The trouble with resources: Water (Part 1)

Image courtesy of US Geological Survey

Water is life.

An old rule of thumb says you could last three months without food, three days without water, and three minutes without air. I deal with water first even though we need air more urgently because of air's ubiquitous nature. Obtaining water requires conscious choice, and lacks the sense of urgency of air, so we may tend to put it off if we do not have a strong and immediate sense of thirst. This leads to varying levels of dehydration that create anything from mild memory loss and fever to death, and this just covers the water needed within our bodies to maintain function. We also use water to grow crops and maintain human health through waste conveyance. To understand whether or not we have enough water to support our life, we need to know how much we have available to us, how fast we use it, and how quickly nature makes it available to us again.

Water is a finite resource. Most of us learn about the water cycle (or hydrologic cycle) in school, but do not pay attention to the most interesting consequence of the use of the word "cycle". It reminds us that we do not create water or destroy it through our existence; water merely changes form, and sometimes location, then becomes available to us again, and again. The table below lists data that the image below does a great job of making visual:





The visual only tells part of the story. As we can see in the table, of that 27,000 cubic miles of surface-available freshwater, almost 25% is either in the atmosphere, in swamps or in us, making it immediately unavailable for use. That leaves about 22,000 cubic miles of surface water. According to the American Water Works Association, the average daily direct water use for Americans is 69.3 gallons inside and an additional 280 gallons per day outside. That use covers daily water intake and personal health. Add to that between 2,500 gallons per day of virtual water that goes into the energy, food, and resources we require each day including construction and production of goods. (Remember, that although equivalent daily, per capita water draws for the US are around 1,350 gallons per day, many of the crops and products we consume come from overseas, so we are not limited to our borders when considering the water needed to support our lifestyle.) If 9 billion people used water at that rate, that would total 25 cubic miles of water a day or about 0.1% of our available surface water. Allowing for water in transit (both to us for our use and to wastewater treatment) and for water in the treatment process for return to the surface water stores, we would have 0.3% of our world surface water supply withdrawn each day for our use.

Assuming we can keep up with the treatment of the water - a task that would require construction of thousands of water treatment facilities across the world - we can make choices that allow us to recharge our sources of freshwater at the same rate we use them. With this, and taking into account the fact that several areas of the world have the ability to tap into the 2.5 million cubic miles of ground water, it would appear that our planet has more than enough water to supply 9 billion people living the American lifestyle. So why does water present such a huge challenge, with 2.7 billion people currently short of water and some calling water the "oil of the 21st century".

The answer to that question is availability and quality...location, location, location.

Next week - water availability and quality.