Before addressing this issue of the shortage of drinking water on Earth, and the nature of solutions to this problem, it would be useful to get some figures and proportions so that we can first get some perspective on what the drought statistics actually mean and why.
As of today, in the middle of 2009, the current estimated global human population is at about 6 and 3/4 billion (http://www.census.gov/main/www/popclock.html) and counting. Some predictions give a rather sobering, if not downright frightening estimate that this will grow to some 9 billion by about 2050 (http://www.globalchange.umich.edu/globalchange2/curr ent/lectures/human_pop/human_pop.html). Now, some nutritional and medical experts indicate that normal adult should consume eight 8oz glasses of water per day. I'm not sure that that's an average, but for dramatic effect, and the "insurance" of overestimation, let's take that as true.
Assuming also the truth that, according to http://timesofindia.indiatimes.com/articleshow/79828 2.cms, there are 1.35 x 10^18 kiloliters of water on the planet, which, when expanded back to gallons at a ratio of 264.18 gal. per kl (http://dictionary.reference.com/browse/kiloliter) gives us 356.643 times 10^18 gallons of water, we have the raw figures with which to work. But, as these are rather clunky to manipulate, at least longhand, and frankly do not present very readably or at all interesting to most of us, why don't we round the population up to 8 billion, and the volume of water up to about 400 times 10^18 gallons. That's a rough estimate of 50,000 gallons of water per person. The real math gives that figure at 52,836 gallons, by the way.
Now, back to our consumption needs. At the need of eight 8oz glasses a day, we are drinking (or supposed to be drinking) a half a gallon of water a day each. That is a daily need, wordwide, of 4 billion gallons. So, our need is at about 4 billion out of the Earth's estimated 400 billion-billion gallons. In other words, we need 1 *billionth* of one percent of the total volume of water available for human consumption on a daily basis. And we have a shortage?
Remember, too, that natural processes (the water cycle and human and animal digestive processes) mean that the water use is temporary - it is always and forever "recyclable". That would be the case, that is, if nature - and HUMAN nature! - were as neat and clean as the arithmetic we've seen so far. Still, even with conservative arithmetic, surely we should be able to access 0.000000001% of Earth's water for drinking, shouldn't we?
It seems likely, therefore, that the problem is not how much water the Earth has, but our ability to use it. We need to be able to get to the water, or get the water to us. The problems that may confound that are myriad and complex. It is anything from a matter of logistics such as manpower and infrastructure, to matters that are hairier still such as property ownership and route interference, to imminent domain, to well-intended but self-defeating regulatory and conservation efforts that protect one region or habitat from being invaded by we from another.
There are also likely some very daunting issues regarding terrain navigability. It isn't we humans getting in our way this time, but nature itself being bigger and stronger than we. For this, it seems the only approach that would work would be to hit it where it lives or, rather, where WE live. We in the United States may have no or limited access to some regions of the Arctic, for reasons of cost effective personnel movement, and even proprietary conflicts or the risk of offending anther region's sovereignty or the *appearance* of imposing some threat to it. It becomes plainly obvious that these are not environmental matters, but political ones.
Still, perhaps northern Canada, Russia, Alaska, Siberia, northern Europe, et cetera, have an incentive to invest in some research and development of ideas to facilitate an efficient and environmentally neutral trickle down - *literally*! This is just some thinking out loud. I am no expert. But surely we need to be thinking globally to address this global issue.
Tips like taking shorter showers and watering one's lawn sparingly can and do help with local conservation, but some regions of the world do not even have these indulgences to sacrifice. That's the global part. Turning off your water while you shave and brush your teeth can save you money on your water bill, and prevent waste as well as the attitudes of taking our access for granted, but it is not going to answer the drought problems in many parts of Africa, Central Asia, and many of our inland and land-locked regions.
It seems that, for the most part, the water crisis is not a matter of excess, but of *access*
I'll leave it to biologists and marine experts to consider the factors that enhance water conservation and aid, even, in the harnessing of UNALTERED environmental processes and climactic factors to this disbursement end. I do not know if it is even realistic. Perhaps the only thing to do is relocate to the coasts, fall out of love with our hydro-costly perfect lawns, and even, dare I say it, change our sexual and social behaviors and attitudes so that we can avoid the unenviable 9 billion people living achievement. THAT would be an example of excess.
It would surely not be humanity's... ...high-water mark.