How much water have we really got? It would seem like quite a lot, since the earth’s surface is 71% water. But appearances can be deceiving.
All the water on earth would fit into a cube not quite 700 miles on a side. If that seems like a lot, remember this includes oceans and icecaps. All the fresh water in the world, including icecaps and groundwater, would fit into a cube just over 200 miles on a side. And if you limit your water to lakes and rivers, all of them in the world would fill a cube a mere 36 miles on a side. Since the icecaps are frozen, and groundwater is replenished very slowly, this 36 mile cube, representing all the water in all the lakes and rivers of the world, is all we’ve got
Moreover, only about half the amount stored in Earth’s lakes and rivers is replenished each year by snow and rainfall. This renewable amount is how much humans, plants, animals and ecosystems get per year to live.
It’s not enough. Industrialized, developed nations consume far more water than developing nations, and the world is developing at a pace unprecedented in human history. Throughout Asia and Latin America, standards of living are increasing and with them, per capita usage of water. Currently an American or Western European uses four times as much water as someone in the developing world. What happens when 1.3 billion Chinese, .5 billion other East Asians, 1.1 billion Indians, and nearly 1.0 billion Latin Americans begin to enjoy a lifestyle that approaches western standards? More meat, which requires grain-fed livestock, more showers, more flush toilets, more factories, more irrigated land. There is not enough fresh water on this planet to allow the per-capita consumption of water in the western world to be matched by the rest of the world.
Water scarcity has become a big issue for environmentalists in recent years, because humans have been living beyond their means for decades, and the day of reckoning is not far off. Skeptics contend that water scarcity will never arrive because human adaptation will solve the problem incrementally. These skeptics compare warnings about water scarcity to those dire warnings put forth back in the ’70s that predicted a world running out of fossil fuel; something that never happened and probably never will.
But water isn’t as easily transported as fuel, nor are there alternatives. These crucial differences make the looming water crisis something that cannot be easily dismissed. Regional shortages will become acute in China, Central Asia, North Africa, India and elsewhere, and one can’t just ship a tanker full of water to solve the problem. That we are going to run out of water if current demographic and consumption trends continue is beyond serious debate, the real question is what should we do?
Conservation is the favorite solution of most environmentalists, and it will be necessary. Other means should also be considered. Redistribution may not be an unthinkable option, although thoughtless disasters such as the canal diversions that destroyed the Aral Sea seem to be the rule to date. Getting more “crop to the drop” is another key method to reduce the world’s per capita water requirements. Drip irrigation, concrete lining on canals, pipe transport instead of canal to reduce evaporation are all ways to save water; all very expensive. New crops that require less water to grow are also part of the solution.
Finally, desalinization may be a solution that offers huge potential. Converting sea water to fresh water is not only a technique which could offer virtually unlimited fresh water, but irrigation using desalinated sea water would not degrade the soil since the salt would be completely removed. Floating platforms offshore that used convection energy generated by the differences in water temperature at varying depths could produce their own power to desalinate water. Enough of them might provide cost-effective desalinization and make a real impact on the supply of fresh water.
Providing the world with enough water for everyone to enjoy a high standard of living will require not only conservation, but creativity and the power of capitalist initiative. Hopefully before entire nations become heedless of anything but their thirst.