Emissions Scenarios - IPCC

272 Emission Scénarios
600
-А1ВА[М
-AlBASF
-AIB
-AIB
IMAGE
MESSAGE
с
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-AlCAIM
-AIC MESSAGE
-AIGAIM
-AIG
MESSAGE
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в
э
â
s
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-AlOMlMCAM
-AITAIM
-AITMESSAGE
-A2ASF
AlAIM
A2G IMAGE
-A2 MESSAGE
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s
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в
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-Bl IMAGE
-Bl AIM
-Bl ASF
-Bl MESSAGE
-BITMESSAOE
-BIHIGH MESSAGE
-B2 MESSAGE
-B2 AIM
B2
ASF
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B2 IMAGE
5%
— medía»
- 15%
1990 2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100
Figure 5-10: Standardized global emissions of NMVOCs for SRES scenarios, classified into four scenario families (each
denoted by a different color code - Al, red; A2, brown; Bl, green; B2, blue). Marker scenarios are shown with thick lines
without ticks, globally harmonized scenarios with thin lines, and non-harmonized scenarios with thin, dotted lines (see Table
4-3). Black lines show percentiles, means, and medians for SRES scenarios. For numbers on the two additional illustrative
scenarios AlFI and AIT see Appendix VII.
2.5 times the cuirent level by 2100 (similar to Bl-ASF).
Emissions in A2-MESSAGE are fairly similar to those of the
A2 marker, while emissions in A2-AIM decline to 170 Mt by
2100, only half of the A2 marker level. The trajectory in the
AIB marker (AIB-AIM) is very distinct - up to 2060 a fast
growth is observed to more than twice the 1990 level, after
which emissions decline to the B2 family marker level (Figure
5-10). A decrease of NMVOC emissions in AIB-AIM after
2060 is explained mainly by the substitution of fossil fuels with
renewables, especially in the transport sector. A very similar
trajectory emerges in the AIB-MESSAGE scenario, while the
AlB-ASF scenario emissions grow continuously up to 2100,
by when they are the highest of the set at 550 Mt, almost four
times the 1990 level.
5.5.1.3. Carbon Monoxide
CO emissions in 1990 are estimated to range between 752 and
984 MtCO across the models used to derive the SRES
scenarios. The same caveats as for N0^^ and NMVOC
emissions (see above) also apply to CO emissions - the number
of models that represent all the emission source categories is
limited and modeling and data uncertainties, such as emission
factors, are considerable. As a resuh, CO emission estimates
across the scenarios are highly model specific, as indicated by
the overlapping ranges of the four scenario families (Figure 5-
11). From a standardized (see Box 5-1) 1990 level of 880
MtCO the range of future emissions is rather wide for both
medium-term and long-term time horizons. By 2020,
emissions range from 630 to 1550 MtCO, by 2050 they range
between 470 and 2300 MtCO, and by 2100 the range is
between 360 and 3760 MtCO (i.e. one order of magnitude
difference between the highest and the lowest projections).
Focusing on the 25* and 75* percentile intervals reduces
uncertainty ranges somewhat, but nonetheless they remain
substantial - between 1260 and 2300 MtCO by 2100. The
median of all 40 scenarios is tracked quite closely by the B2-
ASF scenario at the global level.
Emissions of CO follow rather different trajectories in the SRES
markers than emissions of NMVOCs, except the A2 marker
(A2-ASF). Starting from the standardized (see Box 5-1) level of
880 MtCO in 1990, emissions in the AIB marker (AlB-AlM)
grow continuously and almost double between 1990 and 2100
(Figure 5-11). Emissions in AIB-MESSAGE (Roehrl and Riahi,
2000) increase at a higher rate than in the marker and reach
thrice the curtent level by 2100. Emissions in AlB-ASF grow as
fast as in AIB-MESSAGE until 2040 (1700 MtCO versus 1650
MtCO for AIB-MESSAGE), when the growth stops and
emissions more or less stabilize. Emissions in the B1-IMAGE