Hot or Not?
creon.substack.com
creon.substack.com
I wrote it before and I'll repeat myself, if you look at what changed in the last 100 years or thereabout, it's mass burning of fossil fuels, the cars, fabrics, planes etc. Yes, I know don't jump to conclusions, scientific method and all. The not ignorant person just being observant and applying some common sense can see it bright as day.
https://sealevel.nasa.gov/faq/13/how-long-have-sea-levels-be...
Only difference I see is a slew of tourists packing every cm2 where there were far fewer while I was growing up, a lot of them getting off on how they are participating in "sustainable tourism" because their hotel has solar panels or whatever bullshit is trendy these days.
I have actually done this in terms of snow. I said to myself, it seems like there were bigger snow storms (in termps of inches of snow) when I was a kid. so I got the data to verify it, and yes, not only were the snow as a kid much higher, they were also historical high - a couple record snowfalls when I was a kid. The point of this story isn't meant to tie anything to climate change, but rather be more curious and get data to back up your thoughts.
I hate quoting Bezos about this, but it's catchy and thought provoking: when the anecdotes and the data disagree, the anecdotes are usually right.
My friend's mate's sister says the same thing and the graph shows otherwise. I guess it must be true.
;)
In Christchurch, New Zealand, a notable example for me is that the snow line has receded since I was a child. Low lying ski fields are struggling to stay open. My parents have noticed less snow on the ground during winter at their rural place (they have been there ~30 years).
> remember where the sea level was back when I was little and also see where it's at now
I am a bit skeptical of that claim! Then again, sea level changes would be difficult to notice in Christchurch because we had fast uplift locally: “these events caused ground motion at the Lyttelton TG [tide gauge], the largest single vertical [earthquake] displacement was >50 mm (cumulative displacement ~110 mm)”[1] and slow uplift probably has occurred too “slow slip events has uplifted sites by up to 0.8 mm/year on average in Wellington and Dunedin”. 150km away the coastline uplifted 2 metres (2 yards)[2], boy was that stinky.
I think this quote is interesting: “At interannual and decadal time scales TG records typically show variations in annual means on the order of 5–10 cm and a possible 60-year oscillation of up to 3 cm. Although to estimate the long-term trend in relative sea level (RSL), five to six decades of reliable and essentially complete TG records are typically required, techniques exist that can use sparse data sets. A TG measures the RSL trend or the change in sea level relative to the adjacent land. Independent estimates of the vertical land motion (VLM) are required to estimate the absolute sea level (ASL). Such motion may occur due to tectonic movements, ice mass loading, glacial isostatic adjustment (GIA), or local site instabilities due to, for example, compaction, sedimentation, or water, oil, or gas extraction (Carter et al., ). The stability of a TG site is a critical issue that requires verification (Bevis et al., ) and needs to be considered at both local and regional scales. Historically, many TGs are located in shipping ports where harbor infrastructure is often developed on reclaimed or modified land.”[1].
[1] https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/201...
[2] https://earthobservatory.nasa.gov/images/89206/powerful-eart...
That article was online until about 2015 until it was so widely mocked it was finally deleted. Here’s a screenshot for you.
https://wattsupwiththat.com/wp-content/uploads/2015/11/snowf...
* Lots of possible reasons for apparently more mosquitoes: perhaps they are evolving to match the environment here?
Little Ice Age ended, you see...
In case anyone was curious, the cherry blossoms were first planted in Berlin in November 1990.
This is about as anti-science a stance as you can take. Why believe data when you've got your lyin' eyes?
Climate change deniers can use the exact same argument, so how do we get anyehere?
Weather is really really complicated. More greenhouse gases in the air results in more of the sun's energy staying in our atmosphere as heat, but how that affects the ground-level temperature in a specific city can be very, very complicated. Some areas might even become significantly cooler as climate change affects the weather. Plus, many of the worst effects of rising greenhouse gas levels (droughts, hurricanes, wildfires, flooding, algal blooms) are not a direct result of rising temperatures.
A climate change indicator with fewer confounding factors than "ASOS temperatures for pseudo-random airports" is ocean acidity level [1] [2] (CO2 gets dissolved in our oceans and changes the pH, affecting marine life). Another one is sea level [3].
[1] https://www.epa.gov/climate-indicators/climate-change-indica...
[2] https://www.eea.europa.eu/ims/ocean-acidification
[3] https://www.epa.gov/climate-indicators/climate-change-indica...
