Global Population Growth, Technology, and Malthusian Constraints: A Quantitative Growth Theoretic Perspective

Abstract

The MIT Joint Program on the Science and Policy of Global Change combines cutting-edge scientific research with independent policy analysis to provide a solid foundation for the public and private decisions needed to mitigate and adapt to unavoidable global environmental changes. Being data-driven, the Program uses extensive Earth system and economic data and models to produce quantitative analysis and predictions of the risks of climate change and the challenges of limiting human influence on the environment-essential knowledge for the international dialogue toward a global response to climate change.To this end, the Program brings together an interdisciplinary group from two established MIT research centers: the Center for Global Change Science (CGCS) and the Center for Energy and Environmental Policy Research (CEEPR). These two centers-along with collaborators from the Marine Biology Laboratory (MBL) at Woods Hole and short-and longterm visitors-provide the united vision needed to solve global challenges.At the heart of much of the Program's work lies MIT's Integrated Global System Model. Through this integrated model, the Program seeks to: discover new interactions among natural and human climate system components; objectively assess uncertainty in economic and climate projections; critically and quantitatively analyze environmental management and policy proposals; understand complex connections among the many forces that will shape our future; and improve methods to model, monitor and verify greenhouse gas emissions and climatic impacts.This reprint is one of a series intended to communicate research results and improve public understanding of global environment and energy challenges, thereby contributing to informed debate about climate change and the economic and social implications of policy alternatives. AbstractWe structurally estimate a two-sector Schumpeterian growth model with endogenous population and finite land reserves to study the long run evolution of global population, technological progress and the demand for food. The estimated model closely replicates trajectories for world population, GDP, sectoral productivity growth and crop land area from 1960 to 2010. Projections from 2010 onwards show a slowdown of technological progress, and because it is a key determinant of fertility costs, significant population growth. By 2100 global population reaches 12 billion and agricultural production doubles, but the land constraint does not bind because of capital investment and technological progress.

Long-term economic modeling for climate change assessment

“…For example, Webster et al (2008a) show that because of collinearity in GDP growth and time, a model that includes either a strong autonomous trend in energy efficiency improvement (due implicitly to ongoing technical change) or one that formulates an income elasticity of demand for energy can explain equally well the historical data for 1975 to 2000 for the US, yet these different approaches can lead to very different projections of energy use and GHG emissions for different future growth rates of GDP. In a similar vein, Lanz et al (2014) can predict well historical land use change and population with quite different parameter values that generate similar business-as-usual forecasts but behave differently in response to an exogenous forcing.…”

Twenty Key Challenges in Environmental and Resource Economics

“…It remains a challenge to integrate agricultural and environmental research better, for example by bringing together food production, population, and the environment into a macrodynamic framework (Lanz et al. 2017 ). Environmental migration Migration in times of climate change is an extraordinarily complex, multicausal and controversial challenge (Adger et al.…”

“…It remains a challenge to integrate agricultural and environmental research better, for example by bringing together food production, population, and the environment into a macrodynamic framework (Lanz et al. 2017 ).…”

“…While in classical economics of the eighteenth century the factor land played a dominant role, the effects of pollution externalities, resource scarcities, ecosystem services, and sustainability became important in subsequent time periods. These issues have triggered different waves of research with very prominent results, specifically on optimal policies in the presence of externalities (Pigou 1920 ), optimal extraction of non-renewable resources (Hotelling 1931 ), optimal capital accumulation in the presence of resource scarcities (Dasgupta and Heal 1974 ), and sustainable development (Hartwick 1977 ; Pearce et al. 1994 ).…”

Global Economic Growth and Agricultural Land Conversion under Uncertain Productivity Improvements in Agriculture

“…Inspired by these risks, some long-standing and some only now emerging, in this paper we study the socially optimal global response to the risk of negative shocks to global agricultural productivity. To do so we employ a stochastic version of a quantitative, two-sector endogenous growth model of the global economy introduced in Lanz et al (2017). This provides an integrated framework to study the joint evolution of global population, sectoral technological progress, per-capita income, the demand for food, and agricultural land expansion (from a finite reserve of unconverted land).…”