From Dr. Roy Spencer’s Global Warming Blog
by Roy W. Spencer, Ph. D.
Summary
An improved method for merging weather station temperature data leads to revised temperature trends for the period 1900-2023 for the 6 largest southern provinces of Canada, compared to those I previously posted here and here. The general conclusions remain the same, but the details change somewhat. Because of the improved methodology, this post supersedes those posts. The main conclusions for the period 1900-2023 are:
- Southern Canada daily high summer temperatures [Tmax] have warmed at only 1/3 the rate of daily low temperatures [Tmin]: +0.06 and +0.18 C/decade, respectively;
- Averaged across southern Canada, 2021 and 1961 are the two hottest summers for daily high temperatures;
- Even though 2021 is the hottest for Tmax, none of the individual 6 provinces has 2021 as record warmest; and
- Tmax and Tmin trends are surprisingly uniform across those 6 provinces.
The “New” Methodology
In recent months I’ve spent a lot of time investigating various methods for combining different weather station records for the purpose of quantifying long-term temperature changes. One of the things I discovered is that, if there are few stations in a given year, doing a homogenization process such as the Menne and Williams (2009) Pairwise Homogenization Algorithm (PHA, used by NOAA and the BEST dataset providers) can lead to a random walk behavior as errors in the method in a single year will then propagate through all later years. This is probably not a problem in the U.S. since there are so many stations, but in other parts of the world it could be an issue. So, I think it is worthwhile to use an alternative methodology involving different assumptions.
After my previous posting of the aforementioned analyses of Canadian temperature trends, a few people (including John Christy) correctly pointed out that my straight averaging of all available stations in a province (or U.S. state) isn’t the best way to come up with a long term time series of temperatures. This is because as stations come and go over the years, they might be in different areas with different average weather. Of course, I already knew this, but ignored that nuance for the time being. But when I implemented a method that removes inter-station biases, I discovered that it did make some difference (as expected).
So, I implemented the merging procedure that John and I have used for many years with our UAH satellite temperature dataset, which is to remove relative station (or satellite) biases during overlap periods of time. This takes out any inter-station differences due to geographic location, altitude, urban heat island effects, poor siting of thermometers, equipment differences, etc. What isn’t accounted for is any spurious station temperature trend effects, say due to increasing urbanization, a sensor location or equipment change at that station, etc. So, for this initial version of the method I am assuming those changes average out over time. Of course, UHI effects would not average out over time since they almost always operate in one direction (spurious warming).
One issue is how to start the merging of stations together. I concluded that it is best to start with the stations with the longest periods of record, then add in the other stations, in ranked decreasing order of length-of-record, after removing each station’s offset (bias) relative to the average of all previously merged stations. As an example, the Alberta data merging (results shown later) involves a total of 950 separate stations, with varying lengths of record. The longest operating Alberta station was 111 out of 124 possible years (1900-2023). Half of the Alberta stations had periods of record of 15 years or less. The shortest period of record included was 2 years, because that is the minimum necessary to remove an average inter-station bias as well as have any time-variation information.
Results
The following figure shows the daily high (Tmax) and low (Tmin) summer (June-July-August) temperature trends, 1900-2023, for the 6 provinces from which I analyzed data. The other provinces have very few stations by comparison to these six.
There is a surprising (at least to me) level of consistency in the trends across the provinces. The Tmax trends average only 1/3 the Tmin trends, so summer nights are warming much faster than summer days. Again, urban heat island efects have not been removed, so it remains unknown how much of this difference is due to UHI effects, which are much more pronounced in Tmin than in Tmax.
The next figure shows the yearly time series averaged across those 6 provinces. I’ve included the linear trend as well as a 3rd order polynomial fit to the data, the latter to reveal the warmth during the Dust Bowl years of the 1930s.
Interestingly, even though none of the individual provinces had 2021 (the year of the epic late-June heat wave in western Canada) as the record warmest summer, the average across the 6 provinces did have 2021 as record warmest, barely edging out 1961:
Note that the Dust Bowl years of the 1930s shows up much more in the Tmax than Tmin data, probably due to lower humidity air. The cool summers of 1992-93 after the major eruption of Mt. Pinatubo also show up clearly.
