REPORTS - SPECIAL REPORTS

Emissions Scenarios


Other reports in this collection

Table SPM-1a : Overview of main primary driving forces in 1990, 2020, 2050, and 2100. Bold numbers show the value for the illustrative scenario and the numbers between brackets show the value for the range a across all 40 SRES scenarios in the six scenario groups that constitute the four families. Units are given in the table. Technological change is not quantified in the table.
Family A1 A2 B1 B2

Scenario group 1990 A1FI A1B A1T A2 B1 B2

Population (billion)
1990 5.3
2020
7.6 (7.4- 7.6)
7.5 (7.2- 7.6)
7.6 (7.4- 7.6)
8.2 (7.5- 8.2)
7.6 (7.4- 7.6)
7.6 (7.6- 7.8)
2050
8.7
8.7 (8.3- 8.7)
8.7
11.3 (9.7- 11.3)
8.7 (8.6- 8.7)
9.3 (9.3- 9.8)
2100
7.1 (7.0- 7.1)
7.1 (7.0- 7.7)
7.0
15.1 (12.0- 15.1)
7.0 (6.9- 7.1)
10.4 (10.3- 10.4)

World GDP (1012 1990US$/ yr)
1990 21
2020
53 (53- 57)
56 (48- 61)
57 (52- 57)
41 (38- 45)
53 (46- 57)
51 (41- 51)
2050
164 (163- 187)
181 (120- 181)
187 (177- 187)
82 (59- 111)
136 (110- 166)
110 (76- 111)
2100
525 (522- 550)
529 (340- 536)
550 (519- 550)
243 (197- 249)
328 (328- 350)
235 (199- 255)

Per capita income ratio: developed countries and economies in transition (Annex- I) to developing countries (Non- Annex- I)
1990 16.1
2020
7.5 (6.2- 7.5)
6.4 (5.2- 9.2)
6.2 (5.7- 6.4)
9.4 (9.0- 12.3)
8.4 (5.3- 10.7)
7.7 (7.5- 12.1)
2050
2.8
2.8 (2.4- 4.0)
2.8 (2.4- 2.8)
6.6 (5.2- 8.2)
3.6 (2.7- 4.9)
4.0 (3.7- 7.5)
2100
1.5 (1.5- 1.6)
1.6 (1.5- 1.7)
1.6 (1.6- 1.7)
4.2 (2.7- 6.3)
1.8 (1.4- 1.9)
3.0 (2.0- 3.6)

a For some driving forces, no range is indicated because all scenario runs have adopted exactly the same assumptions.

 

Table SPM- 1b : Overview of main primary driving forces in 1990, 2020, 2050, and 2100. Bold numbers show the value for the illustrative scenario and the numbers between brackets show the value for the range a across 26 harmonized SRES scenarios in the six scenario groups that constitute the four families. Units are given in the table . Technological change is not quantified in the table.
Family A1 A2 B1 B2

Scenario group 1990 A1FI A1B A1T A2 B1 B2

Population (billion)
1990 5.3
2020
7.6 (7.4- 7.6)
7.4 (7.4- 7.6)
7.6 (7.4- 7.6)
8.2
7.6 (7.4- 7.6)
7.6
2050
8.7
8.7
8.7
11.3
8.7 (8.6- 8.7)
9.3
2100
7.1 (7.0- 7.1)
7.1 (7.0- 7.1)
7.0
15.1
7.0 (6.9- 7.1)
10.4

World GDP (1012 1990US$/ yr)
1990 21
2020
53 (53- 57)
56 (52- 61)
57 (56- 57)
41
53 (51- 57)
51 (48- 51)
2050
164 (164- 187)
181 (164- 181)
187 (182- 187)
82
136 (134- 166)
110 (108- 111)
2100
525 (525- 550)
529 (529- 536)
550 (529- 550)
243
328 (328- 350)
235 (232- 237)

Per capita income ratio: developed countries and economies in transition (Annex- I) to developing countries (Non- Annex- I)
1990 16.1
2020
7.5 (6.2- 7.5)
6.4 (5.2- 7.5)
6.2 (6.2- 6.4)
9.4 (9.4- 9.5)
8.4 (5.3- 8.4)
7.7 (7.5- 8.0)
2050
2.8
2.8 (2.4- 2.8)
2.8
6.6
3.6 (2.7- 3.9)
4.0 (3.8- 4.6)
2100
1.5 (1.5- 1.6)
1.6 (1.5- 1.7)
1.6
4.2
1.8 (1.6- 1.9)
3.0 (3.0- 3.5)

a For some driving forces, no range is indicated because all scenario runs have adopted exactly the same assumptions.

