Emissions Scenarios - IPCC

Technical Summary 33
Table TS-1: Income per capita in the world and by SRES region for the IS92 (Leggett et al, 1992) and four marker scenarios by
2050 and 2100, measured by GDP per capita in 1000 US dollars (at 1990 prices and exchange rates).
Income per Capita by World and Regions
(103 1990US$ per capita)
Regions
Year Scenario OECD90 REF IND ASIA ALM DEV WORLD
1990 SRES MESSAGE 19.1 2.7 13.7 0.5 1.6 0.9 4.0
2050 IS92a,b 49.0 23.2 39.7 3.7 4.8 4.1 9.2
IS92c 35.2 14.6 27.4 2.2 2.9 2.5 6.3
IS92d 54.4 25.5 43.4 4.1 5.4 4.6 10.5
IS92e 67.4 38.3 56.9 5.9 7.7 6.6 13.8
IS92f 43.9 21.5 35.8 3.3 4.1 3.6 8.1
AlB* 50.1 29.3 44.2 14.9 17.5 15.9 20.8
A2 34.6 7.1 26.1 2.6 6.0 3.9 7.2
Bl 49.8 14.3 39.1 9.0 13.6 10.9 15.6
B2 39.2 16.3 32.5 8.9 6.9 8.1 11.7
2100 IS92a,b 85.9 40.6 69.5 15.0 14.2 14.6 21.5
IS92c 49.2 17.6 36.5 6.4 5.8 6.1 10.1
IS92d 113.9 51.3 88.8 20.3 17.7 19.1 28.2
IS92e 150.6 96.6 131.0 34.6 33.0 33.8 46.0
IS92f 69.7 31.3 54.9 11.9 10.7 11.4 16.8
AlB* 109.2 100.9 107.3 71.9 60.9 66.5 74.9
A2 58.5 20.2 46.6 7.8 15.2 11.0 16.1
Bl 79.7 52.2 72.8 35.7 44.9 40.2 46.6
B2 61.0 38.3 54.4 19.5 16.1 18.0 22.6
* The two additional illustrative scenarios AlFI and AIT share similar assumptions with AlB. See also Appendix VII for more details
possibilities for development "catch-up" and for narrowing
per capita income gaps in particular explain the wide range in
projected future gross world product levels. Given a
qualitatively negative relationship between population growth
and per capita income growth discussed in Chapters 2 and 3,
uncertainties in future population growth rates tend to narrow
the range of associated gross world product projections. High
population growth would, ceteris paribus, lower per capita
income growth, whereas low population growth would tend to
increase it. This relationship is evident in empiric data - high
per capita income countries are generally also those that have
completed their demographic transition. The affluent live long
and generally have few children. (Exceptions are some
countries with small populations, high birth rates, and
significant income from commodity exports.) This
relationship between affluence and longevity again identiñes
development as one of the most important indicators of human
well being. Yet even assuming this relationship holds for an
extended time into the future, its quantification is subject to
considerable theoretic and empkic uncertainties (Alcamo et
ai, 1995).
Two of the SRES scenario families, AI and Bl, explicitiy
explore alternative pathways to gradually close existing income
gaps. As a reflection of uncertainty, development catch-up
diverges in terms of geographically distinct economic growth
patterns across the four SRES scenario families. Table TS-I
summarizes per capita income for SRES and IS92 scenarios for
the four SRES world regions. SRES scenarios indicate a smaller
difference between the now industrialized and developing
countries compared with the IS92 scenarios. This tendency
toward a substantially narrower income "gap" compared with
the IS92 scenarios overcomes one of the major shortcomings of
the previous IPCC scenarios cited in the literature (Parikh,
1992).
8.3. Structural and Technological Change
In this brief summary of the SRES scenarios, structural and
technological changes are illustrated by using energy and land
use as examples. These examples are characteristic for the
driving forces of emissions because the energy system and land
use are the major sources of GHG and sulfur emission.