Remember when I measured the UHI in Reno, NV? It seems the normally alarmist “Climate Central” is just now getting around to recognizing UHI, but of course, they have to put in the obligatory disclaimer that it cannot possibly contribute to the global warming signal. Well, they are just flat wrong about that, but that’s what they are paid to say.
New Study on Urban Heat Islands and Climate Change Shows Most Large U.S. Cities Getting Hotter Faster than Rural Areas
Since 1970, summer temperatures have been rising. While exact rates of warming differ between regions, most cities have been heating up faster than adjacent rural areas all across the United States. The concrete and asphalt surfaces in city buildings, roads, and infrastructure hold more heat and release that heat more slowly than vegetation and organic surfaces. This is known as the Urban Heat Island (UHI) effect. Climate change then takes that heat and makes cities even hotter.
In a new report, Climate Central analyzes how UHI and climate change have affected 60 of the biggest American cities since 1970. The study examines the difference between average summer temperatures in urban areas and nearby rural areas. Some cities had much higher temperature differences: 23 different cities experienced single days that were an astonishing 20°F warmer than the rural areas around them.
With more than 80% of Americans living in cities, these urban heat islands, combined with rising temperatures caused by increasing heat-trapping greenhouse gas emissions, can cause serious health effects for hundreds of millions of people during the hottest months of the year. Heat is the number one weather-related killer in the United States, and the hottest days, particularly days over 90°F, are associated with dangerous ozone pollution levels that can trigger asthma attacks, heart attacks and other serious health impacts.
The study ranks the 60 cities by the intensity of their heat island effect, shows how heat drives air pollution (ozone levels) in nearly every city analyzed, lists cities that have far more days over 90°F than adjacent rural areas, and shows how most cities are warming faster than the surrounding rural areas.
analysis of summer temperatures in 60 of the largest U.S. cities found that:
- 57 cities had measurable urban heat island effects over the past 10 years. Single-day urban temperatures in some metro areas were as much as 27°F higher than the surrounding rural areas, and on average across all 60 cities, the maximum single-day temperature difference was 17.5°F.
- Cities have many more searing hot days each year. Since 2004, 12 cities averaged at least 20 more days a year above 90°F than nearby rural areas. The 60 cities analyzed averaged at least 8 more days over 90°F each summer compared to adjacent rural areas.
- More heat can increase ozone air pollution. All 51 cities with adequate data showed a statistically significant correlation between higher daily summer temperatures and bad air quality (as measured by ground-level ozone concentrations). Temperatures are being forced higher by increasing urbanization and manmade global warming, which could undermine the hard-won improvements in air quality and public health made over the past few decades.
- In two thirds of the cities analyzed (41 of 60), urbanization and climate change appear to be combining to increase summer heat faster than climate change alone is raising regional temperatures. In three quarters (45 of 60) of cities examined, urbanized areas are warming faster than adjacent rural locations.
- The top 10 cities with the most intense summer urban heat islands (average daily urban-rural temperature differences) over the past 10 years are:
- Las Vegas (7.3°F)
- Albuquerque (5.9°F
- Denver (4.9°F)
- Portland (4.8°F)
- Louisville (4.8°F)
- Washington, D.C. (4.7°F)
- Kansas City (4.6°F)
- Columbus (4.4°F)
- Minneapolis (4.3°F)
- Seattle (4.1°F)
- On average across all 60 cities, urban summer temperatures were 2.4°F hotter than rural temperatures.
Urban heat islands are even more intense at night. Over the past 10 years, average summer overnight temperatures were more than 4°F hotter in cities than surrounding rural areas.
Urban heat measured by satellite in Louisville, Ky. Click image to enlarge.
Several independent studies have shown that urban heat islands (in the U.S., and around the world) do not bias global warming measurements, ruling out the possibility that rising global temperatures have been caused by urbanization alone.
Research suggests that urban planning and design that incorporates more trees and parks, white roofs, and alternative materials for urban infrastructure can help reduce the effects of urban heat islands.
But rising greenhouse gas emissions are projected to drive average U.S summer temperatures even higher in the coming decades, exacerbating urban heat islands and their associated health risks.
Source: http://www.climatecentral.org/news/urban-heat-islands-threaten-u.s.-health-17919
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“Climate change then takes that heat and makes cities even hotter.”
