From Dr. Roy Spencer’s Global Warming Blog
by Roy W. Spencer, Ph. D.
We are now getting close to finalizing our methodology for computing the urban heat island (UHI) effect as a function of population density, and will be submitting our first paper for publication in the next few weeks. I’ve settled on using the CONUS (Lower 48) U.S. region as a demonstration since that is where the most dense network of weather stations is. We are using NOAA’s V4 of the GHCN monthly dataset.
I’ve previously described the methodology, where I use many thousands of closely-spaced station pairs to compute how temperature between stations change with population density at 10×10 km resolution. This is done for 22 classes of 2-station average population density, and the resulting cumulative UHI curves are shown in Fig. 1.
It is interesting that the spatial (inter-station temperature difference) UHI effect is always stronger in the homogenized GHCN data than in the raw version of those data in Fig. 1. The very fact that there is a strong urban warming signal in the homogenized data necessitates that there must be a UHI impact on trends in those data. This is because the urban stations have grown substantially in the last 130 years. A recent paper by Katata et al. demonstrates that the homogenization technique used by NOAA does not actually correct urban station trends to look like rural station trends. It does breakpoint analysis which ends up adjusting some stations to look like their neighbors, whether urban or rural. To the extend that spurious warming from UHI is gradual through time, it “looks like” global warming and will not be removed through NOAA’s homogenization procedure. And since all classes of station (rural to urban) have undergone average population growth in the last 130 years, one cannot even assume that rural temperature trends are unaffected by UHI (see Fig. 2).
The regression estimates of change in temperature with population density (dT/dPD) used to construct the curves in Fig. 1 were used at each individual station in the U.S. and applied to the history of population density between 1895 and 2023. This produces a UHI estimate for each station over time. If I compute the area-average GHCN yearly summertime temperature anomalies and subtract out the UHI effect, I get a UHI-corrected estimate of how temperatures have changed without the UHI effect (Fig. 3).
The data in Fig. 3 are from my 1 deg latitude/longitude binning of station data, and then area-averaged. This method of area averaging for CONUS produces results extremely close to those produced at the NCDC “Climate at a Glance” website (correlation = 0.996), which uses a high resolution (5 km) grid averaged to the 344 U.S. climate divisions then averaged to the 48 states then area averaged to provide a CONUS estimate.
UHI Warming at Suburban/Urban Stations is Large
The UHI influence averaged across all stations is modest: 24% of the trend, 1895-2023. This is because the U.S. thermometer network used in Version 4 of GHCN is dominated by rural stations.
But for the average “suburban” (100-1,000 persons per sq. km) station, UHI is 52% of the calculated temperature trend, and 67% of the urban station trend (>1,000 persons per sq. km). This means warming has been exaggerated by at least a factor of 2 (100%).
This also means that media reports of record high temperatures in cities must be considered suspect, since essentially all those cities have grown substantially over the last 100+ years, and so has their urban heat island.
Outstanding article. Well done Dr. Spencer.
I agree. In particular, Figure 1 in the above article has nice exponentially rolling over trends that are characteristic of actual nature-based systems.
Dr. Roy Spencer rocks! I eagerly await the formal release of his scientific paper on this subject, with it’s sure-to-be-devastating, slap-down implications for the IPCC and CAGW alarmist meme of recent man-made “global warming”.
Then too, such a paper will surely and sadly reveal how NOAA does not know how to do rather simple corrections to GHCN data to account for UHI.
“does not know how to do rather simple corrections to GHCN data to account for UHI.”
Yes they do.. they know to cool the past.. 😉
And warm the present. Which is exactly what UHI does.
So where’s the problem!! 😉
“Corrections” are not the same thing as “manipulations” . . . not by a long shot.
Sorry, I meant… “Corrections™” 😉
corrections are OK if they are correct!
Dr. Spencer’s figure 3 has the same temperature profile as Hansen’s U.S. surface temperature chart. The both show it was just as warm in the United States in the Early Twentieth Century as it is today. Therefore, CO2 is a minor player in the Earth’s atmosphere since there is more CO2 in the air now than there was then, yet it is no warmer today than it was then.
