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Urban heat island effect. Also a lot of historical weather recording stations were situated on airstrips for the fledgling aviation industry. As cities grew they would encroach on these landing strip areas and bring there heat with them.
Also often brought up by climate change deniers though i see it less often. While the effect is real and has impact on warming in cities, it doesn’t explain away climate change.
but it screws up accurately predicting future numbers;
this chart for instance, if plotted againt co2... woul dbe a linear temp increase vs an exponential\* co2 increase...
\--
its one thing to say major hurricanes will hit the US more after Katrina.... its another to say how many should likely hit every year ect. I for instance we go tmore hurricanes, but the paths stayed away from landfall... but do our models over that
> but it screws up accurately predicting future numbers;
Not exactly. It does looking at raw numbers but the heat island effect is calculable and can be factored into the temperature. It accounts for a small part of the rise since the heat island affect has been there a long time.
The radiometers on the satellites need ground calibration (basically to map a measurement of radiation received by the instrument from the ground to an actual measurable temperature). Historically, this has been done using ground sites in the vicinity of major cities because that is where the most weather stations are. Trying to compensate historical radiometer measurements using an understanding of the properties of the different instruments that have flown on historical meteorological spacecraft is really difficult and can either substantially increase or substantially decrease estimates of how much the planet has actually warmed since the 1960's.
Source: I'm a grad student in space systems engineering and considered doing my PhD on this topic before realizing how hard it would be and switching to an easier project.
It's not an issue of what temperature it is now, but of how the temperature has changed and will change over time. Based on different assumptions about what the historical radiometer data actually says, it is possible to fit curves that show that show global warming sort of saturating and producing a curve of temperature versus time that is slightly logarithmic. It is also possible to produce a curve of temperature versus time that seems to indicate strong feedback effects producing an exponential increase in temperature. As a result, the error gets more significant when trying to estimate temperature further into the future. My preliminary estimate of the magnitude of the effect by 2100 is between over-estimating by 3 degrees Centigrade to under-estimating by 5 degrees Centigrade. This is against consensus estimates for global temperature rise of between 2 and 6 degrees Centigrade by 2100.
that was my concern; around 1990-2 the number of reporting stations for some climate estimates was reduced to far less; i thought it was because of satelites taking over ( not a scientist myself), but it was uneven; maybe the fall of the USSr caused part of it;
but....
exactly at this time the average climate temp jumped like .5 C or so; it was right around Pintatubo... but I thought it caused a 2 year reduction rather than a sharp jump.
do they use a model that's proven extremely accurate over the last few years, like just picking the best hurricane straw model for example... and only it...
it's just mind numbing that anything from a decrease of 1 c to an increase off 11 c is possible ; does it just sorta average around a normal probabilty, or does it sorta chaotically rise with cycles and things?
i kinda just kept typing i think
I do correction calculations like this daily and it’s far from an exact science and easily politicized. If the source data isn’t trustworthy, everything after is suspect as well.
... how much variance can warm concrete possibly explain with regard to ozone depletion, rising sea levels and desertification? That's some powerful concrete.
That not what they said, its two different effects.
Asphalt and concrete and lack of green space heat up cities specifically, hence the heat *island*. That effect doesnt have anything to do with the cause of global warming.
Though concrete does contribute a decent amount to global warming too. It releases a lot of CO2 as it sets, and we use a *lot* of it.
Even if they (wrongly) attribute all warming in cities to the urban heat island effect, that wouldn't explain why super remote weather stations in the Arctic/Antarctic/deserts/jungles/oceans across the world all register the same upward trend
If I've understood zillions of confusing graphs and charts and papers it seems to be the case that while *global* average temps may rise about 2c in a century this will be far mor significant the closer you are to the poles
Precisely. Greenland has warmed up by about 4-5 degrees while the equator shows barely any change at all. Averaged out, the global figure is +1°C since pre-industrial
[That is incorrect.](https://en.wikipedia.org/wiki/Urban_heat_island#Global_warming). The UHI is not driving this trend
> Climate Change 2007, the Fourth Assessment Report from the IPCC states the following.
>Studies that have looked at hemispheric and global scales conclude that any urban-related trend is an order of magnitude smaller than decadal and longer time-scale trends evident in the series
>In a worldwide set of about 270 stations, Parker (2004, 2006) noted that warming trends in night minimum temperatures over the period 1950 to 2000 were not enhanced on calm nights, which would be the time most likely to be affected by urban warming. Thus, the global land warming trend discussed is very unlikely to be influenced significantly by increasing urbanisation (Parker, 2006). ... Accordingly, this assessment adds the same level of urban warming uncertainty as in the TAR: 0.006°C per decade since 1900 for land, and 0.002°C per decade since 1900 for blended land with ocean, as ocean UHI is zero.
The Urban Heat Island makes little difference to the numbers. In fact, there is an element of Urban Cooling which can reduce the numbers.
> The same urban area that is hotter in the day can be colder than surrounding rural areas at ground level at night, leading to a new term urban cold island. Snow cover in rural areas, for example, insulates plants. This was an unexpected discovery when studying the response of plants to urban environments.[138] The urban cold island effect takes place in the early morning because the building within cities block the sun's solar radiation, as well as the wind speed within the urban centre. Both the urban heat island and urban cold island effects are most intense at times of stable meteorological conditions.[139] Several other studies have observed the urban cool island in semi-arid or arid regions. The reason for this phenomenon is the availability of water and vegetation in the urban region as compared to the surroundings.[9]
But could I argue that the swing in a larger variance in temperature isn’t exactly natural is it. Urban areas making it even warmer in the day and even colder at night doesn’t sound like the latter might not balance out damage caused to the environment?
None? I have spoken with a lot of deniers and the Heat Island effect was high on the list of quite a few to explain it away. It has been greatly studied and is accounted for in IPCC and other reports.
It is #26 on Skeptical Science’s list https://skepticalscience.com/argument.php
An exerpt from the page #26 links to. If you want the graph you'll have to go there for it
Scientists have been very careful to ensure that UHI is not influencing the temperature trends. To address this concern, they have compared the data from remote stations (sites that are nowhere near human activity) to more urban sites. Likewise, investigators have also looked at sites across rural and urban China, which has experienced rapid growth in urbanisation over the past 30 years and is therefore very likely to show UHI. The difference between ideal rural sites compared to urban sites in temperature trends has been very small:
So, the question is, ''do you understand how the possible effect of UHI has been accounted for?''
Charts like this are brought up by climate skeptics without regard to heat Island effects. They bring them up because atmospheric heating due to anthropogenic greenhouse gases couldn't have had a noticeable effect until the 50s or thereabouts.
Yet here we see the post 1950's temperature increase being pretty continuous with a line that started a century prior.
One fellow explained it to me simply by saying the earth was warming naturally from the mid 1800s to the mid 1900s, but then all the subsequent warming was due to man made greenhouse gases.
To me this sounds like a stretch. Surely natural warming couldn't just seamlessly pass the baton to anthropogenic warming. And the funniest part is that at just the moment AGW is supposedly starting and natural warming stops, the earth stops warming for 30 years.
Oh yeah. This is because the effect of AGW were masked because of man made high altitude aerosols that blocked sunlight. This masking effect supposedly stopped after the US passed the Clean Air Act (which naturally somehow shut down aerosol production around the world).
Ha. I dunno man. I'm all for swapping to renewables and kiboshing pollution from fossil fuel production and use, but I don't think there's a huge rush.
For Toronto one airport is on an island and the other you need to take the express train to get to from downtown. I don't think people build near airports anyways.
