and apologize for bringing it up if you were aware of that.
http://www.physlink.com/Education/AskExperts/ae195.cfm
Willis check this out for the difference between a calorie in food versus the Engineering calorie. During one of my assignments in Mexico I was climbing a 200 foot high tower 2 x per day and wondering why I was not loosing weight. My friend pointed out the difference is 1000 between the 2.
Catcracking,
You are correct: a food calorie is actually 1000 calories (or a kilocalorie), being the amount of energy needed to raise the temperature of 1 kilogram of water by 1°C.
It appears that Willis factored that in, multiplying the food calorie by 1000 to get 107 watts (per hour):
https://www.unitjuggler.com/convert-energy-from-cal-to-Wh.html?val=92300
“Surely some of that fuel energy is converted to mechanical energy”
We can safely assume almost all the mechanical energy quickly converts to heat. Very few of us are pushing rocks or books uphill manually and leaving them there. There is an error there, but it is insignificant compared to other sources of error in that calculation.
Some of the energy escapes as radiation, some as latent heat of sweat. But it is of little meaning here.
Mm. not so sure that we are in fact 100% efficient in turning food fuel into heat.
Like any heat engine, a proportion of the energy emerges from the rear end of the system…
“Surely some of that fuel energy is converted to mechanical energy, like pumping blood, breathing, evapo/transporation, walking, lifting, etc., whereas the heat loss is only the residual that remains after all useful work is accounted for.”
The only case of those you mention where the mechanical energy is not lost as heat locally and quickly is evapo/transpiration, where the water vapor is moved upwards by convection and converted to heat as the water vapor condenses at altritude.
“Like any heat engine, a proportion of the energy emerges from the rear end of the system…”
And is soon converted to heat by busy little bacteria at a sewage plant a few miles away. Which is why it isn’t a good idea to put weather stations at sewage plants, as is often done.
pete j
July 20, 2015 at 10:29 pm
” since humans are 100% efficient at turning fuel into heat”???
Surely some of that fuel energy is converted to mechanical energy, like pumping blood, breathing, evapo/transporation, walking, lifting, etc., whereas the heat loss is only the residual that remains after all useful work is accounted for
=====================================
Just as some of the DLWIR is used to accelerate the hydrological cycle..
160 kilowatthours.
100 joules/second x 1600 hours x 3600 seconds/hours = 576 megajoules
576 megajoules divided by 3.6 kWh per megajoule equals 160
Impossible both the heat and oodles of taxpayer moneys are being sucked into the vacuum at the UN headquarters.
Willis, just one curiosity which I found some time ago. Average energy produced by human body by basic metabolism is 200W. How many people are living on Manhattan? I found around 1,6 million. What is area of Manhattan? 87,5km2. So that means there is 320 million Watts on 87,5 million square meters. This is 3,65W/m2 of heat produced just by human body heat. Human body is able to produce another 200W more during exercise, so real human heat is somewhere between 3,65W/m2 and 7,3W/m2
Average basal metabolism is 100 watts for an adult male, thats no activity, sleeping. Walking briskly maybe 200 watts. A biker or very fit athlete can sustain about 500 watts for an hour.
Mountain climbers know that 8 hours of climbing increases their dietary calorie intake by a factor of 4 or 5 over their regular intake.
Many ore people work in Manhattan than live there. And more still are visiting at any given time.
Yikes! > 570 w/m2 due to energy use. That is greater than both the average solar radiation and the average back radiation. Please explain how the sun and back radiation heat the city, but energy use does not? It seem clear that UHI is vastly under reported.
The reason New York City is still livable even in summer (well, more or less) is that surface heat, contrary to the party line is not removed mostly by IR-radiation, but rather by convection. All that energy use will cause a plume of hot moist air to rise over the city and draw in colder and drier air from the sides.
right, pass the thorium, please
I read years ago, that an average sized adult male puts out about 75W worth of heat. That’s going to add something to the total heat output.
Well, since it was the Manhattan Project which produced the Hiroshima bomb, it would be appropriate I think, to put the UHI value in Hiroshimas, and then figure out how many Manhattan-sized glaciers that would melt.
