Mankind Can Create As Much Fresh Water As We Need
There is no shortage of water on the planet; after all, water covers three fourths of the surface of the earth. And, if we take a rational and scientific approach to the subject, there need be no shortage of fresh water either. Nuclear powered desalination can supply abundant fresh water for a growing population. John F. Kennedy, shortly before he was assassinated, created a task force to investigate the use of nuclear power to create a new source of fresh water for the nation.
It is probably necessary at this point to simply state that nuclear power is the safest, cheapest and cleanest power known to man. Don't take my word for it: research it! There are plenty of resources out there on the subject.
But nuclear power is also the most energy dense. This is an idea that bears further investigation.
Suppose you wanted to weld two steel 3/4" thick plates together, as part of making a hull for a ship. But, suppose all you had available as a source of heat was candles. How many candles would it take to produce the heat necessary to weld the plates together? Answer: you can't do it, even if you had ten billion candles. Because candles do not supply a source of energy sufficiently dense and concentrated to do the job. Or, suppose you wanted to build a rocket ship; how much wood would it take to build the fire hot enough to do the job? Of course, it's impossible. So, energy flux-density turns out to be crucial in getting work done. The higher the energy flux-density, the more work you can do. It is not simply a question of the total amount of energy produced, but how much energy can you bring to bear on a given cross-section, how concentrated the energy source is.
Nuclear power has the highest energy flux-density of any source known to man. We currently use fission power, derived from splitting atoms apart. Soon, we will be able to use fusion power, derived from joining atoms together, which is about 100 times more energy dense than fission. But fission is already a million times more energy-dense than oil or gas. You might want to ponder that for a moment - nuclear power is literally a million times more energy dense than oil and gas! And windmills and solar panels are too intermittent and too diffuse to be worth much of anything, not withstanding the current craze. The fact is, if weren't for massive (stupid) government subsidies, and piggy-backing on other currently existing infrastructure (like using conventional power plants when it's dark, or when it's not windy), no one would even give wind or solar a second thought.
The point is, to do some serious desalination on a large scale, and do it economically, you need nuclear power. The principle of turning sea water into fresh water is pretty simple: boil the water, turn it into steam, and then recondense the steam back into water. What gets left behind is the salt and impurities. The problem is, to convert large amounts of sea water this way, you need large amounts of energy to do it, and you need to concentrate that energy into a very high temperature and a relatively small cross-section to do it effectively and economically.
In January of 1963, John F. Kennedy commissioned a task force to study the use of nuclear power for desalination. The task group issued its report in March of 1964, just months after Kennedy's assassination. They recommended building a demonstration plant, to be operational by 1970, with a capacity of 50-150 mgd (million gallons a day). By 1975, the plan was to have multiple plants in operation with a capacity of 600 mgd. Another 1966 Atomic Energy Commision report said that by the 1980's, we could produce a nuclear power plant that would desalinate 1,300 mgd. The task force recommended building 42 such desalination plants in the United States, not only along coastal areas, but also along rivers, to clean up the water from some of the rivers that have excessively high mineral content (like the Colorado River, for example).
What is the state-of-the-art today?
In the United States, El Paso Texas boasts the largest inland desalination plant in the world, with a capacity of 27 mgd. Israel claims the largest capacity SeaWater Reverse Osmosis plant in the world at 164 mgd. Saudi Arabia claims the largest capacity desalination plant in the world: 211 mgd. In other words, the largest capacity plant in the world today, in 2013, has one third the capacity of a demonstration nuclear plant that was to be operational in 1975!
The difference is, all these other desalination plants do not use nuclear power. It is nuclear power that gives you the capacity to create very large amounts of fresh water, and very economically.
So, why aren't we doing it?
That is a longer answer, beyond the scope of this article. Suffice it to say, that it is entirely political, and not scientific or technological. Mankind has the technology today to produce as much fresh water as is needed.
Now, some people have objected, and asked about the salt that is left over - what is to be done with that? Salt has thousands of uses in our industrial society, from de-icing roads and airplane wings, to making our food tasty, to the manufacture of polyvinyl chloride, chloride, plastics, paper pulp, to softening drinking water, just to name a few. So, the salt is a valuable by-product of desalination.
But, just for the sake of argument, let's suppose that we don't want or need this salt, and that we simply dump it back into the ocean. Keep in mind that nature is "desalinating" salt water every day: it's called evaporation. Every day, hundred of trillions of gallons of water evaporate into the atmosphere from the ocean, and leave behind the salt. Does this cause a problem? Clearly not.
But, suppose we were to operate 10,000 nuclear power plants around the world, each desalinating one billion gallons of water per day. (Keep in mind we don't even have ONE such plant today.) And, suppose we took all the salt thereby produced, and put it straight back into the ocean. Surely, this would cause a problem, wouldn't it?
Simply put: no. That amount of water would amount to .001% of the volume of the ocean per year. That is, 1 thousandth of one percent. (By comparison, every day, 10,000 times more water is evaporated from the ocean than is used by the entire United States per day.)
So, don't worry! There's plenty of water! We won't harm anything by transforming as much as we need into fresh water. And, keep in mind, that by desalinating water, and then using it - we're not using it up. That desalinated fresh water will participate in growing crops, and watering lawns, and be used in manufacturing, and providing drinking water for humans and animals, but eventually, it all is filtered and processed by natural processes like run-off, or human wastewater reprocessing, and it returns to the environment, and the ocean, and the atmosphere.
The point is, mankind can be a gardener of the Planet Earth. Gardeners make beautiful things grow, and take careful care of their garden. It need not be that man is the great destroyer. Of course man can be very destructive - with nuclear war, we could probably destroy all life on the planet. But, we can also make the deserts bloom, and assist nature in increasing the biomass of the planet, and reap the benefits of man-improved nature.
The answer is more and better technology, and scientific and technological progress.