Individual Province Time Series
Following are the 6 individual province time series of yearly summer Tmax and Tmin; all temperature scales span 8 deg. C of range for ease of comparison. I present these without comment, except to point out that the warmest BC year was 1958, not the epic heat wave year of 2021, the effects of which were maximized in this province. My next step after this is to apply the same methodology to the 48 contiguous U.S. states (CONUS), and compare to NOAA’s homogenized trends for those states.
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If rising annual temperatures pose such a threat to Canadians, why isn’t a sizeable proportion of the population shifting further north? After all, Yukon, the Northwest Territories, Nunavut and Labrador are probably the most underpopulated regions in the entire Western Hemisphere and globally rival Siberia on that issue. There might be long periods of sub-freezing winter cold, but the summers are relatively bearable and there’s no shortage of polar bears along the Hudson Bay coast and grizzlies further inland. And if these can be avoided, let’s see people stay clear of the billions of biting insects like mosquitoes and blackflies during their evening barbeques. So why worry about climate change if the Great North is always available for settlement?
There seems to be a warmer climate up through the southern parts of Saskatchewan and Alberta,
… but apart from that, a large part of the population is below the 49th parallel.
Very little population much above the 49th parallel in the eastern states of Ontario or Quebec.
That is because they are migrating south to Florida..,
Because the areas you mention have very little in the way of soil for growing crops or raising livestock. These areas are underpopulated for a host of reasons. Cold temperature is only one and not necessarily the principal one. You cannot build towns and cities on bare rock, in the middle of miles of bogs. The Great North is NOT suitable for settlement.
The coast of Hudson’s Bay is generally uninhabitable. The Bay is frozen over five months of the year, prohibiting all sea transport. Same thing for Newfoundland. It’s nicknamed “The Rock” for a reason. No soil, no farming, no other resources except fishing.
Having been to Canada in winter it could do with some warming up, never been so cold.
Alaska regional anomalies.
Looks like the first decade of this century was cooler than the 1940’s
Four of the six charts in the article above show it was just as warm or warmer in the 1930’s, than it is today.
I look forward to a similar examination of the various States of the United States as promised by Roy.
They will all show the same thing: It was just as warm in the recent past as it is today. They will show that CO2 amounts have not increased the net temperature. We are no hotter today, than we were a hundred years ago, even though CO2 has increased from 280ppm to 430ppm during this period.
The 1.5C increase in warmth the Climate Alarmists wring their hands over took place back in the 1880’s, and it hasn’t gotten any warmer since that time. We are currently 0.5C cooler than the temperature high point in early 2024, and we are currently also cooler than 2016, and 1998. So the temperatures are not climbing, they are cooling.
People who think the world is overheating are not looking at the facts.
What is the sensitivity of the analysis if the series ended in a super El Nino and started with la nada?
Is there some point to this series of posts?
It doesn’t seem to be specified if there is.
My takeaway is 0.05C/decade higher max temps isn’t cause for alarm and 3x warmer mins quite a comforting decrease in the (max-min) range.
Well, Canada can afford a bit of warming. It’s cold. We knew that.But if you look at the Tmax, nothing much happened until 1970, as expected. But in almost all profinces the trend, as shown by Roy’s fitted curve, are very high. Alberta from 2010 to 2020 is about 0.8C/decade. Now you may say 0.8C is not much, but it is 8 C/century. So in 200 years?
Maybe Roy’s planning a flit to Canada to put his feet up?
No, like most normal people, Roy prefers the warmth. !!
Not going to get much of that in Canada. !
So you assume that the trend will continue indefinitely? With all the stupid things you’ve written in various posts on this website, this is one of the most ridiculous. Try to understand this, Mr Fake ID. Continuing trends never do.
No. The trend may increase or decrease. But you have to be able to deal with the likelihood that it will continue. It can happen.