Man, climate change is something else, ain’t it? Stalking around like that, looking for heat to grab.
So this would be excuse # 35?
Funny how heat is blamed for the winter rise in mortality.
Is it a negative function?
Rising heat leaves more people vulnerable to freezing to death?
Any commuter with a air temperature sensor in their car, knows the UHI effect. Ditto all motorcyclists.
I wonder, what other “pause creating factoids” will be rediscovered by these geniuses?
Wait a minute. better ask the Bestiboys… how can such an insignificant effect suddenly be a
doom upon city dwellers?
Moderators..
what has happened to my name?
Is this from my computer or from your web-host?
REPLY: No idea – we have no control over how your name is displayed – Anthony
This comes from an institute akin to the one Douglas Adams named:
MISPWOSO
The Maximegalon Institute of Slowly and Painfully Working Out the Surprisingly Obvious
Yet another gem from H2G2
JohnWho:
At August 20, 2014 at 11:23 am you say
Sorry, but it is not that simple.
There are three issues; viz.
1. the local climate.
2. the global climate.
3. the determinations of global average surface temperature anomaly (GASTA).
UHI is an obvious alteration to the local climate.
The region surrounding an urban area has a cooler climate than the urban area.
UHI is a trivially small effect on global climate.
The area covered by urbanisation is a tiny proportion of the Earth’s total surface area. The UHI warming is localised to urbanised areas and is an indiscernible increase to the average temperature of the Earth’s total surface area (ignoring that temperature is an intrinsic property so has no true average value).
UHI is a significant effect on determinations of GASTA.
The sites of temperature measurements are mostly taken where people live and, therefore, are disproportionally in urbanised areas. This provides error to GASTA and ‘adjustments’ are made in attempt to correct for the error. These adjustments to determinations of GASTA throughout the twentieth century have similar magnitude to the global warming over the twentieth century indicated by time series of GASTA. (Changes to values through these time series are what our host calls “the global warming signal” in his above article.)
Richard
That slide shows a mashed-up skyline of downtown Indianapolis! Looks like even a land-locked city like Indy can be an “island” when it comes to anthropogenic (due to pavement & thermometers) “local warming”.
Ancient Rome was a city of some one million people that stretched for some 50 miles. UHI was well known and after the great fire Nero ordered that it should be rebuilt with narrower streets and higher buildings to create shade.
There is probably some logarithmic progression in temperature build up compared to population/amount of built up area. However at some stage! no matter how built up the area becomes, it will not warm any further. In consequence the uhi affected area spreads from a small central area of the city right into the densely built suburbs.
As many of the worlds thermometers are located in growing urban areas you would expect them to get progressively warmer up to a point and for this to be reflected in global temperatures.
Tonyb
AndyZ says:
August 20, 2014 at 10:42 am
You probably should ask Mosher about that. Either that, or go to the BEST site and try and make sense of their methodology – not methods mind – methodology. Their disucssion is here:
https://dl.dropboxusercontent.com/u/96723180/Influence%20of%20Urban%20Heating.pdf
The general discussion is just vague enough that methodology hangs out there in the foggy fringes of clarity. They say that they adhere closely to the methods advocated by three earlier studies, none of which identified any strong UHI influence on the estimate of change in mean global temperature through time. They did identify regional trends, for instance in the southeastern US, where urban temperatures were trending downward. I believe that trend affects about one third of the urban temperature records in the USHCN. The remainder show warming. The real problem from a methodological view is that few if any discussions, address the genuine realities of where temperature data is collected. Even “rural” land is affected by human land use.
Rural weather stations are primarily associated with agricultural communities. That means that even those stations are subject to an anthropic signal. Further, anthropic changes in rural regions may be in more than one direction over time and quite possibly greater than comparable urban changes. Early land clearing for example would elevate base temperatures so that when the weather stations were finally established, the area was already experiencing an elevated temperature compared to the pre-agricultural past. A shift from say unirrigated winter wheat to summer rice in flooded paddies would significantly change readings in several possible ways. The land clearing and ploughing to grow wheat would initially increase heat measures, decreasing albedo and increasing evaporation rates. A shift to irrigated rice paddies would dampen temperature swings due to evaporation while the paddies are flooded which would tend to cool things during the day, but keep them warmer at night. They also would behave more like normal dry croplands later when the paddies dry, resulting in possible seasonal shifts in temperature patterns and trends. Anyway. there should be a rural effect that I do not see any serious attempt to address. I could easily be mistaken but I am sure that no “rural” corrections are made in any model I have read about.
