This is a small bombshell. I’ve been telling readers about UHI since this blog started. One notable example that I demonstrated by actual measurement is Reno, NV:
Click for larger image
The IPCC reports have minimized the effects of UHI on climate for quite some time.
From Warwick Hughes:
The IPCC drew that conclusion from the Jones et al 1990 Letter to Nature which examined temperature data from regions in Eastern Australia, Western USSR and Eastern China, to conclude that “In none of the three regions studied is there any indication of significant urban influence..” That has led to the IPCC claim that for decades, urban warming is less than 0.05 per century.
A paper in JGR that slipped by last fall without much notice (but know now thanks to Warwick Hughes) is one from Phil Jones, the director of the Hadley Climate Center in the UK. The pager is titled: Urbanization effects in large-scale temperature records, with an emphasis on China
In it, Jones identifies an urban warming signal in China of 0.1 degrees C per decade. Or, if you prefer, 1 degree C per century. Not negligible by any means. Here is the abstract:
Global surface temperature trends, based on land and marine data, show warming of about 0.8°C over the last 100 years. This rate of warming is sometimes questioned because of the existence of well-known Urban Heat Islands (UHIs). We show examples of the UHIs at London and Vienna, where city center sites are warmer than surrounding rural locations. Both of these UHIs however do not contribute to warming trends over the 20th century because the influences of the cities on surface temperatures have not changed over this time. In the main part of the paper, for China, we compare a new homogenized station data set with gridded temperature products and attempt to assess possible urban influences using sea surface temperature (SST) data sets for the area east of the Chinese mainland. We show that all the land-based data sets for China agree exceptionally well and that their residual warming compared to the SST series since 1951 is relatively small compared to the large-scale warming. Urban-related warming over China is shown to be about 0.1°C decade−1 over the period 1951–2004, with true climatic warming accounting for 0.81°C over this period.
Even though Jones tries to minimize the UHI effect elsewhere, saying the UHI trends don’t contribute to warming in London and Vienna, what is notable about the paper is that Jones has been minimizing the UHI issues for years and now does an about face on China. And even more notable is that Jones result are directly at odds with another researcher at Hadley, Dr. David Parker.
It seems that Parker is looking more and more foolish with his attempts to make UHI “disappear” To back that up, the National Weather Service includes the UHI factor in one of it’s training course ( NOAA Professional Competency Unit 6 ) using Reno, NV.
In the PUC6 they were also kind enough to provide a photo essay of their own as well as a graph. You can click the aerial photo to get a Google Earth interactive view of the area. The ASOS USHCN station is right between the runways.
This is NOAA’s graph showing the changes to the official climate record when they made station moves:
Source for 24a and 24b: NOAA Internal Training manual, 2004-2007
What is striking about this is that here we have NOAA documenting the effects of an “urban heat bubble” something that Parker 2003 et al say “doesn’t exist“, plus we have inclusion a site with known issues, held up as a bad example for training the operational folks, being used in a case study for the new USHCN2 system.
So if NOAA trains for UHI placement, and Hadley’s Dr. Jones admits it is real and quantifies it, I’m comfortable in saying that Parker’s claims of UHI being negligible are pure rubbish.
Its all about location, location, location. And climate monitoring stations that are poorly sited and that have been overrun by urban growth clearly don’t give a pure signal for assesment of long term climate trends. This puts a real kink in the validity of the surface temperature data in GISS and HadCRUT and could go a long way towards explaining the divergence between satellite and surface temperatures in recent years.
Forgive my ignorance, but can’t satellites take an IR image (like the FLIR images you posted of weather stations) that will show that actual warming of the city compared to surrounding area?
I will have to watch the video again, but what Dr Christy cites is that the Sierra Nevada Valley where he grew up shows warming because it is no longer a desert – it is now covered with towns, roads, sidewalks, car parks, vineyards, farms, etc so the temperatures have seen a rise there (UHI).
If there was “global warming” (as opposed to just lots of urban warming) then warming should also be evidence at higher altitudes around the valley but there is no warming occurring.
If the widely scattered thermometers were used only for determining local temperatures, and not applied to any further use, no problem. But these widely scattered thermometers are being used to determine the temperatures of huge amounts of air.
So take a large test tube 2/3rds full of water, with a thermometer in it, touching the bottom of the test tube, and hang the test tube in the lab. Noted temperature changes would at least come close to reflecting the overall temperature of the water in the test tube.
