Eli5 if salt water turns to fresh water when it evaporates how do we have water shortages in coastal regions or water shortages in general?

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Eli5 if salt water turns to fresh water when it evaporates how do we have water shortages in coastal regions or water shortages in general?

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Anonymous 0 Comments

Sure, when it evaporates, it turns into theoretical fresh water. As long as it doesn’t come back down in the form of rain though, it might as well be sand for all the good it does us. The process of evaporation, cloud formation, and precipitation can start at the ocean, but the water will be deposited slowly much farther inland. That rate is more or less fixed, as in we can’t speed it up. If we consume or polute the fresh water faster than it is regenerated, we have shortages.

Edit: Technically, there is this thing called cloud seeding, which makes clouds release their rain faster. That’s a very short term hike in fresh water release though, and only farmers can seem to afford it.

Anonymous 0 Comments

Evaporating water is relatively difficult. The sun will evaporate water and produce fresh water rain, but if not enough falls where you are then you can have a shortage. Even if you are near the ocean it doesn’t mean that you can practically produce fresh water from the salt water.

It takes a lot of energy to boil water. People expect their fresh water to be relatively cheap, and the energy required to boil off a bathtub’s worth of water is going to be more expensive than people want to pay for a bath.

Anonymous 0 Comments

I live in San Diego County, where we have a desalination plant. The cost to build it was $1 billion. The cost to operate it is about $59 million per year. It only produces 7% of the water we need for the county (about 50 million gallons a day, out of 100 million gallons of seawater).

Anonymous 0 Comments

Are you maybe thinking of it backwards? Salt water turns into just salt due to evaporation. It’s not the salt that gets sucked into the air and blows away…

Anonymous 0 Comments

Two reasons:

1. Evaporating a lot of water takes a lot of energy

2. Where do you put all the salt?

Anonymous 0 Comments

I’m not sure I’m understanding your question. As salt water evaporates, the remaining water stays salty.

The evaporated portion is water vapor – its not salty, but it’s also not liquid fresh water either; it’s in gas form. It has to condense as dew or rain to become fresh water.

Anonymous 0 Comments

We don’t have water shortages in general. We have a shortage of adequate storage. More dams, increase existing dam capacity would solve any water shortage problem where it rains enough.

Not going to help with droughts for inland areas though. Those places were uninhabited or sparsely inhabited for good reasons.