FAA selects sustainable design for new control towers at smaller airports

This is a good approach to a lot of things, except when said thing also has positive externalites and second order effects associated with it.

Travel is one such example, as it's essential to lubricate the economy. As such, we should encourage as much of it as possible. Business thrives on it.

Without cheap air travel, America is weak. We lack commuter rail infrastructure, and car travel is far too slow. Taxing air travel or increasing its costs are a nonstarter.

If we predicted the era of air travel to be coming to an end, we'd be making rail investments. Air travel is likely to continue growing, however, so there's little rush for domestic rail projects.

America flies.

Indeed they are marvels of engineering. But that doesn't make them "sustainable". It just takes a lot of energy to push something through the air at high speed, no matter how efficient the engines are.

Apart from the CO2 emissions, there's also the issue of the GHG forcing effect of high altitude water vapor emissions. Current estimates are that flight at typical airliner altitudes of ~10 km results in a GHG forcing (over some decades) of roughly 3 times more than burning the same fuel on the ground.

> And for that matter, how would biofuels possibly be worse fossil fuels, given that the whole point is to not emit net CO2 into the atmosphere. Obviously it's "efficient" because all the energy we put in has to come from the sun, rather then obtained for free but that's the point.

The major issue is due to land use changes. Biodiversity is already in a sharp decline (arguably this is an as big, if not bigger issue than climate change), largely driven by converting nature into cropland. Secondly, converting nature into crops, whether for fuel or food, tends to result in large CO2 emissions due to the carbon that has been stored into the soils being released.

And finally, biofuels just don't scale. There isn't enough arable land on the planet to replace the amount of fossil fuels we use today.

I’m talking about biofuels as they exist today, not as they hypothetically exist in the future. Currently, you burn biofuels, you end up releasing more CO2 into the atmosphere, because the production of biofuels produces CO2. It’s not negligible, either.

All of the analyses I’ve seen of biofuel paint an incredibly dismal picture. As far as I can tell, the main strategy to reduce CO2 emissions is to stop burning fuels altogether, not switch to something like biofuel. Airplanes need power density & energy density in order to work which makes technologies like batteries unsuitable. Way easier to power something on the ground, where you’re not spending tons of energy just to keep it from crashing. Or better yet, on an electrified rail.

Energy density. You need large amounts of energy throughout the mining and refining process. Digging, grinding, washing, refining, transporting - all done with petrol and gas. The energy density of solar & wind is just not there.

> Large mining corporations seem to be on the leading edge of decarbonisation.

Source?

> After all, who wants to ship fuel miles out into the desert and then burn it in an enclosed underground space when you can use solar panels and electric motors?

1. Most mining operations today are open mines. 2. Petrol is burned in ICE digging and grinding machines. 3. If you want to mine in the desert you also need large amounts of water in order to wash the ores. Just look at what's happening in Chile [1].

[1] https://www.npr.org/2022/09/24/1123564599/chile-lithium-mini...