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Helios4242 t1_iyc6bfk wrote

Reply to comment by CMDR_kamikazze in People who are promoting hydrogen as a green fuel always forget what water vapor is one of the most powerful greenhouse gases. by CMDR_kamikazze

>water vapor emissions from aircraft only.

Which is miniscule compared to the amount already evaporating from oceans. Double of miniscule is still miniscule.

By and large, the relative impact of using hydrocarbons on greenhouse gases is not the water vapor but the carbon dioxide. Eliminating the impact on carbon dioxide while doubling its miniscule impact on water vapor is considered to be a good tradeoff by experts in the field (if of course we could reach low-carbon hydrogen production). There's also less nitrogen oxides and particilates. The water vapor is taken into account. It's just not much to account for.

Secondly, as I mentioned, since water splitting would be done with water that is already part of the water cycle, it's just moving it through the cycle. The same amount of water remains on the Earth's surface. Combustion of a fossil fuel adds water to the Earth's surface from where it was stored as a hydrocarbon.

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CMDR_kamikazze OP t1_iyc6pk1 wrote

>if of course we could reach low-carbon hydrogen production

The biggest culprit of all issues with using hydrogen. The easiest way of producing it isn't much better for the environment than directly burning hydrocarbons. And it's exactly the way big fuel corporations want it.

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Helios4242 t1_iyc71wl wrote

of course, but it's good to have the mechanisms in place to use it if the attempts to produce enough clean electricity bear fruit, alongside improvements to hydrogen production efficiency and usage.

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