Cooking In New York … in multiple forms.
http://s9.postimg.org/fnyp84san/nyc.jpg
Ha!
http://www.film.com/wp-content/uploads/2012/09/ShawarmaGrill-250.jpg
I don’t know what Tom cooks, but schawarma is real food with its own UHI.
Plus the “cooking” that goes on in Jim Hansen’s apartment!
NYC is very much a water town, the water moderating temperatures year round.
Air conditioning that is not water cooled is prevalent and pumping heat to the outside air.
The Hudson River is a tidal estuary up to about Albany.
It does not do much moderating when it freezes over, like it did this past winter.
The ocean and bays do. And Long Island Sound.
I’ve seen the lower Hudson freeze. Interesting considering the salt content.
It’s all radiated by the middle of winter, there’s no sign of it year to year, but it likely increases the peak temp during the day, in fact it’s probably gone long before fall.
Remember the length of night increases and the day shortens after the end of June.
Since I Did this today thought it applicable
Air temp was 80F
These were taken in my easterly facing front yard at about 11:45AM on a clear sky morning.
Grass = 94F
Concrete = 110F
Asphalt = 125F
I live aways from significant human structures, and my backyard abuts a 300,000 (?) acre National Park.
51sq mile, 20,000 Sq acres
Square acres? Is that a unit of four dimensional volume?
🙂
You ever see 3d chess? This has one more dimension than that!!!!!
You should see the monster deer.
There’s also another 21,000 acres in the Cleveland Metro park district that’s adjacent to the National Park system.
Square acre can be used for renting a four-space. Each nanosecond of renting time corresponds to one foot. So if you want to rent, say a 1000 cubic feet room for 10 ns, you’d rent a 10,000 ft⁴ sized four-space.
I thought people in Manhattan were cool…?
Steam isn’t mentioned – I believe NYC, particularly Manhattan, has a huge underground distribution network of steam to most buildings from huge centralized boilers. In that case, the energy for steam generation isn’t consumed in the buildings and not counted? But the heat is released throughout, contributing to UHI, and I would assume it is not insignificant. In any event, I think steam should be mentioned somewhere as counted or not counted.
Back in 2010, I posted the following analysis on New York City power usage as it related to UHI. One big factor Willis seems to have missed is the ‘Mandated In-City Power Generation’ factor.
DD More February 26, 2010 at 7:22 am
I could never understand how UHI was minimized. If you look at New York City as an example.
Area, including water 468.9 sq mi ( 2,590,000 sq m)
Power used (2008) 54,869 GW-hr
(http://www.nyc.gov/html/planyc2030/downloads/pdf/progress_2008_energy.pdf)
Watts/sq m = 2,416 total. The Mayor says 80 percent is used by buildings and therefore 100 percent ends up as heat loss. So the forcing is 1,933 W/Sq M
The file also remarks that the city has seen a 23 percent increase in the last 10 years, which is close to the increase showing up in the charts.
http://wattsupwiththat.com/2010/02/26/a-new-paper-comparing-ncdc-rural-and-urban-us-surface-temperature-data/#comment-329553
Well it should be updated a little. Clarifying the 80 percent used by buildings was for lighting and heat, so by next day at the same temperature it was all turned to waste heat. I heard later that Reliability concerns require that 80% of the City’s peak load be met with in-City resources under a mandate from the New York State Reliability Council and the New York Independent System Operator.
The original calculation would now be 54,869 GW-hr / year * 1.0 x 1.00E+09 W/GW x 8760 hr/yr = 6,263,600,000 W-hr / hr. that divided by 2,590,000 m^2 = 2418 W / m^2 each hour. But if you take at least 60 percent of power generated in the city generates 40 percent excess waste heat to convert to electrical power = 2418 x (1+ .24) = 3000 W / m^2 of extra energy being dumped in the air of New York City. And that is from electrical power alone, doesn’t include all the vehicle waste heat.
So does 3,000 w / m^2 raise the temperature more than 100 ppm CO2?