Dr Spencer’s Figure 3:
Hansen 1999:
Story tip
https://www.bbc.co.uk/news/world-europe-66923590
Climate change: Six young people take 32 countries to court”Aged from 11 to 24, the six claimants argue that the forest fires that have occurred in Portugal each year since 2017 are a direct result of global warming.
They claim that their fundamental human rights – including the right to life, privacy, family life and to be free from discrimination – are being violated due to governments’ reluctance to fight climate change.
They say they have already been experiencing significant impacts, especially because of extreme temperatures in Portugal forcing them to spend time indoors and restricting their ability to sleep, concentrate or exercise. Some also suffer from eco-anxiety, allergies and respiratory conditions including asthma.”
JohnC: I understand why you suggested that story, however…
My story tip, here: Don’t dignify that nonsense with more publicity. Their claims are baseless. They will lose. The End.
I blame the adults who will use children for a political goal
Useful idiots in training.
I blame the adults who will abuse children for a political goal
They should lose, however the judges that will hear this case were appointed by the same politicians who are pushing the climate crew insanity.
Yes, that’s a problem. Some judges don’t make judgements based on the evidence, but rather on a political agenda.
Like the New York judge yesterday that declared Trump guilty of misrepresenting the value of his real estate. This judge is a real winner. He will end up looking like the fool he is.
The fire problem in Portugal is eucalyptus trees imported from Australia in 18th century. The bark is full of oil and the trees shed bark continuously. The trees are everywhere.
Did Portugal import the drop-bears that invest eucalyptus trees in Australia as well?
Travelling in the USA recently, I noticed too a prevalence of Australian eucalyptus trees … also imported from Australia and despised for personal safety and fire risks.
Reminds me of the ‘Oakland, California, firestorm of 1991’ – not just gum trees, but they contributed mightily to the conflagration. Parts of Oakland looked like they had been bombed afterward.
That’s credible Steve. Eucalyptus are nature’s answer to the Tiki-Torch. Unfortunately, they are about the only large tree that does well in the long, hot dry season and occasional quite dry Winters in Mediterranean climates. So they are widely used as ornamentals or in windbreaks in places like California. The native vegetation in California at least is nowhere near as flammable. But it’s also not as large and not as pretty.
What? CO2 discriminates?
Other story tip
https://www.theguardian.com/australia-news/2023/sep/27/tesla-lithium-battery-fire-bouldercombe-energy-storage-site-project-rockhampton
https://cowboystatedaily.com/2023/09/22/ev-battery-factory-will-require-so-much-energy-it-needs-a-coal-plant-to-power-it/
https://tiremeetsroad.com/2023/05/31/ford-lightning-ev-truck-remote-kern-county-city-kernville-forced-charge-off-propane-powered-portable-generator/?expand_article=1
Was warmer in Portugal in the 1940s according to graph harvest records.
Yes, everywhere you look, it was just as warm in the Early Twentieth Century as it is today.
Except when you look at a bogus, bastardized Hockey Stick global “temperature” chart, which shows that we are experiencing unprecedented warming today.
The Bastardizers of the Hockey Stick chart wanted to hide the fact that it was just as warm in the Early Twentieth Century as it is today, otherwise they couldn’t sell their scary “hotter and hotter and hotter” CO2 scenario.
The truth is it is not “hotter and hotter and hotter” today. Instead, it is no warmer now than in the past. This of course, blows up the Human-caused Climate Change narrative, and is the reason the Temperature Data Mannipulators bastardized the temperature record, to avoid having their narrative blown up.
But the bastardizers couldn’t mannipulate every chart on Earth, so they left evidence behind that shows they are lying about the Earth’s temperatures. The bogus Hockey Stick chart does not represent reality and Dr Spencer gives us another reason to shoot down the Hockey Stick chart.
Maybe if they had spent more time outside they wouldn’t have these issues.
Heat-related deaths cause an estimated 500,000 deaths per year. Cold-related deaths cause and estimated 4.6 million deaths per year mainly through increase strokes and heart attacks caused when the blood vessels constrict to conserve heat and raise blood pressure.
