Environmental Engineering Reference
In-Depth Information
11 Energy
ENERGY IN A SUSTAINABILITY CONTEXT
Energy and food production
Before fossil fuels, humanity was powered largely by photosynthesis. Firewood and charcoal
took care of heating needs, animal fat provided light, and animals and humans supplied
mechanical energy and transportation. The other two sources of mechanical energy were
water and wind. Where water streams combined with ground-level drops, water wheels were
used to produce mechanical energy; and in windy areas, windmills powered grain grinders and
water pumps.
The growth of economies in those times was severely limited by the availability of biomass
that came from cutting down forests and crops that were used to feed people and working
animals as well. As a consequence, population growth was strictly limited to the availability
of food and energy.
It is important to remember that the world was not globalized as it is today and human set-
tlements were supported by land located in their vicinity and that their sustainability depended
on the rate of exploitation of the resources. It would be a misleading notion to believe that the
biobased economy developed by our ancestors was sustainable just because of the reliance on
renewable resources. There are many accounts of civilizations that have been lost to what is
believed to be the depletion of natural resources such as forests and water (Mays, 2007).
The bases for the world as we know today (with a secure supply of food) started being set
in the eighteenth century with the introduction of massive use of coal followed by oil and gas
in the nineteenth century. These events led to the production of abundant and relatively inex-
pensive food that caused the world population to explode. It can be argued that hunger still
exists in many parts of the world, which is true, but looking at a global scale, the population
growth in the last century correlates with the use of inexpensive sources of energy and the
production of food.
About two-thirds of developing countries, most poor countries, and several developed
countries are net food importers (Ng and Aksoy, 2008). Does this happen just because of the
principle of comparative advantage? Or it is because their population is beyond what can be
sustained by their agricultural land. Several of those countries produce other things instead of
food that generate enough revenue to import food. But in most cases their population number
is beyond what can be sustained by their own land, and they are currently subsidized by inex-
pensive fossil fuels.
