Not to mention, besides the wood material being, well, wood... it's a relatively small amount when you think about it, and the amount of processing involved which basically turn it into a different material altogether outweighs any sustainability. Plus, with all the glues / epoxies / whatever they use, that wood-based material isn't going to be degradable at all. It puts me in mind of "bamboo" products, which also relies on a lot of glues and processing to make it a wood analog.

> Plus, with all the glues / epoxies / whatever they use, that wood-based material isn't going to be degradable at all.

That's kinda the point though. You don't want it degrading in situ. That's why we treat wood.

In a situation indoors like here it will suffer less but still.. I used to live in a wooden house and the maintenance was a PITA. Having to repaint every 5 years or so. And that was wood that was treated already.

Well the fact that it doesn't degrade means the carbon stays trapped.

Sadly, it's true. In my opinion, this is the hypocrisy of the modern 'green' agenda - we endlessly discuss pollution, yet we cling to the comforts of modern life, many of which cause even greater harm.

Personally I'd love to take more trains instead of planes, and bike more instead of driving, but the system (at least in the US) just isn't set up for that.

Train travel is expensive and sparse and slow, biking most places is uncomfortable and unsafe due to crappy infrastructure.

I agree. Trains are often a more efficient, more comfortable, and greener way to travel. I would love to be able to take them more often on weekends here in the UK, but they are expensive to the point of costing more than air travel, which makes no sense.

Planes are cheaper as a function of the infrastructure needed to allow their use (? Feel free to correct me). As long as we allow airplanes companies to not pay for the long term externalities that they are creating planes will stay cheaper.

In the EU, jet fuel isn't taxed at all, quite the contrast with gasoline prices.

Isn't clinging to the comforts of modern life worth heating the planet a bit? It doesn't seem like an unreasonable tradeoff to me.

Yes it is, but we've already heated the planet a bit. What we're trying to do now is prevent heating the planet a lot, which will come with much greater consequences (mass migration to escape heat and rising seas, droughts, famines, "natural" disasters, etc.).

We can have it both ways. In ~50 years in the US, 99% of cars will be electric and 99% of electricity generation will be carbon negative. We can keep our comforts of modern life, like cars, while not damaging the planet.

I accept there is not a story for air travel, yet.

Air travel industry is investing into a biofuel future

Modern comforts like electricity, cars, heating, and cooling. Those are most of the CO2 that people produce.

It is dumb to give up modern comforts when we know how to make them green by making electricity renewable and electrifying everything. Changing habits like reducing driving and increasing transit would help. Some things will be hard, like airplanes and concrete.

I agree somewhat that there is lots of distractions. There is a lot of talk about plastic and recycling that really has little to do with climate change.

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. So... there actually is a finite number of wooden airports that completely offsets airplane carbon emissions.

1 kilo of wood sequesters (temporarily for the most part) about 2kg CO2 equivalent, so for the GP's example of a single seat one-way from Boston - NYC, you'd need to sequester 350kg of wood.

To sequester the ~800 Mt of CO2 emitted by aviation annually, you'd need to sequester about 400 billion kilograms of wood. So a finite but absurd amount.

Not only that, you have to build new wooden airports every single year to keep up.

Or you transition the airline industry to biofuels that are inherently carbon neutral.

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 is left in the ground. Worth following up.

1.6kgCO2/kgLumber * 5MkgLumber = 8MkgCO2 = 8KtCO2 embodiment/sequestration from the PDX roof project. (tho there's a lot more to the project that probably goes in the other direction)

Global CO2 emissions from commercial flights is ~60MtCO2/month [CF], so we need roughly 12,000 airports per month, 144,000/yr, to offset flight CO2 emissions.

There's 9000 commercial airline airports [NA] (tho obv many smaller than PDX, but they would also represent less CO2 from their flights), so 144,000/9000 is a 16x annual airport rebuild rate we'd need to offset CO2 emissions from the flights they service.

So yeah, this is absurd on the face of it.

But, how much of the mass of an airport is the roof? If it's like 1/100th the total mass, and you start building airports with all wood (foundation, runways, etc) you'd get to 16% annual rebuild rate to offset flight emissions. Still too high to be plausible. But another 10x somehow and you get to ~1% range of annual airport rebuild rate to offset emissions.