The average day to day change in Min temp for the Northern Hemisphere (1940 to 2013) is -0.004297849F , the 1×1 degree cell that is NYC, which has a number of weather stations is 0.000786342F
Here’s the annual temperature data from 1940 to 2013
https://micro6500blog.files.wordpress.com/2015/07/y_n41w73.xls
Something I never expected when I moved there is that NYC is a geothermal area with fumaroles randomly erupting and capped with a ready inventory of orange and white striped chimney funnels , and steam explosions closing entire blocks every few years .
Of course one of the things that contributes to its per-capita energy efficiency is a substatial use of waste steam for building heating .
Wilis, I think the “calories” in our diet are actually kilo-calories, or 1000X a physics ‘calorie’.
that is correct = Kcals
Large C…Calories, not calories.
Hmm… Since AGW is for many the goose that laid the golden egg, with a little bit of focus 570 watts is just about enough to cook that egg!
It should be noted that much of this heat/energy is released far above ground level. So the impact on official temperature measurements would be some fraction of the total.
Thank you.. The issue is power / area x duration. But the are isn’t just the ground area. There are many floors to a skyscraper.
Not that I doubt the existence of HI (despite the Chinese records that were sadly lost when the dog ate the homework). But this is too simplistic.
And it misses the point:
“Midtown Manhattan uses more energy than Kenya” SO Kenya needs more energy – not Manhattan needs less.
all depends which way the wind blows.
When talking about surface area, is that just the surface area of the land occupied or the surface area of all the buildings as well as the exposed land surface area?
I feel the mass of all the structures that act as heat sinks should have a place in any formulas used in calculating UHI.
Here is a paper from Rice Univ. on the subject of UHI. Stored heat in the physical infrastructure is factored in.
http://www.ruf.rice.edu/~sass/UHI.html
Hot night summer in the city – Urban Island heat effect is not so silly!
“Midtown Manhattan uses more energy than Kenya”
…but does it use more energy than Al Gore’s empire?
Seriously, though, that should be enough reason to build coal-fired power plants to raise the Kenyans’ well-being.
My Kenyan friend was car-jacked recently and lost friends in the terrorist attacks a while back. She’s not too worried about where her power comes from.
No, no coal! We must end it!
Didn’t anyone tell you that burning fossil fuels hurts the poor the most?
/sarc off
“And since humans are 100% efficient at turning fuel into heat,”
Not really, or we would have taken over the galaxy and be expanding outward at the speed of light. Every conversion of energy comes at a cost. So far biological ones are far more efficient than the best our engineering. Consider also the human battery. How many W/M2 is the, shall we say, plumping effect?
Well, provide us an estimate how much of the traditional calory content of food eaten by Willis has converted to heat so far, and how much remains in other forms – like stored fat. Lets assume Willis is an 80kg male doing paperwork.
Way over my pay grade (and interest level). I’m sticking with the human=100w light bulb.
“Every conversion of energy comes at a cost”
Not in terms of energy it doesn’t!
According to classical physics, energy cannot be created nor destroyed. This Law is known as ‘The Conservation of Energy’ or, more formally, the 1st Law of Thermodynamics.
What you end up with, is what you started with.
Maybe that’s why we haven’t taken over the galaxy.
‘The Conservation of Energy’ or, more formally, the 1st Law of Thermodynamics.
That’s one of the Laws that should be repealed and replaced with a ‘fairer’ more ‘Democratic’ one. That way everyone could have it all! Sorry, I couldn’t resist.
Not a loss of energy. A cost in efficiency. Fossil fuel to electricity efficiency around 40%. The other 60% is conserved, but it will not run your toaster.
Willis This is the hometown for UN headquarters I think you’ve made an error
Willis: Did you account for the fact that dietary “calories” in the US are more properly expressed as kilocalories when speaking in scientific terms?
His use of 107 watts is a good start. For NYC I would have used 125 watts.
Average activity adds to the basal metabolism. Typical male basal metabolism of 100 watts increases to 135 to 150 watts for most average office workers. Some jobs are more strenuous than others. Most people don’t use stairs, they use the elevator.
Adult female basal metabolism is 70 watts on average. Adding typical working activity means a real metabolism of 100 watts averaged over 24 hours. Those numbers directly translate into average daily food caloric intake.
Active teenagers often have higher metabolism on a per weight basis, but they are smaller than adults. Some teens just sit like blobs.
“Average activity adds to the basal metabolism.”