Until the advent of USCRN in the early 21st century, data from actual wild lands was a very minor component of the US temperature record. And please mark that only in wild lands can a clear baseline of natural temperatures (and thus climate theoretically) be acquired.
So, the short of it for me is that no available “climate” study based on historical weather data has a shot at yielding a trustworthy model of “climate” trends.
Shifting to a philosophy of science viewpoint, climate is an epistemological nightmare. It is true that we blithely toss the term “climate” around as if everyone not only understood, but agreed that there actually >i>was such a critter. But . . . . The idea of “climate science” is an example of a reification, a form of a logical fallacy. No one experiences, or has ever experienced “climate.” The concept is a generalization of historical experience concretised by “climatologists” and “climate science.”
All that humans experience is weather on a day-to-day basis. All that our weather stations record is weather data, again on a day-to-day basis. Even tree rings and varves are “records” of weather, not climate, since even trees respond to weather changes rather than “climate,” and varves only respond to changes in erosion. Climate cannot logically be shown to exist independently of weather. Climate is always a generalization OF weather. The idea that climate actually determines weather remains completely and absolutely an unproven inference. There is quite seriously no scientific grounds for even implementing a concept of “climate” scales where finer-grained weather data and proxies are available. The smallest time scale at which a concept of “climate” might be even remotely useful is in scales of 10,000 years or greater. Even then climate remains a gloss for really coarse grained information about weather over long time spans.
Back in September 1995, we had some unusually cold air headed into the Cornbelt. The corn and especially the soybean crop was not yet mature and temperatures below freezing would do quite a bit of damage which would reduce yields and the crop size(supply).
I had already made a chunk of money being long soybeans a week before the freeze as the market price spiked higher after updated weather forecasts became increasingly cold.
On the Friday before the weekend with the coldest air that would hit, I decided that the market was still under priced and was not anticipating enough damage from temperatures that I figured would be cold enough to end the growing season in some areas of Illinois and Indiana, where the soybeans were still green and not mature.
The markets were closed back then until Monday morning. The opening price would reflect actual damage or lack of it.
I was up early on Saturday morning and first checked our local National Weather Service temperatures, here in Southern Indiana, a location that was effected by the expected freeze. I was horrified. The low was 39 degrees F. I knew it got colder in the outlying, rural areas, where all the soybeans are grown but my first impression after seeing 37 degrees was that it meant a big loss on Monday morning.
1995 had been a very dry Summer(extremely dry soils were one factor in why I thought temps would bottom out lower than what the market thought).
I went outside to water my rain starved garden with the hose hooked up to the outside faucet. We lived in the country, 3 miles north of the National Weather Service location at the airport. We were also on well water and had been having a problem with the well drying up.
I turned the faucet on and no water came out. Dang, that’s all I needed. First losing money from a forecast that was too cold and now we don’t have any water…..again. I disconnected the hose and water gushed out………..what the?
The water in the hose water completely frozen! That couldn’t happen unless temperatures were well below freezing for numerous hours overnight.
I called a friend who had numerous farmer contacts and they all reported the same sort of thing. Actual thermometer readings at rural sites bottomed out in the mid 20’s F in a large area of Illinois and Indiana, even some low 20’s, while none of the official NWS thermometers dropped as low as 32 degrees F.
The exact same thing happened on Sunday morning. 37 degrees at the NWS, while the water in my garden hose outside was frozen.
Turns out that this was a bit unique for several reasons. The ground was bone dry as mentioned earlier(top soil moisture was almost nothing). The air mass was cold and dry but we had ideal radiational cooling, with clear skies and calm winds both nights. The center of a surface high pressure system was right on top of us.
Additionally, we had extreme cold air drainage taking place between high and low elevations.
Here in Southern Indiana, the ground is pretty flat but we have plenty of hilly ground and lower lying spots. Since cold air is more dense, as the temperature falls under these conditions, it drains into the valleys and lower lying spots, with the higher spots staying as much as 10 degrees warmer, even higher by just 5 feet in some cases, causing an extreme vertical temperature inversion.
In this instance, the inversion must have been incredible, with air at least 10 degrees colder hugging the ground in the low spots…….which is where may garden hose was located. Much of the soybean plants are close to the ground too.
