171–180 of 276 posts
Think of it: the moment you get into your airport of departure, you become a hamster that enters a giant virtual tube that ends at the exit doors at your destination airport. You are not even allowed to go outside and breathe fresh air, like in hi-security prison. A prison with nice wooden ceilings though.
Earlier quoted context omitted.
Yeah that's true, even in the Netherlands our high-speed line between Amsterdam, Rotterdam and Antwerp was a nightmare. It cost billions, way more than budgeted, many of the bridges turned out to have construction faults (despite all the cost overruns) so the trains aren't able to actually go fast, and the high-speed trains were bought on a budget and had so many flaws that the Belgians refused to allow them. Now we'…
I'm not surprised, building a new high-speed line between the largest cities in the Netherlands must be a nightmare, that's connecting and going through some of the most densely populated areas in Europe. The German railway network (including the high-speed part of it) has loads of issues, and it's hardly working like a dream. That said, the interconnect between large cities is pretty great when it works . For these…
Well, yes and no. Most of it goes through the 'green heart' of the most populated area. There's mostly farms there. The route also goes mostly along existing highways and train tracks so it was just a matter of widening the infrastructure zones that were already there. Holland is very planified so usually these things are already taken into consideration. We don't build housing right besides infrastructure anymore.
However, the environmental red tape is pretty heavy these days. The whole country is at a standstill (house building, traffic, farming) due to limits of nitrogen deposits being exceeded.
So I think it was more that than actual infringements on people's living space. Some tunnels and overpasses were made, yes. Those are the ones that are falling apart already after 10 years :')
I agree it looks nice, but dressing up an airport in sustainable materials won't materially change the fact that a flight Boston - NYC (one-way!) blasts through ~0.7t[1] of CO2eq of your yearly budget of 1-3t[2]. It won't change the fact, but I'm sure it'll make it easier to forget or ignore. [1] https://co2.myclimate.org/en/portfolios?calculation_id=75775... [2] e.g. https://ieep.eu/publications/carbon-inequality-in…
I agree it looks nice, but dressing up an airport in sustainable materials won't materially change the fact that a flight Boston - NYC (one-way!) blasts through ~0.7t[1] of CO2eq of your yearly budget of 1-3t[2]. It won't change the fact, but I'm sure it'll make it easier to forget or ignore. [1] https://co2.myclimate.org/en/portfolios?calculation_id=75775... [2] e.g. https://ieep.eu/publications/carbon-inequality-in…
The carbon emission is not a problem, the imbalance is. When we burn fossil fuels, we use carbon that was stored by dead plants being buried. We take carbon from the ground and dump it in the atmosphere. Plants take carbon from the atmosphere. If were to bury the equivalent amount of wood, we would be equal. Buried wood is not useful, but building from it also locks the carbon somewhere else that isn't an atmosphere.…
Earlier quoted context omitted.
Just finished the full edit.. check it out. If the full airport is made out of wood, seems like it's getting towards plausible, or at least not obviously wrong Most uncertainty is how much mass the ceiling is compared to rest of airport. Maybe it's more like 1/10th. Hmm
Apparently they used 4.4 million cubic yards of concrete during the construction of Denver airport around 1993. That's 3.364×10^6 m3, 1 m3 of concrete weighs 2.4 tonnes (I'm sure it varies), so roughly 8 million tonnes of concrete. https://www.concreteconstruction.net/_view-object?id=0000015... I'm not convinced the wood used in the Portland airport project is net negative in itself, once you factor in the emissions…
The Embodied Carbon figure they use is 1.64kgCO2/kg timber as a rule of thumb [ISE-EC], and agrees with what I posted above
For processing that yields built lumber, they account in stages, with % CO2 emissions added:
A1) Raw Material Extraction, 20-25% A2) Transport to Facility, 8-10% A3) Manufacture, 5-10% A4) Transport to Site, 50-55% A5) Construction, 10-15%
A1 to A3 reduce sequestration by 0.28, for a net of 1.36. They then say A4&5 account for 1.5x more emissions than A1-3, so .42kg total factor, for a net sequestration of 1.22kgCO2/kgBuiltLumber. They separate these as the transport is the largest variable between projects.