Then you'd have something.

[SK] https://www.usa.skanska.com/what-we-deliver/projects/278172/...

[PL] https://www.forbes.com/sites/johnoseid/2024/08/19/portlands-...

[DFM] https://www.globalwood.org/tech/tech_wood_weights.htm

[DFC] https://www.douglasfir.co.nz/net/environment/carbon-footprin...

[CF] https://www.statista.com/statistics/1500409/global-aviation-...

[NA] https://sentinel-aviation.com/blog/over-40000-airports-in-th...

> tho there's a lot more to the project that probably goes in the other direction

I mean, this is obviously why this is just a fun math exercise and not much else. Building an airport, even if you build part of it out of wood, is not net carbon-negative.

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 of harvesting, processing and transporting it. I.o.w. leaving the ugly old roof in place would probably have been better, in terms of CO2eq emitted.

I found a more authoritative reference, from the Institute of Structural Engineers, which appears to be a major international organization [ISE].

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.

The e is short for equivalent.

https://chancerylaneproject.org/glossary/carbon-dioxide-equi...

thanks. Also forgot to note size difference between those airports.. DEN is #4 in the US with 38M passenger boardings/year, PDX #33 with 8M. So maybe 4x larger

https://en.wikipedia.org/wiki/List_of_the_busiest_airports_i...

Based on the discussion in the descendent thread with morsch, it seems like the runways are the real story, at 1000x the mass of the airport roof.

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...

Does burying wood actually work? I'm assuming it's a little more complicated than literally burying it, cause wouldn't it decay and release carbon at some point anyway?

Without oxygen, any decay is going to be incredibly slow. They're still pulling usable timber from trees that sank in rivers after being cut in the southeastern US 200 years ago. It's not cheap, but if you want some real old-growth oak, it's a viable source. And that's not a completely anaerobic environment.

200y is not really an incredibly long time at all

No, it's not, but that's without any noticeable decay. A tree that's been felled in that environment and left above ground will rot very quickly.

As most of the heavy construction and earth moving equipment you'd use to bury the wood will be burning diesel and releasing carbon the entire time, you enter some new Tyranny of the Rocket/Wagon equation.

There's a simple way to think about this that doesn't require doing a ton of research and number crunching. Think about the volume of fuel in a single airplane, about 7,000 gallons for a 737, or about 100 55 gallon drums. It's nowhere near exact, but you can roughly equate that volume of fuel to the volume of volume of wood to compare carbon - I'm pretty sure this is being very generous to the energy density of the wood, but it gives you an upper limit on what the wood could be sequestering (I think in reality jet fuel is something like 2-3x as energy/carbon dense per m^3). Now think about how many planes take off every day from an airport, and the volume of n*100 drums.

It's just nowhere near in reality, and we're not going to make a large dent via sequestration, the "finite" airports is functionally infinite for our purposes. We have to start making carbon neutral fuel.

That said, manufacturing concrete is incredibly carbon intensive, so avoiding making the amount we would've needed for this building is a pretty good win.

> If were to bury the equivalent amount of wood, we would be equal.

Burying wood that would have taken decades to decay is not equal to instantly releasing the equivalent amount of carbon. I'm not sure it's physically possible to remove CO2 from the atmosphere at the same rate a plane emits it, which would be the only way to genuinely "offset" the emissions.

It is however looking much nicer. For that reason alone I would love to see more projects like this.

Sometimes, dressing up a problem can breed apathy and desensitize people to harsh realities.

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 being planned, but projects like these are never certain: https://secretnyc.co/high-speed-train-nyc-to-boston/

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're stuck with a non-highspeed train on the track that was supposed to be highspeed and cost a fortune to build.

In other countries like Germany, France and Spain the high-speed network works like a dream though. Though the good stuff is all nationally focused.

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 intermediate distances (around 500 km) it's about as fast as flying would be once you factor in getting to/from the airport (vs the more central train station), being there early etc; and much faster than driving by car.

> 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.