‘Global, regional and national burden of mortality associated with nonoptimal ambient temperatures from 2000 to 2019: a three-stage modelling study’
https://www.thelancet.com/journals/lanplh/article/PIIS2542-5196(21)00081-4/fulltext
“the forest fires that have occurred in Portugal each year since 2017 are a direct result of global warming”
good luck with trying to PROVE that /sarc
Didn’t their grade school teachers teach them how fire works? Fuel, oxygen, and a spark? The spark is to get the fuel above its ignition temperature, which for wood is apparently about 700 F. How hot is it in Portugal these days, exactly? 🙂
“Climate change: Six young people take 32 countries to court”Aged from 11 to 24, the six claimants argue that the forest fires that have occurred in Portugal each year since 2017 are a direct result of global warming.”
Who are the adults putting these kids up to this? No doubt, there’s a leftwing billionaire behind the scenes somewhere pushing this agenda.
What about fires before 2017?
Were there more or less back then?
Did whatever caused any earlier fires quit causing fires, so that man’s CO2 could become the new cause?
It might be interesting to apply this to more densely populated countries like England (not the U.K. as other nations are not as densely populated) 1124 per square mile, or the Netherlands 1346 per sq mile.
Great idea. 🙂
Scotland would make an interesting comparison study.
Scotland has an urban Central Lowlands, the population of the country in total doubled 1850 to 1950. And is still increasing. At the same time the the population of the Highlands and Islands declined after peaking in 1861. It has fallen 20% since 1980 . The Borders too have had decades of declining populations.
There weather stations in rural Scotland which regularly make appeances of the weather and which have long records.
Handling a dropping population is tricky.
The problem is that houses, roads, etc don’t go away just because the people moved out.
Unpaved roads will return to nature, eventually, but not immediately.
For that matter, paved roads and buildings will also return to nature, it will just take a bit longer.
In California paved roads return to nature all too quickly
I don’t know if yoy’ve been to Sutherland, Caithness or Wester Ross?
Wester Ross has one of the lowest population densities in Europe, with just 1.6 people per km2. For Caithness and Sutherland it’s 5 people per sq. km, In the Clearance Villages the black houses are just piles of stones covered in grass. The roads in the highlands are not what most people think of as the King’s Highway. The highly popular NC500 Route is hardly a six lane motorway and comes as a shock to many Southerners who encounter it. At times single track with passing places. Nor is the region criss crossed with roads.
It’s a good idea, but only works if the temperature monitoring stations are of the same quality and temperature-measuring resolution capability as those of GHCN stations.
toldyouso,
Correct for Australia.
Geoff S
UK population increase has been pretty much a straight line for a couple of hundred years.
By comparing CET with the pristine Valentia record (NW Ireland) we can see the urban effect as a constant warming trend.
Here’s the UK population chart.. pretty constant growth since 1800.
Nice chart
BTW ( Valentia is in SW Ireland) It lies off the Iveragh Peninsula in the southwest of County Kerry.
oops.. At least I got the country right 🙂
The data confirm what anyone who drives a late model car in/to urbanized areas sees on a daily basis when it is sunny outside – the outdoor thermometer clearly shows that temperatures rise at least several degrees from the outdoor air temperature in lower density well vegetated/landscaped areas to areas of medium to high density development, particularly on major roads and especially at intersections that combine multiple travel lanes in both directions with multiple turn lanes, resulting in quite large continuous paved areas. Ditto in large paved parking lots typical of shopping centers, large industrial facilities, etc.
Or, just pay attention to local weather reports in urban areas where higher daily highs in sunny weather are recorded in medium to densely developed areas than the daily highs in rural to suburban areas with lower density of development.
The physics of UHI are extremely easy to understand – you don’t have to have a PhD in physics to understand that some surfaces, particularly pavements, exposed rocky surfaces, and metallic surfaces absorb a lot of thermal energy from direct sunlight that gets “stored up” and then dissipates at least partially when the sun goes down.
That the same yahoos that claim to educated in science but ignore the urban heating effect just reveals their utter hypocrisy.
Yes, indeed. Back in the days when I spent many hours riding a motorcycle, I very well noticed the effects to which you re referring.
On my old drive from work I drove entirely through suburbs. During spring and fall, I would drive with the window down. There was a half mile stretch that was still completely wooded, no houses as far back into the woods as I could see. No driveways either. When I drove through this section, the air temperature would drop 2 or 3 degrees. It didn’t register on the cars thermometer because the change was for too short a period.
To summarize, the lawns, driveways, and houses of even low density suburbia (I’m talking homes on 5 to 10 acre lots) was enough to increase the air temperature by 2 to 3 degrees.
