A paper presented at the FEASTA Conference, "What Will We Eat
as the Oil Runs Out?", June 23-25, 2005, Dublin Ireland
Food is energy. And it takes energy to get food. These two facts, taken together,
have always established the biological limits to the human population and always
The same is true for every other species: food must yield more energy to the
eater than is needed in order to acquire the food. Woe to the fox who expends
more energy chasing rabbits than he can get from eating the rabbits he catches.
If this energy balance remains negative for too long, death results; for an
entire species, the outcome is a die-off event, perhaps leading even to extinction.
Humans have become champions at developing new strategies for increasing the
amount of energy - and food - they capture from the environment. The harnessing
of fire, the domestication of plants and animals, the adoption of ards and plows,
the deployment of irrigation networks, and the harnessing of traction animals
- developments that occurred over tens of thousands of years - all served this
The process was gradual and time-consuming. Not only were new tools developed,
but, over centuries, small inventions and tiny modifications of existing tools
- from scythes to horse-collars - enabled human and animal muscle power to be
leveraged more effectively.
This entire exercise took place within a framework of natural limits. The yearly
input of solar radiation to the planet was always immense relative to human
needs (and still is), but it was finite nevertheless, and while humans directly
appropriated only a tiny proportion of this abundance the vast majority of that
radiation served functions that indirectly supported human existence - giving
rise to air currents by warming the surface of the planet, and maintaining the
lives of countless other kinds of creatures in the oceans and on land.
The amount of available human muscle power was limited by the number of humans,
who, of course, had to be fed. Draft animals (bred for their muscle-power) also
entailed energy costs, as they likewise needed to eat but also had to be cared
for in various ways. Therefore, even with clever refinements in tools and techniques,
in crops development and animal breeding, it was inevitable that humans would
reach a point of diminishing returns in their ability to continue increasing
their energy harvest, and therefore the size of their population.
By the nineteenth century these limits were beginning to become apparent. Famine
and hunger had long been common throughout even the wealthiest regions of the
planet. But, for Europeans, the migration of surplus populations to other nations,
crop rotation, and the application of manures and composts were gradually making
those events less frequent and severe. European farmers, realizing the need
for a new nitrogen source in order to continue feeding burgeoning and increasingly
urbanized populations, began employing guano imported from islands off the coasts
of Chile and Peru. The results were gratifying. However, after only a few decades,
these guano deposits were being depleted. By this time, in the late 1890s, the
world's population was nearly twice what it had been at the beginning of the
century. A crisis was again in view.
But again crisis was narrowly averted, this time due to fossil fuels. In 1909,
two German chemists named Fritz Haber and Carl Bosch invented a process to synthesize
ammonia from atmospheric nitrogen and the hydrogen in fossil fuels. The process
initially used coal as a feedstock, though later it was adapted to use natural
gas. After the end of the Great War, nation after nation began building Haber-Bosch
plants; today the process produces 150 million tons of ammonia-based fertilizer
per year, equaling the total amount of available nitrogen introduced annually
by all natural sources combined.
Fossil fuels went on to offer still other ways of extending natural limits
to the human carrying capacity of the planet.
Early steam-driven tractors came into limited use in 19th century; but, after
World War I, the size and effectiveness of powered farm machinery expanded dramatically,
and the scale of use exploded, especially in North America, Europe, and Australia
from the 1920s through the '50s. In the 1890s, roughly one quarter of US cropland
had to be set aside for the growing of grain to feed horses - most of which
worked on farms. The internal combustion engine provided a new kind of horsepower
not dependent on horses at all, and thereby increased the amount of arable land
available to feed humans.
Chemists developed synthetic pesticides and herbicides in increasing varieties
after WWII, using knowledge pioneered in laboratories that had worked to perfect
explosives and other chemical warfare agents. Pesticides not only increased
crop yields in North America, Europe, and Australia, but also reduced the prevalence
of insect-borne diseases like malaria. The world began to enjoy the benefits
of "better living through chemistry," though the environmental costs,
in terms of water and soil pollution and damage to vulnerable species, would
only later become widely apparent.