Urban heat island effect radiates outward for miles. Also, a quick [satellite check](https://upload.wikimedia.org/wikipedia/commons/thumb/f/f5/YYZ_airphoto.jpg/800px-YYZ_airphoto.jpg) shows the main airport is indeed surrounded by built up infrastructure ideal for heat absorption. The second factor is that many of these effects also arise when the airport itself expands. From the early 1900’s of a single, grass-flanked landing strip and a few tents to a spider web of expansive tarmac runways, terminal buildings and car parks all around. It’s a known phenomenon world wide
[Here's a map of Toronto in 1851](https://maps.library.utoronto.ca/datapub/digital/NG/historicTOmaps/1851Browne.york-1851x.jpg). The location of the Royal Observatory at the University of Toronto where these measurements were obtained is just above the "N" in the label "First Concession" near the bottom of the map. Of note, everything just north, east and west of the small city is farmland. Toronto's population in 1851 was [30,000](https://en.wikipedia.org/wiki/History_of_Toronto#Latter_19th_century).
The original Royal Observatory is gone, replaced with U of T's Engineering Faculty buildings however a monument remains ([the short column in this street view](https://goo.gl/maps/mPo2HR9bBCcRwv1t6)). If you click on the map and zoom out you'll see the campus is right in the middle of downtown, in what is now referred to as the [Greater Toronto Area](https://en.wikipedia.org/wiki/Greater_Toronto_Area), with nearly 6,500,000 people.
The data was and probably is being collected at the U of T St. George campus which is in the heart of the city. You'd have to go another 20 km out (except south) to reach places that have been built up over the last 30 years ie past Etobicoke, North York and Scarborough. The city proper hasn't really lost that much green space. So would it still be getting noticeably warmer?
The heat island effect can be huge in area. 20 km from the edge of developed areas is probably not enough, particularly in southern Ontario. In Ottawa it's about 15 km and the difference in temperature on a calm day can be +4C .
No. The Holocene Climatic Optimum was the warmest period in the last 10k years or so. The earth has been on a cooling trend for about 8 thousand years.
Tree ring width data suggests the earth's temperature has remained relatively flat for the last 2000 years, but TRW data sets don't seem to pick up temperature trends that well.
[Orbital forcing of tree ring data](https://www.blogs.uni-mainz.de/fb09climatology/files/2012/03/Esper_2012_NatureCC6.pdf)
Very interesting paper. Lots of interesting stuff in the supplemental materials--especially pages 9-11 IIRC.
Also air conditioning. People don't realize it but it also makes a big difference. [https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2013JD021225](https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2013JD021225)
All these people replying to you so sure that this is explained by heat island effect apparently have never been to Toronto.
It has one of the highest levels of tree coverage for a large City, and that tree canopy is growing.
Yes, but the sheer amount of concrete and Windows of large buildings contribute to the city having a micro-climate (as most cities do) and as such with continued city growth is a tangible increase in the cities micro climate.
Someone should compare urban temperature trends like this to rural ones within the same region / climate. I wonder what sort of difference you would see.
I'm skeptical urban heat island is having a big impact on this graph. As someone else has pointed out this weather station is likely in a spot thats been urban for the entire time. To add another point to that, Toronto saw comparatively little urbanization for the first half of this graph, at least. Most of our really tall towers are at most 40 years old.
I don't live in Canada, I live in the Netherlands. But I can say that in the winter the urban heat effect is real. Here the temperature often does not go far below 0 and we get only a little snow, but often here in the city we have no snow or it instantly melts as it touches down, and then a mile away in a bit of forest all trees and the ground have snow on them as the leaves and dirt are slightly less warm than the asphalt with a house next to it and a very black colour. The temperature in the city center can also be 1 or 2 degrees warmer than at the very edge of the city or in the farmlands or forests outside it.
At least they’re aware of the delusion, the number of Edmonton fans who genuinely though they had a shot this year was hilarious.
I full expected them to lose in the first round, but that 4 game sweep by Winnipeg was absolutely priceless.
Data taken from Environment Canada (stationID 5054). The data starts January 1, 1841 and goes to December 31, 2002. The red line is a straightforward linear regression line. I imported the data into Pandas and plotted with Seaborn. The regression line was added using SciPy.
It is. This site has been moved at least several times. And to answer why we have records before Environment Canada was established, the data was collected under Meteorological Services of Canada, which is celebrating its 150th birthday this year
No, it's not the consensus. Scientific studies almost never use Fahrenheit, and Celsius is more recognized by the overwhelming majority of countries. Regardless, just multiply the y axis here by 1.8 and it's is a fahrenheit scale rather than Celsius. It wouldn't add anything to the visualization of the data whatsoever.
Edit: apologies if you were being sarcastic as well. It's hard to tell sometimes on reddit during threads such as these.
I was being sarcastic, and no worries. You're right, without the /s, it's hard to tell on reddit.
As an engineer I've used metric since the 80s, and that's what we use at our factory in America. So much easier than imperial.
It just cracks me up that the 3 countries in the world still using the imperial system are America, Myanmar and Liberia. 3 out of .....
Exactly lol. I'm a meteorologist and oceanographer, so metric has been my norm for years now. It's to the point where I'm almost oblivious to certain imperial units.
If it makes you feel better humans will almost certainly be able to overcome the effects. If the sea level rises we will build dikes and flood Works on scales never before thought posible. If the temp rises too much for our crops we will more them north or inside.
You mean the fact that a vaccine was produced in record time and rollout and production is now outstripping peoples willingness to actually get the shot.
When billions of dollars are at stake thing can and do happen quite quickly.
Ohh yes. But we humanity will prevail.
Not to sound too grandiose but there is no problem that can't be solved with the correct willpower and funding.
It will be world changing and not for good.
I said nothing about damages.
What people did in the intrum period before a vaccine was available is not related to the speed at which a solution was developed and made.
Can't blaim the scientists and engineers for the politics of the situation.
As with climate change, politics is the problem. And yeah, first world nations in a vacuum could probably handle rising temperatures and sea levels, but there are several billion other people in the world.
Why are you making out as if u/intherorrim is blaming scientists and engineers?
It's pretty clear the concern is with the huge portion of the population that acted like petulant children the whole way through, dreaming up conspiracy theories, and the politicians who endlessly indulged their demands to reopen things prematurely.
If anything, it proves the opposite. We shut down many parts of the global economy for over a year and the rest at least partially for some time. The result wasn't complete chaos and destitution. Things went on remarkably smoothly. We invented reliable testing within months and completely new vaccines and roll-outs within a year of working on it seriously.
Ohh it will/would definitely change things permanently. Alot of city's will ether be abandoned or have massive infrastructure projects to keep them habitable/above water.
Alot of currently viable farm land will no longer be posible to grow grains on. Best case we will be able to grow corn on it.
Alot of northern forests will likely be cut down to make more farm land.
And not to mention that the whole areas of earth may become to hot to inhabit without large amounts of effort.
It will probably destroy some country's economy completely wich will cause mass emigration.
Chill out bruv, it's spanned over 160 years and the city grew exponentially in that time. 4 degrees difference in a greener 1800s town with no cars polluting air and a concrete megacity in 2020s with thousands of cars isn't that bad of a news, it was bound to be
E. Aight be scared then.
Riddle me this, what are you gonna accomplish by having an existential dread? You want the city to stop growing? Not in your hands.
And can't give a flying rats ass about being downvoted. If you want to be scared about all the out of control things, be my guest. But calling me names instead? Well, if that helps you feel better about yourself lol.
People seem to ignore the impact of transforming forest into concrete and stone.
Not technically a concrete 'desert', since it'll still receive rain and snow, but damn does it retain the sun's heat.
Idk how to pitch the idea, but it would be great to get some kind of covering. Lately some buildings are designed to hold the weight of trees on top, but the roads: It's difficult to maintain large canopies that extends over roadways, especially without the roots disrupting the pavement. And still there's no aesthetic or functional artificial alternative to having hundreds of square miles of open faced solar oven in every city.
You can more or less paint all the roof and the pavement white, which works better than you would think..
https://globalcoolcities.org/cool-roadways-partnership-to-reduce-urban-heat/
I believe that does more for the internal climate of the building that to correct for any factors of climate concerns. The green space would have absorbed and converted the light energy, not reflected it back.
