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Reverse traffic pyramid (mastodon.green)
submitted 3 months ago* (last edited 3 months ago) by mapto@feddit.bg to c/bicycling@lemmy.world
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За да подобрим живота в нашите градове, тези приоритети трябва да бъдат управлявани.

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[-] atzanteol@sh.itjust.works 2 points 3 months ago

air travel is an unmitigated disaster on the level of personal carbon footprints - there's basically no way to make it sustainable

Compared to cars? Or just trains?

[-] JubilantJaguar@lemmy.world 1 points 3 months ago

Compared to everything.

[-] atzanteol@sh.itjust.works 1 points 3 months ago

You're telling me that 140 people driving from New York to California is more efficient than 140 people taking a single 737?

[-] mech@feddit.org 1 points 3 months ago* (last edited 3 months ago)

If they share 35 cars, yes.
If they each drive their own cars, no, it's close, and depends on what cars they drive.

[-] atzanteol@sh.itjust.works 1 points 3 months ago* (last edited 3 months ago)

Shared rides is a step above on the pyramid.

From what I can tell it's not really close. At least for "average cars" and "typical commercial airlines".

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

[-] mech@feddit.org 1 points 3 months ago* (last edited 3 months ago)

this represents 28 g of fuel per kilometer, or a 3.5 L/100 km (67 mpg‑US) fuel consumption per passenger, on average.

Now take into account that CO2 released at altitude is twice as bad as on the ground, since it absorbs all sunlight before part of it gets filtered out by the atmosphere or reflected by clouds.

[-] atzanteol@sh.itjust.works 2 points 3 months ago* (last edited 3 months ago)

I hardly think that's relevant. CO2 doesn't stay where it was released.

The concentration of carbon dioxide in the mid-troposphere lags the concentration found at Earth's surface as mixing from the lower to upper altitudes usually takes days to weeks.

https://airs.jpl.nasa.gov/resources/107/concentration-of-atmospheric-carbon-dioxide-from-earths-mid-troposphere-2002-to-2013/

We're talking about yearly averages and decades of warming. Days to weeks is very short by comparison.

[-] mech@feddit.org 2 points 3 months ago

You're right, I misremembered. It's not the CO2 that has a higher effect when released at altitude than on the ground.
It's Nitrogen Oxides, water vapor and soot.

"In 1999, the IPCC estimated aviation's radiative forcing in 1992 to be 2.7 (2 to 4) times that of CO2 alone − excluding the potential effect of cirrus cloud enhancement.[6] This was updated for 2000, with aviation's radiative forcing estimated at 47.8 mW/m2, 1.9 times the effect of CO2 emissions alone, 25.3 mW/m2.[7]"

https://en.wikipedia.org/wiki/Environmental_impact_of_aviation#Factors

this post was submitted on 08 Feb 2026
40 points (95.5% liked)

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