Suddenly, there is this idea in my mind that if an important effect of global warming is rainfall reduction and drought, is it possible to use volcanoes as water vaporizers (regardless of costs)?
Is it possible to create clouds by pumping water into volcanoes?
Maybe, but it's a really bad idea. Here's why:
- Volcanoes are unexpected and change with time. You can waste two years building a facility that does it, only for the volcano to cease being active and become dormant. Alternatively, the volcano might blow up and destroy your infrastructure.
- You actually need lava to do so. Very few volcanoes have persistent lava lakes. Two are in tropical islands (Vanuatu, Hawaii), two are in rainforests (Nicaragua, DRC), one is in Antarctica, and only one is in a desert where it would actually be somewhat useful (Ethiopia).
- In the absence of a lava lake, you can pump the water into the underground magma chamber and hope that it escapes in the form of steam. This is a bad bad bad idea, because you can cause a phreatic or phreatomagmatic eruption. Here's an example:
- You need water. If you have fresh water, you better use that water to solve the drought directly instead of pumping it into a volcano. If you're using sea water, you have the problem of laze. At the moment the opposite is happening: Kilauea in Hawaii is erupting lava that reaches the ocean. The reaction between the hot lava and the sea water creates releases acid into the air. Bad idea. Here's how it looks like:
- If somehow you managed to avoid exploding the volcano or creating acid rain, you would rapidly cool the top layer of the lava, solidifying it into rock. Rock is a poor thermal conductor, so you're forming a lid on top of the lava, making the thing much less effective.
if an important effect of global warming is rainfall reduction and drought...(regardless of costs)
Just use desalination. A very effective yet expensive way to get fresh water.
You could generate a lot of steam for a time, but it would require a lava lake like in Hawaii that was constantly refreshing itself or some kind of access to a large consistent magma chamber.
Pouring water directly onto a lava lake would probably create an eruption on its own. If the lava cooled enough you would end up with a thick insulating crust and stop getting any steam to make clouds out of it.
For a stratovolcano (think St Helens) or something less active, maybe you could pump water down and have it come out as steam the same way a geothermal power plant does. The scale would be huge.
And in either case, the steam would quickly condense into clouds so you would only get a local effect if you wanted to create rain. And to create rain you'd still need a water source which if you had could be used to irrigate. So you'd have to pump some kind of water to wherever you wanted it to begin with. Maybe you can get away with seawater for it, but still a long way to pump it where you want to turn it into steam.