The NWS instrument shelter/Stevenson screen? 5 feet above the ground, as well as being on somewhat higher ground and also located within what you would call our small urban city.
A few days later, an inspection of miles of soybean fields was very revealing. The high ground soybeans were still mostly green, the rest, especially those on lower ground and effected by the cold air drainage all turned black……they were dead.
The soybean market opened higher on Monday, knowing that the above freezing temperatures over the weekend in the urban locations didn’t matter……….they don’t grow soybeans in the city!!!
“The low was 39 degrees F. I knew it got colder in the outlying, rural areas, where all the soybeans are grown but my first impression after seeing 37 degrees was that it meant a big loss on Monday morning.”
Both those temperatures should be 37 degrees F
JohnWho (August 20, 2014 at 11:23 am)
The heat from UHI either makes the climate warmer or it doesn’t.
—
i don’t think the two statements are contradictory – the second sentence seems to mean that the UHI heat plus AGW makes cities hotter – try parsing the statement “Climate change then takes that heat and makes cities even hotter” – i don’t think it was meant to be taken literally
—
i wonder about a couple of claims made by the original article (linked at the end of the above article)
“Heat is the No.1 weather-related killer in the U.S.”
“Summers in the U.S. have been warming since 1970.”
i recall an post on this site that debunked the first claim – but i don’t know about the second claim – (and note that the original article limits the area to the US)
JEyon says:
August 20, 2014 at 12:50 pm
JohnWho (August 20, 2014 at 11:23 am)
The heat from UHI either makes the climate warmer or it doesn’t.
—
i don’t think the two statements are contradictory – the second sentence seems to mean that the UHI heat plus AGW makes cities hotter – try parsing the statement “Climate change then takes that heat and makes cities even hotter” – i don’t think it was meant to be taken literally
I understand. However, they make the statement that implies that UHI heat adds to the atmospheric heat after they previously say that UHI isn’t making the atmosphere warmer.
At least, that’s what I got. If I’m the only one, then so be it.
JohnWho August 20, 2014 at 12:55 pm
I understand. However, they make the statement that implies that UHI heat adds to the atmospheric heat after they previously say that UHI isn’t making the atmosphere warmer.
At least, that’s what I got. If I’m the only one, then so be it.
i think we can agree that UHI adds a miniscule amount to the global average temperature – but probably a significant amount to the global average temperature reading
This is the real Man Made Global Warming and shows that the (s)warmies were right all along.
Roy Spencer says:
August 20, 2014 at 10:30 am
OMG! So Global Warming is obviously worse in the cities!!! Where most of the people live!!!
++++++
Perfect Roy!
Are we allowed to just extrapolate for simplicity’s sake… So Urban Heat Island Warming is obviously only in the cities!!! Where most of the people live!!! //sarc off 🙂
Yup. Captain Obvious……..
Nice to see someone attempt to quantify the effect, but who on earth didn’t already know it to be a fact? I notice the authors paid the usual homage to AGW establishment interests. Always a good idea if you wish to get published.
Stay after it, Anthony. I know you don’t do it for glory, but at least you will be able to enjoy the last laugh.
I predict reason #99 for the pause will be:
“We over adjusted upward in the past. So now making new corrections we see here a trend since 199x rising perfectly with CO2 levels.”
you are all missing the point,as the best homogenization process takes that uhi and smears it over thousands of square miles ensuring it has no effect on the inhabitants of the cities or the global average temperature data series 😉
AGW is like living under a fishnet. It reflects a small portion of the heat back to the ground. Base on quick calculations, the fishnet equivalent to the increase in CO2 of the last century would look like this: if the threads of the fishnet were 1/8 in.(3mm) wide, they would have to be spaced by around 8in(20cm) in both directions. I don’t think this kind of fishnet would make the nights much warmer. So it is safe to say that the increase in CO2 over the last century cannot have changed the diurnal temperature range by a significant amount.
It is also interesting to see that months with snow cover often have higher daily max temperatures in cities. The snow often melts on the roof and a layer of warm air is created and it stops convection underneath.
I have also seen temperatures get 5C higher day after day in summer because the warm air heated on the roof was pushed by a constant wind and convection was completely dead under it.
Well, the present California, unprecedented mega drought, is having a disruptive technology emergence in Silicon Valley.