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 :')

My understanding is that the problems of NYC -> Boston high speed rail are purely political, and basically come down to CT resistance to change

The current track alignment is not conducive to high speed travel, and CT as a state has no interest in supporting a new alignment that is conducive because they would likely get _negative_ value out of it: as it stands, Acela trains pretty much all stop in New Haven and Stamford: why wouldn't they?

If you go with a high speed link that aims to speed up Boston <> New York travel, it's more likely that you have trains that skip those stops, because additional stops are much more expensive for HSR from a speeding up and slowing down perspective, from a percentage of time added to trip perspective, and for an inefficient alignment perspective.

In my view this is kind of a microcosm of the political problems of the geographically small states of the north east: states like CT/RI/DE especially have very narrow and niche concerns but because of their geographical position have effective veto power over regionally important things like "how expensive are the tolls to drive between New York and DC?" and "can you have HSR between new york and boston?"

It's not about skipping stops, it's about the amount of eminent domain you'd have to do to eliminate curves thru Connecticut's oldest and richest suburbs.

Which is why proposals to route it via Long Island and building a 16-mile tunnel under Long Island Sound get consideration.

Flying has been the preferred travel mode of both the well-to-do and the aspirational for over half a century. Air travel only needs working airplanes, and a relatively simple airport at each end. So, in general, there's ample social pressure to get the job done quickly.

Vs. high-speed trains went out of fashion (in America) well before most people's memories. And their tracks have to be threaded, foot-by-foot, across a landscape which is overflowing with red tape and jurisdictions and NIMBY's and existing infrastructure. Said threading to be planned by yet more politicians and bureaucrats and planners, then done by America's low-functioning construction industry.

Nations with good high-speed rail systems have quite different priorities and local governance structures than America.

> Nations with good high-speed rail systems have quite different priorities and local governance structures than America.

Hmm true but Europe has most of the same red-tape/NIMBY/environmental impact studies etc issues as America. Those are not unique.

However considering climate impact it pays itself back.

Plus you get to use the atmosphere as a free sewer, filling it with pollution without paying the actual cost to clean it up, which makes flying really cheap

Boston to Portland, OR? The city discussed in the article?

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.

I'm guessing they meant Portland Maine, but yeah confusing given the article being discussed. :)

Oh yeah I saw Portland on the map, thought was was the one discussed :) It was the one in Maine indeed

the same people telling me to save on my carbon emission are the ones who are ok with free trade to have stuff made thousands of miles away (in jurisdictions with very lax environmental laws) that could be made right here and employ blue-collar workers. Those container ships arrive full and leave empty. What's the CO2eq of that?

Those are not the same people.

It is the same people unfortunately. People who want to reduce the global carbon footprint should be rejoicing about tariffs and returning manufacturing to America. The two party system forces people to hold conflicting values though. Both sides have belief systems that are full of inconsistencies.

Cargo ships are the most efficient form of transport. They use scale of big ships carrying lots of cargo.

It takes about the same amount of CO2 to carry container across the Pacific as to truck it across the country. Producing it here or there doesn't make much difference. If anything, it is more efficient to produce in China cause they have higher percent of renewable electricity.

Yeah, take a look at this then…

https://celebrityprivatejettracker.com/leaderboard/#gr

I'm extremely pro-rail but Portland is not the city to bash for short haul domestic flights.

Amtrak Cascades is very popular for trips to Seattle.

To put it in context: Cascades is popular because it magically takes the same amount of time (~3 hours), has no traffic, costs less than a tank of gas, and puts you into downtown seattle without having to park and potentially have your car stolen.

That is to say.. people will take trains as long as they're truthfully better. We should work on making them better. Even the lovely people of Portland, as concerned as we are about the environment, don't take the train out of the goodness of their hearts.

I think it's a little bit misleading to casually drop a "yearly budget" like this, as if this is something we're currently following. In the US the average car emits 4.6t of CO2 per year [1]. If you really think we need to be following this yearly budget the implications on our society (including basically a ban on most car trips being currently taken) are extremely drastic.

[1] https://www.epa.gov/greenvehicles/greenhouse-gas-emissions-t....