Let me add it is not just land use. How much air conditioning has been added since 1950 in urban areas. Growing up, we didn’t have air conditioning until the mid-60’s. How many high rise apartments and office building have been added since then with many having units hanging off the sides? How about car radiators in high traffic low speed downtowns in the big cities? A lot of energy is injected through mechanized means. The evidence? Electricity growth and fuel usage.
Although I can’t find it on the internet anymore, I had a perfect example of this. Portland Oregon started keeping weather records downtown in 1859. That showed a steady increase in temperature until 1941, when they relocated the weather station to the Portland airport, which was much more urban. The ‘temperature’ dropped in 1941 when it was relocated. Now the airport area is built up. And, the temperature has been increasing since 1941.
You could probably say the temperature change describes the growth of the Portland area but has little to do with temperature.
I’d be interesting to see what some of the temperature trends would look like if just airport weather station values were removed from the calculation.
“More rural” or “less urban” for “more urban”?
In Roy’s post, “to the extent” for “to the extend”.
In 1941, it the airport could easily have been more rural.
In the late 90’s early 2000’nds I searched for and found numerous pages of data on Heating/Cooling degree days. I was looking for an area that had four seasons but that was not miserable in the summer or winter. With the Mega-Hype on Global warming I looked at these charts, some that went back to the early 40’s and most to the early 50’s. I added the number of Degree days for the year in about a dozen of these areas and noted that there was no significant change in the total of either Heating Degree days or Cooling degree days. In 2012 when I retired I wanted to do this for each of the major cities and random areas in each of the states. Problem was that I could not find any of these charts or data sets. They were all “Disappeared”, removed, canceled.
In my humble opinion Climate Change should be based upon the degree days not two numbers taken at a time of the day that appears to be selected to get numbers that will PROVE temperatures are getting warmer.
Take a Sine wave; the average of a sine wave is ZERO. However you can pick two points on that sine wave, and unless they are exactly 1/2 the distance of the total cycle it will NOT average to ZERO. Same applies to the cyclical nature temperature through the year.
Millions more people die from cold weather compared to hot weather each year
This recent study shows that the cold weather we have every year causes about 4.6 million deaths a year globally mainly through increased strokes and heart attacks, compared with about 500,000 deaths a year from hot weather. We can’t easily protect our lungs from the cold air in the winter and that causes our blood vessels to constrict causing blood pressure to increase leading to heart attacks and strokes.
‘Global, regional and national burden of mortality associated with nonoptimal ambient temperatures from 2000 to 2019: a three-stage modelling study’
https://www.thelancet.com/journals/lanplh/article/PIIS2542-5196(21)00081-4/fulltext
.
When I walk on very cold days here in Wokeachusetts I now wear an N95 face mask. It does warm the air going into my lungs. So I finally found a good use for them!
That sounds like a good idea.
There is data out there, you just have to look to find it. Let me add that HVAC people have moved on from just periodic temperatures throughout the day to using actual integrals of the entire temperature profile gathered from the new temperature stations that have minute level (or smaller) for the entire day. Shame you can’t find one paper on climate that has tried to do the same. Most of these stations also provide data that allows the calculation of enthalpy (heat) that is more useful than a temperature that isn’t a great proxy for heat.
Duh. News reports show everyone trying to fry an egg on the sidewalk during a heatwave, but never on a green lawn.
LOL!
Insert common sense into a discussion, and the climatistas are sure to panic.
Insert historical data into a discussion, and the climatistas are sure to panic.
In my experience, even green lawns are hotter than wooded areas.
That would be messy, right?
Sand gets really hot too..
Eggs turn out rather crunchy, though 😉
doonman,
Not so.
Main difference is concrete is high mass density and able to store more heat than grass of similar volume. Also, concrete might have a different thermal conductivity to grass.
Geoff S
even worse than the UHI effect is the measuring at airports effect.
That varies upon the size of the airport, the number of flights, and the expanse of concrete. There are still many (but not as many as before!) airports that use grass landing strips. Those measurements are likely to be consistent.
These days the only airports with grass runways are ones that cater to single engine, propeller driven planes and only a small number per day.
I would hate to see what might happen if the lawn clippings got sucked into a jet engine.
Biofuel?