Indeed. The way I currently tend to think about the difference in my head is this: human activity has caused a large amount of extra energy to remain inside the atmosphere. Some of it is in the atmosphere itself, some in the oceans and lakes, some in ice, some in land. You can't trivially predict what a lot of extra energy will do when it ends up in such different storage "media". The obvious conclusion is "global warming", but there's no inherent reason for that to be correct. The extra energy could, for example, all go it into generating humungous sized and crazy fast storm systems, which would result in little change in temperature but very noticeable changes in weather and safety.
Of course, it is unlikely that all the extra energy will be directed into a single phenomena, but the example is enough for me to remember that it's really non-trivial to understand what it could do, let alone predict what it will do.
This type of discourse ("here is what I did and here is what I saw") leaves room to comment and make progress. People can discuss measurement methods, statistical analysis, and other objective things about a tightly scoped project like this.
This is very clear reading the comments in the substack. A comment exchange that reminded me of my days in grad school:
commenter: "What I think can be taken conclusively from this survey is that temperature is quite regionally variable, and there are a variety of different trends over time in these locations. Do you feel that there is some more significant conclusion that can be drawn from this?"
author: "I am hesitant to draw any conclusions. I am more in a state of examining the data itself and asking questions."
Let me rephrase that to make it even more clear: if climate change to date would be such that it would show up in datasets like these then we would not have needed any climate research to begin with. We're talking about 1 degree average change over a 60 year period across the globe. So that includes the oceans, the poles and a ton of other places where you won't find airports (or thermometers, for that matter).
"I don't have the data or tools at my disposal to do this properly" Should not prevent you from trying, sharing, and learning. However, it definitely should prevent you from trying to change other people's minds.
What data or tools do you have so that you are in the position to change other people's minds?
People who go out to change minds should be versed in all this and more. But I don't believe they are required to roll up your sleeves and play with some data! :)
Wait a minute, do you think Al Gore was, or even claimed to be, the person doing the research he was popularizing?
Mike E. 14 hr ago edited 14 hr ago
You maybe missing the trees for the forest. Global or local mean or median temperature is a nebulous (no pun intended) indicator. It's the increases in daily weather variance, incomprehensibly-fast melting of major glacial masses, rising sea levels, and frequency and intensity of storms, fires, famines, and species' extinctions that are the "forest". These are consequences of anthropogenic GHGs that reduced Arctic sea ice (nearing an inevitable blue ocean event) and increased global sea thermal energy absorption which destabilized the jet stream from more predictable cycles. GHGs lead to a -11 F snowpocalypse in Austin, megadrought in US West and SW, "Hurricane Alley" shifting eastward, 100 F in the high Arctic town of Verkhoyansk, water trains of India, and slumping and melting of Siberian and other permafrost areas releasing absurd amounts of methane.
The variance (locally) is shown in the plots. What do you see re: variance?
"Incomprehensible" glacier movement? As I understand it nine time in the life of the human species the glaciers have advanced to cover much of N. America and then retreated to where there was little or no polar ice at all.
Frequency and intensity of storms? I suggest downloading the data on all hurricanes for the last ~100 years (as long as they've been recorded) from the NOAA national hurricane data center. I did that. I plotted it. Guess what I found?
Fires... I lived in Napa California during the big Napa fires. How much was due to climate change, and how much was doe to terrible forest management by the forest service and the state? (don't thin the forests, don't clear dead trees, etc).
Species diversity is very complicated. A whole different matter. So much to say at another time.
Famines? Have you looked at famines vs. time for the last 1000 years? Other than the global covid mismanagement disasters of 2020-2022 (lockdowns, etc) famines are becoming a thing of the past - though if we continue killing our soils with mono-crop soy, etc they will recur.
Arctic (and Antarctic) sea ice is another deep topic.
Austin was a fluctuation. They happen. Don't kill your local electric utilities - you may want them when things get dicey (or icy :).
Look into the history of draughts (and floods) over the last 200 years in the W and SW US.. Write a post and send me the link.
You raise a lot of points. (or less politely, you are shifting the goalposts 12 times in one paragraph). I am just plotting local temperatures for 75-100 years. Nothing more.
I do still disagree though with that most of the scientific predictions has been wrong. I think a lot of what was pushed as scientific predictions were not really what was said by the scientific community.
For example, I find the chart #3 misleading a little.
> The global median temperature (of the entire dataset) is uniformly subtracted from every data point, to keep things relative to an arbitrary x-axis of 0.