“Some jobs are more strenuous than others. Most people don’t use stairs, they use the elevator.”
“Active teenagers often… are smaller than adults.”
I feel like I just sat through a Captain Obvious commercial.
Is that you, Cap’n?
*sorry, could not resist*
I remember an infomercial that ran in the middle of the night some years back, made by a guy who claimed the secret to weight loss was just to drink cold water in large amounts.
He sat there and did all these calculations, showing that by the time your body heated up ice water to body temp a person would burn a huge amount of calories.
I suppose the idea was just to get people all excited about the prospect of losing weight by sitting back and drinking ice cold water, so they would buy his book. Either that or he did not know that a food “Calorie” is a kilocalorie, which is why it is always (properly) spelled with a capital C.
Whatever was the actual case, of course his calculations were off by three orders of magnitude. Drinking a liter of ice water will not force your body to burn 37,000 calories. Only 37.
You would die long before you drank enough to burn off a bag of chips.
So my drinking red wine with ice cubes is not helping me lose weight???? OMG…/Sarc off
Keep drinking the wine, but do it outside in a nice windy spot in the shade where you will lose more heat by evaporation of perspiration. 🙂
Urban Heat island also involves wind reduction by buildings, making air cooling less effective.
Please provide references for what you are talking about. Downtown high-rises typically increase wind speed, increasing convective heat losses.
Structures increase wind speed inasmuch as they decrease the area through which the air is flowing (tunneling). Upwind, the air is heated by compression. But even if the heating is negligible, buildings are air-conditioned when the outside air is warm. How will convective heat loss from an air-conditioned building be increased if the building is cooler than the air flowing around it?
There will be convection from air conditioning compressor exhaust on the rooftops. But buildings also create turbulence, and some of that hot air could be sucked down on the lee side of the building where air pressure may be reduced.
Really surprised you are not using BTUH like most US engineers do. Humans typically emit 250 BTUH sensible and 250 BTUH latent, based on ASHRAE analysis in an office environment. This is accounted for already in the building energy use, so you can’t double count it.
If you have ever flown into NYC, and looked at all the rooftops and observed all the louvers in the elevator penthouses? Those represent air losses due to thermal stack effect, which contributes greatly to UHI.
The energy waste in NYC is absolutely sickening due to poor architectural and engineering design.
” … (metabolism)… is accounted for already in the building energy use, so you can’t double count it.”
THIS. I don’t think there is not a lot of heavy manufacturing going on there, so it seems likely that the majority of the energy is expended for climate control. ALL of the heat absorbed or emitted by life forms (whether for heating or cooling) inside the building gets accounted for in the energy consumption for climate control.
Plus something else I looked for and did not find:
Presumably the energy consumption (and dissipation) for the area is elevated primarily due to the presence of high-rise buildings. Often the waste energy from air conditioning is discharged from these buildings by heat exchangers at roof level. In winter when the energy is purposely spent for heating, virtually all of the dissipation by radiation and convection happens at elevations above ground level. Figuring out how much of an increase will be measured by temperature sensors at ground level due to heat being dumped at a higher elevation is problematic at best. So the map is interesting but the relation of anthropogenic energy dissipation to Urban Heat Island effect is not so easy to establish as first-approximation intuition might suggest.
Thermodynamics modeling gets complicated even in simple scenarios. It might be that alteration of emissivity and reverbration of long-wave radiation between buildings dominates the micro-climate that comprises the Heat Island effect. On most days.
I think a lot of any effect is based on where the weather station is located. I’m about 35 miles from the airport, and there tends to be as much as a 5F difference between the airport and local stations. At 9:25AM there’s a 2F difference.
By itself that single station at the airport doesn’t have a lot of impact, but because of processing that 2F get spread around to potentially thousands (if not 10’s of thousands) of sq miles of surface area.
Willis this comment
To be found at an interesting blog here
http://clivebest.com/blog/?p=6721
More significant in winter than in summer. It’s not simply the energy used, but the tempersture at which the energy is emitted. A car engine has more effect than a bunch of humans producing the same energy. If the ambient air temperature is 37C then all the humans in New York won’t add to it, but the car engines still will. In Winter however, the human energy will cause heat flow into the surrounding atmosphere
Metabolic energy gets dissipated regardless of ambient temperature or you die. That’s why we sweat.
