[detaro]

uh, no?

[iso1210]

Well technically yes

[throw37388]

Yes

》Water vapor is known to be Earth’s most abundant greenhouse gas

https://www.nasa.gov/topics/earth/features/vapor_warming.htm...

[toiletaccount]

Run it through a condenser, feed it into a holding tank and dispose of the water at each filling station?

[jbotz]

No need, the atmosphere is a sufficient condenser. Unless you heat the atmosphere with a lot more energy than the little bit you get from combusting the hydrogen in question... but then you'll have bigger problems as your oceans begin to evaporate.