In the 1960s, industrial-chemical agricultural practices began to be exported
to what by that time was being called the Third World: this was glowingly dubbed
the Green Revolution, and it enabled a tripling of food production during the
At the same time, the scale and speed of distribution of food increased. This
also constituted a means of increasing carrying capacity, though in a more subtle
The trading of food goes back to Paleolithic times; but, with advances in transport,
the quantities and distances involved gradually increased. Here again, fossil
fuels were responsible for a dramatic discontinuity in the previously slow pace
of growth. First by rail and steamship, then by truck and airplane, immense
amounts of grain and ever-larger quantities of meat, vegetables, and specialty
foods began to flow from countryside to city, from region to region, and from
continent to continent.
William Catton, in his classic book Overshoot, terms the trade of essential
life-support commodities "scope expansion."1 Carrying capacity is
always limited by whatever necessity is in least supply, as Justus von Liebig
realized nearly a century-and-a-half ago. If one region can grow food but has
no exploitable metal deposits, its carrying capacity is limited by the lack
of metals for the production of farm tools. Another region may have metals but
insufficient topsoil or rain; there, carrying capacity is limited by the lack
of food. If a way can be found to make up for local scarcity by taking advantage
of distant abundance (as by exporting metal ores or finished tools from region
A to help with food production in region B, and then exporting food from B to
A), the total carrying capacity of the two regions combined can be increased
substantially. We can put this into a crude formula:
CC of A+B > (CC of A) + (CC of B)
From an ecological as well as an economic point of view, this is why people
trade. But trade has historically been limited by the amount of energy that
could be applied to the transport of materials. Fossil fuels temporarily but
enormously expanded that limit.
The end result of chemical fertilizers, plus powered farm machinery, plus increased
scope of transportation and trade, was not just a three-fold leap in crop yields,
but a similar explosion of human population, which has grown five-fold since
dawn of industrial revolution.
Agriculture at a Crossroads
All of this would be well and good if it were sustainable, but, if it proves
not to be, then a temporary exuberance of the human species will have been purchased
by an eventual, unprecedented human die-off. So how long can the present regime
be sustained? Let us briefly survey some of the current trends in global food
production and how they are related to the increased use of inexpensive fossil
Arable cropland: For millennia, the total amount of arable cropland gradually
increased due to the clearing of forests and brush, and the irrigation of land
that would otherwise be too arid for cultivation. That amount reached a maximum
within the past two decades and is now decreasing because of the salinization
of irrigated soils and the relentless growth of cities, with their buildings,
roads, and parking lots. Irrigation has become more widespread because of the
availability of cheap energy to operate pumps, while urbanization is largely
a result of cheap fuel-fed transportation and the flushing of the peasantry
from the countryside as a consequence of their inability to buy or to compete
with fuel-fed agricultural machinery. Roads that cover former cropland are built
from oil, and the erection of buildings has been facilitated by the mechanization
of construction processes and the easy transport of materials.
Topsoil: The world's existing soils were generated over thousands and millions
of years at a rate averaging an inch per 500 years. The amount of soil available
to farmers is now decreasing at an alarming rate, due mostly to wind and water
erosion. In the US Great Plains, roughly half the quantity in place at the beginning
of the last century is now gone. In Australia, after two centuries of European
land-use, more than 70 percent of land has become seriously degraded.2 Erosion
is largely a function of tillage, which fractures and loosens soil; thus, as
the introduction of fuel-fed tractors has increased the ease of tillage, the
rate of soil loss has increased dramatically.
The number of farmers as a percentage of the population: In the US at the turn
of the last century, 70 percent of the population lived in rural areas and farmed.
Today less than two percent of Americans farm for a living. This change came
primarily because fuel-fed farm machinery replaced labor, which meant that fewer
farmers were needed. Hundreds of thousands - perhaps millions - of families
that desperately wanted to farm could not continue to do so because they could
not afford the new machines, or could not compete with their neighbors who had
them. Another way of saying this is that economies of scale (driven by mechanization)
gave an advantage to ever-larger farms. But the loss of farmers also meant a
gradual loss of knowledge of how to farm and a loss of rural farming culture.
Many farmers today merely follow the directions on bags of fertilizer or pesticide,
and live so far from their neighbors that their children have no desire to continue
the agricultural way of life.
The genetic diversity of domesticated crop varieties: This is decreasing dramatically
due to the consolidation of the seed industry. Farmers on the island of Bali
in Indonesia once planted 200 varieties of rice, each adapted to a different
microclimate; now only four varieties are grown. In 2000, Semenis, the world's
largest vegetable seed corporation, eliminated 25 percent of its product line
as a cost-cutting measure. This ongoing, massive genetic consolidation is also
being driven by the centralization of the seed industry (the largest three field
seed companies - DuPont, Monsanto, and Novartis - now account for 20 percent
of the global seed trade), which is in turn consequent upon fuel-fed globalization.
