This book focuses on the future of the global population and proposes revising Malthus' Law.
The United Nations estimates that the global population will top 11 billion by 2100 at which
point its growth will be near an end: it will find a new equilibrium in a long demographic
transition from high birth and death rates to low ones. However the author reviews the
fertility developments reported in the World Population Prospects 2017 which are near or below
the replacement level in most regions with the important exception of Sub-Saharan Africa and
warns of a possible scenario of the extinction of human society. Returning to Malthus his
Essay on the Principle of Population is critically reconsidered. Simple simulations show that
exponential growth and decay are unsustainable beyond the narrow ranges of the net reproduction
rate. In addition the length of reproduction periods which depends on women's lifespans
plays a pivotal role. The limits of growth are given in any case to the extent that time and
space will permit. From this perspective teleological conditions such as instinct passion or
even natural reproductive tendencies are irrelevant and unnecessary. When the population
deviates too far from the replacement level either its shrinking or massive growth will
overshoot the limits of its existence. This principle of sustainable population indicates that
the demographic transition must follow a logistic curve. Using a system dynamics approach the
author constructs a simulation model based on four major loops: fertility reproduction timing
social capital accumulation and lifespan. Using only endogenous variables this model
successfully reproduces the historical process of the demographic transition in Japan. Thereby
it shows that the timing and periods of reproduction maximum fertility and maximum lifespan
hold the key to sustainability. Based on these findings the author subsequently discusses
recovering replacement fertility extending lifespans and the demographic future of the human
race.
