Rate Equations approach to simulate World population trends

According to UN statistical data and projections world population will begin to decrease by the middle of this century. This paper uses rate equations (fully analogous to those employed in condensed matter physics) to simulate the time evolution of world population, making use of UN population data in the time interval 1900-2010, and to extrapolate the evolution of world population into the near future. This approach has not been used in economics and population dynamics. The simulation predicts a population decline by mid-century. The economic consequences of population decline would be far reaching.