Emissions Scenarios - IPCC

248 Emission Scenarios
40
jEnergy & Industry
Ш
AlB AIM
AlB ASr
Al Family
à
AIE IMAGE
—К Л1В MESSAGE
AlB MINICAM
• \Ш MARIA
« AlC AIM
~* AlC
MESSAGE
— AlC MINICAM
fl
Л10 .AIM
-A AIG
VfESSAGE
* AIG MINICAM
О
Ú
Al VI MINICAM
1IV2 MINICAM
« AITAIM
• AIT MESSAGE
1990 2010 2030 2050 2070 2090
- - AIT MARIA
Figure 5-3a: Global emissions from fossil fuels and industry in the SRES Al scenario family (standardized). The marker
scenario is shown with a thick line without ticks, the globally harmonized scenarios with thin lines, and the non-harmonized
scenaiios with thin, dotted lines (see Table 4-3). In the SPM, AlC and AIG scenarios are merged into one fossil-intensive AlFI
scenario group (see also footnote 2).
While still adhering to the "balanced" supply-mix assumption
(see Section 4.3.1), other scenarios within the Al balanced
group span a larger range of future emissions around the AlB-
AIM scenario. In part this results from different assumptions
on global and regional GDP growth and energy-intensity
improvements, but also from altemative 1п1ефге1а11оп5 of how
to translate the concept of a "balanced" pathway of
technological change (as described in the Al scenario
storyline) into model-specific technology assumpfions.
The AlB-ASF and AlB-IMAGE scenarios depict futures with a
stronger reliance on fossil fuels (especially coal) than that m
AlB-AIM. In 2050 this results in higher emissions (19 to 26
GtC versus 16 GtC for the AlB-AIM; see statisfical tables in
Appendix VII for more details). The emission pattem in the
AIB-MARIA scenario (Mori, 2000) is quite different. This
scenario does not reproduce an initial rapid growth in emissions,
which reach a maximum around 2050 and subsequently decline.
Instead, emissions grow more slowly and then level off. By
2050, the emissions in AIB-MARIA are well below those in
AlB-AIM (13 versus 16 GtC). Two out of three Al scenarios
developed using the MiniCAM model (AlVl-MiniCAM and
AlV2-MiniCAM) were based on somewhat different
assumptions with respect to key scenario driving forces, which
included lower energy intensity, less rapid decline in population
after 2050, and lower incomes per capita (see Chapter 4 for more
details). Emissions in these scenarios increase continuously
during the 2P' century to reach about 18 MtC by 2100 (see
statistical tables in Appendix VII for more details).
The emissions range spanned by all the Al balanced scenario
group in 2100 is from 13 to 18 GtC. Total, cumulative carbon
emissions range from 1301 to 2073 GtC by 2100. This
illustrates the importance of different assumptions on rates and
direction of technological change in the energy sector for longterm
emissions scenarios, which is further explored in the three
additional scenario groups discussed below.
Two altemative Al scenario groups, AIG (oil and gas) and
AlC (coal), explore high-fossil futures and one group, AIT,
explores advanced technology futures. AIG and AlC have
been combined into one fossil intensive scenaiio group AlFI m
the SPM (see also footnote 2). Energy-related carbon
emissions vary widely across these scenario groups in
conjunction with the scenario assumptions as to roles of
different energy sources (Figure 5-3a). The high fossd
scenarios explore worlds that consume vast amounts of coal, or
oil and gas, while with the advanced technology assumptions
the role of fossil fuel declines strongly as nuclear and/or
renewable sources are favored to supply the reduced fmal
energy demand.
The Al fossil scenarios have essentially the same population,
GDP, and final energy demand as the AlB marker, but have a
primary eneigy system that relies mainly on fossil fuels. Based
on cumulative CO2 emissions, scenarios from the Al fossil
groups (AIG and AlC) fall within the high emissions category,
with AlG-MiniCAM falling roughly in the middle of the range
spanned by the six Al fossil scenarios (Table 5-2). The primary
energy system in the AlG-MiniCAM scenario emerges as a
result of rapid increases in the efficiency with which fossil
resources can be recovered, especially in the most expensive
grades of these resources; unconventional resources play an
increasingly important role toward the end of the 2P' century.