 

Table SPM- 2a : Overview of main secondary scenario driving forces in 1990, 2020, 2050, and 2100. Bold numbers show the value for the illustrative scenario and the numbers between brackets show the value for the range across all 40 SRES scenarios in the six scenario groups that constitute the four families. Units are given in the table.
Family A1 A2 B1 B2

Scenario group 1990 A1FI A1B A1T A2 B1 B2

Final energy intensity (106 J/ US$)a
1990 16.7
2020
9.4 (8.5- 9.4)
9.4 (8.1- 12.0)
8.7 (7.6- 8.7)
12.1 (9.3- 12.4)
8.8 (6.7- 11.6)
8.5 (8.5- 11.8)
2050
6.3 (5.4- 6.3)
5.5 (4.4- 7.2)
4.8 (4.2- 4.8)
9.5 (7.0- 9.5)
4.5 (3.5- 6.0)
6.0 (6.0- 8.1)
2100
3.0 (2.6- 3.2)
3.3 (1.6- 3.3)
2.3 (1.8- 2.3)
5.9 (4.4- 7.3)
1.4 (1.4- 2.7)
4.0 (3.7- 4.6)

Primary energy (1018 J/ yr)a
1990 351
2020
669
(653- 752)
711
(573- 875)
649
(515- 649)
595
(485- 677)
606
(438- 774)
566
(506- 633)
2050
1431
(1377- 1601)
1347
(968- 1611)
1213
(913- 1213)
971
(679- 1059)
813
(642- 1090)
869
(679- 966)
2100
2073
(1988- 2737)
2226
(1002- 2683)
2021
(1255- 2021)
1717
(1304- 2040)
514
(514- 1157)
1357
(846- 1625)

Share of coal in primary energy (%)a
1990 24
2020
29 (24- 42)
23 (8- 28)
23 (8- 23)
22 (18- 34)
22 (8- 27)
17 (14- 31)
2050
33 (13- 56)
14 (3- 42)
10 (2- 13)
30 (24- 47)
21 (2- 37)
10 (10- 49)
2100
29 (3- 48)
4 (4- 41)
1 (1- 3)
53 (17- 53)
8 (0- 22)
22 (12- 53)

Share of zero carbon in primary energy (%)a
1990 18
2020
15 (10- 20)
16 (9- 26)
21 (15- 22)
8 (8- 16)
21 (7- 22)
18 (7- 18)
2050
19 (16- 31)
36 (21- 40)
43 (39- 43)
18 (14- 29)
30 (18- 40)
30 (15- 30)
2100
31 (30- 47)
65 (27- 75)
85 (64- 85)
28 (26- 37)
52 (33- 70)
49 (22- 49)

a 1990 values include non- commercial energy consistent with IPCC WGII SAR (Energy Primer) but with SRES accounting conventions. Note that ASF, MiniCAM, and IMAGE scenarios do not consider non- commercial renewable energy. Hence, these scenarios report lower energy use.

 

Table SPM- 2b : Overview of main secondary scenario driving forces in 1990, 2020, 2050, and 2100. Bold numbers show the value for the illustrative scenario and the numbers between brackets show the value for the range across 26 harmonized SRES scenarios in the six scenario groups that constitute the four families. Units are given in the table.
Family A1 A2 B1 B2

Scenario group 1990 A1FI A1B A1T A2 B1 B2

Final energy intensity (106 J/ US$)a
1990 16.7
2020
9.4 (8.5- 9.4)
9.4 (8.7- 12.0))
8.7 (7.6- 8.7)
12.1 (11.3- 12.1)
8.8 (6.7- 11.6)
8.5 (8.5- 9.1)
2050
6.3 (5.4- 6.3)
5.5 (5.0- 7.2)
4.8 (4.3- 4.8)
9.5 (9.2- 9.5)
4.5 (3.5- 6.0)
6.0 (6.0- 6.6)
2100
3.0 (3.0- 3.2)
3.3 (2.7- 3.3)
2.3
5.9 (5.5- 5.9)
1.4 (1.4- 2.1)
4.0 (3.9- 4.1)

