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Q & A: Could we use the water from the ice glaciers?

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Most recent answer: 03/03/2015
Q:
If we ever ran out of water could we use the water from the ice glaciers?
- Hailey (age 13)
Canada
A:

In theory, yes. Some ice is sea ice, that is frozen sea water. According to The National Snow and Ice Data Center (),  "When sea ice forms, most of the salt is pushed into the ocean water below the ice, although some salt may become trapped in small pockets between ice crystals", so there could be a little salt trapped.   But glaciers around the mountain peaks, the ice layer covering the arctic and antarctic polar regions or the icebergs that break off from such large glaciers are not salty. In some regions of the world, they are already used as water source, for example by mountaineers.

In practice there are difficulties. There may be frozen pathogens, which may require boiling before consumption. Another problem is with the logistics: people tend not to accumulate around cold regions, so one needs energy to transport the water to cities. However there is a far more serious problem with your strategy for most cities far from the big ice sheets. Nearby mountains would probably be the easiest sources, but our giant cities quench their thirst with millions of cubic meter per year (). So beside the destruction of the high altitude ecosystems, I hardly suspect that it could be sustainable. This strategy simply resembles usage of wood as energy source: the nature can replenish the trees to an extent, but not enough for a 7 billion human population. So better save our natural resources, I would say.

Tunc


(published on 03/02/2015)

Follow-Up #1: Why are we having a water shortage?

Q:
If water can't be destroyed why is it that we are having a water shortage
- Bryce (age 13)
Toronto
A:

First of all, it is not true that water is cannot be destroyed. It is composed of two hydrogen atoms and an oxygen (H

O), and you can actually set up a small electrolysis setup at home by a 9V battery and observe that two gases emerge: oxygen (O2) and hydrogen (H2). And in fact, destruction or generation of water is an extremely important thing in biochemistry. An example is digestion, where water is split into two functional groups this time: -OH and -H.

But your point is a good one, and I think one could argue that free water quantity of Earth may actually be slightly increasing, because oxidative respiration generates H2O; photosynthesis consumes water and plant population is on decline due to human activities. But our water shortage is not because of the decreased abundance of H2O molecules. Although the Earth may be covered by 75% water, we cannot consume any type of water, but fresh water only. There should be no salt, no waste and no pathogens, and such water resources constitute only a minor fraction of all water on Earth. See . The reason behind the trouble is selective depletion of this fraction and also pollution.

Tunc


(published on 03/03/2015)

Follow-up on this answer.