Grain production per capita: A total of 2,029 million tons of grain were produced
globally in 2004; this was a record in absolute numbers. But for the past two
decades population has grown faster than grain production, so there is actually
less available on a per-head basis. In addition, grain stocks are being drawn
down: According to Lester Brown of the Earth Policy Institute, "in each
of the last four . . . years production fell short of consumption. The shortfalls
of nearly 100 million tons in 2002 and again in 2003 were the largest on record."3
This trend suggests that the strategy of boosting food production by the use
of fossil fuels is already yielding diminishing returns.
Global climate: This is being increasingly destabilized as a result of the
famous greenhouse effect, resulting in problems for farmers that are relatively
minor now but that are likely to grow to catastrophic proportions within the
next decade or two. Global warming is now almost universally acknowledged as
resulting from CO2 emissions from the burning of fossil fuels.
Available fresh water: In the US, 85 percent of fresh water use goes toward
agricultural production, requiring the drawing down of ancient aquifers at far
above their recharge rates. Globally, as water tables fall, ever more powerful
pumps must be used to lift irrigation water, requiring ever more energy usage.
By 2020, according to the Worldwatch Institute and the UN, virtually every country
will face shortages of fresh water.
The effectiveness of pesticides and herbicides: In the US, over the past two
decades pesticide use has increased 33-fold, yet, each year a greater amount
of crops is lost to pests, which are evolving immunities faster than chemists
can invent new poisons. Like falling grain production per capita, this trend
suggests a declining return from injecting the process of agricultural production
with still more fossil fuels.
Now, let us add to this picture the imminent peak in world oil production.
This will make machinery more expensive to operate, fertilizers more expensive
to produce, and transportation more expensive. While the adoption of fossil
fuels created a range of problems for global food production, as we have just
seen, the decline in the availability of cheap oil will not immediately solve
those problems; in fact, over the short term they will exacerbate them, bringing
simmering crises to a boil.
That is because the scale of our dependency on fossil fuels has grown to enormous
In the US, agriculture is directly responsible for well over 10 percent of
all national energy consumption. Over 400 gallons of oil equivalent are expended
to feed each American each year. About a third of that amount goes toward fertilizer
production, 20 percent to operate machinery, 16 percent for transportation,
13 percent for irrigation, 8 percent for livestock raising, (not including the
feed), and 5 percent for pesticide production. This does not include energy
costs for packaging, refrigeration, transportation to retailers, or cooking.
Trucks move most of the world's food, even though trucking is ten times more
energy-intensive than moving food by train or barge. Refrigerated jets move
a small but growing proportion of food, almost entirely to wealthy industrial
nations, at 60 times the energy cost of sea transport.
Processed foods make up three-quarters of global food sales by price (though
not by quantity). This adds dramatically to energy costs: for example, a one-pound
box of breakfast cereal may require over 7,000 kilocalories of energy for processing,
while the cereal itself provides only 1,100 kilocalories of food energy.
Over all - including energy costs for farm machinery, transportation, and processing,
and oil and natural gas used as feedstocks for agricultural chemicals - the
modern food system consumes roughly ten calories of fossil fuel energy for every
calorie of food energy produced.4
But the single most telling gauge of our dependency is the size of the global
population. Without fossil fuels, the stupendous growth in human numbers that
has occurred over the past century would have been impossible. Can we continue
to support so many people as the availability of cheap oil declines?
Feeding a Growing Multitude
The problems associated with the modern global food system are widely apparent,
there is widespread concern over the sustainability of the enterprise, and there
is growing debate over the question of how to avoid an agricultural Armageddon.
Within this debate two viewpoints have clearly emerged.
The first advises further intensification of industrial food production, primarily
via the genetic engineering of new crop and animal varieties. The second advocates
ecological agriculture in its various forms - including organic, biodynamic,
Permaculture, and Biointensive methods.