This only means that relative to the median, the temperatures do no fluctuate crazily on an average. This says nothing about the overall trend in global medians, nor does it say anything about the frequency of extreme temperatures. These need to be accounted for because in data visualization, you can use the same data to tell a different story depending on the design choices you made in you viz.
For instance for his Palm Springs example consider
https://oehha.ca.gov/epic/changes-climate/annual-air-tempera...
If you were interested in studying the relationship between bias and funding you might do a survey of published papers and articles on the subject.
If you can identify some measurable criteria that can be used to rate how "green" a paper's funding is then you can use that as an axis and compare the surveyed papers to reveal trends.
There was no real effort to understand the possible sources of noise or error in the measurements.
In 1920 the Industrial Revolution has been going on for over 100 years, the US petroleum industry was already big enough to have been affected by antitrust action, and Henry Ford's assembly line has been enabling mass motorization for the better part of a decade.
It's too bad that humanity hasn't figured out a way to record and share and pool knowledge yet, but them's the breaks.
There are many additional areas of analysis you could do with this dataset, for example, although the temps may be in the same range, how have those temps changed seasonally? A warmer January and a cooler September can average out to what looks like no change annually, but a couple degrees warmer in January can have huge environmental affects.
Quick, what is the median of these numbers: -2,-1,0,1,2 And what is the median of these numbers: -7,-1,0,1,2
Of course the average and median are identical for a perfectly distributed normal distribution. But part of science is supposed to be reducing the noise from your signal. Why are you adding noise in your quest to investigate the average temperature of the earth?
Not if outliers are REALLY FUCKING IMPORTANT, like, say, extreme weather events.
A: The median temperature is the calculation that allowed him to deny planetary warming while using statistics.
Look, when you want to show something to be true that is actually false, statistics will help you to do so.
In america the justice system has the judge (representing the state) and the jury (representing citizens). other countries have similar tribunals , each member with a different allegiance.
For science, we need a strong and formal amateur tier to review and corroborate results. Though this exists now, it's not formally engaged with science reporting. and there's no method to compare amateur results to professional.
What OP is doing here is bolstering amateur observation and he should be praised for that. I'd like to see research like this given more resources and exposure to build trust in scientific findings.
Ministry of Truth?
People who 'distrust science community' will simply distrust the new Institution you are proposing.
I find it interesting to see that the median temps in these select cities don't seem to be wandering up that much. I wonder if there is some statistical tool to analyze the slight upward angle on the linear regressions of the medians.
I am surprised that these data do not show a more extreme departure. I believe that we are getting hotter temperatures, etc etc. But perhaps my observations are colored by the media on this - if I were a lizard, would I see climate change?
I can think of three possibilities:
1. The cold days have been getting colder, and the hot days have been getting hotter. The median temperature could still be somewhat constant in this scenario if the not-too-cold and not-too-hot days have temperatures that haven't changed much.
2. Even if the cold days have stayed roughly the same temperature, spikes and outliers in the hotter temperatures could still fail to move the medians that much. Consider that the median is often used to actively reduce the contribution of outliers to the data. Then it becomes a question of whether or not those spikes and outliers are meaningful or important.
3. Climate change is just a hoax (not something I believe, but it's certainly a "possibility").
I appreciate the value of getting up-close with the data to see quality issues, put things in context, etc. But the lack of an overall analysis leaves the most relevant question unasked, leaving us only with the author's biases (as they themselves admit.)
One possible explanation for the data is that, regardless of whether or not the Earth is getting warmer, cooler, or staying the same temperature, you would always expect some places to be getting warmer over a given time period, some places to get colder, and some places to stay the same. That's just a property of a random system. Without sampling enough points, you can't say how the global temperature is changing because you don't have enough data. Another issue is that the author largely chooses cities. It may be that cities are more likely to be built in an area if that area has a stable climate. As other have mentioned, even a 1 degree change is temp is significant, so the scale of the graphs is wrong too.
A good illustration of how random systems can do weird things is this wealth simulator: https://www.masswerk.at/misc/wealth/
In this simulator, 55 "participants" are given $45 and at each step in the simulation, each participant randomly gives another participant $1. Even though all of the action in this simulation is random, some participants typically acquire much more wealth than others. If you sampled random participants after N steps, some would gain money, and others would lose money. Rarely would the wealth of a participant stay the same. If you didn't understand the rules of the simulation, and were only presented with the data, you'd need to analyze data from all of the participants to conclude that total wealth had stayed constant.
https://climate.nasa.gov/scientific-consensus/
For someone who worked at NASA and has a whole pile of claims to his name I would expect a far better researched piece of work. Thermometers placed randomly with a certain goal (to provide temperature data to pilots) and read out by people on irregular times during the day are a rotten source to extract climate change data from anyway.
