Hacker News new | comments | ask | show | jobs | submit login

This technology could be a boon to country like India where huge population relies on rain and some of the reservoirs are at about 40% despite decent rainfall this year. On the other note will desalination and consumption of sea water by humans balance the rising sea level ?

The amount of water consumed by humans is a literal drop in the ocean, on the global scale, fear-mongering aside. I wouldn't worry about the impact of a handful of desalination plants.


California uses 1/26 millionth's of the ocean's volume per year (50bn m^3 out of 1.3 bn km^3). So a drop is quite right! According to [1], it takes 87 mi^3 (~320km^3) to raise the ocean level by 1mm. You'd need several Cali's worth of water use just to negate to that 1mm rise. And that's assuming you destroy the water after use, which basically does not happen.

If you _could_ destroy the water (freeze it all or fuse it all or something) it'd still take a million years to use it up.

1: http://www.sealevel.info/conversion_factors.html

If we started doing this on a global scale I don't think we'd have much trouble negating sea level rise for a while. If energy became so cheap as to allow desalination and gargantuan pumping networks to distribute water across the world, the water used in agriculture alone would drastically change the water cycle and weather patterns. Combined with the increasing temperatures increasing evaporation I think we could one day make a difference. We don't need to destroy it, we need to get that pumped water as far out of the water cycle of the ocean as possible and lock it into reagions. Many new rivers will still flow back to the ocean but we can promote agriculture to siphon off the rivers. Imagine undoing the desertification of the once fertile crescent, the dustbowl, or the Colorado river Basin and Texas?

I don't know how to calculate what it'd take to undo desertification of the dustbowl. But 1mm = 320km^3 of water that _doesn't_ go back into the ocean. To stop the current 2-3mm rise that's 1000 cubic km a year. I suppose over something the size of the dust bowl (400,000 sq km) that's not that much.

But I'd take a wild guess that by the time we get to that level of terraforming, we can build solar reflectors and just prevent the warming in the first place. Desal'ing all that water is going to require massive amounts of power (big fusion plants) plus all sorts of machinery. Tossing a bunch of mirrors into space seems easier to my engineering-ignorant mind.

Thanks, this was very insightful reply.

Pretty much all the desalinated water that is "consumed" will just flow right back out to sea.

Eventually, according to the water cycle:


Either that, or end up evaporating in the atmosphere, precipitating somewhere, and then flowing into the sea.

Countries like India, Israel, and the US have plenty of geographic areas where solar arrays could be created with tons of sun exposure. Plus, these countries all have nuclear (weapon) capability.

Couldn't solar or nuclear power allow for desalination pretty easily in countries like these?

Sure, but nuclear power has lots of political resistance.

> On the other note will desalination and consumption of sea water by humans balance the rising sea level ?

Is this a serious question?

Guidelines | FAQ | Support | API | Security | Lists | Bookmarklet | Legal | Apply to YC | Contact