Is there a corresponding infra red of New York? This is the only one I can find:
http://exonews.org/wp-content/uploads/2012/05/New_York_City_from_space-SPL.jpg
It does seem difficult finding IR images of the earth’s surface although I may not be looking hard enough.
‘the bogus temperature “record” at Heathrow.’
____
A righteous blueprint for non BBC adhearants.
_____
Well done. Thx – Hans
Half the cause of the rise of the CAGW conjecture and the accompanying attempt to induce panic is that there are too many people in zip codes 02138, 10021 and 20001 and that they extrapolate from their own experience.
The problem doesn’t occur in the Northwest Territories or Eastern Siberia or among those who spend time aboard small sailboats crossing oceans.
[Cambridge, Mass; upper East Side (Central Park), NY; Washington DC .mod]
I resent that remark as a former resident of 02138 (we didn’t move, the Post Office switched ZIP codes in the middle of the night. Even worse they didn’t give 01776 to Lexington or Concord). The real problem is 80305.
[Boulder Colorado, National Center for Atmospheric Research (the climate modeling Mecca-Medina-Gaia-Utopia.) .mod]
I’ll add 80305 to the list.
I have discovered (the hard way, of course) that the use of zip codes helps confound the Thought Police of NPR who do their utmost to suppress contrary climate opinion.
Willis,
I might be completely out in left field, but your calorie calculation of human heat output may have left out the caloric value of human waste. I might consume three thousand calories of food, that does not mean that I have every calorie at my disposal, because some of them ended up in the disposal [fixture]
A couple of years back I was in New Orleans. In a park there was a temperate recording station. Across from the park was a 20 year old tourist building made of concrete. The road was black asphalt. And, to top it off a four lane black asphalt road between the park and tourist center filled with tour busses with engines running.
The global warming is a bad joke perpetuated by special hires who are seriously mentally challenged. Of course they are Democrats and true to their collective insanity. The government of the United States is a sick joke, as well as, lethal to its’ citizens.
The most dangerous thing that can be attributed to climate change are the effects of government policy intended to “combat climate change”.
Thanks for this – it has given some food for thought.
I am inclined to think that there is a limit to the UHI efect on temperatures such that once a city is fully built there would be no more increase from greater growth – sort of a step jump from rural to urban and then a constant difference to the rural. With this in mind, I was cautious in using a straightforward “UHI is proportional to city population size” kind of calculation to try and adjust for it.
However, I see that there can still be further intensification within a developing city (as nicely shown by the images provided here) and that there may not be the same kind of step change. At the same time, most towns and small cities still grow out rather than up these days and once you have made the first change to concrete and asphalt I think the rate of change (compared to non-urban affected temperatures) would be quite a bit less.
Bottom-line – UHI effect on surface temp is more complicated than a simple “proportional to city population” effect, but also not a single step change as I (used to) think.
At the end of the day, why are we still trying to use surface stations to measure climate? Weather stations are just that – for measuring the weather not the climate!
I used this as part of the ‘Theory’ I used processing surface data, I look at the day to day change for each station by itself, how the station cools over night as well as in winter. I [think new construction] would alter the temps for a day, then the new day to day change blends in with weather and climate, thousands of stations while they are all building, won’t build on the same day, as long as cooling during the winter wipes it out, all it can do is make the summer peak warmer. On the longest day of the year, it also has the shortest night, on clear nights it cools until the Sun comes up. All the way to the shortest day which has a very short warming period followed by a long cooling night.
When you look at the data like this, UHI will be small steps randomly placed, weather which at least on some scales overpowers UHI, and the seasonal change completely removes it’s year to year effect. This leave Climate, but only climate that exceeds the average weather for any particular collection of stations.
For instance, looking at all global stations, would you expect weather to force all of the the same amount? I would expect weather to average out once you have some arbitrarily large sized collection of stations. Climate would effect that collection, UHI as long as it doesn’t carry over from one year to the other disappears. Leaving the impact of Climate, but what I found was a strong regional effect that was not a trend, but periodic effects, and there’s only one large periodic forcing that moves around the planet, the oceans.