I wont have to deal with anything in 200 years and neither will you.
And extrapolating out a short-term wavy trend, 200 years, is sheer mathematical nonsense.
Trend could turn down.. and Canadians would flood to the USA. !
People like the warmth, much harder to live with bitter cold.
Cold is 10 x as deadly !
Well, Nick’s a mathematician doncha know.
Warming in Canada will be absolutely zero problem.. In fact a great benefit.
If they get cooling , there will be lots of “climate refugees” heading south. !!
Wrong! Do an internet search for warnings about making conclusions on curves that don’t take into account the underlying trend. Many stock market gurus have been broken by doing what you are doing.
But many scare-mongering grifters have made fortunes by doing what he is doing.
“nothing much happened until 1970, as expected.” Well that’s if you don’t count the second highest Tmax in 1961 or virtually all of the years in 1930’s and the temps around 1920, etc., that are about equal to most of the last few years (with the exception of the past couple of years spike, which appears to be receding.) Neither you, me or Dr. Spencer knows what it’s going to do over the next decade. And, as far as 8 C/ century, I’ll choose the years from 1960 to 1970 (approx.) that is about the exact opposite of your chosen years, so that would be -8 C/ century. Since we don’t have data that goes back far enough, I’ll just stick with the sinusoidal Tmax that is likely to drop back down like the UAH figures currently: +.43, lower than many years in that brief data set.
Good comment!
Ask ole Nick what the trend from 2024 to present is.
Tmin matches population growth quite well.. So is classic urban warming.
Oh look some ignorant red thumber doesn’t know that populations cause urban warming.. why are they so dumb !!
Aw cmon Nick…The log term average for Alberta is 0.05 °C/decade. You know better than to use the short 10 yr average and extrapolate to 100 yrs !
The “long term” covers about 70 years where no warming from GHGs was expected, and then fifty years or so where GHGs were expected to cause warming, and warming happened and accelerated. It is the effect of the latter that is of interest for the future, with GHGs ever increasing. The trend may be uncertain, but that doesn’t mean it isn’t there. If our best estimate is 0.8 C/decade, that is what we need to be able to manage.
Yeah but the trend from about 1970 to the end of the record looks to be more like about 0.23 °C to me. Not 0.8
Doesn’t matter it’s a Stokes(tm) approved extrapolation so we are going to use this for a lot of arguments back at him going forward.
“no warming from GHGs was expected,”
No warming from CO2 is expected now.
There is no measured scientific evidence that CO2 causes warming
All true.
Nick assumes too much. Just like all Climate Alarmists.
That’s an amazingly big IF there…
“You know better than to use the short 10 yr average and extrapolate to 100 yrs !”
Terry,
Naughty Nick is a zealot, so he would use a 30-day average and extrapolate to 100 years & still argue he was correct !!
No, I do not agree that Nick is a zealot. IMHO he is usually right when commenting on the science. But this time he was out of line, and too hasty in calling the 0.8 °C/decade as being representative of the “warming period”
So you are admitting defeat are you Nick?
According to you it’s burning fossil fuels that is causing the warming so apparently we are still going to be burning them in 200 years ….. oh poor NET ZERO
Do I really think you are puerile stupid enough to believe what you have written … … NOPE YOUR JUST A STUPID TROLL.
“ut if you look at the Tmax, nothing much happened until 1970,”
Nick is in denial.
Roy’s charts obviously show that it was just as warm in the 1930’s, in Canada, as it is today. You want to concentrate on a trend that began in the 1970’s, and just ignore anything that took place before that time.
I understand why you ignore the past because the data from the past destroys your worldview. You don’t want your worldview destroyed, so you ignore the facts.
Let’s see what Tmax says about your country:
It says the same thing that Roy’s Canada charts say: That it was just as warm in the recent past as it is today. CO2 has had no visible effect on the Earth’s temperatures. It is not any hotter today with more CO2 in the air, than it was in the past with less CO2 in the air.
Those are indisputable facts.