Scientific consensus does not mean the average of all opinions (i.e. "scientists on average believe in 2 degrees warming"), nor does it mean the average of all possible values of opinions ("there are people that believe in 2 degrees, and there are people that believe in 0 degrees"). These heuristics are wrong.
It's a summary that needs to include reputation, credibility, trajectory of findings and a lot of structural knowledge of how the field has evolved over time. All of these are not things that an outsider can easily know to even look for.
Sorry, but no.
A lot of people have an academic education, for example, and are capable of reading scientific papers. You have to be able to make a solid point that other people can verify. The last couple of years have already shown that institutions are also of little use.
Don't confuse science with scientific institutions.
Take the evolution of temperature measurements through proxies (although that is not my field). If at some point it becomes known that some method of measurement is biased, then that implies a re-evaluation of past research.
Every time such adjustments happen, there is a meta-learning regarding the pace of adjustments and the severity, and also regarding which people andinstitutions prefer to stick to "old" or perhaps more conservative interpretations in some sense.
When you try to summarize the scientific consensus, you need to do so by literature because (1) the composition of the field is always changing to some degree and (2) you will never get all scientists to tell you their opinion at the same point in time.
But when you do this - summarize the literature - it is crucially important to adjust for historic biases, drift in methods adoption and interpretation and so on.
And this is just the measurements part: There is also the problem of predatory journals etc etc. - all of these can skew the "consensus" if you don't account for them.
So I'm pretty convinced that your argument of a pure, "individually verifiable" science is desirable, but has never existed and never will.
But doesn't this very sentence from you imply that there is no such consensus as you claim? Apparently there are lots of publications that disagree, so where do you get your consensus from?
" the composition of the field is always changing to some degree and (2) you will never get all scientists to tell you their opinion at the same point in time"
That is why I don't care about a "consensus" - science is not a democracy. I care about verifiable facts, and open discussion.
"So I'm pretty convinced that your argument of a pure, "individually verifiable" science is desirable, but has never existed and never will."
I am not saying that science should output 100% true facts only. Everything only has probabilities. I am saying that scientific output should be verifiable by other people. Scientific facts are not determined in a democratic way, they already exist and are only being discovered.
But that does not mean that when there are two possible outcomes that these carry equal weight: the evidence for human influenced climate is so vast and so well researched that it would take an absolute miracle to displace it at this point.
> I am saying that scientific output should be verifiable by other people.
It is. Reproducibility and peer review are part and parcel of science and it is always done by other people than the ones involved in the original research.
But to you 'other people' may include people that have not studied the subject matter and that are not capable of following the arguments. Those people will end up having to pick a side, just like you have done, you are on the side of the 0.1% versus the 99.9%, likely because that decision works better for you in some way or other. But that does not make you a scientist any more than it makes me one. And I'll throw my lot in with the 99.9%, not because it makes my life any easier but simply because that makes good sense.
Even now there are various scenarios, not a single consensus. And I rather doubt that you personally have verified the climate science, so what makes you so sure?
Btw it is not about humans influencing climate (of course they do), but about the doomsday scenarios.
"Reproducibility and peer review are part and parcel of science and it is always done by other people than the ones involved in the original research."
Peer review is not a a guarantee for good science, it was invented for the government grant system. Sorry if people call on the peer review system, to me it just shows they are delusional about the workings of the science systems in most places.
"But to you 'other people' may include people that have not studied the subject matter and that are not capable of following the arguments"
Everybody can study the subject matter, that is the thing. It is you who claims only certain people of your choosing are capable of doing so.
"And I'll throw my lot in with the 99.9%, not because it makes my life any easier but simply because that makes good sense."
Do you even know what the 99.9% say? You can check how that number was derived - it was people evaluating abstracts and judging whether those papers agree that humans affect climate. It doesn't say everybody agrees on the doomsday scenarios.
I also read that report, but I got a different vibe from it than you did. What I read was a bunch of settled stuff, a bunch of stuff where the results are predictable but the exact circumstances are not and a bunch of still open stuff requiring more research hopefully resulting in being able to settle other questions. It's pretty much like any other scientific report that I've read with the difference that it spans the globe.
The tricky bit is that the countries that are doing the least to help stave this off are also the ones best positioned to ride it out unless we end up with one of the worst case scenarios.