Oh, green exhaust.
I had green exhaust awhile back.
I’m never eating that again.
🙁
Green Energy !!
UHI = the only proven cause attributed to AGW that I’m aware of. 15 minute cities will exacerbate it.
Exaggeration is the rule in mainstream climate science – experts are alarmed, don’t you know?
“”Why scientists are using the word scary over the climate crisis”” – Roger Harrabin
https://amp.theguardian.com/environment/2022/nov/07/why-scientists-are-using-the-word-scary-over-the-climate-crisis
They give off more heat than light..
Very nice. Do you see any problem getting published?
Solar panels, wind-farms, lawsuits, hysteria, curriculum, additional taxes, electric vehicles, and a whole lot of bologna all over a made up boogey man perpetuated by inaccurate, biased data. Sounds a lot like the witch trials of the 1600’s. How did society digress so far? McDonalds and fast food?
The woke mind virus
The Lysenkoism of the West.
The UN IPCC
The fact that the UHI effect is stronger in the homogenized data simply says the homogenization does NOT work as intended. OOPS.
A cynical person might say that this shows the homogenisation is working exactly as intended.
Was just thinking the same thing!
Not working as claimed.
Over the last 40 years I have lived on the outskirts of eight cities where the population of the city, including the local airport, was over one million and the have always been at least 5 degrees F warmer and some even 7 than the urban area I live in. It was also even warmer in the Winter months. To include the data from these cities has no other purpose than to bolster their propaganda. Strangely, They also use numbers from areas where the data is collected during the hottest time of the day but hours after the coldest part of the day.
In case anyone is interested, the link below takes you to a Wikipedia article with a table that lists U.S. cities by population density in both square miles and square kilometers.
List of United States cities by population density – Wikipedia
Allow me to add my kudos to Dr Spencer for this project that pounds another nail in the fraudulent character of the CAGW narrative.
And kudos to everyone who contributes to WUWT who have enabled it to be the best website on the internet on CAGW, energy and other issues. In case no one noticed, the blog stats for this website just went over a half billion hits recently. This milestone speaks volumes for the excellence of this website. A number like that doesn’t lie. Again, congratulations to all involved.
Here’s a chart of urban v rural global population growth.
Urban really takes off around 1950
A real hockey stick.
One thing I’ve noticed is that the heat island effect can be seen even in a very small, localized area, as well as in large cities. I live in a semi-rural area, on a residential street that is bordered mostly by farms, fields and forested areas. Three years ago I decided to plant some gladiolus bulbs out by my mailbox. They were rated for zones 9-10, and much of central Maryland is a zone 7 (actually a 6B outside of urban areas) I figured that even if I didn’t bother to dig them up in the fall I’d still be able to enjoy them that summer.
Well, here it is the third summer and they keep coming back. This despite the fact that the past three winters have had periods where the temps have gone below freezing for hours – or even a few days, at a time. Now, some people would immediately leap to conclusions that “OMG it’s climate change and we’re all gonna die because my glads survived the winter!”. I had to think about it for a moment, then it dawned on me that those bulbs I had planted were only about a foot away from the edge of the asphalt road in front of my house. I realized that the road itself was what was keeping my bulbs from freezing in winter! It absorbs enough warmth from the sun – even in winter – that it can radiate that back to the surrounding air (and ground), especially at night.
It is very unfortunate that so many people can’t logically think something like that thru and instead jump to conclusions. And accept the CAGW propaganda hook, line and sinker….
Quite so, Lee. The micro climate around your house also affects planting … sunny side stays warmer for longer to shaded side cooling more quickly and for longer.
Great point. I live near a town of 2.5 square miles and 2,700 residents with an airport located within the city limits. The official weather station is located in town, and that station routinely shows an 8° higher temperature than the countryside two miles away, so even the rural stations reveal an UHI effect.
I wonder what Zeke and his minions have to say about this.
“ homogenization technique used by NOAA does not actually correct urban station trends to look like rural station trends. “
That is NOT the intent.
The aim is to correct rural station trends to look like urban station trends. “
The aim of the CAGW Charlatans is to make things look “hotter and hotter and hotter”.
Roy just knocked their legs out from under them. Thanks, Roy. 🙂
I’ve always suspected that at least 50% of the reported warming is from a combination of UHI and badly located surface weather stations.