Only NAmerica and Eurasia have enough stations to dampen out weather, but even then you can see that annually average weather doesn’t have a residual trend, only the oceans moving around. That was the warming of the 80/90’s the oceans moved a lot of warm water downwind of first Eurasia, then the US.
It should be
Here’s a link to the data for the 1×1 cell of 40N 73W
https://micro6500blog.files.wordpress.com/2015/07/y_n41w73.xls
micro6500
Rather, new construction occurs over a long time of
(1) nearby disruption and demolition – which will open up space and can dramatically change the local sunshine and local heat island issues.
(2) construction itself (includes landscaping!) of 9 – 18 months. Not actually too much “energy” used at the local site, but frequent sunshine blockage or temporary building construction or roadway and ramp changes.
(3) initial occupancy = AT LEAST one year before the local “climate” stabilizes: New energy released (heat and AC changes to the local air), new wind patterns all year, new sunshine site angles and shadows and solar-reflected energy to and from local buildings and parking lots, new traffic patterns, etc.
Fair enough, but don’t you think that day to day changes will be more transient in nature, and look more like weather than climate?
@RACookPE1978
BTW, I finally got through doing all (well most all) of the code to calculate station solar forcing from the equation you gave me, it’s the daily forcing in the first graph, I wanted to again say thanks!
@micro6500When you look at the data like this, UHI will be small steps randomly placed, weather which at least on some scales overpowers UHI, and the seasonal change completely removes it’s year to year effect. This leave Climate, but only climate that exceeds the average weather for any particular collection of stations.
Climate would effect that collection, UHI as long as it doesn’t carry over from one year to the other disappears.
How can a dumb thermometer know the difference between “Climate Change” and someone erecting brick buildings, shiny glass wall, and multi-kilowatt air conditioners that influence the thermometer? Having thousand of thermometers doesn’t help if most of them are subjected to the same urban development influences. Thermometers cannot tell the difference between UHI and (real) Climate Change.
The fatal assumption that BEST makes is that they can spot just the hypothesized UHI step changes, and snip the record at that point. But all they do is bake in REAL UHI changes and instrument drift over months and years and tag it mistakenly as climate change. I believe you are making the same mistake.
UHI change is a longer lived event than is the sun-spot cycle and ENSO.
Which is why I don’t do what BEST does, the best description is I look for trends in the day to day change that end up in the yearly average , not short term trends that average way with a group of stations.
Stephen,
I saw your post again, and it reminded me of something I think is not well described.
What exactly are we looking for in the temperature record?
A change in peak temperature?
A change in minimum temperature?
A change in how much temps go up each day?
Annual average where most of the planet isn’t actually measured?
Annual average of station measurements?
As we consider this, we have to understand how each cause(UHI,Co2, etc) impacts each of these measurements, can we tell the difference between UHI and Co2 in the measurements?
Glad to see the direct heat production of megalopoles considered . I did 20 years in Manhattan ; was lucky to be along a edge by the East River , But walking thru the heating and air conditioning vents from highrises on a ninety degree anyway day was an unappreciated additional shirt-soaker . The extra heat generated by the valiant efforts of the industrial AC units working to produce islands of comparative comfort in the subway stations always made me think of how much heat they were adding to the ambient temperature they were battling .
And , of course , for all the electric energy released in the city , an equal amount has to be dissipated at the power station . These terawatt hours are not negligible .
The human heat load would be factored into the Air Conditioning load.
Thanks, JN, but I don’t think so. Consider. A person is standing in a room. They are putting out 100 W/m2. When you turn on the air conditioning, it doesn’t get rid of that 100 W/m2. Energy can’t be created or destroyed. All it does is pump the 100 W/m2 from inside the building to outside of the building.
Now, as soon as you turn on the air conditioner it has to do work to move that heat outside … but that is work IN ADDITION TO the heat that it is moving.
All the best,
w.
Years ago I went to an EPA seminar about addressing UHI. Four years later the same group effectively told me that UHI has no impact on warming. I just wish the government could come up with consistent data.
It is amazing, and must surely give some UHI.
But think of it opposite: So much energy released artificial (equal to the insolation which is still there), and even then the temperature rise is benign.
