Population as a Source of Long−Term Growth: From Malthus to Japan’s Postmodern Regime

This paper introduces a simple macroeconomic time series model incorporating a key concept of GDP elasticity with respect to population (population elasticity). Using this model, we conducted empirical analyses of 158 countries each covering 25 to 180 years of history. As a result, we found first that the estimated population elasticity demarcated the countries according to regime, showing clearly whether a country was in the ‘Malthusian regime’, in the ‘modern growth regime’ or in the ‘postmodern regime’. We found that the poorest countries as well as some oil-rich countries were in the Malthusian regime. The modern growth regime prevailed in most European, Asian and American countries in the 20th century. We then predicted long-term real GDP for each country while they stayed in modern growth regimes. Third, we observed that both Germany and Japan went into a postmodern regime after a demographic transformation. Focusing on Japan, we argued that if the nation remained in the modern growth regime, it would face a precipitous decline in GDP. We suggested that Japan must reduce dependence on population as a source of growth in the postmodern era. This lesson might be important for the two thirds of countries in the world that are expected to enter a postmodern regime around the middle of this century.