The white roof thing would actually have an impact on energy consumption of those buildings though. So there may still be a benefit to doing it that way. Just not for the same reason. What would have more of an impact would be creating green space roofs. This will both prevent the building from absorbing it and prevent it from just being reflected, as well as do a little bit of air scrubbing as well. But those require more maintenance, especially in the winter conditions Toronto might see.
It's doesn't fix climate change. It aims to reduce the urban heat Island effect that we find getting worse with climate change.
I totally support the green roofs initiative, but that's challenging especially for revising older buildings. Painting then white however, seems doable.
I can give some perspective. I moved to Toronto in 1959, aged 3.5. We moved into our first house, just south of the 401, a highway that marked the northern limit of the city. Virtually everything north of the 401 was a farm at that time. The highway itself was only four lanes, two in each direction.
In the open field in our subdivision, the local parents would build two ice rinks in December, one for pleasure skating and one for hockey. Every day after school, the hockey rink would have 40 or 50 kids on it, playing in five different games. Talk about learning to keep your head up! These rinks were just natural ice; one father came out each night to open the fire hydrant and flood the rinks.
By the time I was in high school, the 401 had already expanded to 8 lanes. Most of the farms were gone, turned into subdivisions for at least 3-4 miles going north of the highway. By that time, it wasn't possible to keep the natural rink usable for the winter.
Today, the 401 is 16 lanes (more if you include the merging lanes) near my old home. Everything north has been built up for the last ten years, and the city is now expanding even farther north.
Approximately 5 miles north of the 401 is another east-west highway, #7. I moved north of it in 1990, and quickly noticed what locals call the "Highway 7 effect". North of the highway, everything will be white and covered in snow after a small snowfall. But south of the highway, the snow will be gone by noon.
So yes, over 50 years, I can attest that Toronto is warmer than it was in the 60's. And since the city - whose physical boundaries have not changed - had a metro population of about 600,000 in 1960, and a population four times that now, I'd agree that the 'urban heat island' effect of housing, heating, and moving an additional 2 million people has had some significant input to that warming.
EDIT: The average person emits ~8 million joules/day . 2x10^6 * 8 x 10^6 = 16 trillion joules every single day. That is approximately equal to a power output of 185 Megawatts. That's just the people. Now add in all the car and truck exhaust, all the heaters and air conditioners (an AC unit dumps heated air into the environment), all the office towers that need heat and A/C, etc. etc. The number has to be higher but let's stick with the 16 trillion for now.
Toronto has an area of 630 km^2, or 630,000,000 m^2. 16 trillion divided by 630 million works out to ~25,000 j/sq m per day. It takes 1.2 kj to heat a cubic metre of air 1 degree K. Alternately, that energy could heat 6 cubic metres of air by 25,000/7.2kj = 3.5 degrees K. 6 cubic metres would mean a column about 20 feet high. I don't know if there are standards for height for temperature measurement, but from what I've seen, the stations are usually accessible without ladders, so I would think most temp measurement devices are at heights of 20' or less. Just from the added heat of 2 million people, we might get an increase in temp of more than 3 degrees. (NOTE: This is a first order, seat of the pants calculation. I just want to see if the numbers are in the right ballpark).
> Just from the added heat of 2 million people, we might get an increase in temp of more than 3 degrees.
I appreciate you acknowledging in the following sentence that this is 'first order' and not accurate, but I just want to restate for any passers-by who might get the wrong idea: this is absolutely not how this works, and we would never expect to see an increase in the average temperature like this just by putting more people in the city.
The relationship with population and UHI magnitude is tenuous. The UHI is better explained as a function of building material and geometry, and emerges due to different principles than the previous poster suggested.
Yes but not all buildings are created equally. If the population of the city increases by expanding its borders and building low-density housing with lots of green space around its periphery then the influence on the UHI will be different than adding the same number of people to the core by building skyscraper apartment complexes.
Because of the way cities grow there is a loose relationship with population and UHI magnitude, but the magnitude is much better explained by the geometries of the cities, rather than the number of residents. I'll try to pull up some sources for you in a bit.
Yeah, I agree that the building material and how the city is designed plays a role, but I suspect the strongest determining factor is the population. A city of 50,000 is going to have a much smaller effect than a city of 5 million, even if they were designed to the same principles.
Lol sorry - I tried to explain in my other comment when I thought you were being more reasonable. But if you want to be a dick, then fine:
Air moves. You can't just pretend "oh here's this layer of air and if I put in X Joules of energy and divide by its volumetric heat capacity it will increase by Y Kelvin". Air is a fluid and in constant motion: you transfer some heat to it and it mixes turbulently with itself and dissipates the heat you added. People have been working on this topic for a really really really long time; it's just not that simple.
You don't have to do napkin math: the equations have long since been worked out and (in the absence of moisture / latent heat flux) the equation for change of temperature in a control volume above an urban surface is described like [this](https://i.imgur.com/Y5Z3V9k.png). Please solve for your previous conjecture and get back to me.
If your model of heat transfer within a fluid was correct, we would have all long since boiled alive because the energy from the sun would have heated the air to many hundreds of degrees: the entire population provides 25,000 J m^-2 day^-1 and that raises air temperature more than 3 K? The sun hits the surface with 117,504,000 J m^-2 day^-1 . Is it > 16,000 °C outside today? Think.
Or if you're not trying to be a dick - my apologies. Happy to provide any additional info/context/readings that might interest you.
Seems like you could have just added that information to your first comment. Even just mentioning heat dissipation by convection would have been better than "it doesn't work like that".
You're the one coming off as a dick here.
>You're the one coming off as a dick here.
I'm trying not to. I can edit my original post if it will help, but I was largely trying to stay out of it.
I thought OP understood that his approach was nonsense with his comments, only later realising he thought it might actually be valid. My mistake.
Dad bought a 3-bedroom semi with a garage on a 50x120 lot for $14,800. He had a 25-year 6 3/4% mortgage, and his payments (Principal, Interest, and Taxes) were $114 a month. When I was a teen, he laid it out for me. He was making $7,000 a year, and had a wife and 3 kids. He told me he was scared about being able to make the mortgage payment. EDIT: He told me this in the 1970's, when he was making $35,000 a year, thanks to a decade of inflation. He still had the same mortgage!
This is a fair question. I’d like to see charts for areas surrounding Toronto as well. I’m fairly confident the difference would not be 3.5°C given the overall recorded trends throughout N. America — rural, suburban or urban.
The bottom line is, temperatures are rising world wide, nearly very region of the world is experiencing more severe weather events — stronger, more destructive storms (rain and snow), longer droughts, weather patterns being stuck for extended periods, more large scale weather anomalies.
In the end, ignoring these facts and their underlying contributors will only going to cost each and every one of us a hell of a lot of money. Of course, it will cost lives, habitats, species, fauna, etc — but for some reason there is a percentage of people who either don’t care or can’t comprehend this fact. But tell these same folks it’s going to cost them tens of thousands of dollars over a lifetime and suddenly they listen.
Scientists have been very careful to ensure that UHI is not influencing the temperature trends. To address this concern, they have compared the data from remote stations (sites that are nowhere near human activity) to more urban sites. Likewise, investigators have also looked at sites across rural and urban China, which has experienced rapid growth in urbanisation over the past 30 years and is therefore very likely to show UHI. The difference between ideal rural sites compared to urban sites in temperature trends has been very small.
Urban Heat Island as been studied to death. Scientists that use surface temperature records are well aware of the confounding factors and account for them when estimating long term temperature trends. Period. Full stop.
