Adapted from Colin Butler, “Human Carrying Capacity and Human Health.” © 2004 by Colin Butler. The passage refers to carrying capacity, or the maximum population size of a species that an environment can support.
The question of human overpopulation and its relationship
to human carrying capacity has been controversial for over two
centuries. In 1798 the Reverend Thomas Malthus put forward
the hypothesis that population growth would exceed the growth
of resources, leading to the periodic reduction of human
numbers by either “positive checks”, such as disease, famine,
and war, or “preventive checks”, by which (in the absence of
contraception) Malthus meant restrictions on marriage. This
“Malthusian view” was rapidly accepted by most politicians,
demographers, and the general public, and remained popular
until fairly recently.
Malthus’s worst fears were not borne out through the
century following his death in 1834—food production largely
kept pace with the slowly growing global population. However,
soon after 1934, the global population began to rise steeply as
antibiotics, vaccines, and technology increased life expectancy.
By the 1960s, concerns of a mismatch between global
population and global food supply peaked—expressed in books
such as Paul Ehrlich’s 1968 The Population Bomb. This book
predicted a future scarred by increasing famine, epidemic, and
war—the three main Malthusian positive checks.
In 1966, United States President Lyndon Johnson shipped
wheat to India to avert a famine on the condition that the
country accelerate its already vigorous family planning
campaign. Johnson was part of an unbroken series of US
presidents concerned with the harmful effects of rapid
population growth in developing countries. This line extended
(at least) from John F. Kennedy to Jimmy Carter. George H.
W. Bush was also sympathetic to this view, prior to becoming
vice president in 1981.
But the 1970s surprised population watchers. Instead of
being a period shadowed by calamitous famine, the new crop
strains introduced by the “Green Revolution” (especially grains
such as rice, wheat, and maize) caused a dramatic increase in
the global production of cereals, the main source of energy in
the global diet. Among the development community, despair
turned into cautious optimism. By the end of the decade, the
public health community felt sufficiently empowered to
proclaim “Health for All by the Year 2000”. Average life
expectancy continued to zoom upwards almost everywhere.
The introduction of safe contraception contributed to a rapid
fertility decline in many countries. But while the rate of global
population growth declined from its peak in the late 1960s, the
absolute increment of increase in annual global population
continued to grow. Most population-related scientists,
including food scientists and demographers, as well as US
President Jimmy Carter, continued to be very concerned about
global overpopulation. In 1970, the father of the Green
Revolution, the agricultural scientist Norman Borlaug, was
awarded the Nobel Peace Prize. In his Nobel lecture, Borlaug
warned that the success of the Green Revolution would buy a
breathing space for humankind of three decades, unless
equivalent action was taken to reduce fertility rates.
The question of human overpopulation and its relationship
to human carrying capacity has been controversial for over two
centuries. In 1798 the Reverend Thomas Malthus put forward
the hypothesis that population growth would exceed the growth
of resources, leading to the periodic reduction of human
numbers by either “positive checks”, such as disease, famine,
and war, or “preventive checks”, by which (in the absence of
contraception) Malthus meant restrictions on marriage. This
“Malthusian view” was rapidly accepted by most politicians,
demographers, and the general public, and remained popular
until fairly recently.
Malthus’s worst fears were not borne out through the
century following his death in 1834—food production largely
kept pace with the slowly growing global population. However,
soon after 1934, the global population began to rise steeply as
antibiotics, vaccines, and technology increased life expectancy.
By the 1960s, concerns of a mismatch between global
population and global food supply peaked—expressed in books
such as Paul Ehrlich’s 1968 The Population Bomb. This book
predicted a future scarred by increasing famine, epidemic, and
war—the three main Malthusian positive checks.
In 1966, United States President Lyndon Johnson shipped
wheat to India to avert a famine on the condition that the
country accelerate its already vigorous family planning
campaign. Johnson was part of an unbroken series of US
presidents concerned with the harmful effects of rapid
population growth in developing countries. This line extended
(at least) from John F. Kennedy to Jimmy Carter. George H.
W. Bush was also sympathetic to this view, prior to becoming
vice president in 1981.
But the 1970s surprised population watchers. Instead of
being a period shadowed by calamitous famine, the new crop
strains introduced by the “Green Revolution” (especially grains
such as rice, wheat, and maize) caused a dramatic increase in
the global production of cereals, the main source of energy in
the global diet. Among the development community, despair
turned into cautious optimism. By the end of the decade, the
public health community felt sufficiently empowered to
proclaim “Health for All by the Year 2000”. Average life
expectancy continued to zoom upwards almost everywhere.
The introduction of safe contraception contributed to a rapid
fertility decline in many countries. But while the rate of global
population growth declined from its peak in the late 1960s, the
absolute increment of increase in annual global population
continued to grow. Most population-related scientists,
including food scientists and demographers, as well as US
President Jimmy Carter, continued to be very concerned about
global overpopulation. In 1970, the father of the Green
Revolution, the agricultural scientist Norman Borlaug, was
awarded the Nobel Peace Prize. In his Nobel lecture, Borlaug
warned that the success of the Green Revolution would buy a
breathing space for humankind of three decades, unless
equivalent action was taken to reduce fertility rates.