These figures are from Austria to UK. From the reporting, the PDX project is using mostly local wood.
So I think they're getting a net sequestration for the roof project.
It's really interesting that building with wood has this major sequestration factor. It'd be really something if we could build our way out of the environmental crisis just by switching to wood! :)
[ISE] https://en.wikipedia.org/wiki/Institution_of_Structural_Engi...
[ISE-EC] https://www.istructe.org/IStructE/media/Public/Resources/ARU..., p17: "The amount of carbon sequestered can be assumed as -1.64kgCOe per kg of timber when product-specific data is not available". I take the e to be emission, so a negative is a sequestration.
Earlier quoted context omitted.
The carbon emission is not a problem, the imbalance is. When we burn fossil fuels, we use carbon that was stored by dead plants being buried. We take carbon from the ground and dump it in the atmosphere. Plants take carbon from the atmosphere. If were to bury the equivalent amount of wood, we would be equal. Buried wood is not useful, but building from it also locks the carbon somewhere else that isn't an atmosphere.…
Interesting point! It looks like Skanska is GC for the Project, and cites it as a 9 acre (!) lumber roofing system[SK], and that it uses 3.5M board foot of Douglas Fir Project Lumber[PL]. Douglas Fir is 3.2 pounds per board foot, or 1.45kg [DFM]. So 1.45 * 3.5M = 5Mkg of lumber for PDX airport. DF has an Embodied CO2 of 1.6kgCO2/kgLumber [DFC]. A little hard to believe? But maybe that's bc a lot of the mass of a tree…
But concrete is not so CO2 intensive. Lumber has a +1.6 sequestration factor of CO2 emitted vs built mass, compared with concrete at -0.8.
So we'd need runways made mostly of wood, or combined with a Woodcrete that was net sequestering, and then maybe there's a way to make even our most CO2 intensive industries net neutral so long as we rebuild continuously.
Also, since construction is about 40% of global CO2 emissions, if it could become a net sequestration as a whole, maybe it could flip the sign to -40% and offset most of the rest of our industrial emissions.
This also got me interested in what's a good number for rebuild rate.
Found a study that concludes the "Apparent ecosystem carbon turnover time [T]" is 43±7 years.
So maybe we should be rebuilding our built environment at 2.3%, or probably higher since species have evolved to be more energy intensive, humans especially.
[T] https://essd.copernicus.org/articles/12/2517/2020/essd-12-25...
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I believe the other improvement people don't pay attention to is the new TSA scanners you don't have to take your laptop out.
> people don't pay attention Let's start from the fact that people never asked for TSA. It was imposed on them and never went away.
The wood is pretty, but as someone who uses this terminal, the key improvement is that they raised the ceiling and significantly increased the amount of natural light. Here's a good photo of what it looked like before: https://commons.wikimedia.org/wiki/File:Portland_Internation... The major functional drawback is that wayfinding for both arrivals and departures is much worse. The overall flow of foot traffic is way…
I believe the other improvement people don't pay attention to is the new TSA scanners you don't have to take your laptop out.
I agree it looks nice, but dressing up an airport in sustainable materials won't materially change the fact that a flight Boston - NYC (one-way!) blasts through ~0.7t[1] of CO2eq of your yearly budget of 1-3t[2]. It won't change the fact, but I'm sure it'll make it easier to forget or ignore. [1] https://co2.myclimate.org/en/portfolios?calculation_id=75775... [2] e.g. https://ieep.eu/publications/carbon-inequality-in…
It boggles my mind why the US doesn't simply offer high-speed trains for easy distances like those. That whole Northeast is just screaming for it with easily managable distances. Boston, NYC, Philly, Baltimore, DC.. All easily high-speed-trainable. Boston to Portland too, for that matter. Instead of spending 1 hour queueing at the airport, spend one hour on the train and you're there.
It's 3000 miles! I would personally love to live in a world where you can go 200mph on a train and do it in 15 hours but I wouldn't call it easy.