A Dynamic Analysis of Human Welfare in a Warming Planet
John E. Roemer
Anthropogenic greenhouse gas (GHG) emissions have caused atmospheric concentrations with no precedents in the last half a million years, inducing serious uncertainties about future climates and their effects on human welfare. Recent climate science supports the view that the climate stabilization will require very low GHG emissions in the future. We ask: Is a path of low emissions compatible with sustainable levels of human welfare? With steady growth in human quality of life? Addressing these questions requires both defining welfare criteria and empirically estimating the possible paths of the economy. We specify and calibrate a dynamic model with four intertemporal links: education, physical capital, knowledge and the environment. In line with Nordhaus (2008a) and with the Stern Review (2007), we assume that GHG emissions allow increased production, while a higher stock of atmospheric carbon decreases production. Our index of human welfare, which we call quality of life (QuoL), emphasizes education, knowledge, and the environment, affected by greenhouse gas emissions, in addition to consumption and leisure. Thus, we avoid a Consumptionist Fallacy – that welfare depends only on commodity consumption and perhaps leisure. We reject discounted utilitarianism as a normative criterion, and consider two alternatives. The first is an intergenerational maximin criterion, which maximizes the quality of life of the first generation subject to maintaining at least that level for all successive generations. The second is human development optimization, that seeks the maximization of the QuoL of the first generation subject to achieving a given, constant rate of growth in all subsequent generations. Hence, our analysis focuses on a human notion of sustainability, as opposed to the conventional “green” sustainability, limited to keeping the quality of the environment constant. Because our dynamic optimization programs defy explicit analytical solutions, our approach has been computational. As a benchmark, we consider a simple model with physical and human capital, for which we prove a turnpike theorem. We then devise a computational algorithm inspired by the turnpike property to construct feasible, although not necessarily optimal, paths in the more complex and realistic model. Our analysis indicates that, with GHG emission paths entailing very low emissions in the future, positive rates of growth in QuoL are possible while the first generation experiences a QuoL higher than the historical reference level. We also observe a tradeoff between the quality of life of the first generation and the rate of growth in the quality of life. Yet Generation 1’s sacrifice for the sake of a higher growth rate appears to be small. The paths that we compute involve investments in knowledge at noticeably higher levels than in the past.
Climate science indicates that climate stabilization requires low GHG emissions. Is this consistent with nondecreasing human welfare? Our welfare index, called quality of life (QuoL), emphasizes education, knowledge, and the environment. We construct and calibrate a multigenerational model with intertemporal links provided by education, physical capital, knowledge and the environment. We reject discounted utilitarianism and adopt, first, the Intergenerational Maximin criterion, and, second, Human Development Optimization, that maximizes the QuoL of the first generation subject to a given future rate of growth. We apply these criteria to our calibrated model via a novel algorithm inspired by the turnpike property. The computed paths yield levels of QuoL higher than the year 2000 level for all generations. They require the doubling of the fraction of labor resources devoted to the creation of knowledge relative to the reference level, whereas the fractions of labor allocated to consumption and leisure are similar to the reference ones. On the other hand, higher growth rates require substantial increases in the fraction of labor devoted to education, together with moderate increases in the fractions of labor devoted to knowledge and the investment in physical capital.
Quality of life, Climate change, Education, Maximin, Growth
In order to set up a list of libraries that you have access to,
you must first login
or sign up.
Then set up a personal list of libraries from your profile page by
clicking on your user name at the top right of any screen.