Now I have often asserted, that the best kind of grass to grow for a front lawn, would be a nice slab of green concrete; hopefully colored through and through, so it would last forever; rather than just a paint job.
So now all over the Valley , well Sunnyvale anyway, the water starved brown micro hay, is being dug out, and replaced, with mosaics of paving stones. They now run from the sidewalk / footpath, up to the very garage door.
One house just across the street from me, had a lively crew of “immigrant” stone masons, who took a jack hammer to the footpath / sidewalk, and broke the whole thing up , into pieces of concrete, that a typical immigrant mason, could pick up by gloved hands, and put in the back of a truck for hauling to a landfill. Then the dust blower crew came in, and blew all the concrete pieces, too small to pick up, over onto my driveway, and all over my cars’ shiny paint.
Next, a large cement mixer truck, came and poured a new concrete sidewalk, which the mason artisans smoothed by hand trowel, into their idea, of a new footpath, to merge with the mosaic tiled brickyard, that once was the front lawn (and pre garage addition). The new side walk set up over night, so, the next morning; crack of dawn, the jack hammer crew could return, and demolish the new footpath again, down to immigrant stone mason size. Meanwhile, the Mosaic artists, would restack the red and brown brick tiles, after the house resident, had ruled nyet, on the artistic design.
So in about ten days overall, this sidewalk was dismantled, and re-poured, four times in all, that I counted, each time with an intervening dust blower encorpse, to re-decorate my cars.
I’m guessing that the rock quwarriers, did the first job, sans any sort of city approval, or building permit; who needs a building permit ??
Well the instant replays, were probably for some sort of road code violations. And four times, the moasicticians, did actually reshuffle, and re-stack, and re-lay the tiled art work.
So the last re-incarnation of this project, actually took place with the new residents, actually having moved in; in the interval, between the rock truck, leaving for the land fill, and the next arrival of the cement mixer truck.
I really would like to know the full history of this project, and what the final grade was, that the immigrant Stone Mason students received for their project.
Bottom line is; the home’s new water usage, is about the same, since the new residents , number more than the previous occupants, of the small lawned residence that use to be there. No doubt, the house flipper, on this deal, made a killing. The start up stone masonry, likely will seek, whatever substitutes, for Chapter Eleven, in failed DIY enterprises.
So this coming winter, should be warmer, due to the lawnless neighbor, and no need for evaporative cooling of his driveway artistry.
It would be nice to get a couple of showers, to remove the speckled concrete new paint job on my cars.
The concrete and asphalt surfaces in city buildings, roads, and infrastructure hold more heat and release that heat more slowly than vegetation and organic surfaces. This is known as the Urban Heat Island (UHI) effect. Climate change then takes that heat and makes cities even hotter.
Let’s not forget about Residential / Building services power. I remember calculating New York City’s waste heat from a news article with Mayor Rudy G telling about 80% of the power going to building services and the amount. Worked out the square meters and the waste heat was around 35 W/m^2, back when the CO2 return was near 3 W/m^2. Later in the post a reply informed use that the city had a contract that a percent of the power (40%??) had to be produced in the city, so a lot of waste heat added to that number.
So they only took 4+ years to learn what a 6th grader figured out and reported Dec 2009?
http://wattsupwiththat.com/2009/12/09/picking-out-the-uhi-in-global-temperature-records-so-easy-a-6th-grader-can-do-it/
Although there can be no doubt that these urban heat islands exist and are significantly warmer than their surroundings, it seems intuitively obvious to me that it is the *growth* and development of these urban heat islands that leads to measurable *warming*.
Static long-established urban areas (e.g. Oxford, UK) may have a measurable UHI – but if it hasn’t grown or intensified significantly in time then there will not be much UHI-driven warming there.
On the other hand, temperatures at a location (e.g. Heathrow, UK) that was a rural pastoral district 60 years ago and is now one of the worlds busiest airports around just two runways (and surrounded by urban sprawl) are going to include lots of UHI-driven warming.
Static or slow-developing UHIs = negigible UHI warming;
Rapidly expanding and developing UHIs = rapid UHI warming.
So how much more Co2 is there in the air in cities than in rural areas? Is the concentration really enough to effect the temperature in Reno by 17 C in spikes, and .6C on average.
It would be interesting to know the CO2 levels between the urban and rural locations. 🙂