Comparison A1-SRES with A1-IMAGE2.4/2007
Detlef van Vuuren / Elke Stehfest
Scenario drivers
Figure 1 compares the main scenario drivers (population and income) for the SRES A1Marker scenario (developed by the AIM team) and the A1 scenario developed by the IMAGE
team in 2007 for ENSEMBLES. Differences are relatively small: The population data trend
for the IMAGE-A1 is based on the development of the Global Orchestration scenario of the
MA which is very similar to the SRES A1 trend (MA, 2006).
600
10000
500
Income (trillion 1990$)
Population (million)
8000
6000
4000
2000
0
1970
400
300
200
100
2020
A1-SRES
2070
A1new
0
1970
2020
A1-SRES
2070
A1new
Figure 1: Population and income trends
The IPCC A1 marker assumes a very energy intensive development pathway leading to a
primary energy consumption in 2100 more than 5 times higher than in 2000. A very
considerable share is provided by non-fossil resources, including bio-energy (400 EJ) and
other renewables (nearly 1000 EJ). The IMAGE 2007 implementation of the same scenario
assumes a much lower energy intensity, leading in 2100 to only 3 times 2000 energy
consumption. At the same time, however, penetration of non-fossil technologies is much
slower (as a consequence of the model finding that fossil fuels remain competitive across the
whole century). The result is that fossil fuel consumption is higher in the new IMAGE
scenario than in the original marker.
IMAGE 2.4 A1
2000
2000
Fossil
Non-Fossil
Fossil
20
90
19
90
20
90
20
70
0
20
50
0
20
30
500
20
10
500
20
70
1000
20
50
1000
1500
20
30
1500
20
10
Energy (EJ)
2500
19
90
Energy (EJ)
SRES A1 -marker
2500
Non-Fossil
Figure 2: Trends in primary energy use
Land Use
Figure 3 shows the difference in land use between the A1b Marker scenario and the IMAGE
2.4 implementation of A1b provided in 2007 for Ensembles. Additionally, the older IMAGE
2.2 implementation was added, as it had been used in an earlier stage of Ensembles. In
general, the new 2.4 implementation is much closer to the marker than the 2.2
implementation. While for the 2.2 implementation, the IMAGE agricultural demand model
had been used, the new 2.4 implementation is based on the Global Orchestration scenario of
the Millennium Ecosystem Assessment (MA, 2006) and differs in terms of agricultural
consumption, production and management. The largest difference is observed for grassland,
which strongly decreases in the 2.2 implementation, giving more room for biofuels.
agricultural area [Mio ha]
4000
3500
3000
2500
2000
1500
1000
500
0
1980
2000
2020
2040
2060
2080
2100
2120
A1b M arker Cropland
A1b M arker Grasslands
A1b M arker Bio-energy
IM AGE24_A1b Cropland
IM AGE24_A1b Grasslands
IM AGE24_A1b Bio-energy
IM AGE22_A1b Cropland
IM AGE22_A1b Grasslands
IM AGE22_A1b Bio-energy
Figure 3: Trends in land use
Emissions
Figure 4 shows trends in emissions. For some species, emissions in the IMAGE
implementation is similar to that of the IPCC-marker: NOx and N2O. For others, different
trends can be observed.
NOx
NMVOC
Emissions (Tg)
40
30
20
1800
300
1600
250
200
150
100
50
0
1970
2020
0
1970
2070
A1-SRES
A1-new
1200
1000
800
600
200
2020
A1-SRES
SO2
700
100
600
80
60
40
20
A1-new
2020
A1-SRES
2070
A1-new
N2O
9
8
500
400
300
200
0
1970
2070
A1-SRES
2020
10
A1-new
7
6
5
4
3
2
100
0
1970
0
1970
2070
CH4
120
Emissions (Tg CH4)
Emission (Tg S)
1400
400
10
Emission (Tg N)
Emissions (tg N)
50
CO
350
Emission (Tg CO)
60
1
2020
A1-SRES
2070
0
1970
A1-new
2020
2070
A1-SRES
A1-new
Figure 4: Trends in global emissions
NMVOC: The IMAGE implementation assumes deep reductions – based on air pollution
control policies (in order to avoid tropospheric ozone). CHECK
CO: The emission trends for CO are determined both by energy and land use trends. CHECK.
SO2: Different between the IMAGE implementation and the IPCC marker are the trends in the
first few decades. In the IMAGE implementation it is assumed that the current trends in rapid
implementation of air pollution control technologies in Asia will prevent a mid-century peak
in emissions.
CH4:
The total greenhouse gas emissions of the IMAGE implementation are about 20% above the
A1 marker by the end of the century. This is mainly caused by differences in CO2 emissions
from energy/industry, which on its turns is a consequence of the differences in energy trends
discussed earlier.
20
CO2 energy/industry
30
Total GHG
18
25
Emissions (GtC-eq)
Emission (GtC)
16
14
12
10
8
6
4
20
15
10
5
2
0
1970
2020
2070
0
1970
2020
2070