April 24 was the one-year anniversary for Common Science.  I’ve covered a wide variety of topics including, lightning, cells phones, bananas, and even neodymium.   The topic I have touched on the most has been the impending scarcity of critical resources, particularly oil and fresh water, which I expect to be the dominant factor in world events in the upcoming century.  For a preview, Google “Egypt-Ethiopia water dispute.”
In this column, the fifth and final installment on water, I want to draw your attention to some noteworthy parallels between petroleum and fresh water.

  1. By the time that the Industrial Age began in 1850 the earth had accumulated tremendous reserves of solar energy (oil) and water below ground (sub-surface aquifers).

As a quick review, it is important to understand that oil is a storage medium for solar energy.  Ancient algae and bacteria captured solar energy via photosynthesis and stored this energy in the chemical bonds of the molecules which made up their bodies.  They then fell to the bottom of the body of water in which they lived, were buried deeply as a result of the movement of tectonic plates, and converted into liquid petroleum over time in the high-pressure, high-temperature environment underground.  When we burn petroleum products like gasoline and diesel, we release the original solar energy previously captured by the algae and bacteria.  At the dawn of the industrial age, this solar energy storage process had been creating our petroleum reserve over a period of approximately 300 million years. 
In a somewhat analogous way to petroleum, Mother Nature was also storing extra water underground.  As rain seeps into the ground, some of it accumulates in porous underground structures.  Humans have been tapping into these reserves for water wells for thousands of years, but until the Industrial Revolution brought improved pumps, we did not exploit underground aquifers in a significant way. 
The second half of the 1800’s heralded an impressive array of scientific and technological advances resulting in increased industrial productivity and agricultural output.  Over the next 100 years the effects of these advances were amplified by the availability of the overabundance of oil and water which the earth had been accumulating.  This made humans feels like they were gods and blessed with a future of never-ending growth and progress.   In our associated irrational exuberance, we denuded the earth and grew our numbers to 7 billion.

  1. Oil and fresh water supplies are both about to hit their peaks.

First let’s talk about what a peak really means by using the example of petroleum.  Currently the world is extracting 90-95 million barrels of oil a day.  Sometime in the next decade, this production rate is going to drop, even if we exploit tar sands and oil shale.
When someone, like me for example, starts talking about peak oil, a typical dismissive response is “what are you worried about, we have plenty of oil left”.  It’s true that when we hit the peak, we will still have around half of our oil reserve left.  The key point about the peak is not that we are on the verge of running out.  The point is that the supply will no longer grow.
Fresh water supplies are also about to peak.  Today we use all of the rain water provided by Mother Nature by tapping into lakes and streams, and we supplement this by extracting water from subsurface aquifers.  Many of these aquifers are rapidly approaching exhaustion and this part of the water supply cannot be replaced.  When the aquifers are exhausted, rain water will become the limiting resource for food production. 
Most analyses on this topic conclude that feeding our current 7 billion people on our annual allotment of rain will be difficult and require dietary changes away from high water-consuming foods like beef.  None of these analyses suggest a viable pathway to feeding the 9 billion people projected by the UN to live on the earth by 2050 on just the food we can grow from rainwater.

  1. For both water and oil we are about to experience guilt about how brazenly we blew through the endowments bestowed upon us by Mother Nature.

 Recently I was trying to think of an analogy to help people conceptualize how quickly we are burning through the oil that Mother Nature made.  My friend Robert Newton gave me the idea for the following “iPod Analogy”.  As discussed above, oil is the storage medium for solar energy exactly in the way that a battery is a storage medium for electrical energy.  It took the earth 300 million years to make our petroleum reserve and we are on pace to use it up in 200 years.  This is the equivalent of charging your iPod for 24 hours so that you can listen to music for 0.06 seconds.  If an iPod worked like that no one would buy one.  Our 0.06 seconds of music is already half way over and we are really going to be disappointed when the music stops.
Since aquifers around the world have been filled at different rates, the iPod analogy for water is less easy to define with precise numbers. Nevertheless, the dynamic is the same.  The aquifers filled slowly over a long period of time and now we are blowing through them like a drunken sailor on payday.
It’s not surprising or even necessarily wrong that humanity utilized the endowments of water and solar energy (oil) that we found.  What is disappointing, to the point of being inexcusable, is that we did not plan or prepare for their limits.  Reasonable people can disagree about approaches to resource allocation, but what is not open to debate is that in the not-too-distant future we need to learn how to live on our yearly allotments of rain and sun.  So far we have not faced this challenge.
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