90% of the worlds weather stations are in unban areas.
I have made the point before that Hansen 1998 on page 1 showed two graphs, usa and the world
USA showed 30s warmer, overall ambivalent graph while world graph showed much more linear warming world. But in most of the world those stations are urban and so it’s mostly a graph of UHI.
Funny how the best unadulterated records from England and North America don’t show much warming
And from conniving Temperature Data Mannipulators pushing their Catastrophic Anthropogenic Global Warming (CAGW) agenda.
So, urban parasites cause global warming? Can’t we solve this non-problem by eliminating them?
Thought I heard a government urban planning officer think something like that 🙂
Yes, it’s called Net Zero
I believe that one big issue concerning UHI effect on overall warming trends is accounting for heat exchange between different areas. Especially, heat exchange between urban areas ( high population density areas and the source of UHI warming ) and rural area areas ( low population density areas and the using these areas as the baseline for detecting global warming ). I don’t understand how this heat exchange is handled in Dr. Spencer’s analysis.
For example, let’s assume that the entire earth consisted of 1 high density urban area and 1 rural area with zero population density. If there was no heat exchange between the two areas, it would be relatively simple to compare temperature trends of the 2 areas and conclude if and how much of the extra warming in the urban area was due to the UHI effect. However, I believe that there is significant heat exchange ( due to fronts & atmospheric mixing ) between the 2 areas. However, I believe that it is humanly impossible to calculate how much the heat exchange affects the temperature trends of each of the 2 areas. And that is the basic problem in trying to sort out the impact of UHIs on temperature trends. If Dr. Spencer has figured out how to mathematicaly handle the complex heat exchange issue, I would be interested in how it can be computed.
On a windy day the UHI impact can be seen for *miles* downwind. Far unto the surrounding rural areas. If the urban area is in a river valley it can extend even further!
If you could figure it out somehow, I suspect you would find an urban heat signal even in UAH.
Wot? No troll comments?
Just thinking the same thing…where’s Nick?
Does anyone really care ? !
It is almost as though they are told which posts to comment on. 😉
I can’t imagine anyone paying for their level of ineptitude, though.
Another graph showing the enormity of the UHI effect.
Why is the USCRN absent from the article and all comments? It conclusively shows that there has been no increase in rural US temps since 2005. I know, we’re 6 % of the globe but the rest of US surface temp reports and the rest of the world are influenced by jet exhausts, asphalt, or a/c units.
The UHI influence averaged across all stations is modest: 24% of the trend, 1895-2023. This is because the U.S. thermometer network used in Version 4 of GHCN is dominated by rural stations.
Is that averaged across all stations in the contiguous U.S.? Or globally? I would have thought from your discussion that it was higher. Clearly it is a lot higher for urban/suburban areas, but does that mean that most of the stations (in the U.S.? globally?) are rural? Please explain. What you say above is a little confusing.
Also, do Hadley HADCRUT, NASA GISTEMP, and Berkeley BEST temperature data sets use GHCN or something else?
Yep they use GHCN.. post GHCN adjustments.
BEST uses even more rubbish urban data, and adjust whatever they want to get whatever result they want.
Are you not familiar with USCRN? It’s a 100 plus very rural top class monitors spread across the country. In theory it has no UHI effects. Not widely known or publicized because it doesn’t fit the narrative.
Sorry to be thick. I see that you said this is a demonstration of the UHI difference in GHCN using only the CONUS (U.S. lower 48) data. I get it. So the U.S. stations reporting temperature data used in GHCN are mostly rural, which explains the relatively low (24%) difference when looking at the average across all U.S. stations? Interesting. I thought more stations were suburban/urban than rural. It’s an important study but I would have thought the UHI would have been higher overall. It certainly is in suburban/urban areas where we get the dramatic summer news reports of “record” temperatures that come from airport stations and others surrounded by massive heat islands.
Even rural stations are subject to microclimate impacts on their readings. If a farmer upwind of the stations decides to plant soybeans instead of corn the downwind measurement stations will see an impact on the wind flow by the station. If someone builds a new pond upwind of the station the humidity and temperature readings at the station will see some kind of impact. If the county maintenance of a nearby farm-to-market road decides to oil seal the gravel road that can have an impact the station readings.
