Monday, April 9, 2012

Dirt: The Erosion of Civilizations

Professor David Montgomery’s book Dirt provides a fascinating discussion about an extremely precious substance that we can’t live without, but treat like dirt.  He begins with an intimate explanation of what dirt is, how it’s formed, and how it’s destroyed — in plain, simple English. 
Then, he proceeds to lead us on an around-the-world tour, spanning many centuries, to examine the various methods that societies have devised for mining their soils, and diminishing their future via agriculture.
The book is impressively thorough, and it’s likely to blow more than a few minds, but the voice is a bit soft.  A neutral tone is mandatory for textbooks, and this may encourage casual readers to be less concerned about the future than they should be.  Connect the dots.
From a human perspective, soil is a non-renewable resource, because new soil is created very slowly, a process often measured on a geological timeframe.  For example, the soils of the Mediterranean basin were largely destroyed by 2,000 years ago, and they remain wrecked today.  They are quite likely to remain wrecked for many, many thousands of years.  Much of the region that once fed millions is a desert today.
If smoking a single pack of cigarettes reliably caused a painful death by cancer within weeks, nobody would smoke, because it’s clearly not smart.  But cancer normally takes decades to become apparent, and by the time you learn about the tumor, it’s too late to make smart decisions.  Life does not have an undo button.
It’s a similar story with societies that take up the dirty habit of agriculture, which is almost always fatal.  Once you get started, it’s nearly impossible to quit, because it’s unbelievably addictive.  Yet we continue to act like it’s a cool thing to do, because it’s a clever way to acquire trade trinkets and status, and all the other cool societies are doing it, too.  The disease often advances so slowly, over the course of generations, that nobody realizes the mistake.  But once the soil is ruined, it’s too late to become smart.  There is no wonder cure.  Game over.
Eventually, Montgomery’s world tour brings us to the United States, where the white invaders imported their dirty habit.  In Europe, many farmers were quite careful to do what they could to slow erosion, and improve fertility, using time-proven techniques, because starvation was the alternative.  American settlers promptly threw these prudent practices overboard, because they were time-consuming, and because there was an unbelievable supply of fertile soil that was readily available.  In the New World, dirt was a disposable commodity.
Settlers could get rich quick by raising tobacco and cotton.  A field of rich virgin soil could support three or four crops of tobacco, and then it would be abandoned.  It was cheaper to pack up, move on, and clear new fields than it was to manure the fields they had already cleared.  This careless attitude fueled an explosion of erosion and deforestation.  One gully near Macon, Georgia was 50 feet deep, 200 feet across, and 300 yards long.  Soil exhaustion was a primary driving force behind the westward expansion of the colonists.  Rape and run agriculture seems to have set the mold for the emerging American mindset.
In the twentieth century, when farmers bought millions of big, powerful machines, the 10,000 year war on soils mutated into a new and horrifying form.  Erosion rates skyrocketed to levels never before believed to be possible, leading to catastrophes like the Dust Bowl.  Montgomery says it like this: “Continued for generations, till-based agriculture will strip soil right off the land as it did in ancient Europe and the Middle East.  With current agricultural technology though, we can do it a lot faster.”
Here’s a line that made me jump: “Everything else — culture, art, and science — depends upon adequate agricultural production.”  Like air and water, food is essential for our survival.  Without food, our entire techno-wonderland turns into fairy dust and blows away.  We can’t live without it, but at the same time we are rapidly destroying what makes food possible — because profits today are more important than existence tomorrow.  Sorry kids!
On a bright note, Montgomery gives us a quick tour of Tikopia, a society on a tiny island that is one of the few exceptions to the rule.  They seem to have devised a sustainable form of agriculture that majors in agroforestry (food-producing trees).  They combined this with a draconian method for maintaining a sustainable population, which was far less painful and destabilizing than the effects of over breeding. 
Looking toward the future, Montgomery foresees a large number of serious problems.  Explosive population growth continues.  We are moving beyond the era of cheap and abundant energy, and this will continuously drive the price of everything upward.  Climate change is likely to deliver unwanted surprises.  Widespread destruction of soils continues, and simply converting to organic farming will not fix this.  Nor will no-till technology, which will eventually be forced into extinction by rising energy costs, or herbicide-resistant weeds.  We are running out of tricks for increasing productivity.  The end of the chemical fertilizer game is inevitable, and it will largely be replaced with recycled sewage — a priceless treasure that we are now throwing away via expensive, energy-guzzling treatment plants.
Our current system is simply not up to the task of feeding the world in the coming decades, because it’s a design that self-destructs.  We try to force the ecosystem to adapt to our food production technology, and this doesn’t work.  Instead, we need to make farming adapt to the needs of the ecosystem.  In short, we need a serious revolution in the way we do agriculture — a new philosophy that gives top priority to the health of the land, not to maximizing income by any means necessary.  How likely is this?  Don’t hold your breath.
The subject of this book centers on soil erosion.  In the good old days of muscle-powered organic agriculture, soil destruction took a thousand years to ruin a civilization, on average.  Industrial agriculture is much quicker.  It now keeps seven billion people alive by using soil to convert fossil energy into food.  But the clock is running out on cheap energy, and industrial agriculture has an expiration date.  This will give birth to a new agricultural revolution — the return to muscle-powered farming, on severely depleted soils, fertilized once again by nutrient-rich sewage.  Farm productivity will plummet.  We are close to peak food production now.

Montgomery, David R., Dirt: The Erosion of Civilizations, University of California Press, Berkeley, 2007.
NOTE: If you find this subject interesting, the first edition of Topsoil and Civilization (1955) is available for free online as a PDF download.  It follows a parallel course, but provides a different banquet of information, while coming to similar conclusions:

No comments: