71
3.3.2 Population and the Legacy of Malthus
Modern awareness of food security rose to prominence with the 1798 book “An
Essay on the Principle of Population” by Thomas Malthus (1766–1834). Malthus
asserted that when resources such as food were available, the human population
grew geometrically; that is, the population grew at some fixed rate, resulting in an
ever-larger absolute increase in population number each year. However, Malthus
also asserted that food production would only increase arithmetically, that is by
some constant amount each year.
Malthus concluded that “[t]he power of population is indefinitely greater than the
power in the earth to produce subsistence for man” and that “positive checks” to
population growth such as famine and starvation would operate as an inevitable
check on human population growth unless “negative checks” to population growth
such as practices to limit childbirth occurred.
While Malthus’ conclusions have been influential for over two centuries, they were
immediately controversial and contested, and have remained so. It is now clear that
population need not grow geometrically, or even at all, as demonstrated by such countries as Italy, Japan, and Russia, where populations are declining. Of course, some of the
reasons for low birth rates, such as modern contraception, were unknown to Malthus.
Further, food production has, during many periods of time, increased at rates far
more rapid than the linear arithmetic growth postulated by Malthus. In particular,
the widespread use of new crop varieties, irrigation, fertilizers, and other practices
in the second half of the twentieth century, known as the Green Revolution, has
resulted in waves of dramatic increases in food production.
While many of the assumptions upon which Malthus based his reasoning have
proven to be inaccurate, the core challenge of providing sufficient food and other
resources to a growing human population remains. Those who emphasize efforts to
limit population growth are grouped under the label “neo-Malthusian” while those
who emphasize the ability of humanity to find innovative solutions, especially market and technological solutions, are grouped under the label “cornucopian.” Human
development requires, among other things, that we avoid a “Malthusian trap” that is,
a situation where food, energy or water cannot be provided in sufficient quantities
to feed a large human population made possible by prior success in expanding their
production, whether that be 10, 15, 20, or more billion people.
In 1972, the Club of Rome published a landmark model of the earth’s resource
consumption dynamics in its report, “The Limits to Growth.” This model describes
the Earth as an ecosystem with fixed sustainable resource carrying capacities, geometrically growing populations, and resource demands, and resource “stockpiles,”
or buffers, that can be consumed when resource demands exceed carrying capacities. This model predicts overshoot, which is where large consumable buffers enable
the growth of population and consumption far past the sustainable carrying capacity, followed by a collapse of population and consumption when the resource buffers are degraded. The Earth’s human population and is ecological resources roughly
fit this model. In 2004, an update to the “The Limits to Growth,” concluded that the
1972 model’s predictions remained sound.
3 Development
3.3.2 Population and the Legacy of Malthus
Modern awareness of food security rose to prominence with the 1798 book “An
Essay on the Principle of Population” by Thomas Malthus (1766–1834). Malthus
asserted that when resources such as food were available, the human population
grew geometrically; that is, the population grew at some fixed rate, resulting in an
ever-larger absolute increase in population number each year. However, Malthus
also asserted that food production would only increase arithmetically, that is by
some constant amount each year.
Malthus concluded that “[t]he power of population is indefinitely greater than the
power in the earth to produce subsistence for man” and that “positive checks” to
population growth such as famine and starvation would operate as an inevitable
check on human population growth unless “negative checks” to population growth
such as practices to limit childbirth occurred.
While Malthus’ conclusions have been influential for over two centuries, they were
immediately controversial and contested, and have remained so. It is now clear that
population need not grow geometrically, or even at all, as demonstrated by such countries as Italy, Japan, and Russia, where populations are declining. Of course, some of the
reasons for low birth rates, such as modern contraception, were unknown to Malthus.
Further, food production has, during many periods of time, increased at rates far
more rapid than the linear arithmetic growth postulated by Malthus. In particular,
the widespread use of new crop varieties, irrigation, fertilizers, and other practices
in the second half of the twentieth century, known as the Green Revolution, has
resulted in waves of dramatic increases in food production.
While many of the assumptions upon which Malthus based his reasoning have
proven to be inaccurate, the core challenge of providing sufficient food and other
resources to a growing human population remains. Those who emphasize efforts to
limit population growth are grouped under the label “neo-Malthusian” while those
who emphasize the ability of humanity to find innovative solutions, especially market and technological solutions, are grouped under the label “cornucopian.” Human
development requires, among other things, that we avoid a “Malthusian trap” that is,
a situation where food, energy or water cannot be provided in sufficient quantities
to feed a large human population made possible by prior success in expanding their
production, whether that be 10, 15, 20, or more billion people.
In 1972, the Club of Rome published a landmark model of the earth’s resource
consumption dynamics in its report, “The Limits to Growth.” This model describes
the Earth as an ecosystem with fixed sustainable resource carrying capacities, geometrically growing populations, and resource demands, and resource “stockpiles,”
or buffers, that can be consumed when resource demands exceed carrying capacities. This model predicts overshoot, which is where large consumable buffers enable
the growth of population and consumption far past the sustainable carrying capacity, followed by a collapse of population and consumption when the resource buffers are degraded. The Earth’s human population and is ecological resources roughly
fit this model. In 2004, an update to the “The Limits to Growth,” concluded that the
1972 model’s predictions remained sound.
3 Development