Emissions scenarios: A final response

This note is a final response to the debate raised by Mr. Castles and Mr. Henderson (for brevity, we refer here to the two authors simply as C&H) in this Journal (vol 14, no 2&3, and no 4) on the issue of economic growth in developing countries in some of the emissions scenarios published in the IPCC Special Report on Emissions Scenarios (SRES) (Nakicenovic et al., 2000). We first outline areas of agreement and then the remaining areas of disagreement. Two important areas of agreement have emerged from the debate according to our view. First, both parties agree that scenarios assuming a conditional convergence in income levels, i.e., a higher growth in per capita income in poorer countries when compared to countries with higher levels of affluence, are both "plausible and well attested in economic history" (C&H, p. 424). Thus, the fundamental, structural characteristic of some of the SRES scenarios contested by C&H are not challenged per se, but rather how fast such trends could unfold in the future