June 2001 version
Paper to be presented at IUSSP Conference in Brazil/session-s09 Population Growth and Global Carbon Dioxide Emissions
Development Research Group
The World Bank
Keywords: Population, global warming, Carbon Dioxide Emissions, projections Abstract: Previous studies on the determinants of carbon dioxide emissions have primarily focused on the role of affluence. The impact of population growth on carbon dioxide emissions has received less attention. This paper takes a step forward providing such empirical evidence, using a data set of 93 countries for the period of 1975-1996. The paper has following findings. (1) Population growth has been one of the major driving forces behind increasing carbon dioxide emissions worldwide over the last two decades. It is estimated that half of increase in emissions by 2025 will be contributed by future population growth alone. (2) Rising income levels have been associated with a monotonically upward shift in emissions. __________________________
The findings, interpretations, and conclusions are entirely those of the author. They do not necessarily represent the views of the World Bank, its Executive Directors, or the countries they represent. I thank Bob Cull, Phillip Keefer, Steve Knack, Brian O’Neill, and William Martin for very helpful comments. Author’s email address: email@example.com.
The last two decades have witnessed an unprecedented global warming. This has brought about great concerns over its causes and consequences. Scientists claimed that the increasing carbon dioxide emissions (CO2) produced a massive build-up of greenhouse gas, which gave rise to recent warm temperatures (IPCC 1995; Watson et al. 1996). International negotiations have been underway to try to reach consensus in curbing the rapid growth of carbon dioxide emissions worldwide. A historic agreement was reached in Kyoto in 1997, which required its 38 developed countries of Annex 1 signatories to reduce their annual carbon emissions to an average of 5.2 percent below 1990 levels for the years 2008-12 (United Nations 1997).
In discussing the determinants of global CO2 emissions, the conventional view holds that the rapid growth of CO2 emissions is primarily due to increasing energy consumption as affluence grows. The impact of population growth on global CO2 emissions has not received enough attention. Recent studies suggest that population growth has been one of the major factors in causing carbon emissions in both developed and developing countries (Bongarrts 1992; Dietz and Rosa 1994; Engelman 1994, 1998; O’Neill et al 2001; Smil 1990). However, there has not been ample empirical evidence to support this claim.
This paper’s aim is to examine the impact of population growth on carbon dioxide emissions by using a panel data of 93 countries during 1975-1995 period. Specifically, I quantify the impacts of changes in population, income level, and energy efficiency of economic production on emissions in one single model. The data suggest the following conclusions. (1) One percent of population growth is associated with a 1.28 percentage ________________________________________
increase in emissions on average. (2) The impact of population pressure on emissions has been more pronounced in developing countries than developed countries. (3) It is estimated that global emissions will reach as high as 13.72 gigatons in 2025 under the business-as-usual assumptions (this implies that the annual population growth rate will be under the UN medium growth scenario, and the annual real GDP per capita growth rate will be 1.9%). This magnitude more than doubles the emissions level of 1990, and half of the gains will be attributed to the future...