4. The cumulative CO2 emissions simply sum up annual emissions to the period indicated.
5. "Family planning" effects are calculated as the difference in population between a given group and the next lower group, multiplied by the income multiples of the group. Thus they represent the amount of increased emissions if the population were as large as it would be with the next lower group's population. For the lowest-income economies, the family planning effect is presumed to be the difference between the actual 2.8 percent growth rate over the 1965 to 1987 period and the 2.6 percent projected for 1987 to 2000.
These calculations are based on actual evidence to a considerable extent. A number of countries in the low-income category are actually experiencing no per capita income growth, and many are experiencing population growth more rapid than 2.6 percent. Construction of scenarios for these cases would not be very realistic.
The major points of this exercise are that family planning impacts on greenhouse gas emissions are important at all levels of development. It is probably not feasible to achieve low population growth rates without moving up the development scale. The reduced population growth associated with higher-income growth (and to a small degree with lower-income elasticities as income rises) offsets in large part the higher greenhouse gas emissions associated with faster economic growth.
The family planning effects indicate that as of the year 2020, carbon emissions will be about 15 percent lower for the lower-middle- and upper-middle-income countries than they would be without family planning. Strong family planning programs are in the interests of all countries for greenhouse gas concerns as well as for broader welfare concerns.
Siddayo, C. 1987. Petroleum resources in the Pacific rim: The roles played by governments in their development and trade. In The Pacific Rim: Investment, Development, and Trade, P. Nemetz, ed. Vancouver, B.C.: University of British Columbia Press.
World Bank. 1989. 1989 World Development Report. Washington, D.C.: World Bank.