These, plus so many other things, can all contribute to the measurement uncertainty associated with a measurement station. It’s why trying to identify differences in the hundredths digit for “average” temperature readings is a fool’s errand.
There really are no “pristine” temperature measuring stations, not even in rural environments.
Tim,
That is a conclusion that I am also about to show for Australian data. I have selected some really pristine sites. One has has a population of 1 for much of the past 50 years, that being the observer with no towns of any size for 200 miles in any direction.
Yet the daily temperature time series has variability that I cannot link to causes. Geoff S
Dr Spencer,
Thank you for this preview.
I am close to finishing a related study of Australian data. Here we have population density of about 1 person per sq km. So, there is a chance of much more pristine station data.
It is taking a long time because of noisy data. Almost every pristine station has ups and downs of significant size that do not seem related to UHI or indeed to any factor I can think of apart from the usual station moves and instrument drift and jumps. So I have deleted a lot of candidates.
The remaining 40 or so pristine sites do not display a close range of trends. They are all over the place, from -1 to +4 deg C/century equivalent in Tmax and in Tmin. I do not use the average of these to get a Taverage.
Cheers. Geoff S
Error correction.
Australian population density now is 3 people per sq km. Geoff S
Yep.. we really pack them in tight ! 😉
GS: Microclimate changes can be almost anything. They aren’t just station moves or instrument calibration. Insect infestation, dirt in the air intake, ice covering the instrument, grass changing from brown to green and back to brown, and on and on. I have even had to remove spider webs from inside my station in the past when I noticed both the rain gauge and thermometer readings changed abruptly. Identifying *when* these happen is almost as hard as figuring out *what* happened. They are all part of systematic bias in the instrument readings and not amenable to statistical analysis.
If this gets established, then the last pillar of the AGW scam is exposed.
1) Failed on the “Hot Spot” prediction.
2) Failed on the Positive Feedback Loop prediction.
3) Failing on the UHI effect that is being exposed as a major driver of warming temperature data.
Warmist/Alarmists really should stop sniffing the CO2 gas and get on with life.
Spot on, but you failed to mention, that historically CO2 has nothing to do with driving temperature, it’s vice versa. Human emissions are between 3 and 15% of total CO2 in the atmosphere, so humans cannot be responsible for global warming.
4) Failed on the predicted disappearance of Arctic ice.
This showed up in mainstream online news: but only for one day:
UHI. Western Sydney was 2C hotter , now up to 10C hotter than east.
“Western Sydney is one of the fastest growing—perhaps the fastest growing urban population anywhere in Australia. The mistakes [in urban design] being made in Western Sydney are being made in Melbourne, Brisbane, Perth. We’re not really thinking ‘How do we deal with the changing climate, particularly heat?’,” says Dr. Sebastian Pfautsch, Associate Professor of Urban Studies at Western Sydney University.
He describes the side-effects and challenges of overheated suburbs: from strains on public health, to economic instability, and low community cohesion.
https://www.climatecouncil.org.au/urban-heat-island-effect-western-sydney/
Up to 10°C between different urban areas due to micro climate differences.
https://www.westernsydney.edu.au/newscentre/news_centre/research_success_stories/first_western_sydney_microclimate_maps_reveal_extent_of_heat_variation_in_region
Among the measurement locations in each council, temperatures differed up to 6°C, and during days of extreme heat, more than 10°C. For example, peak air temperature in Sydney Olympic Park was 32°C while it was 45°C in Toongabbie during a heatwave at the end of 2018.
“The significant temperature variations recorded suburb-to-suburb and even street-to-street across the three local government areas demonstrate the need to assess and combat extreme heat at a local level,” said Dr Pfautsch.
And yet the CAGW crowd thinks they can identify global average temperature differences in the hundredths digit. They just ignore the statistical variance associated with the data and assume all temperature readings are 100% accurate with no measurement uncertainty.
““The significant temperature variations recorded suburb-to-suburb and even street-to-street across the three local government areas demonstrate the need to assess and combat extreme heat at a local level,” said Dr Pfautsch.”
There’s a practical idea. Let’s do things like this, instead of destroying our economies by trying to reduce CO2 emissions, which, apparently, looking at Dr Spencer’s new study, has little effect on the temperatures. Take out the UHI effect and CO2 is nowhere to be seen.