Then apply a bunson burner to the very bottom of the test tube for perhaps 30 to 40 seconds. Would the temperature measured by the thermometer still give a valid reflection of the average temperature of the water in the entire test tube? Of couse it wouldn’t.
The thermometers used for determining temperatures of huge quantities of air will always be sensitive to local changes of temperature which in no way can be applied on the broader scale.
Attempting to use so few thermometers for such a broad purpose is the height of foolishness. To then do some sort of averaging and say that the results represent the average temperature of a hemisphere or the entire planet is beyond foolhardy. And it surely has nothing to do with valid science, or proper scientific method.
I agree with you. Lou Dobbs of CNN said the other night that world population would reach 9 billion or so. I pointed out to Lou (because he failed to) that world population growth has been declining for a long time and is now at approximately 1.0% , down from over 2% around 1962.
Census Link
The fact is, the world population growth rate has been declining since around 1962 and is projected to continue to decline well into the 2050’s and perhaps beyond. The wealthiest countries in the world have the lowest population growth rates, as well as the lowest mortality rates (best of both worlds). The lesson here is that the better off a population is (wealth, prosperity, technology) the lower the population growth rate and the higher quality and longevity of life. Cap’N Trade and various CO2 taxation schemes, will surely work to undermine prosperity and the associated benefits. Further, the greater the prosperity in developed countries (such as the US), the lower the population growth rate in undeveloped countries (trickle down effect) as their own prosperity rises as well. Cap’N Trade and other CO2 taxation schemes will impact these undeveloped countries the most.
If cities exhibit the UHI effect and they surely do then as this heat rises from the cities it will have some effect on the atmosphere above the city.
Yes, but Roy you are not supposed to measure air above a city. That is just asking for contamination.
We shouldn’t be measuring temperatures in or near cities as a proxy for global warming trends in the first place. It should only be in the countryside, out in a field, and up a pole.
Every single surface station that isn’t like that should be scrapped, unless urban warming trends have scientific value.
Dr. Jones says:
I’m assuming, perhaps wrongly, that he means they haven’t changed in relation to rural sites in the surrounding areas.
I simply fail to see how you can introduce hundreds of thousand cars in London over the span of 100 years, and not effect urban temperatures. And that is just cars. Are they saying that conditions are exactly the same in 1900 as they were in 2000?
>someone obviously failed spelling……
Neil, perhaps you might tells us how large the UHI island effect must be to explain global warming given earth’s geography.
I look forward to your response.
A correction for the urban heat island (UHI) effect is applied to many temperature stations. However, this paper by DeGaetano and Allen indicates that these corrections are not efficient.
For 1960–96, they looked at the temperature records that showed the most extremes in maximums and minimums, greater than the 90th, 95th or 99th percentiles. They found, for example, that the rate of increase in extreme warm minimum temperatures at urban stations to be nearly three times greater than the rate of increase at rural stations (those less affected by growing urban heat islands).
Trends in Twentieth-Century Temperature Extremes across the United States
Arthur DeGaetano and Robert Allen
Journal of Climate Vol. 15 (2002) 3188–3205
http://ams.allenpress.com/perlserv/?request=get-document&doi=10.1175%2F1520-0442(2002)015%3C3188%3ATITCTE%3E2.0.CO%3B2
Another article on the inefficiency of urban heat island corrections. Changnon looked at 50 years of rural soil temperature measurements and found UHI-corrected data to overestimate the temperature change. He found that the stated increase of 0.6° was too large by 0.2°C.
A Rare Long Record of Deep Soil Temperatures Defines Temporal Temperature Changes and an Urban Heat Island
Stanley A. Changnon
Climatic Change Vol. 42 (1999) 531-538
http://www.springerlink.com/content/v4h5r00770rn4782/
Abstract:
A long-term set of deep soil temperature data collected over a 64-year period beginning in 1889 in a rural Illinois area provide a rare opportunity to assess the natural shifts in temperatures in a pristine environment without any urban or instrument bias. Temperatures from 1901 to 1951 increased 0.4 °C, and this was 0.2 °C less than nearby values from two high quality surface temperature data sets that supposedly are without any influence of urban heat islands, shifts in station locations or instrumentation, or other changes with time. Comparison of the soil values with surface air temperatures from a nearby weather station in a growing university community revealed a heat island effect of 0.6 °C. This value is larger than the adjustment based on population that has been recommended to eliminate the urban bias in long-term temperature trends in the U.S. Collectively, the results suggest that additional efforts may be needed to eliminate the urban influence on air temperatures, beyond techniques that simply use population as the basis. Population is only an approximation of urban factors affecting surface temperatures, and the heat island influences inherent in the values from weather stations in smaller communities which have been used as control, or data assumed to be unaffected by their urban environment in the adjustment procedures, have not been adequately accounted for.
