Our Questionable Climate "Catastrophe" - Part 1
Exciting news for dwellers of the Great White North. A 118-year temperature study of a small prairie town.
On July 5th, 1936 in Morden, Manitoba, Canada (my current hometown) the deadliest heatwave in Manitoba's history began. It wasn't just Morden, (it affected mostly Manitoba and Ontario) but it was hotter here than it was in Winnipeg, just over an hour to the north.
For 13 days in a row, the daytime high was over 35°C, with a two-week average temperature of 36.6°C.
Eight of those days were over 38° and four of them were hotter than 41°. For the month of July that year, the average daytime high was 33.5° Celsius. For comparison, the normal average high here in July is around 28°.
The hottest day was July 11 at 43.9° Celsius.
Only three other times in the last 118 years have we ever cracked 40° here. All three were in the month of August - once in 1949 (40.6°), once in 1964 (40°), and once on August 1st, 1989, when it reached 40°C. That one I remember.
Even the heat wave that hit British Columbia in 2021 wasn't technically as severe as this one was because it only lasted four or five days. The biggest difference there is that those guys simply aren't cut out for that kind of heat. They weren't at all prepared for it. I'm not sure we were either in 1936 but still likely better adapted to it than western BC.
If you're not from here, then I'll let you in on a little secret: the summers in southern Manitoba are awesome - just way too damn short. It's not unheard of to see temperatures of 35° here in the summer. That's pretty hot, but thankfully not too common, and we can certainly deal with it if it's only for a day or two. Usually if it gets to about 28° or so, you can already hear people complaining. I never do, because I know all too well what's coming in just a few short months. By the way, so much of how we handle this (maybe all of it?) comes down to adaptation, and I did write something about that a while back. You can read it in The Coziness of Glaciers.
What follows is a collection of charts representing the weather in my hometown of Morden, Manitoba. I'm really hoping I don't lose any of you in the geography lesson and the powerpoint(ish) demonstration that follows it. If you really can't handle charts and stuff like that, you can just skip to the end and read my conclusion. It's up to you. Either way, here we go…
Morden is in southern Manitoba, 12 miles north of the US border, in the Pembina Valley, and right on the ancient shores of what used to be the humungous Lake Agassiz in prehistoric times. Because of this, the remains of huge prehistoric sea creatures are often found in the area.
Lake Agassiz is what drained into Hudson Bay at the end of the last ice age and left us with around 100,000 lakes or so (at least according to the old license plates). One of these lakes is Lake Winnipeg, which is the 6th largest lake in the country - bigger than Lake Ontario. Just thought you might want to know that…
Charts
As a word of explanation, these charts are all made with Excel spreadsheets which I created with data from the Canadian government’s historical weather site.
There's a trendline on each chart so you can get some idea of where we're headed. And before you say it - I'm well aware this is localized weather (hence the subtitle). But guess what comprises global weather patterns - thousands of local weather patterns. So if you have some to add for your hometown, I'd love to see them.
One final word about these charts. If you're an analytical type, you might notice that only certain months are displayed on the bottoms of these charts. This is not because I've “cherry-picked” data, as some have accused me of doing. Keep in mind that there are over 1400 months of data here, and then imagine how long this chart would be (or how miniscule the text would be) if every single one of those months were written out on the bottom.
Average Maximum
This first chart is the average monthly maximum temperature for Morden, which is to say that it's the average of each day’s highest temperatures over the course of the month to come up with one number for the month.
If you’ve got a really accurate ruler, you might be able to notice an almost imperceptible rise in temperature. I think it’s about half a degree or so over the last 118 years.
Monthly Maximum
Here's the chart for the monthly maximum temperature for Morden. This is the highest recorded temperature for each month. Again, you can haul out that serious ruler you may or may not have and you might actually notice a bit of a decline in temperature on this one. Looks to me like it might be around 0.75 degrees or so.
Average Temperature
This is the mean monthly temperature for Morden, which is the average temperatures for each day (all day and all night) all taken together and averaged over each month. So, this is the average temperature for each month.