But locally some countries are already experiencing the first set of symptoms and it isn't pretty. (Notably: the South of Europe and North Africa)
> Btw it is not about humans influencing climate (of course they do), but about the doomsday scenarios.
The doomsday scenarios will come to pass if we don't make some pretty drastic changes. Personally I won't live to see it, but my kids most likely will, even if they're off by a couple of decades.
Because the thing that there is a lot of discussion about is the exact dates, not necessarily on what the consequences are.
Anyway, you seem to have made up your mind on this and I have more important things to do (in the short term...).
You read the 1000 pages? Respect! But is it even "science" or just a bunch of predictions?
"The doomsday scenarios will come to pass if we don't make some pretty drastic changes."
They won't, and afaik even the IPCC scenarios are not all doomsday scenarios. But there is no point arguing it with true believers.
"But locally some countries are already experiencing the first set of symptoms and it isn't pretty. (Notably: the South of Europe and North Africa)"
Are they? I have asked the question a lot to point out a real climate change impact, and never received an answer. There were answers, but when I looked into it, the real reason was always something else, like drilling wells and depleting the ground water and so on. Non climate change human actions still do enormously more environmental damage than climate change.
Of course if you can claim "it was climate change", especially as a third world country, you are eligible for receiving a lot of monetary compensation. So most articles and claims attach it as a footnote, "also because of climate change".
FWIW, the author Michael Crichton encountered much the same phenomenon in his novel "State of Fear" for which he was castigated for doing the same thing. Just looking at the data.
(People without that monomaniacal background and focus still write about science, but they’re prone to making basic errors. We call them “journalists.”)
Climate science is full of well-meaning laypeople rehashing basic facts, and doing so poorly. I’m not a climate scientist, and I don’t know the details, but I know enough to know that figuring out historical temperatures is a whole branch of science with massive amounts of work and research behind it. This amateur comes along with a naïve data collection methodology and gets some results that casts doubt on one of the fundamental facts of climate science—that the world is getting warmer.
At this point, he could have stopped and said, “this data is completely out of line with the established science. Maybe there’s something I don’t understand.” Perhaps do a literature search to find out how data is collected and confounding factors are addressed.
Or he could throw his crap data up “without comment,” implying that he’s found some secret. Pfeh. Lazy and irresponsible. At the bare minimum, he could have shown a little intellectual courage and asked what he was missing, and why his data was at odds with the scientific consensus.
The scientific community encounters these sorts of well-meaning amateurs all the time, particularly in physics. They combine ignorance and enthusiasm into an unending firehose of time-wasting ideas. They’re called “crackpots.”
These alarms bells have been pulled repeatedly over the past 50 years. Calls for imminent catastrophe in just 10 years if nothing is done. That was 20 years ago. At some point, you have to wonder just who is profiting off of your fears while flying around in their private jets. That should tell you something.
I'll let you have the last word.
Shellenberger and Lomborg have presumable studied the issue for decades, so at what point does one cross into "being a scientist" territory? Years of study apparently doesn't do it, so what does? Obama's seal of approval?
You are confusing science and specific systems of doing science, like say a countries university system. A specific system of doing science does not automatically produce good science.
All he did so far was provide some data points. The "real" scientists should be able to explain them easily.
Btw, since I was just talking about her elsewhere, would you say Greta Thunberg qualifies as a scientist?
If one wants to redo all the scientific research that has led to the consensus about Climate Change again, they can do so over and over again.
But in 2022, most of us are past the 'discussion' phase. We really, really, need to be in _Action_ phase. The discussions have been had for decades now - I implore you to find a new argument - almost every objection to climate change has multiple scientific papers published.
Worship your idol at your own pleasure, but don't call it science.
Given some of their commentary, I'm not sure it can be claimed they were making a good-faith effort. There is a clear agenda to their analysis.
they did much more work than the random person who believes evrything they see on TV. that should be saluted, not derided.
Compare that with typical media science reporting which is often much worse and misleading at best when not grossly wrong.
Quality work starts with data exploration and data mining. I see this article as an invitation to check the actual data thats available, if anything.
It isn't. The only thing it does is stir the pot and give the climate change deniers another straw to try to cling to.
If it's not the case, and you allow for a possibility that a private person could do useful data analysis, you would have to prove why her analysis isn't that.
Also, the IPCC put out a like 1000 page report, it's not like this information is being hidden.
"Also, the IPCC put out a like 1000 page report, it's not like this information is being hidden."
Yeah that is actually more fishy than convincing. They should be able to present it in a digestible manner. A 1000 page report is just spam, created with billions of funding. It is also not all hard science afaik, it is a lot of bla bla "this and that will become an issue because of climate change", difficult to find the meat.