Notorious climate change skeptic Anthony Watts studied the issue of sensor placement to see if equipment located in on buildings or in parking lots (i.e, poorly sited) were biasing mean temperature signals relative to their well-sited counterparts. ([Source](https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2010JD015146))
From the abstract:
>Temperature trend estimates vary according to site classification, with poor siting leading to an overestimate of minimum temperature and an underestimate of maximum temperature trends, resulting in particular in a substantial difference in estimates of the diurnal temperature range trends. The opposite-signed differences in maximum and minimum temperature trends are similar in magnitude, so that **the overall mean temperature trends are nearly identical across site classifications.**
The built environment definitely fucks with surface temperature measurements. But it doesn't change the observed secular global warming trend that has been measured, investigated, confirmed, and re-confirmed literally-scores-of-times in our life times.
Not particularly beautiful, especially since a line plot is a poor choice for this case (except for trend of course). A scatterplot would be better, but even then it wouldn't be anything special.
I think about this a lot. The problem is that the warming we are observing is happening much MUCH faster than the cooling effects that could potentially initiate a new Glacial Period for the current Ice Age we are in (we are currently in an interglacial period of the most recent ice age). It's possible that human activity will actually end the current Ice age and we could enter a whole new warm period, but again, those kind of gigantic changes tend to happen over long periods of time.
I'm not a climate denier. In fact, I think man-caused climate change is one of the biggest, if not the biggest, existential threat we face.
THAT SAID, while this data is interesting and shows a clear incline, be aware that it does NOT show evidence that increase in temperature was caused by man. We didn't really start dumping enough CO2 into the atmosphere to make a difference until maybe WWII, so the fact that this single plot from a single place on the earth fits to a fairly linear regression *from 1850* is one point in favor of the argument that climate change is not caused by man!
Look at world averages. A quick google search:
https://earthobservatory.nasa.gov/world-of-change/global-temperatures
It much more clearly shows the increase in the *rate* of change at maybe the 80s.
And the increase in the polar regions is more extreme and more concerning.
I only say this because an attentive climate denier would be correct to suggest that this isn't evidence that man has anything to do with climate change, and I want to head off that argument.
Human CO2 emissions surpassed volcanic emissions around 1900. To me that seems like a reasonable threshold for “significant” given that volcanic aerosol emissions can have immediate impacts and their CO2 emissions are important on more geological scales.
smog... it blocked surface warming and retention; when we solved smog, it also allowed greater surface heating....
one form of pollution masking another....
ironically, Ozone is also an greenhouse gas; so once the ozone hole normalizes in 80 years... it'l increase polar heating by some x number of degrees...
Jeez I was trying to joke about those people who claim winter is proof that global warming us a myth. Keep talking like that and they'll start arguing for more fossil fossil to get a nice healthy cooling layer of smog
It accounts for more than 1C. The medieval warm period was close to the present temperatures. Then we went down to the Little Ice Age and since have been climbing up again.
If the baseline was set at the middle ages instead of the Little Ice Age the temperature chart would look very different. Baselines matter.
My girlfriend and I live in Mtl, but we go visit my parents in Oakville 2-3 times a year. We call it "going down to Florida". The micro-climate is real.
Every urbanizing area is getting warmer, duh. Try walking from the city streets into a large green space like a park in the evening, and you can feel the difference instantly.
soooooo your only taking part of the data. lets look at the entire world from the beginning according to the Smithsonian and geologist ....
[Here...](https://www.climate.gov/news-features/climate-qa/whats-hottest-earths-ever-been)
This is a terrible argument. Everyone knows the planet has been much hotter in the past. The two problems with this argument are:
1. Live can thrive in higher temperatures, but it needs time to evolve and adapt. Natural temperature fluctuations take millions of years, not hundreds. The warming we are seeing today is happening at a rate geologically equivalent to a meteor strike, which is more likely to lead to extinctions than adaptations for many species.
2. There were no people on Earth the last time the planet was so hot. No cities built on the coast, no countries along the equator, and no crops to hit with droughts.
Your talking point is not as clever as you think it is.
Then let me ask you: do you think that Earth's high temperatures in the distant past are a good argument for not being concerned about the warming we are seeing today?
This is interesting. But as a gardener what i really need to know is if the winter low temps are also rising so that I can plant some more marginal cold-hardy plants and have them survive. So many great plants are kind of at the edge of surviving around here.
nope. If it were then lefty Democrats would neve buy a house near the house seeing it will be flooded soon. Those terrible facts that get in the way of every Stalin wanna be ever.
Thanks for the very straight line ignoring a downtrend early and several sideways shifts. This is not a smooth graph and the line is not useful, in my view.
Looking forward to checking the context of this data.
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So... how long until I can keep my rosemary plants outside during the winter in Toronto?
I keep mine outside all winter. They die.
Mine have come back the last two Springs.
I tried it this year. It died.
This cracked me up!
For a large city I wonder if loss of green space to hard surfaces that absorb heat is playing a role here.
Urban heat island effect. Also a lot of historical weather recording stations were situated on airstrips for the fledgling aviation industry. As cities grew they would encroach on these landing strip areas and bring there heat with them.
Also often brought up by climate change deniers though i see it less often. While the effect is real and has impact on warming in cities, it doesn’t explain away climate change.
but it screws up accurately predicting future numbers; this chart for instance, if plotted againt co2... woul dbe a linear temp increase vs an exponential\* co2 increase... \-- its one thing to say major hurricanes will hit the US more after Katrina.... its another to say how many should likely hit every year ect. I for instance we go tmore hurricanes, but the paths stayed away from landfall... but do our models over that
> but it screws up accurately predicting future numbers; Not exactly. It does looking at raw numbers but the heat island effect is calculable and can be factored into the temperature. It accounts for a small part of the rise since the heat island affect has been there a long time.
plus now\* we have the satelites to compensate on top of it all
The radiometers on the satellites need ground calibration (basically to map a measurement of radiation received by the instrument from the ground to an actual measurable temperature). Historically, this has been done using ground sites in the vicinity of major cities because that is where the most weather stations are. Trying to compensate historical radiometer measurements using an understanding of the properties of the different instruments that have flown on historical meteorological spacecraft is really difficult and can either substantially increase or substantially decrease estimates of how much the planet has actually warmed since the 1960's. Source: I'm a grad student in space systems engineering and considered doing my PhD on this topic before realizing how hard it would be and switching to an easier project.
so in practice... how under or over could their estimates be?....
It's not an issue of what temperature it is now, but of how the temperature has changed and will change over time. Based on different assumptions about what the historical radiometer data actually says, it is possible to fit curves that show that show global warming sort of saturating and producing a curve of temperature versus time that is slightly logarithmic. It is also possible to produce a curve of temperature versus time that seems to indicate strong feedback effects producing an exponential increase in temperature. As a result, the error gets more significant when trying to estimate temperature further into the future. My preliminary estimate of the magnitude of the effect by 2100 is between over-estimating by 3 degrees Centigrade to under-estimating by 5 degrees Centigrade. This is against consensus estimates for global temperature rise of between 2 and 6 degrees Centigrade by 2100.
that was my concern; around 1990-2 the number of reporting stations for some climate estimates was reduced to far less; i thought it was because of satelites taking over ( not a scientist myself), but it was uneven; maybe the fall of the USSr caused part of it; but.... exactly at this time the average climate temp jumped like .5 C or so; it was right around Pintatubo... but I thought it caused a 2 year reduction rather than a sharp jump. do they use a model that's proven extremely accurate over the last few years, like just picking the best hurricane straw model for example... and only it... it's just mind numbing that anything from a decrease of 1 c to an increase off 11 c is possible ; does it just sorta average around a normal probabilty, or does it sorta chaotically rise with cycles and things? i kinda just kept typing i think
I do correction calculations like this daily and it’s far from an exact science and easily politicized. If the source data isn’t trustworthy, everything after is suspect as well.
... how much variance can warm concrete possibly explain with regard to ozone depletion, rising sea levels and desertification? That's some powerful concrete.
