How is water a diminishing supply? Is the earth somehow losing water vapor?
Many areas use more water than they receive in rain. Their main source of water is aquifers. Those aquifers are dropping. The fill-rate of those aquifers is determined by precipitation, but the drain rate is determined by humans draining them.
The primary use of aquifer water is irrigation. Our irrigation policies aren't very efficient, mainly because we currently price the cost of aquifer water too lowly.
I'm not saying we shouldn't drain those aquifers:
it only makes sense to use them for our benefit. But we should be getting proper
value for our water.
So make more.Its not hard.Catch rain water.Desalinate.
Absolutely! But those options cost money. I don't mind that, of course: but it will increase the price of water. We should be amortising that cost
now. Not doing so is just stupid accounting.
India is a good example of the potential problem. They grow 75% of their food using aquifer water (and India is already low-meat, high-grain diets), but their aquifers are dropping year-to-year.
Because the price of water is so low (the cost of extracting) then any amount of water usage is justified by a farmer - if it increases their profits. If doubling water usage would increase their yields by 2%, they're motivated to do so - because the water is too cheap. Water returns a diminishing return on usage (the first hour of irrigation does
much more for the crop than the second hour), and so you want a proper price for it.
