This appendix contains two tables of results, discussed briefly in the text of the paper, obtained in an analysis using an input-output model and data base of the world economy. Table 1 shows the emissions of carbon dioxide and oxides of sulfur and carbon, for the period 1980 through 2020, under a scenario that assumes moderate economic growth in the developing countries, modest growth in the rich countries, and the rapid adoption in all countries of technologies that reduce emissions in part by economizing on energy and materials. The scenario, described in detail in Duchin and Lange (1992), is based on the kinds of assumptions that are described in the Brundtland Report, Our Common Future (World Commission on Environment and Development, 1987). While the analysis was carried out on the basis of 16 geographic regions, the results in Table 1 are presented on a more aggregated basis.
Projections for the future can be compared only with projections made by others, but for past years the technical literature contains more direct measures and estimates. The sulfur emissions reported in the first table for 1980 are compared in Table 2, on a 16-region basis, with the results of many other studies that are reported in two surveys. This table illustrates two main points. First, by using the input-output case study methodology, it is possible to build a comprehensive data base from the bottom up based on technical assumptions. Only in this way are we able to arrive at an estimate for worldwide emissions of sulfur (in the last column of the table). Second, the input-output methodology is sufficiently explicit about underlying assumptions that one can analyze the reasons for major discrepancies between the World Model results and other results. The greatest discrepancies reported in Table 2 are with the official estimates of sulfur emissions in the former Soviet Union and in Eastern Europe. In the first case, an independent estimate by another researcher is very close to ours. In both cases, it is safe to conclude that the official estimates are unrealistically low.