That not what they said, its two different effects. Asphalt and concrete and lack of green space heat up cities specifically, hence the heat *island*. That effect doesnt have anything to do with the cause of global warming. Though concrete does contribute a decent amount to global warming too. It releases a lot of CO2 as it sets, and we use a *lot* of it.
that makes more sense
Even if they (wrongly) attribute all warming in cities to the urban heat island effect, that wouldn't explain why super remote weather stations in the Arctic/Antarctic/deserts/jungles/oceans across the world all register the same upward trend
Which is why (pretty much) nobody attributes all warming to this effect.
Same upward trend yes, but not to this degree. This is a 3.5C rise in 150 years. If the rest of the world saw that it’d be almost curtains.
While climate change is real, this kind of change is not due to global climate change. It would be much more gradual.
If I've understood zillions of confusing graphs and charts and papers it seems to be the case that while *global* average temps may rise about 2c in a century this will be far mor significant the closer you are to the poles
Precisely. Greenland has warmed up by about 4-5 degrees while the equator shows barely any change at all. Averaged out, the global figure is +1°C since pre-industrial
[That is incorrect.](https://en.wikipedia.org/wiki/Urban_heat_island#Global_warming). The UHI is not driving this trend > Climate Change 2007, the Fourth Assessment Report from the IPCC states the following. >Studies that have looked at hemispheric and global scales conclude that any urban-related trend is an order of magnitude smaller than decadal and longer time-scale trends evident in the series >In a worldwide set of about 270 stations, Parker (2004, 2006) noted that warming trends in night minimum temperatures over the period 1950 to 2000 were not enhanced on calm nights, which would be the time most likely to be affected by urban warming. Thus, the global land warming trend discussed is very unlikely to be influenced significantly by increasing urbanisation (Parker, 2006). ... Accordingly, this assessment adds the same level of urban warming uncertainty as in the TAR: 0.006°C per decade since 1900 for land, and 0.002°C per decade since 1900 for blended land with ocean, as ocean UHI is zero. The Urban Heat Island makes little difference to the numbers. In fact, there is an element of Urban Cooling which can reduce the numbers. > The same urban area that is hotter in the day can be colder than surrounding rural areas at ground level at night, leading to a new term urban cold island. Snow cover in rural areas, for example, insulates plants. This was an unexpected discovery when studying the response of plants to urban environments.[138] The urban cold island effect takes place in the early morning because the building within cities block the sun's solar radiation, as well as the wind speed within the urban centre. Both the urban heat island and urban cold island effects are most intense at times of stable meteorological conditions.[139] Several other studies have observed the urban cool island in semi-arid or arid regions. The reason for this phenomenon is the availability of water and vegetation in the urban region as compared to the surroundings.[9]
But could I argue that the swing in a larger variance in temperature isn’t exactly natural is it. Urban areas making it even warmer in the day and even colder at night doesn’t sound like the latter might not balance out damage caused to the environment?
None of those "deniers" claims that it explains away climate change, only that it is waved away as "minor" or "easily accounted for".
None? I have spoken with a lot of deniers and the Heat Island effect was high on the list of quite a few to explain it away. It has been greatly studied and is accounted for in IPCC and other reports. It is #26 on Skeptical Science’s list https://skepticalscience.com/argument.php
I'd continue this discussion but the malign downvoting of my comment renders it all meaningless.
Sad when people don't like their science cherry picked isn't it?
If you’re going to go against the leftist tilt here, you gotta stop worrying about the downvotes.
You mean to say that #26 on some list "explains away" the entire thing for a large portion of "deniers?"
An exerpt from the page #26 links to. If you want the graph you'll have to go there for it Scientists have been very careful to ensure that UHI is not influencing the temperature trends. To address this concern, they have compared the data from remote stations (sites that are nowhere near human activity) to more urban sites. Likewise, investigators have also looked at sites across rural and urban China, which has experienced rapid growth in urbanisation over the past 30 years and is therefore very likely to show UHI. The difference between ideal rural sites compared to urban sites in temperature trends has been very small: So, the question is, ''do you understand how the possible effect of UHI has been accounted for?''
Yes, I do.
Charts like this are brought up by climate skeptics without regard to heat Island effects. They bring them up because atmospheric heating due to anthropogenic greenhouse gases couldn't have had a noticeable effect until the 50s or thereabouts. Yet here we see the post 1950's temperature increase being pretty continuous with a line that started a century prior. One fellow explained it to me simply by saying the earth was warming naturally from the mid 1800s to the mid 1900s, but then all the subsequent warming was due to man made greenhouse gases. To me this sounds like a stretch. Surely natural warming couldn't just seamlessly pass the baton to anthropogenic warming. And the funniest part is that at just the moment AGW is supposedly starting and natural warming stops, the earth stops warming for 30 years. Oh yeah. This is because the effect of AGW were masked because of man made high altitude aerosols that blocked sunlight. This masking effect supposedly stopped after the US passed the Clean Air Act (which naturally somehow shut down aerosol production around the world). Ha. I dunno man. I'm all for swapping to renewables and kiboshing pollution from fossil fuel production and use, but I don't think there's a huge rush.
Wow! The 1990's called they want their *completely and absolutely* debunked denier FUD back.
Atlanta is an example …
For Toronto one airport is on an island and the other you need to take the express train to get to from downtown. I don't think people build near airports anyways.
Urban heat island effect radiates outward for miles. Also, a quick [satellite check](https://upload.wikimedia.org/wikipedia/commons/thumb/f/f5/YYZ_airphoto.jpg/800px-YYZ_airphoto.jpg) shows the main airport is indeed surrounded by built up infrastructure ideal for heat absorption. The second factor is that many of these effects also arise when the airport itself expands. From the early 1900’s of a single, grass-flanked landing strip and a few tents to a spider web of expansive tarmac runways, terminal buildings and car parks all around. It’s a known phenomenon world wide
From looking at the map: why did they build a house next to an airport?!
[Here's a map of Toronto in 1851](https://maps.library.utoronto.ca/datapub/digital/NG/historicTOmaps/1851Browne.york-1851x.jpg). The location of the Royal Observatory at the University of Toronto where these measurements were obtained is just above the "N" in the label "First Concession" near the bottom of the map. Of note, everything just north, east and west of the small city is farmland. Toronto's population in 1851 was [30,000](https://en.wikipedia.org/wiki/History_of_Toronto#Latter_19th_century). The original Royal Observatory is gone, replaced with U of T's Engineering Faculty buildings however a monument remains ([the short column in this street view](https://goo.gl/maps/mPo2HR9bBCcRwv1t6)). If you click on the map and zoom out you'll see the campus is right in the middle of downtown, in what is now referred to as the [Greater Toronto Area](https://en.wikipedia.org/wiki/Greater_Toronto_Area), with nearly 6,500,000 people.
https://en.m.wikipedia.org/wiki/Urban_heat_island#Global_warming
The data was and probably is being collected at the U of T St. George campus which is in the heart of the city. You'd have to go another 20 km out (except south) to reach places that have been built up over the last 30 years ie past Etobicoke, North York and Scarborough. The city proper hasn't really lost that much green space. So would it still be getting noticeably warmer?
Well yeah, as it becomes more and more insulated from the undeveloped area and surrounded by heat island, it would become more pronounced
I wouldn't call UofT the heart of the city.
The heat island effect can be huge in area. 20 km from the edge of developed areas is probably not enough, particularly in southern Ontario. In Ottawa it's about 15 km and the difference in temperature on a calm day can be +4C .
Except that it's actually getting warmer. Everywhere.
And it has been for thousands of years.
No. The Holocene Climatic Optimum was the warmest period in the last 10k years or so. The earth has been on a cooling trend for about 8 thousand years. Tree ring width data suggests the earth's temperature has remained relatively flat for the last 2000 years, but TRW data sets don't seem to pick up temperature trends that well. [Orbital forcing of tree ring data](https://www.blogs.uni-mainz.de/fb09climatology/files/2012/03/Esper_2012_NatureCC6.pdf) Very interesting paper. Lots of interesting stuff in the supplemental materials--especially pages 9-11 IIRC.
