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Re: The Limits To Growth



Mike Asher wrote:
 
> As an aside, I will note that the majority of agricultural land in the
> world is farmed with low-tech inefficient methods.  Expantion of the use of
> modern agriculture, new species, and good infrastructure, can more than
> double world food production.  All without an additional acre being farmed,
> though, in the US at least, agricultural land usage has been on the decline
> for many years.   Perhaps you have some statistics here?

Modern agriculture is not sustainable.

=========================================================================

       THERMODYNAMICS AND THE SUSTAINABILITY OF FOOD PRODUCTION
       by Jay Hanson <jhanson@ilhawaii.net> — revised 11/04/96

All matter and energy in the universe are subject to the Laws of
Thermodynamics. In the discipline of Ecological Economics, systems are
delimited so that they are meaningful to our economy. What does
thermodynamics have to do with the sustainability of food production?

The two essential forms of stored thermodynamic potential are "energy"
(e.g., a barrel of oil) and "order" (e.g., clean drinking water and deep
topsoil). "Entropy" is a measure of the unavailability of energy: the
entropy of oil increases as it burns, and the entropy of a water table
increases as it falls because more energy will be required to pump it to
the surface.

Entropy can also be thought of as a measure of disorder in a system:
polluted water that requires purification has higher entropy than the
same
water unpolluted, and the entropy of topsoil increases when it erodes or
is
polluted by salt from evaporating irrigation water.[1]

Sustainable systems are "circular" (outputs become inputs)—all linear
physical systems must eventually end. Modern agriculture is increasing
entropy in both its sources (e.g., energy, soil, and ground water) and
its
sinks (e.g., water and soil). Thus, modern agriculture is not
circular—it
can not be sustained.

Consider the most important limiting variable—energy.[2]

There is NO substitute for energy. Although the economy treats energy
just
like any other resource, it is NOT like any other resource. Energy is
the
precondition for ALL other resources and oil is the most important form
of
energy we use, making up about 38 percent of the world energy supply.

40 years ago, geologist M. King Hubbert developed a method for
projecting
future oil production and predicted that oil production in the lower-48
states would peak about 1970. These predictions have proved to be
remarkably accurate. Both total and peak yields have risen slightly
compared to Hubbert's original estimate, but the timing of the peak and
the
general downward trend of production were correct.[3]

In March of this year, World Resources Institute published a report that
stated:

     "Two important conclusions emerge from this discussion. First, if
     growth in world demand continues at a modest 2 percent per year,
     production could begin declining as soon as the year 2000. Second,
     even enormous (and unlikely) increases in [estimated ultimately
     recoverable] oil buy the world little more than another decade
(from
     2007 to 2018). In short, unless growth in world oil demand is
sharply
     lower than generally projected, world oil production will probably
     begin its long-term decline soon—and certainly within the next two
     decades."[4]

Well, so much for oil! Should we be alarmed? YES! Modern
agriculture—indeed, all of modern civilization—requires massive,
uninterrupted flows of oil-based energy.

To really understand the underlying causes and implications of oil
depletion, one must stop thinking of the "dollar cost" of oil, and take
a
look at the "energy cost" of oil. We note that the energy cost of
domestic
oil has risen dramatically since 1975.[5] As oil becomes harder and
harder
to find and get out of the ground, more and more energy is required to
recover each barrel. In other words, the increasing energy cost of
energy
is due to increasing entropy (disorder) in our biosphere.

Optimists tend to assume that the "type" of energy we use is not
significant (e.g., liquid vs. solid), that an infinite amount of social
capital is available to search for and produce energy, and that an
infinite
amount of solar energy is available for human use. Realists know that
none
of these assumptions is true.

In fact, all alternative methods of energy production require oil-based
energy inputs and are subject to the same inevitable increases in
entropy.
Thus, there is NO solution to the energy (entropy or disorder) problem,
and
the worldwide energy-food crisis is inevitable.

When we can no longer subsidize modern agriculture with massive fossil
energy inputs (oil-based pesticides and fertilizers, machine fuel,
packaging, distribution, etc.), yields will drop to what they were
before
the Green Revolution![6] Moreover, billions of people could die this
coming
century when the U.S. is no longer able to export food[7] and mass
starvation sweeps the Earth.

Is there nothing we can do?

We could lessen human suffering if all the people of Earth cooperated
for
the common good. But as long as political systems serve only as
corporate
errand boys, we're dead.
---------------------------------------------------------------------------

Many entropy references are archived at: :
http://csf.Colorado.EDU/authors/hanson/page17.htm

  1. p.p. 42-43, ENERGY AND THE ECOLOGICAL ECONOMICS OF SUSTAINABILITY,
     John Peet; Island Press, 1992. ISBN 1-55963-160-0. Phone:
800-828-1302
     or 707-983-6432; FAX: 707-983-6164 http://www.islandpress.com
  2. http://www.igc.apc.org/millennium/g2000r/fig13.html
  3. p. 55, BEYOND OIL, Gever et al.; Univ. Press Colorado, 1991.
     303-530-5337 See also:
     http://www.wri.org/wri/energy/jm_oil/gifs/oil_f4-5.html
  4. http://www.wri.org/wri/energy/jm_oil/index.html
  5. http://csf.Colorado.EDU/authors/hanson/page20.htm
  6. p. 27, Gever et al., 1991.
  7. Estimated in 1994 to be about 2025 by Pimentel. See:
     http://csf.Colorado.EDU/authors/hanson/page40.htm

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                   SELECTED EXAMPLES OF SOIL DEGRADATION

  Country    Extent of Degradation

             Erosion affects more than a third of China's territory some
             3.67 million square kilometers. In Guangxi province, more
             than a fifth of irrigation systems are destroyed or
  China      completely silted up by eroded soils. Salination has
             lowered crop yields on 7 million hectares, use of untreated
             urban sewage has seriously damaged some 2.5 million
             hectares, and nearly 7 million hectares are polluted by
             industrial wastes.