If you’ve got a good eye, you might see a slight rise in this one as well. Like, maybe about 1.5° in total.
Average Minimum
The mean monthly minimum temperature is the average of all the lowest daily temperatures in each month, generally considered “nighttime lows”.
I saved this one for last because this appears to be the real reason (or the only reason) our average temperature has increased here. You don’t even need a fancy ruler to see the increase in temperature here. It looks like it’s more than a two degree rise over the same period.
Apparently, what’s driving whatever meager increase in temperature there’s been (at least in Morden, MB) is our nighttime temperatures not being quite so low. And not just nighttime temps, but it seems to be even more pronounced in the colder months.
Winter Lows
The following chart is simply our winter temps. For the purposes of this study, I chose November to February to represent winter as those are normally our coldest months here.
This is really a beautiful sight and I don't know any native Manitoban who would complain about this kind of trend. There's probably about 3° Celsius there. This is awesome, although I can't honestly say I've noticed it - every winter still feels colder than the last one to me.
Summer Highs
On the other end of the spectrum, here's our summer. I chose the months of June to September, even though it starts getting warm here about mid-May and starts cooling off about halfway through September. Just trying to keep it simple.
As you may have noticed, your fancy ruler won't help you at all on this one. I think there is technically a bit of an increase here, to the tune of about an eighth of a degree. In 118 years. Maybe. For all intents and purposes, the trend here is flat. So, in southern Manitoba at least, aside from the odd heatwave that has always been a part of our climate, our summers are not getting hotter, although the nights are a little less cool.
Conclusion:
Here's a fun fact:
When you turn on the news and you hear, “Today we smashed the previous heat record from 120 years ago!”, most of the time what they're referring to is not that we just broke the record for the hottest temperature EVAH. Usually, it just means we broke the record for the hottest temperature ever recorded on that date.
A prime example of this happened this summer when CBC posted this article:
21 new heat records set on sweltering Father's Day in Manitoba
To their credit, the article did say that “Extreme heat isn't unusual for this time of year.” This would be a useful fact to keep in mind when discussing summer temperatures almost anywhere on the planet.
While it's true that there were 21 locations in the province that broke records on Father's Day (June 19 in Canada this year), these temps were not even close to the actual records that were set in July of 1936, or even several other years, for that matter. Now, I can already hear you saying, “Yes, but that was in July, and this was in June!” Also true. A difference of about three weeks. Hindsight, of course is 20/20 so now that we can look back at July of 2022, we can see that Winnipeg barely broke 30° all month. In fact, July was a fair bit cooler than normal this year. Obviously, you won't see that on CBC News because that's “just weather” …
None of this means that we don't set the odd real record these days. British Columbia's heatwave of 2021 was a legit, crazy hot few days - especially for those guys. And people died, so it's obviously not nothing. They set actual historic heat records that hopefully will stand for a long time.
In case you're curious, a town called Rabbit Kettle in the Northwest Territories set a new all-time cold temperature record just before Christmas this year at -52.1°C (merely a week and a half ago as I write). That's cold. Still not as cold as some other places in NWT in previous years, but it's a record for them. Also, five of the 30 coldest temperatures ever recorded in Canada happened in the last ten years, and as an added point of interest, the 4th coldest temperature ever recorded in Canada was also in the NWT and in 1936 (the same year as that killer heat wave in Manitoba and Ontario that I opened with). Because hey, it's weather. And it's Canada. And real weather doesn't give a shit what a computer model says it's supposed to be doing.
So basically, what I'm saying here is that yes, our average temperature has indeed increased slightly, but when you look at when it has increased (and more importantly when it hasn't), it's pretty hard to sell the whole “climate catastrophe” deal to people who actually live here. If anything, our climate is becoming less extreme, not more. And just because you hear “MORE HEAT RECORDS DEMOLISHED!!!” on the news in the middle of summer, that doesn't necessarily mean that any actual records were set.
It’s usually just more weather.
Well done Ken!
Have you taken a ride out to your local weather station? Where was it located 120 years ago, and, is there some heat island effect at play there? Let us know!