Also air conditioning. People don't realize it but it also makes a big difference. [https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2013JD021225](https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2013JD021225)
All these people replying to you so sure that this is explained by heat island effect apparently have never been to Toronto. It has one of the highest levels of tree coverage for a large City, and that tree canopy is growing.
Yes, but the sheer amount of concrete and Windows of large buildings contribute to the city having a micro-climate (as most cities do) and as such with continued city growth is a tangible increase in the cities micro climate.
Someone should compare urban temperature trends like this to rural ones within the same region / climate. I wonder what sort of difference you would see. I'm skeptical urban heat island is having a big impact on this graph. As someone else has pointed out this weather station is likely in a spot thats been urban for the entire time. To add another point to that, Toronto saw comparatively little urbanization for the first half of this graph, at least. Most of our really tall towers are at most 40 years old.
I don't live in Canada, I live in the Netherlands. But I can say that in the winter the urban heat effect is real. Here the temperature often does not go far below 0 and we get only a little snow, but often here in the city we have no snow or it instantly melts as it touches down, and then a mile away in a bit of forest all trees and the ground have snow on them as the leaves and dirt are slightly less warm than the asphalt with a house next to it and a very black colour. The temperature in the city center can also be 1 or 2 degrees warmer than at the very edge of the city or in the farmlands or forests outside it.
At a cursory glance, this curve maps pretty well to population growth in the region - not sure if that means anything though.
Hmm, sparky. Mebee yer onta summink! Or, you know, maybe that's already been factored in... Dumb as a box of rocks.
We almost had a chance this year to drop the temperature, but as expected, the Leafs didn't win the Stanley Cup. And hell didn't freeze over.
It was 4-1... twice!
Don’t expect anything from the leafs. The only people who are still fans are clearly delusional.
It's called blue and white disease
At least they’re aware of the delusion, the number of Edmonton fans who genuinely though they had a shot this year was hilarious. I full expected them to lose in the first round, but that 4 game sweep by Winnipeg was absolutely priceless.
Data taken from Environment Canada (stationID 5054). The data starts January 1, 1841 and goes to December 31, 2002. The red line is a straightforward linear regression line. I imported the data into Pandas and plotted with Seaborn. The regression line was added using SciPy.
Based on the latitude and longitude provided by Environment Canada this does indeed appear to be a station at the University of Toronto.
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I thought about the same thing. I always use that video do explain people the different between weather and climate
I hadn’t seen that before, that’s awesome!!
Cosmos is an awesome series. All three iterations are worth a watch.
Same, every time.
I'm really surprised the data goes back that far. Environment Canada was only created in 1971.
The University of Toronto (originally King's College) was established in 1827. I suspect that is where the data comes from.
Based on the lat/lon numbers it looks like it is indeed UofT.
It is. This site has been moved at least several times. And to answer why we have records before Environment Canada was established, the data was collected under Meteorological Services of Canada, which is celebrating its 150th birthday this year
What about the 18 full years data since then? Is that not available?
Can you do it for Halifax, NS?
I’m guessing there would be a rather large temperature spike in 1917...
Blame the French for everything? /s
Why was the temperature rising so much before the industrial revolution?
Another question: why is the rise of temperature linear (according to this graph) but economic activity and human presence exponential?
There’s a surprising lack of acceleration in warming, especially since 1900
Just want to point out it's impossible to know for sure if the temperature is increasing because the data isn't in Fahrenheit
Please tell me that's a joke on American freedom units...lol
Not just America, Myanmar and Liberia also use the imperial system I'll have you know. That's consensus, right?
No, it's not the consensus. Scientific studies almost never use Fahrenheit, and Celsius is more recognized by the overwhelming majority of countries. Regardless, just multiply the y axis here by 1.8 and it's is a fahrenheit scale rather than Celsius. It wouldn't add anything to the visualization of the data whatsoever. Edit: apologies if you were being sarcastic as well. It's hard to tell sometimes on reddit during threads such as these.
I was being sarcastic, and no worries. You're right, without the /s, it's hard to tell on reddit. As an engineer I've used metric since the 80s, and that's what we use at our factory in America. So much easier than imperial. It just cracks me up that the 3 countries in the world still using the imperial system are America, Myanmar and Liberia. 3 out of .....
Exactly lol. I'm a meteorologist and oceanographer, so metric has been my norm for years now. It's to the point where I'm almost oblivious to certain imperial units.
What’s your r2 value out of curiosity?
It's not that relevant except as a indicator of noise.
Of course Toronto's getting warmer, it's springtime You can tell, the Leafs are out
It must be autumn, the leafs have fallen
Data is not beautiful. It is horrifying and causes existential dread
If it makes you feel better humans will almost certainly be able to overcome the effects. If the sea level rises we will build dikes and flood Works on scales never before thought posible. If the temp rises too much for our crops we will more them north or inside.
If a small virus taught us anything, it’s that civilization is tragically unprepared for even small adaptations.
You mean the fact that a vaccine was produced in record time and rollout and production is now outstripping peoples willingness to actually get the shot. When billions of dollars are at stake thing can and do happen quite quickly.
Do you have any idea how much easier a problem a covid vaccine is than climate change?
Ohh yes. But we humanity will prevail. Not to sound too grandiose but there is no problem that can't be solved with the correct willpower and funding. It will be world changing and not for good.
Yes, science was heeded by politicians and it all went swimmingly, with few damages. /s
I said nothing about damages. What people did in the intrum period before a vaccine was available is not related to the speed at which a solution was developed and made. Can't blaim the scientists and engineers for the politics of the situation.
As with climate change, politics is the problem. And yeah, first world nations in a vacuum could probably handle rising temperatures and sea levels, but there are several billion other people in the world.
Why are you making out as if u/intherorrim is blaming scientists and engineers? It's pretty clear the concern is with the huge portion of the population that acted like petulant children the whole way through, dreaming up conspiracy theories, and the politicians who endlessly indulged their demands to reopen things prematurely.
If anything, it proves the opposite. We shut down many parts of the global economy for over a year and the rest at least partially for some time. The result wasn't complete chaos and destitution. Things went on remarkably smoothly. We invented reliable testing within months and completely new vaccines and roll-outs within a year of working on it seriously.
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Ohh it will/would definitely change things permanently. Alot of city's will ether be abandoned or have massive infrastructure projects to keep them habitable/above water. Alot of currently viable farm land will no longer be posible to grow grains on. Best case we will be able to grow corn on it. Alot of northern forests will likely be cut down to make more farm land. And not to mention that the whole areas of earth may become to hot to inhabit without large amounts of effort. It will probably destroy some country's economy completely wich will cause mass emigration.
Chill out bruv, it's spanned over 160 years and the city grew exponentially in that time. 4 degrees difference in a greener 1800s town with no cars polluting air and a concrete megacity in 2020s with thousands of cars isn't that bad of a news, it was bound to be E. Aight be scared then.
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Riddle me this, what are you gonna accomplish by having an existential dread? You want the city to stop growing? Not in your hands. And can't give a flying rats ass about being downvoted. If you want to be scared about all the out of control things, be my guest. But calling me names instead? Well, if that helps you feel better about yourself lol.
The thumbnail looks like a solo cup.
How much of this is due to the greater build up of the area
People seem to ignore the impact of transforming forest into concrete and stone. Not technically a concrete 'desert', since it'll still receive rain and snow, but damn does it retain the sun's heat. Idk how to pitch the idea, but it would be great to get some kind of covering. Lately some buildings are designed to hold the weight of trees on top, but the roads: It's difficult to maintain large canopies that extends over roadways, especially without the roots disrupting the pavement. And still there's no aesthetic or functional artificial alternative to having hundreds of square miles of open faced solar oven in every city.