Why not pick the 1970s. There was a cooling trend that tilts the chart.
It is no different than picking the 1850-1880 time frame which was on the colder side of the 19th century.
So now you are reduced to picking out short trends to prove your point? What happened to all the fiddling with data in order to keep “long” trends from 1850?
I might add that exponential curve fitting is always dangerous to forecast with. It can show changes inside actual measured data but is generally useless once you look into the future. Anyone familiar with forecasting knows this.
Hmmm….The 70’s….about when weather stations started going to electronic sensors, Canada added many passenger jet airports with new weather stations, jet engine takeoff horsepower increased 10-fold….I’m wondering if .17 C per decade at night when jet exhaust is going to disturb the nightime inversion more than it does at .07 per decade during the convective daytime…..
In fact probably it is right on with about a degree of general warming since the Little Ice Age ended circa 1860
“Is there some point to this series of posts?”
Well, Part Un showed no trend, which some might think significant. But after this correction, it shows a not surprising upward trend.
Massive increase in population and urban development will do that.
Of course it did.
Is there some point to your post?
It doesn’t seem to be specified if there is.
Canada is in desperate need of warming up, even a little bit would help.
Can send a blanket & some candles (:-))
No need – according to NASA –
and of course, Kiel and Trenberth’s fantasy cartoon world at NASA shows Canada receiving 24 hour sunlight the same as the rest of the planet.
No need for candles, either.
So what’s your hypothesis Roy? Do you believe that adding CO2 to air makes thermometers hotter?
Measurement means nothing, by itself.
I think Roy is showing that adding CO2 to the air does *not* make things warmer.
Roy shows it is no warmer today than it was in the past, even though there s much more CO2 in the air now that there was in the past.
There is more CO2 in the air, but it’s not any hotter, means CO2 effects are lost in the noise and have no effect on the temperature trend.
It’s not any hotter today than it was in the 1930’s. And that’s not just in Canada, it’s all over the world.
CO2 has no measurable effect on the Earth’s temperatures. Study of the instrument-era temperature data shows this clearly. Roy’s study shows it.
“I think Roy is showing that adding CO2 to the air does *not* make things warmer.”
Nope. 100% wrong Tom. Roy Spencer agrees that CO2 is a greenhouse gas and that when you add more to the atmosphere it will warm things. He is a climate scientist after all. He just doesn’t believe the outcome will be catastrophic.
That may have something to do with the fact that it’s so small it can’t be measured.
“That may have something to do with the fact that it’s so small it can’t be measured.”
Umm…. I think you will find it can be measured… which is what Mauna Loa is has been doing for the last 65 years.
https://gml.noaa.gov/ccgg/trends/
Funny those cycles seen in the plots.
Today, the local weather informed us that so far December (1/3rd done) is the coldest start in 20 years. DC, VA, MD area.
Having lived all of my 83 years in rural areas within about 100 miles of Edmonton, Alberta, I believe I have a good perspective on regional climate and its changes.
If anything, it seems there are fewer days of extreme heat than were experienced in my youth. It also seems that there are fewer days of extreme cold. Precipitation seems to have lessened, but then drought has always been a major factor in prairie climate.
Warmer winters are probably a result of the development that has drastically changed the albedo of the land surface. Less precipitation could at least be partly the result of a significant reduction in tree cover over this area.
Overall, changes have hardly been noticeable.
If we are still emerging from a glacial period, it seems reasonable to expect a gradual reduction in ice cover and some increase in temperatures. We should be thankful, as a cooling trend would present much more reason for concern.
BTW, my area just experienced one of the nicest summers in memory. I spent most of the summer on my patio, and the farmers had a very good growing season. Thank you for a warming climate.
Has anyone ever done a Fourier analysis of the temperature data?
It would be interesting to see what, if any, cycles are in the data.
It is noteworthy in that cascading sinewaves that peak together can cause an upward (or downward) linear trend in the data.
I was born in late 1961 just outside of Toronto, my poor mom must have felt the heat, no air con back then.