Doing the “best you can” with inadequate resources is most often counter-productive, and in a goodly number of instances, is far worse than doing nothing at all. Applying data which is sketchy at best, and then killing the economies of most of our world by applying the results of these inadequate resources to cause great increases in our costs of energy is a crime against all humanity.
I believe the UHI definitely exists and greater than most was assert, however, I do not believe its contribution to actual global temperatures is measurable. Those “extra acres” you are talking about, amount to not even a drop in the bucket … not measurable. The impact is not the additional heat that UHI contributes to global temperature, the impact is our MEASURING of the global temperature.
There is a pretty good summary paper on UHI if anyone is interested:
Rizwan Ahmed Memon, Dennis Y.C. Leung & Liu Chunho (2008), ‘A review on the generation, determination and mitigation of Urban Heat Island’, Journal of Environmantal Sciences 20, pp. 120-128.
Having been involved (decades ago) in intercept and relay of weather data broadcasts from Southern China, I will note that the CW broadcasts were very reliable and started precisely when scheduled.
Their reports were (mostly) Synoptic and so contained much more than just temperatures. But the question to be asked is how good was the data from these Chinese stations? My suspicion is that the observations were more accurate than the majority of our USGHCN stations at present, but then that is pure speculation.
John, you wrote, “Can someone explain to me how surface station readings impact satellite readings (in laymans terms)? I’m curious to understand it better.”
Surface readings do not impact satellite readings. They’re two totally different measurements. There’s a minor problem on this thread–multiple problems being jumbled under a single heading of Urban Heat Island. The first problem is weather station siting, which Anthony is studying and reporting on at his Surface Stations website and here at WUWT. That’s not Urban Heat Island effect. That’s poor temperature sampling. Satellites would not have that sampling problem.
Urban Heat Island effect is primarily caused by changes to the land surface that results from urban development. Satellites will pick up this phenomenon and include it in their readings.
Many researchers consider UHI to have a small impact on global temperatures. Are they right? Land surface area only represents ~30% of the globe. How much of that 30% is actually urban area or rural area that’s impacted by the urban development?
I think the anxiety over this subject is caused by the way land surface temperatures appear to have accelerated since 1975 or so, where sea surface temperatures have not accelerated. (SSTs from 1975 to present have the same rate of rise as the warming period in the first half of the 20th century.) Some of this additional warming of land surfaces IS caused by urban development. Some of it is caused by the poor weather station siting. Some of it is caused by the impacts of natural ocean variability (Atlantic Multidecadal Oscillation and El Nino-Southern Oscillation) on land surface temperatures and the fact that the ocean cycles were in synch (which isn’t always the case). And some of it appears as polar amplification, which is a natural response when global temperatures rise.
Did that help, or did I confuse matters more?
More fear factor from the Guardian
http://www.guardian.co.uk/environment/2009/mar/18/west-antarctic-ice-sheet-melt
It’s like they get together every morning and say “How much old news can we keep repeating until people believe it to be true?”
Here in the UK we have had the coldest winter in the past 10 years or so. TV Weather forecasts during that time have regularly quoted temperature forecasts in cities with rural temperatures expected to be 3 to 4 degrees C lower. That, if nothing else, is surely a clear demonstration of the recognition of the UHI effect by professional meteorologists whose professional competence is tested daily. Who to believe; these weather forecasters or some “climate scientist”? I know who my money is on.
OT a little, my bad.
Our local “Science” Guy (hey, at least I didn’t use that pesky latinate SIC) at the Houston Chronicle (locally called the Comical) has posted a telephone interview with Joe Bastardi. (BTW, I love that guy, and not ONLY for his excellent name. Talk about latinate.)