Have you ever even looked at the IPCC report?
Interestingly, there are animations of the changes in the hardiness zones over time:
https://www.arborday.org/media/mapchanges.cfm
Difficult to argue with that, I think.
Needless to say, this is not global climate change, which is what all the discussion is about.
The majority of the concern has to do with ocean temperatures, sea levels, melting of permafrost, etc. how these cause changes in climate patterns, chemical changes to the oceans and atmosphere (besides GHG, water vapor affecting the ozone layer and UV) among many other factors, including extreme weather patterns- all of which affect the ecological balance in ways that may be disastrous as fauna and flora are not able to adapt at a fast enough pace to survive. Each of these things causes a domino effect of simultaneous chain reactions that also directly impact human life.
Additionally these temperature readings don't factor the specific location of the thermometers, correlating variables specific to airports, the reality that climates of different regions are affected differently by climate change, among other considerations not explored.
This seems like an overly simplistic "I am skeptical of scientists and science", when in fact climate change is much more complex than "temperatures are higher everywhere"- just looking at thermometers in airports isn't going to bring clarity or disprove the science that has been repeatedly warning about the impact of releasing excess greenhouse gasses for over a century now.
From that somewhat unusual assessment of source data, he arrives at somewhat unusual conclusions.
I can also see some trends like the variation increasing.
What's different when using another temperature data source? It would be nicer if the R source was just public without having to ask for it.
The author is clearly a knowledgeable person, they still might benefit from asking themselves what they don't know before drawing any strong conclusions.
Edit: trying to understand the decomposition of average temperatures increasing (more hot days, hotter hot days, etc)
https://news.cornell.edu/stories/2021/10/more-999-studies-ag...
Might be good to find some new words there. Last time I heard those it was after government leaders were lying to me about masks.
ok google, define "cherry pick"
cher·ry-pick
/ˈCHerēˌpik/
verb
choose and take only (the most beneficial or profitable items, opportunities, etc.) from what is available.
"the company should buy the whole airline and not just cherry-pick its best assets"
- we had 'tropenrooster' (tropical schedule) several times when the temperature went above 30°C, this entailed an early start to the school day so we could go home around noon. The main reason was that the heat in the class rooms was too much to bear.
- roads were closed several times because of the asphalt melting from the heat
- ...while at the same time I skated (as in ice skates) to school several times, once even over the roads when they were covered in a few cm of ice
We had some hot summers and some cold winters, this was in the same period when there were warnings of "a new ice age". That ice age did not materialise just yet [1], nor did those hot summers mark the beginning of a trend.
During my first years at university I lived in a little house on a farm somewhere in the countryside. The first winter I was snowed in for a week. The toilet froze, there was a snow ledge on the inside of the front door. The "Elfstedentocht" - a 200+ km ice skating marathon between 11 cities in Friesland - was held twice during my time at university after a hiatus of several decades. It has not been held since.
All of this is anecdata but the story it tells is clear: it was hot back then, it was cold back then. It was hot in between, it was cold in between. It can be hot now, it can be cold now. It would be possible to draw a regression line in an attempt to show some trend but whatever it would show would be misleading, the period is too short and the data points too few. Have a look at the temperature graph for the Holocene [2] to see a trend line over a somewhat longer period, in this case about 11.800 years. Even there it is necessary to even out the bumps over several hundreds of years to get at the real trend which was a stark rise from ~11.800 years ago culminating in a maximum around ~8500-4000 years ago followed by a slow decline. Looking closer the "Little Ice Age", the Viking age warm period and the Roman warm period can be recognised, all of which had a large impact on human activities and development. As to whether the "Little Ice Age" never saw hot summers or the Viking/Roman warm periods never saw cold winters we can only assume they did, just like the supposedly cooler 70's saw some hot summers while the supposedly warmer 90's and early 2000's saw some cold winters.
[1] ...or rather we are still in the same ice age as before, to be more specific in the Holocene interglacial period which is probably running on its last legs if previous interglacials are something to go by, just a few thousand years from now there will most likely be a new glaciation - https://en.wikipedia.org/wiki/Holocene
[2] https://upload.wikimedia.org/wikipedia/commons/c/ca/Holocene...
These are just arbitrary cities.
Not to mention that, most climate change stuff looks at the start of the industrial revolution, so a starting point of around 1920 is going to necessarily look a lot different.
Either way, these graphs look flat from 1920 on. That’s the point of the article.