Critics of the latter contend that traditional, chemical-free forms of agriculture
are incapable of feeding the burgeoning human population. Here is a passage
by John John Emsley of University of Cambridge, from his review of Vaclav Smil's
Enriching the Earth : Fritz Haber, Carl Bosch, and the Transformation of World
If crops are rotated and the soil is fertilized with compost, animal manure
and sewage, thereby returning as much fixed nitrogen as possible to the soil,
it is just possible for a hectare of land to feed 10 people - provided they
accept a mainly vegetarian diet. Although such farming is almost sustainable,
it falls short of the productivity of land that is fertilized with "artificial"
nitrogen; this can easily support 40 people, and on a varied diet.5
This seems unarguable on its face. However, given the fact that fossil fuels
are non-renewable, it will be increasingly difficult to continue to supply chemical
fertilizers in present quantities. Nitrogen can be synthesized using hydrogen
produced from the electrolysis of water, with solar or wind power as a source
of electricity. But currently no ammonia is being commercially produced this
way because of the uncompetitive cost of doing so. To introduce and scale up
the process will require many years and considerable investment capital.
The bioengineering of crop and animal varieties does little or nothing to solve
this problem. One can fantasize about modifying maize or rice to fix nitrogen
in the way that legumes do, but so far efforts in that direction have failed.
Meanwhile, the genetic engineering of complex life forms on a commercial scale
appears to pose unprecedented environmental hazards, as has been amply documented
by Dr. Mae Wan-Ho among many others.6 And the bio-engineering industry itself
consumes fossil fuels, and assumes the continued availability of oil for tractors,
transportation, chemicals production, and so on.
Those arguing in favor of small-scale, ecological agriculture tend to be optimistic
about its ability to support large populations. For example, the 2002 Greenpeace
report, "The Real Green Revolution: Organic and Agroecological Farming
in the South," while acknowledging the lack of comparative research on
the subject, nevertheless notes:
In general . . . it is thought that [organic and agroecological farming] can
bring significant increases in yields in comparison to conventional farming
practices. Compared to "Green Revolution'"farming systems, OAA is
thought to be neutral in terms of yields, although it brings other benefits,
such as reducing the need for external inputs.7
Eco-agricultural advocates often contend that there is plenty of food in the
world; existing instances of hunger are due to bad policy and poor distribution.
With better policy and distribution, all could easily be fed. Thus, given the
universally admitted harmful environmental consequences of conventional chemical
farming, the choice should be simple.
Some eco-ag proponents are even more sanguine, and suggest that their methods
can produce far higher yields than can mechanized, chemical-based agriculture.
Experiments have indeed shown that small-scale, biodiverse gardening or farming
can be considerably more productive on a per-hectare basis than monocropped
megafarms.8 However, some of these studies have ignored the energy and land-productivity
costs of manures and composts imported onto the study plots. In any case, and
there is no controversy on this point, Permaculture and Biointensive forms of
horticulture are dramatically more labor- and knowledge-intensive than industrial
agriculture. Thus the adoption of these methods will require an economic transformation
Therefore even if the nitrogen problem can be solved in principle by agro-ecological
methods and/or hydrogen production from renewable energy sources, there may
be a carrying-capacity bottleneck ahead in any case, simply because of the inability
of societies to adapt to these very different energy and economic needs quickly
enough, and also because of the burgeoning problems mentioned above (loss of
fresh water resources, unstable climate, etc.). According to widely-accepted
calculations, humans are presently appropriating at least 40 percent of Earth's
primary biological productivity.9 It seems unlikely that we, a single species
after all, can do much more than that. Even though it may not be politically
correct in many circles to discuss the population problem, we must recognize
that we are nearing or past fundamental natural limits, no matter which course
Given the fact that fossil fuels are limited in quantity and we are already
in view of the global oil production peak, the debate over the potential productivity
of chemical-gene engineered agriculture versus that of organic and agroecological
farming may be relatively pointless. We must turn to a food system that is less
fuel-reliant, even if it does prove to be less productive.
The Example of Cuba
How we might do that is suggested by perhaps the best recent historical example
of a society experiencing a fossil-fuel famine. In the late 1980s, farmers in
Cuba were highly reliant on cheap fuels and petrochemicals imported from the
Soviet Union, using more agrochemicals per acre than their American counterparts.
In 1990, as the Soviet empire collapsed, Cuba lost those imports and faced an
agricultural crisis. The population lost 20 pounds on average and malnutrition
was nearly universal, especially among young children. The Cuban GDP fell by
85 percent and inhabitants of the island nation experienced a substantial decline
in their material standard of living.
