[usrusr]

Yeah, this can't be some prank by a renegade flight crew, it can only be a farewell celebration act with a kick-off meeting, a budget and a dozen people who signed off. But I'm not criticising, by that measure we'd have to question any resource expenditure that exceeds the bare minimum for sustaining life.

[ant6n]

Well this admittedly cool looking stunt represents more than 5 persons worth of annual sustainable co2 budget (estimated at 3T/year), so I‘d say it’s a smidgeon above the „bare minimum for sustaining life”.

[usrusr]

That's why you don't do stuff like this for each and every subvariant. This is a once in half a century occasion, it absolutely pales in comparison to the amount of fuel the type has burned for trade show visits, photo opportunities and numerous other nonessentials. Arguably there isn't a single use case for jet aviation that isn't far out of the range of sustainable co2 budget.