s
alternatives to petroleum, biofuels such as ethanol and biodiesel have
two major advantages. Firstly, they are theoretically
carbon-neutral, in that they recycle carbon dioxide already in the
atmosphere rather than adding to it from fossil fuel deposits.
Secondly, they can be used to run our existing motor vehicle fleet and
infrastructure. This makes them extremely attractive to a
society that wants to keep enjoying the mobility of personal
automobiles without (further) disrupting the global climate.
Unfortunately, these
qualitative advantages are overshadowed by enormous problems, which
become obvious once we actually do the math and look at biofuels from
a quantitative standpoint.
A barrel of oil contains
6100 megajoules of energy. Today, the world uses about 30
billion barrels of petroleum and natural gas liquids each year.
Roughly half of that,1 or 91.5 trillion
megajoules' worth, is used for transport fuels.
A barrel of oil contains
6100 megajoules of energy.
(photo: Engines of Our
Ingenuity)
There have been a number
of studies on how much total biofuel (including byproducts) can be
produced per hectare. These range from 57,650 MJ/ha2
to 108,800 MJ/ha.3 This works out to
between 850 million and 1.6 billion hectares of land required to
produce the gross equivalent of the oil we use today for
transportation.4
There are between 1.5
billion5 and 2.4 billion hectares6
of arable land on Earth. So, it would take the equivalent of
between 35% and 107% of all the potential farmland on the planet to
produce enough biofuels to replace today's transport oil consumption.
Today, even with
unprecedented farm productivity, plus the ability to store and
transport food over long periods and distances, 800 million people
worldwide are still chronically malnourished. Futhermore,
today's productivity is itself dependent on enormous fossil fuel
inputs, the main limiting factor being the artificial nitrogen
fertilizers made from natural gas. Research by Wolf (2003)
suggests that without these nitrogen inputs, per-hectare farm yields
would drop by between one-third and one-half.7
Since natural gas is itself being depleted, we can look forward to a
day when we need a lot more farmland -- between half again and twice as
much-to sustain today's farm yields.
Today's productivity is itself dependent on enormous fossil fuel
inputs.
(photo: Dexter's Farm)
It has been suggested that
biofuel produced from cellulosic plants such as switchgrass could make
use of marginal grasslands, leaving the more fertile farmland for food
production. And there is, in fact, a lot of grassland on
Earth-some 3.5 billion hectares of it.8
But there are still several problems with this approach. First,
as mentioned above, we'll need all our farmland and then some to
produce food. The "and then some" is going to have to
come out of our grasslands. The reason humans domesticated meat
animals in the first place is that they can produce food from
otherwise marginal land. A cow basically takes a plant that
humans can't eat (grass) and turns it, albeit very inefficiently, into
something we can (meat and milk). We are likely to need our
grasslands to raise cattle the old-fashioned way.
Secondly, it would be
painfully naive to assume that the best land will be saved for food
production. Will farmers use their most productive land to grow
food for poor people when they could use it to produce luxury goods
for the rich? It's hardly as if they do today. Currently
the market devotes a huge part of the world grain crop not to feeding
hungry people, but to fattening up cattle to produce meat for
wealthier markets. A more ominous example is the recent (very
small) increase in ethanol production in the United States, whose
effect on corn prices in turn helped drive a 400% increase in the
price of tortillas in Mexico.9
The third problem is that
even if we stick to growing switchgrass on marginal land, the
large-scale growth and removal of plant matter may quickly deplete the
soil's nutrients. The graveyard of history is full of
civilizations that collapsed because-even with farming practices that
were in many ways more sustainable than today's-they over-exploited
and destroyed their farmland.
Will farmers use their most productive land to grow
food for poor people when they could use it to produce luxury goods
for the rich?
(Photo: Tim Moerman)
And, as bad as the numbers
are for biofuels today, they are likely to get worse. The
world's population, having already overshot its sustainable carrying
capacity, is still growing. The International Energy Agency
projects a 50% increase in global energy demand by 2030.10
Climate change, combined with the already-advanced depletion and
erosion of our existing farmland, and exacerbated by the depletion of
the natural gas we currently use to make artificial fertilizers, are
likely to reduce our ability to grow crops in the future. Many
of our alternate food supplies, such as ocean fisheries, have been
completely decimated. In other words, we face a future of more
mouths to feed, higher demand, declining supply of critical resources,
and reduced flexibility. To devote our fertile land to producing
motor fuels, while blindly assuming that the food situation will
somehow work itself out, is to flirt with genocide.
What is
to be done?
The situation is grim but
not hopeless. Today's consumption of energy and resources is so
badly managed (or not managed at all, this being the defining trait of
a pure market economy) that there are enormous opportunities for
improved efficiency. These will require substantial lifestyle
changes on the part of the world's wealthy nations.
Unfortunately, the current
vogue for biofuels is driven by people's desire to believe that they
don't have to modify their behaviour-that they can have their cake,
eat it, and burn it in the gas tank. Dispelling this foolish and
dangerous notion must be our first priority.
