[Throw73849]

It may be still more efficient to pump water underground. Isolating CO2 is very energy intensive, for the same amount of energy we may isolate 100x more H2O. Sometimes it even condenses spontaneously!

There is also huge amount of natural CO2, single vulcano eruption... It is about reducing green house gas emissions generated by humans. And there are many artificial lakes, fields and forests that generate huge footprint on water vapour..

[qzw]

Clippy: It looks like you’re trying to turn Earth into Arrakis. Would you like some help with that?

More seriously though, as the effects of climate change intensify, I think it’s all but inevitable we’ll have to seriously look at manipulating whatever environmental factors we can in order to counteract the worst of them. Maybe we can’t do much about the sea level rise, but maybe it would be possible to moderate storm and drought/flooding intensities. As you pointed out, water vapor levels may be one of the easier things we could manipulate, as least on a local or regional scale.

[saalweachter]

Ignoring all the other problems with that, there is also nearly 100x more water in the atmosphere than carbon dioxide, and roughly 10000x more water in the oceans than the atmosphere. Do you expect sequestering H2O to have a significant impact on the amount in the atmosphere before you dry up the oceans, whence it is evaporating?