             Eroded area increases by 400,000-500,000 hectares each
  Russia     year, and now affects two-thirds of Russia's arable land.
             Water erosion has created some 400,000 gullies covering
             more than 500,000 hectares.

             Nearly all—94 percent—of Iran's agricultural land is
             estimated to be degraded, the bulk of it to a moderate or
  Iran       strong degree. Salination affects some 16 million hectares
             of farmland, and has forced at least 8 million hectares
             from production.

             Gullies occupy some 60 percent of the 1.8 million hectare
  Pakistan   Pothwar Plateau. More than 16 percent of agricultural land
             suffers from salination. In all, more than 61 percent of
             agricultural land is degraded.

             Degradation affects one-quarter of India's agricultural
             land. Erosion associated with shifting cultivation has
  India      denuded approximately 27,000 square kilometers of land east
             of Bihar. At least 2 million hectares of salinized land
             have been abandoned.

             32 percent of land is suitable for farming, but 61 percent
  Haiti      is farmed. Severe erosion eliminated 6,000 hectares of
             cropland per year in the mid-1980s.

             More than 4.5 million hectares of drylands—10 percent of
  Australia  all cropland—and more than 8 percent of irrigated area are
             affected by salting. Area affected by dryland salting
             doubled in size between 1975 and 1989.

Worldwatch Institute, Paper #131, Gary Gardner, July 1996, p.p. 28-29.


---------------------------------------------------------------------------

       GROUNDWATER DEPLETION IN MAJOR REGIONS OF THE WORLD, c. 1990

  Region/Aquifer      Estimates of Depletion

                      Net depletion to date of this large aquifer, which
                      underlies nearly 20% of all U.S. irrigated land,
                      totals some 325 billion cubic meters, roughly 15
  High Plains         times the average annual flow of the Colorado
  Aquifer System,     River. More than two-thirds of this depletion has
  United States       occurred in the Texas High Plains, where irrigated
                      area dropped by 26% between 1979 and 1989. Current
                      depletion is estimated at 12 billion cubic meters
                      per year.

                      Groundwater overdraft averages 1.6 billion cubic
                      meters per year, amounting to 15% of the state's
  California,         annual net groundwater use. Two-thirds of the
  United States       depletion occurs in the Central Valley, the
                      country's (and to some extent the world's) fruit
                      and vegetable basket.

                      Overpumping in Arizona alone totals more than 1.2
                      billion cubic meters per year. East of Phoenix,
  Southwest, United   water tables have dropped more than 120 meters.
  States              Projections for Albuquerque, N.M., show that if
                      groundwater withdrawals continue at current rates,
                      water tables will drop an additional 20 meters on
                      average by 2020.

                      Pumping exceeds natural recharge by 50-80%, which
  Mexico City and     has led to falling water tables, aquifer
  Valley of Mexico    compaction, land subsidence, and damage to surface
                      structures.

                      Groundwater use is nearly three times greater than
                      recharge. Saudi Arabia depends on nonrenewable
                      groundwater for roughly 75% of its water, which
  Arabian Peninsula   includes irrigation of 2-4 million tons of wheat
                      per year. At the depletion rates projected for the
                      1990s, exploitable groundwater reserves would be
                      exhausted within about 50 years.

                      Net depletion in Libya totals nearly 3.8 billion
  North Africa        cubic meters per year. For the whole of North
                      Africa, current depletion is estimated at 10
                      billion cubic meters per year.

                      Pumping from the coastal plain aquifer bordering
  Israel and Gaza     the Mediterranean Sea exceeds recharge by some
60%;
                      salt water has invaded the aquifer.

  Spain               One-fifth of total groundwater use, or 1 billion
                      cubic meters per year, is unsustainable.

                      Water tables in the Punjab, India's breadbasket,
                      are falling 20 centimeters annually across
  India               two-thirds of the state. In Gularat, groundwater
                      levels declined in 90% of observation wells
                      monitored during the 1980s. Large drops have also
                      occurred in Tamil Nadu.

                      The water table beneath portions of Beijing has
  North China         dropped 37 meters over the last four decades.
                      Overdrafting is widespread in the north China
                      plain, an important grain-producing region.

                      Significant overdraft has occurred in and around
  Southeast Asia      Bangkok, Manila, and Jakarta. Overpumping has
                      caused land to subside beneath Bangkok at a rate
of
                      5-10 centimeters a year for the past two decades.

Worldwatch Institute, Paper #132, Sandra Postel, September 1996, p.p.
20-21.



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