ESSAYS ON ECONOMIC GROWTH: TECHNICAL PROGRESS, POPULATION DYNAMICS AND THE ENVIRONMENT

This thesis analyzes economic growth and how this is related to diff erent issues, namely technical progress, population change and environment. It studies each of these issues in a separate paper. The choice of these issues has been driven by their growing importance in the analysis of the development process of modern economies. Technological progress, jointly with the accumulation of human capital, is one of the most relevant causes of the consistent growth showed in the last century by industrialized countries; therefore, it is important to understand what are its features in order to promote further technical improvements. Demographic growth has dramatically changed during and after the transition from stagnation (before the industrial revolution) to growth (after that): fertility and mortality rates have dropped and many economies now show a rate of population growth just over the replacement one; studying the implications of population change for economic growth can be really important in order to understand whether population policies can be necessary or not for the economy. The environment is an important source of welfare services to people and just in the last decades such a fact has been widely recognized: this is due to the fact that as the economy reaches a certain level of development, its agents feel the importance of some aspects which in a previous phase they did not care about; human activity is the main source of environment degradation and an increasing need for the policy makers to understand how regulating it has arisen. As it may be clear, these topics are crucially interrelated: population growth a ffects technical progress (through the number of researchers employed in R&D activity) and the environment (through the necessity of satisfying the needs of a larger population, in terms of consumption demand and waste production), while technical progress a ffects the environment (switching from polluting to clean technologies such an e ffect can crucially change).