This particularly caught my eye:
Still, Joe is picking 13 named storms for this year, which is above the long-term average for the Atlantic of 10 named storms a year. This is because he says the new leadership of the National Hurricane Center tends to name about two storms more a year that wouldn’t have been named a decade or two ago. . ..
[WHAT??? Did I get to the party late? When did this happen? Doesn’t “a decade or two ago” correspond to The Era of Hansen, which, I recall, started circa 1988??
So how is an INTEGER NUMBER of NAMED STORMS “data”, if the criteria changed? Why not use only an estimate of total cyclonic energy or such? As usual, Just curious.]
See the full skreed at http://blogs.chron.com/sciguy/archives/2009/03/joe_bastardi_ma_1.html
DJ (12:38:08) :
Someone asked me the other day what “sceptics” would start talking about now that La Nina and solar minimum had passed and global warming ceased to be hidded by these two short term factors.
My response – they would start to attack the “data”.
If nothing else you are predictable. Those who think this is a bombshell have not bothered to read the literature and failed geography (noting the planet is 70% water).
DJ – It has always been about the data!
Please start with http://www.surfacestations.org/ and provide a good reason why a poorly sited network of stations with a large number of rural station drop-outs can be trusted to measure global warming?
Then follow with the extensive discussion of the Mannian Hockey Stick at http://www.climateaudit.org/ and explain how Mann’s data can be trusted to explain away the existence of natural variation in climate over the last 1000 years (i.e. disappearance of the MWP and the Little Ice Age)?
Could you also please explain why accessing the data and methods of Climate Scientists is so difficult – why is there an absence of openess and transparency in the Climate Sciences?
Also if the AGW Data is so solid – why is there an almost comprehensive reluctance by AGW Proponents to engage in open televised debate?
Do you consider the running of Computer Models to be “Data”? If so, how is that data validated?
LarryOldtimer (13:42:47) :
All you are measuring are micro climates surrounding the weather stations and those weather stations which were once rural are now mainly urban, no brainier. To many experts not enough common sense.
Quoting:
“A problem arises in that if UHI effects could account for much if not all of the observed warming then where does that leave the supposed effects of a high level of solar activity and a positive PDO with an exceptional dominance of El Nino during the same period ?”
Commenting:
As I see it, much, if not all UHI and much if not all solar activity and PDO/El nino, are not exclusive, but complementary – and leave little room for AGW.
Also, I think you may well see more of the second tier in the alarmist camp putting out CYA papers like this. ‘Tis they who are finding graffiti on the room separators.
And they want a little plausible deniability.
“We show examples of the UHIs at London and Vienna, where city center sites are warmer than surrounding rural locations. Both of these UHIs however do not contribute to warming trends over the 20th century because the influences of the cities on surface temperatures have not changed over this time.”
That assumes a heat sink does not exaggerate a warming trend, and I suspect it does indeed.
Bob (09:09:19) :
I don`t get it, why would Jones publish such a study.
It so happens that last Sunday Peter Risdon reported that right now mathematician Doug Keenan is seeking to have Jones’ co-author Prof Wang prosecuted for fraudulent falsification of data relating to UHI, that was key information for the IPCC. Not just that, but there is evidence of conspiracy to conceal the truth by the first disciplinary inquiry, that is surfacing with Dr Keenan’s second request.
>Also if the AGW Data is so solid – why is there an almost comprehensive reluctance by AGW Proponents to engage in open televised debate?
Science debates don’t play out in the media. They play out in science journals. A media debate is designed to influences minds and policy assisted by media norms which give people the false impression that the “sceptics” have science to offer.
According to the IEA, the US consumed about 1.03*10^29 joules in 2002. Assuming it all ended up as heat, that worked out to about 0.34 watts/m^2 for the US.
According to Vincent Gray, it was 0.81 watts/M^2 for California, 89.2 watts/m^2 for San Francisco, and 221.6 watts/m^2 for Essen Germany. This compares to slightly less than 4 watts/m^2
for a doubling of CO2 for the earth as a whole.
Besides adjusting for albedo in the UHI effect, you’ve also got to adjust for energy usage. I have a sneaking suspicion this urban factor is also a major reason for a majority of the warming showing up at night, and during the winter.
Scientific journals are not the final arbiter of truth in science, nor are consensus surveys.
http://www.nature.com/nature/peerreview/debate/index.html