Conversely, the increase in the average annual temperatures across all Underground lines from 2013 to 2024 was merely *seven percent*, placing Victoria’s temperature rise vastly above that."
Using percentages to talk about changes in non-Kelvin temperatures is crazy.
I would still say that the in the Rankine scale percentage increases make sense, and Fahrenheit changes to not.
The thing that matters isn't the slope, but the zero point; "X% farther from absolute zero" is a useful measurement, "X% farther from an arbitrary zero point" is not. Especially when negative or zero temperatures are involved.
If anything Fahrenheit should be less insane because at least the artificial 0 is likely to stay much further away in the data they're quantifying so the percentages stay reasonable.
Kelvin is refined measurements used to relate to a wider scale of temperatures. Celsius is a metric human scale subset of Kelvin.
Edit: this comment was deeply stupid for obvious reasons and I regret trying to interact with other people when I should be asleep.
The trouble (of course) is that Celsius properly is not a proper unit, but a "scale", or a "unit of difference" (equal to kelvin), or even torsor[1].
The trouble with the kelvin here is that if you see the 7 kelvin increase as a proportion of the 295K starting temperature the you only get a 2% increase. Nobody is going to buy your newspaper if you're putting up weak numbers like that.
[0] https://mathematicalcrap.com/2024/03/05/the-feynman-story/ [1] https://math.ucr.edu/home/baez/torsors.html
It’s a huge increase, if not for the reasons they describe.
== The Victoria Line average temperature in August last year was 60% higher in temperature than the average external temperature that month, measured at 19.5 degrees. ==
Certainly for January it must have been hundreds of percent higher.
And what would the numbers be for e.g., the Moscow metro in winter months where the average outside temperature is negative?
Everyone knows where the zero is in Celsius using countries anyway and days in the negative are so rare in the UK you can discount them (plus they are none inside the tube).
I apologise.
Moving more air through the tunnels, adding A/C systems - both have a problem of needing room up on the surface for blowers and compressors, something that is hard to do in modern London. Tough problem.
So, I can imagine that this is a long-term problem, but it seems odd that the panic is setting in already, when some platforms in the NYC subway regularly exceed 40C / 104F every summer? This article seems in a similar genre to the breathless advice to remain inside in Britain when the outside temperature might get above 27C / 81F, otherwise known as a not-particularly-warm spring day in much of the US in most years.
It’s really not breathless, because high temperatures and how to handle them is completely absent from the cultural baggage. I don’t live in the UK, but in a place which similarly does not have much in the way of high temperatures historically and low AC penetration, and during heat spikes I see a significant fraction of my neighbours with windows wide open at 4PM.
Habituation is also a significant factor. The UK does not get a smooth transition into higher normals, it gets heatwaves.
If I had to suffer overcrowded trains with standing room only, people’s armpits in my face and all, at 40C temperatures everyday in the summer, then I wouldn’t be laughing at London for trying to avoid the same fate. I’d be complaining that my own city isn’t taking their problems seriously enough.
The hoops TfL jumps through just to not extend AC to the rolling stock in more lines are baffling. At least we finally got some AC in the new Piccadilly rolling stock.
The entire issue is that the earth surrounding the tubes is acting as a giant buffer. Enough heat has been dumped into it over the years that it has permanently warmed up. Draw heat from it during the winter to warm up homes, and it'll be able to absorb more heat from the tunnel air during the summer.
I've surely got a too naïve view of economics but if the goal were to not waste resources then there will be things you can do before dumping it into the hot summer air
Ground source heat pumps are expensive to build, even more so in a dense area like London. So even if everything you said is true, I suspect the juice isn't worth the squeeze.
These are some of the deepest tunnels going under some of the most built up parts of the UK.
Your pipe becomes a tiny worm of cold pipe in a big lump of hot clay and you’ve done very little to cool the underground or warm your water. That is, if heat moved easily through the stuff then the problem of heat buildup would be easy to solve but in that case heat wouldn't build up so there wouldn't be a problem; and vice-versa.
The thermal time constant of a lump of matter scales as the square of its linear dimensions (for a given geometry). This can easily reach many years for large enough chunks of underground stuff. This is why geothermal energy works at all; the heat energy flowing up from the deep earth is stored for many thousands of years at reachable depths and can be mined. And, if one has excess energy, it could be reinjected underground as heat and later recovered.
Of a special tube train with blocks of ice. You’d need to have various pits dug in, and pumps to drain the water. Yes water and power electronics is “fraught”.
I just like the idea of trains trundling along, blocks of ice being carted out and gradually melting.
Another idea is to move mechs-bots via Underground in a post-apocalyptic scenario, but that’s not so relevant here.
Y_Y•4h ago
A century of burrowing commuter-worms unfortunately managed to bake all the beautiful wet clay that kept the tunnels tolerable when the sun was shining about.
It seems straightforward to me that it would be enough to rehydrate the ground. Just need (approximately),
Sounds like a lot but it's only about 1/300th of the yearly flow of the Thames.