How does it compare with the climateers prediction of a boiling planet for just a few more w/m2?
The ice extend in Arctic is often measured in Manhattans, so how many Manhattans of ice would be needed to cool it down.
12,000 BTU per ton of ice. That is a lot of air conditioning systems locked up in all of that ice.
And consider how much ice is lost in the summer and then regrows every winter, the cooling to space as well as energy from the Sun in the summer is astounding.
And as you rightly note, they’ve gone all buggered over a couple watts/meter^2.
Willis, thanks for a brilliant take
W/m^2 is a UNfamiliar unit to most people, but it is a fair unit of measure for the climate crowd.
Convert the waste energy going into NYC into cataclysmic climate change energy densities and then ask, “Where is the cataclysm? “
I find that more data is always good for extending the conversation. Here, from the marvelous site GapMinder, I’ve taken their data to create the following chart …
Curiously, the anthropogenic energy per square metre of China and the US are about the same … always more for me to learn.
w.
Willis,
I am wondering if there is another factor to include which I started wondering about when reading your Heathrow analysis. Would the concentration of CO2 be higher in a city (or airport for that matter)? Does that suggest that there would also be higher CO2 inspired down welling radiation? So is it reasonable to assume that the classic “greenhouse” effect would actually be more pronounced in cities and other places of concentrated CO2 emission? I am not sure where to start with that calculation. Does anybody actually measure CO2 concentration in New York – or is it too low in the atmosphere, or too rapidly dispersed to matter, or would the aerosols from the city effectively cancel it out?
When you look at satellite data, the spread of min to max is only 5-10 ppm, not a lot.
But as I showed with my IR temps, I took them again at midnight, and while the sir, grass and sky were much colder, the concrete and asphalt were still much warmer, I’ll put up a graph shortly.
Air temp = 63F at midnight
Concrete=~70F
Grass=~59F
Asphalt=~75F
Sky= – 22F
Sunset was a couple minutes before local 9:00pm, Air temp peaked ~6:00pm @ 80F, in 6 hours air temps dropped 17F, min temp this morning was @ Sunrise 59F (sorry I didn’t get up early enough to get IR temps before the Sun was up).
But I think air temp isn’t the only player involved, it’s the ground temp + water vapor, just like the oceans radiating to space.
micro6500,
Thanks for replying. Interesting. So it looks like there would be no significant greenhouse effect island with such a small elevation in the co2 level, and likely that the surface radiation would substantially outweigh it even if there was.
Once again, thanks for responding.
It seems to me that the real players in air temps are water vapor, both because it carries a lot of latent heat with it and it’s impact on cooling rates, and land use/land temps.
Then the ratio of day to night as the seasons change.
If Co2 changes this it’s so small to be insignificant.
I haven’t a clue how to track it down. But, I’ve long wondered if our ‘air conditioning’ of our living spaces is a significant contributor to UHI. I’m not talking about accounting for the energy used to do the air conditioning or the heat generated by the machinery doing the conditioning. Rather, the actual conditioning.
We refer to our air conditioners as ‘heat pumps’ because that is exactly what they do. They move heat from a volume and push it into the surrounding environment.
If, when we are conditioning our air, we cool more than heat, accounting for geographies (northern heaters vs southern coolers) and seasons and stuff, then we are necessarily temporarily moving more heat out of our living spaces than we’re pushing in. Ergo, until air conditioning stops, we would be heating the environment in our urban areas with our ‘heat pumps’ by creating our little cool spaces.
The energy used to do the “moving” is all that really counts. Think of it as “pumping” the heat from the inside of the wall to the outside where it is leaking back to the inside, all you are really doing is “circulating the “heat”.
Reblogged this on Climate Collections and commented:
Willis Eschenbach discusses the Urban Heat Island on Manhattan
A guest post provides a glimpse of human body contribution.
Here’s a link to the 1969 paper by Dr. Leonard O. Myrup on UHI:
http://journals.ametsoc.org/doi/pdf/10.1175/1520-0450%281969%29008%3C0908%3AANMOTU%3E2.0.CO%3B2
A key component of UHI remains water: evaporation, irrigation, evapotranspiration, etc.