Cuban authorities responded by breaking up large state-owned farms, offering
land to farming families, and encouraging the formation of small agricultural
co-ops. Cuban farmers began employing oxen as a replacement for the tractors
they could no longer afford to fuel. Cuban scientists began investigating biological
methods of pest control and soil fertility enhancement. The government sponsored
widespread education in organic food production, and the Cuban people adopted
a mostly vegetarian diet out of necessity. Salaries for agricultural workers
were raised, in many cases to above the levels of urban office workers. Urban
gardens were encouraged in parking lots and on public lands, and thousands of
rooftop gardens appeared. Small food animals such as chickens and rabbits began
to be raised on rooftops as well.
As a result of these efforts, Cuba was able to avoid what might otherwise have
been a severe famine. Today the nation is changing from an industrial to an
agrarian society. While energy use in Cuba is now one-twentieth of that in the
US, the economy is growing at a slow but steady rate. Food production has returned
to 90 percent of its pre-crisis levels.10
The Way Ahead
The transition to a non-fossil-fuel food system will take time. And it must
be emphasized that we are discussing a systemic transformation - we cannot just
remove oil in the forms of agrochemicals from the current food system and assume
that it will go on more or less as it is. Every aspect of the process by which
we feed ourselves must be redesigned. And, given the likelihood that global
oil peak will occur soon, this transition must occur at a rapid pace, backed
by the full resources of national governments.
Without cheap transportation fuels we will have to reduce the amount of food
transportation that occurs, and make necessary transportation more efficient.
This implies increased local food self-sufficiency. It also implies problems
for large cities that have been built in arid regions capable of supporting
only small populations on their regional resource base. One has only to contemplate
the local productivity of a place like Nevada, to appreciate the enormous challenge
of continuing to feed people in such a city such as Las Vegas without easy transportation.
We will need to grow more food in and around cities. Currently, Oakland California
is debating a food policy initiative that would mandate by 2015 the growing
within a fifty-mile radius of city center of 40 percent of the vegetables consumed
in the city.11 If the example of Cuba were followed, rooftop gardens would result,
as well as rooftop raising of food animals like chickens, rabbits and guinea
Localization of the food process means moving producers and consumers of food
closer together, but it also means relying on the local manufacture and regeneration
of all of the elements of the production process - from seeds to tools and machinery.
This would appear to rule out agricultural bioengineering, which favors the
centralized production of patented seed varieties, and discourages the free
saving of seeds from year to year by farmers.
Clearly, we must minimize chemical inputs to agriculture (direct and indirect
- such as those introduced in packaging and processing).
We will need to re-introduce draft animals in agricultural production. Oxen
may be preferable to horses in many instances, because the former can eat straw
and stubble, while the latter would compete with humans for grains.
Governments must also provide incentives for people to return to an agricultural
life. It would be a mistake simply to think of this simply in terms of the need
for a larger agricultural work force. Successful traditional agriculture requires
social networks, and intergenerational sharing of skills and knowledge. We need
not just more agricultural workers, but a rural culture that makes agricultural
Farming requires knowledge and experience, and so we will need education for
a new generation of farmers; but only some of this education can be generic
- much of it must of necessity be locally appropriate.
It will be necessary as well to break up the corporate mega-farms that produce
so much of today's cheap grain. Industrial agriculture implies an economy of
scale that will be utterly inappropriate and unworkable for post-industrial
food systems. Thus land reform will be required in order to enable smallholders
and farming co-ops to work their own plots.
In order for all of this to happen, governments must end subsidies to industrial
agriculture and begin subsidizing post-industrial agricultural efforts. There
are many ways in which this could be done. The present regime of subsidies is
so harmful that merely stopping it in its tracks might in itself be advantageous;
but, given the fact that a rapid transition is essential, offering subsidies
for education, no-interest loans for land purchase, and technical support during
the transition from chemical to organic production would be essential.
Finally, given carrying-capacity limits, food policy must include population
policy. We must encourage smaller families by means of economic incentives and
improve the economic and educational status of women in poorer countries.
All of this constitutes a gargantuan task, but the alternatives - doing nothing
or attempting to solve our food-production problems simply by applying more
technological intensification - will almost certainly result in dire consequences.
In that case, existing farmers would fail because of fuel and chemical prices.
All of the worrisome existing trends mentioned earlier would intensify to the
point that the human carrying capacity of Earth would be degraded significantly,
and perhaps to a large degree permanently.
In sum, the transition to a fossil-fuel-free food system does not constitute
a utopian proposal. It is an immense challenge and will call for unprecedented
levels of creativity at all levels of society. But in the end it is the only
rational option for averting human calamity on a scale never before seen.