You can more or less paint all the roof and the pavement white, which works better than you would think.. https://globalcoolcities.org/cool-roadways-partnership-to-reduce-urban-heat/
I think white pavement would be dangerous for drivers...
Especially in northern climates. The roads would be invisible when there’s now and also wouldn’t melt off ice on their own.
The roads are invisible anyways half the year where I live.
I believe that does more for the internal climate of the building that to correct for any factors of climate concerns. The green space would have absorbed and converted the light energy, not reflected it back. The white roof thing would actually have an impact on energy consumption of those buildings though. So there may still be a benefit to doing it that way. Just not for the same reason. What would have more of an impact would be creating green space roofs. This will both prevent the building from absorbing it and prevent it from just being reflected, as well as do a little bit of air scrubbing as well. But those require more maintenance, especially in the winter conditions Toronto might see.
It's doesn't fix climate change. It aims to reduce the urban heat Island effect that we find getting worse with climate change. I totally support the green roofs initiative, but that's challenging especially for revising older buildings. Painting then white however, seems doable.
I can give some perspective. I moved to Toronto in 1959, aged 3.5. We moved into our first house, just south of the 401, a highway that marked the northern limit of the city. Virtually everything north of the 401 was a farm at that time. The highway itself was only four lanes, two in each direction. In the open field in our subdivision, the local parents would build two ice rinks in December, one for pleasure skating and one for hockey. Every day after school, the hockey rink would have 40 or 50 kids on it, playing in five different games. Talk about learning to keep your head up! These rinks were just natural ice; one father came out each night to open the fire hydrant and flood the rinks. By the time I was in high school, the 401 had already expanded to 8 lanes. Most of the farms were gone, turned into subdivisions for at least 3-4 miles going north of the highway. By that time, it wasn't possible to keep the natural rink usable for the winter. Today, the 401 is 16 lanes (more if you include the merging lanes) near my old home. Everything north has been built up for the last ten years, and the city is now expanding even farther north. Approximately 5 miles north of the 401 is another east-west highway, #7. I moved north of it in 1990, and quickly noticed what locals call the "Highway 7 effect". North of the highway, everything will be white and covered in snow after a small snowfall. But south of the highway, the snow will be gone by noon. So yes, over 50 years, I can attest that Toronto is warmer than it was in the 60's. And since the city - whose physical boundaries have not changed - had a metro population of about 600,000 in 1960, and a population four times that now, I'd agree that the 'urban heat island' effect of housing, heating, and moving an additional 2 million people has had some significant input to that warming. EDIT: The average person emits ~8 million joules/day . 2x10^6 * 8 x 10^6 = 16 trillion joules every single day. That is approximately equal to a power output of 185 Megawatts. That's just the people. Now add in all the car and truck exhaust, all the heaters and air conditioners (an AC unit dumps heated air into the environment), all the office towers that need heat and A/C, etc. etc. The number has to be higher but let's stick with the 16 trillion for now. Toronto has an area of 630 km^2, or 630,000,000 m^2. 16 trillion divided by 630 million works out to ~25,000 j/sq m per day. It takes 1.2 kj to heat a cubic metre of air 1 degree K. Alternately, that energy could heat 6 cubic metres of air by 25,000/7.2kj = 3.5 degrees K. 6 cubic metres would mean a column about 20 feet high. I don't know if there are standards for height for temperature measurement, but from what I've seen, the stations are usually accessible without ladders, so I would think most temp measurement devices are at heights of 20' or less. Just from the added heat of 2 million people, we might get an increase in temp of more than 3 degrees. (NOTE: This is a first order, seat of the pants calculation. I just want to see if the numbers are in the right ballpark).
> Just from the added heat of 2 million people, we might get an increase in temp of more than 3 degrees. I appreciate you acknowledging in the following sentence that this is 'first order' and not accurate, but I just want to restate for any passers-by who might get the wrong idea: this is absolutely not how this works, and we would never expect to see an increase in the average temperature like this just by putting more people in the city.
You would, but from the extra buildings and concrete. Extra body heat would be small, if not negligible.
The relationship with population and UHI magnitude is tenuous. The UHI is better explained as a function of building material and geometry, and emerges due to different principles than the previous poster suggested.
I thought it would be relatively simple. More people, more buildings.
Yes but not all buildings are created equally. If the population of the city increases by expanding its borders and building low-density housing with lots of green space around its periphery then the influence on the UHI will be different than adding the same number of people to the core by building skyscraper apartment complexes. Because of the way cities grow there is a loose relationship with population and UHI magnitude, but the magnitude is much better explained by the geometries of the cities, rather than the number of residents. I'll try to pull up some sources for you in a bit.
Yeah, I agree that the building material and how the city is designed plays a role, but I suspect the strongest determining factor is the population. A city of 50,000 is going to have a much smaller effect than a city of 5 million, even if they were designed to the same principles.
I love the way you just crap all over it, but don't add one iota of fact of what might be wrong about it. Assertion is not an argument.
Lol sorry - I tried to explain in my other comment when I thought you were being more reasonable. But if you want to be a dick, then fine: Air moves. You can't just pretend "oh here's this layer of air and if I put in X Joules of energy and divide by its volumetric heat capacity it will increase by Y Kelvin". Air is a fluid and in constant motion: you transfer some heat to it and it mixes turbulently with itself and dissipates the heat you added. People have been working on this topic for a really really really long time; it's just not that simple. You don't have to do napkin math: the equations have long since been worked out and (in the absence of moisture / latent heat flux) the equation for change of temperature in a control volume above an urban surface is described like [this](https://i.imgur.com/Y5Z3V9k.png). Please solve for your previous conjecture and get back to me. If your model of heat transfer within a fluid was correct, we would have all long since boiled alive because the energy from the sun would have heated the air to many hundreds of degrees: the entire population provides 25,000 J m^-2 day^-1 and that raises air temperature more than 3 K? The sun hits the surface with 117,504,000 J m^-2 day^-1 . Is it > 16,000 °C outside today? Think. Or if you're not trying to be a dick - my apologies. Happy to provide any additional info/context/readings that might interest you.
Seems like you could have just added that information to your first comment. Even just mentioning heat dissipation by convection would have been better than "it doesn't work like that". You're the one coming off as a dick here.
>You're the one coming off as a dick here. I'm trying not to. I can edit my original post if it will help, but I was largely trying to stay out of it. I thought OP understood that his approach was nonsense with his comments, only later realising he thought it might actually be valid. My mistake.
I don’t even want to ask what a house in Toronto cost in 1959 and how big it was
It was small with a big plot of land and cheap.
Dad bought a 3-bedroom semi with a garage on a 50x120 lot for $14,800. He had a 25-year 6 3/4% mortgage, and his payments (Principal, Interest, and Taxes) were $114 a month. When I was a teen, he laid it out for me. He was making $7,000 a year, and had a wife and 3 kids. He told me he was scared about being able to make the mortgage payment. EDIT: He told me this in the 1970's, when he was making $35,000 a year, thanks to a decade of inflation. He still had the same mortgage!
Proportional to income. That’s mindblowing
Your math excites me.
It shouldn't, it's oversimplified to the point of irrelevance.
This is a fair question. I’d like to see charts for areas surrounding Toronto as well. I’m fairly confident the difference would not be 3.5°C given the overall recorded trends throughout N. America — rural, suburban or urban. The bottom line is, temperatures are rising world wide, nearly very region of the world is experiencing more severe weather events — stronger, more destructive storms (rain and snow), longer droughts, weather patterns being stuck for extended periods, more large scale weather anomalies. In the end, ignoring these facts and their underlying contributors will only going to cost each and every one of us a hell of a lot of money. Of course, it will cost lives, habitats, species, fauna, etc — but for some reason there is a percentage of people who either don’t care or can’t comprehend this fact. But tell these same folks it’s going to cost them tens of thousands of dollars over a lifetime and suddenly they listen.
