The two main environmental news stories of the past year or so have been the twin impending disasters of global warming and water shortages. There is a scientific consensus that global warming is occurring, and many governments (including, belatedly, the Bush Administration) have taken steps to address the problem.

But the more pressing issue is water; people can live with global warming (and have been for some time), but people cannot live without water.

While drinking water is the most obvious need, everything around us takes water to produce, from food to telephones to tires. Not only is agriculture dependent on water [the U.S. Geological Survey estimates it takes about 1,300 gallons of water to grow a hamburger] but so is virtually every industry. Even energy production needs water, in hydroelectric dams and nuclear reactor cooling towers.


Demand soars

The barrage of news reports warn of a dire water shortage, and provide sobering statistics:

The global demand for water has tripled over the last 50 years, while water tables are falling in many of the world's most populated countries, including the United States, China, and India.
Many of the world's great rivers are a fraction of the size they once were, and some have dried up completely.
Earth's lakes are vanishing at an alarming rate; the Aral Sea, for example, is less than a quarter its original size. Nevada's Lake Mead is half its original capacity; a recent study concluded that there is a 50/50 chance that the lake will be gone in less than fifteen years.
It's true that there is cause for alarm, but to understand the problem people need to read behind the headlines to understand one little fact: There is no water shortage.

Our planet is not running out of water, nor is it losing water. There's about 360 quintillion gallons of water on the planet, and it's not going anywhere except in a circle. Earth's hydrologic cycle is a closed system, and the process is as old as time: evaporation, condensation, precipitation, infiltration, and so on. In fact, there is probably more liquid water on Earth than there was just a few decades ago, due in part to global warming and melting polar ice caps.

The problems

No, there is plenty of water. The problem is that the vast majority of Earth's water is contained in the oceans as saltwater, and must be desalinated before it can be used for drinking or farming.

Large-scale desalination can be done, but it is expensive.

But nor is the world running out of freshwater, either. There's plenty of freshwater on our blue globe; it is not raining any less these days than it did millennia ago. As with any other resource, there are of course regional shortages, and they are getting worse. But the real problems are availability and transport; moving the freshwater from where it is plentiful (such as Canada, South America, and Russia) to where it is scarce (such as the Middle East, India, and Africa). Water is heavy and costly to transport, and those who can afford it will always have water.

Water, not global warming, is likely to be the greatest environmentalchallenge facing the world in the coming decades and centuries.

To find solutions, it's important to understand the problem. Water is never really "wasted." It simply moves from one place to another. If you let your faucet drip all day, that's clean water going back into the system, the water isn't "lost." What is lost is usefulness, money, and energy, because it takes energy to purify and distribute the water.

Water conservation is very important, but not because there is a shortage of water; it is the ultimate renewable resource. As with any resource, the issue is getting it to those who need it.