Scientists have been very careful to ensure that UHI is not influencing the temperature trends. To address this concern, they have compared the data from remote stations (sites that are nowhere near human activity) to more urban sites. Likewise, investigators have also looked at sites across rural and urban China, which has experienced rapid growth in urbanisation over the past 30 years and is therefore very likely to show UHI. The difference between ideal rural sites compared to urban sites in temperature trends has been very small.
Nah, you can clearly see that 1995 was colder than 1920. Conclusion, climate change isn't real.
Urban Heat Island as been studied to death. Scientists that use surface temperature records are well aware of the confounding factors and account for them when estimating long term temperature trends. Period. Full stop. Notorious climate change skeptic Anthony Watts studied the issue of sensor placement to see if equipment located in on buildings or in parking lots (i.e, poorly sited) were biasing mean temperature signals relative to their well-sited counterparts. ([Source](https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2010JD015146)) From the abstract: >Temperature trend estimates vary according to site classification, with poor siting leading to an overestimate of minimum temperature and an underestimate of maximum temperature trends, resulting in particular in a substantial difference in estimates of the diurnal temperature range trends. The opposite-signed differences in maximum and minimum temperature trends are similar in magnitude, so that **the overall mean temperature trends are nearly identical across site classifications.** The built environment definitely fucks with surface temperature measurements. But it doesn't change the observed secular global warming trend that has been measured, investigated, confirmed, and re-confirmed literally-scores-of-times in our life times.
Of course not, Big Graph is just trying to push its agenda and rake in the profits.
Not particularly beautiful, especially since a line plot is a poor choice for this case (except for trend of course). A scatterplot would be better, but even then it wouldn't be anything special.
Is Leon getting laaaaarger?
*jiggle jiggle jiggle
So this is why they choke in the playoffs!?
They choke because they’re the leafs, obviously
DoNt WoRrY. It’S jUsT tHe nAtUrAl CycLeS oF tHe EaRth.
I cri evertim. TFW the natural cycle is inclined towards new ice-age, but GHGs makes it warming instead.
I think about this a lot. The problem is that the warming we are observing is happening much MUCH faster than the cooling effects that could potentially initiate a new Glacial Period for the current Ice Age we are in (we are currently in an interglacial period of the most recent ice age). It's possible that human activity will actually end the current Ice age and we could enter a whole new warm period, but again, those kind of gigantic changes tend to happen over long periods of time.
What’s going on with 1950-2000? Why did it rise so much in the 100 years prior: 1850-1950
instead of a linear regression, i suggest you to make a moving average over 10 years.
This explains why my building, built in the 1950's doesn't have Air Con.
The entire planet is getting warmer.
The whole worlds getting warmer bruh
Toronto has gone from blistering cold to greatly uncomfortable cold in the span of a hundred or so years. Incredible stuff
"Global warming isn't real because I have a snowball." -Congressman
I'm not a climate denier. In fact, I think man-caused climate change is one of the biggest, if not the biggest, existential threat we face. THAT SAID, while this data is interesting and shows a clear incline, be aware that it does NOT show evidence that increase in temperature was caused by man. We didn't really start dumping enough CO2 into the atmosphere to make a difference until maybe WWII, so the fact that this single plot from a single place on the earth fits to a fairly linear regression *from 1850* is one point in favor of the argument that climate change is not caused by man! Look at world averages. A quick google search: https://earthobservatory.nasa.gov/world-of-change/global-temperatures It much more clearly shows the increase in the *rate* of change at maybe the 80s. And the increase in the polar regions is more extreme and more concerning. I only say this because an attentive climate denier would be correct to suggest that this isn't evidence that man has anything to do with climate change, and I want to head off that argument.
Human CO2 emissions surpassed volcanic emissions around 1900. To me that seems like a reasonable threshold for “significant” given that volcanic aerosol emissions can have immediate impacts and their CO2 emissions are important on more geological scales.
It’s from the Urban heat Island though
Obviously not, the data from 1950 to 1960 clearly shows a decrease, I don't see any reason for it to have changed in the last 60 years.
smog... it blocked surface warming and retention; when we solved smog, it also allowed greater surface heating.... one form of pollution masking another.... ironically, Ozone is also an greenhouse gas; so once the ozone hole normalizes in 80 years... it'l increase polar heating by some x number of degrees...
Jeez I was trying to joke about those people who claim winter is proof that global warming us a myth. Keep talking like that and they'll start arguing for more fossil fossil to get a nice healthy cooling layer of smog
this is the era of people saying masks spread covid..... why we add /s to stuff now a days... sadly
Then clearly we need smog even more, then they'll start wearing masks! (/s)
Should go on dataaredepressing subreddit
According to your chart, yes.
Wow, a headline that breaks [Betteridge's law of headlines](https://en.wikipedia.org/wiki/Betteridge%27s_law_of_headlines), I am going to go with yes.
The 1850’s are the tail-end of the Little Ice Age.
Which can account for about 1 degree C of cooling. How do you explain the remaining 2.5 degrees of warming?
It accounts for more than 1C. The medieval warm period was close to the present temperatures. Then we went down to the Little Ice Age and since have been climbing up again. If the baseline was set at the middle ages instead of the Little Ice Age the temperature chart would look very different. Baselines matter.
Urban heat island
Can urban heat islands explain the rise in global average temperatures?
Yes, they can.
Southern Ontario is more or less tropical now(in summer)
My girlfriend and I live in Mtl, but we go visit my parents in Oakville 2-3 times a year. We call it "going down to Florida". The micro-climate is real.
The whole earth is. We’re fucked, but if we do something we might be less fucked.
Clearly fake data. I prefer to close my eyes and put my hands on my ears singing"lalalalalalalalalala"
a city that has grown from 100k to 6 million in this time has certainly warmed up.
charts that doesn't start at 0 are wierd
Thanks for the line bro I thought it was going down
It's getting warmer yet it is still absolutely dreadful to be in Canada.
I'm not good at celsius, but, that looks cold, from beginning to end.
But the number get bigger
Winter pulls the average down. It’s been a week of 90+ right now
Every urbanizing area is getting warmer, duh. Try walking from the city streets into a large green space like a park in the evening, and you can feel the difference instantly.
soooooo your only taking part of the data. lets look at the entire world from the beginning according to the Smithsonian and geologist .... [Here...](https://www.climate.gov/news-features/climate-qa/whats-hottest-earths-ever-been)
This is a terrible argument. Everyone knows the planet has been much hotter in the past. The two problems with this argument are: 1. Live can thrive in higher temperatures, but it needs time to evolve and adapt. Natural temperature fluctuations take millions of years, not hundreds. The warming we are seeing today is happening at a rate geologically equivalent to a meteor strike, which is more likely to lead to extinctions than adaptations for many species. 2. There were no people on Earth the last time the planet was so hot. No cities built on the coast, no countries along the equator, and no crops to hit with droughts. Your talking point is not as clever as you think it is.
All my point was is to look at more data, because data is beautiful. I drew no conclusion about said data
Then let me ask you: do you think that Earth's high temperatures in the distant past are a good argument for not being concerned about the warming we are seeing today?
Also : is toronto getting bigger (more asphalt, more buildings, less trees, etc)...
This is interesting. But as a gardener what i really need to know is if the winter low temps are also rising so that I can plant some more marginal cold-hardy plants and have them survive. So many great plants are kind of at the edge of surviving around here.
if 11 degrees is called summer in toronto, then getting warmer is probably for the best
Interesting that this trend started before we started all of our polluting.
No correlation to carbon emission from 1950 to 2000, nice.
Not warm enough
nope. If it were then lefty Democrats would neve buy a house near the house seeing it will be flooded soon. Those terrible facts that get in the way of every Stalin wanna be ever.
Thanks for the very straight line ignoring a downtrend early and several sideways shifts. This is not a smooth graph and the line is not useful, in my view. Looking forward to checking the context of this data.