Primary energy (1018 J/ yr)a
1990 351
2020
669
(657- 752)
711
(589- 875)
649
(611- 649)
595
(595- 610)
606
(451- 774)
566
(519- 590)
2050
1431
(1377- 1601)
1347
(1113- 1611)
1213
(1086- 1213)
971
(971- 1014)
813
(642- 1090)
869
(815- 941)
2100
2073
(2073- 2737)
2226
(1002- 2683)
2021
(1632- 2021)
1717
(1717- 1921)
514
(514- 1157)
1357
(1077- 1357)

Share of coal in primary energy (%)a
1990 24
2020
29 (24- 42)
23 (8- 26)
23 (23- 23)
22 (20- 22)
22 (19- 27)
17 (14- 31)
2050
33 (13- 52)
14 (3- 42)
10 (10- 13)
30 (27- 30)
21 (4- 37)
10 (10- 35)
2100
29 (3- 46)
4 (4- 41)
1 (1- 3)
53 (45- 53)
8 (0- 22)
22 (19- 37)

Share of zero carbon in primary energy (%)a
1990 18
2020
15 (10- 20)
16 (9- 26)
21 (15- 21)
8 (8- 16)
21 (7- 22)
18 (12- 18)
2050
19 (16- 31)
36 (23- 40)
43 (41- 43)
18 (18- 29)
30 (18- 40)
30 (21- 30)
2100
31 (30- 47)
65 (39- 75)
85 (67- 85)
28 (28- 37)
52 (44- 70)
49 (22- 49)

a 1990 values include non- commercial energy consistent with IPCC WGII SAR (Energy Primer) but with SRES accounting conventions. Note that ASF, MiniCAM, and IMAGE scenarios do not consider non- commercial renewable energy. Hence, these scenarios report lower energy use.

 

Table SPM- 3a : Overview of GHG, SO2, and ozone precursor emissions a in 1990, 2020, 2050, and 2100, and cumulative carbon dioxide emissions to 2100. Bold numbers show the value for the illustrative scenario and the numbers between brackets show the value for the range across all 40 SRES scenarios in the six scenario groups that constitute the four families. Units are given in the table .
Family A1 A2 B1 B2

Scenario group 1990 A1FI A1B A1T A2 B1 B2

Carbon dioxide, fossil fuels (GtC/ yr) 6.0
2020
11.2 (10.7- 14.3)
12.1 (8.7- 14.7)
10.0 (8.4- 10.0)
11.0 (7.9- 11.3)
10.0 (7.8- 13.2)
9.0 (8.5- 11.5)
2050
23.1 (20.6- 26.8)
16.0 (12.7- 25.7)
12.3
(10.8- 12.3)
16.5 (10.5- 18.2)
11.7 (8.5- 17.5)
11.2 (11.2- 16.4)
2100
30.3 (27.7- 36.8)
13.1 (12.9- 18.4)
4.3 (4.3- 9.1)
28.9 (17.6- 33.4)
5.2 (3.3- 13.2)
13.8 (9.3- 23.1)

Carbon dioxide, land use (GtC/ yr) 1.1
2020
1.5 (0.3- 1.8)
0.5 (0.3- 1.6)
0.3 (0.3- 1.7)
1.2 (0.1- 3.0)
0.6 (0.0- 1.3)
0.0 (0.0- 1.9)
2050
0.8 (0.0- 0.9)
0.4 (0.0- 1.0)
0.0 (- 0.2- 0.5)
0.9 (0.6- 0.9)
-0.4 (- 0.7- 0.8)
-0.2 (- 0.2- 1.2)
2100
-2.1 (- 2.1- 0.0)
0.4 (- 2.4- 2.2)
0.0 (0.0- 0.1)
0.2 (- 0.1- 2.0)
-1.0 (- 2.8- 0.1)
-0.5 (- 1.7- 1.5)

Cumulative carbon dioxide, fossil fuels (GtC)
1990-2100
2128
(2079- 2478)
1437
(1220- 1989)
1038
(989- 1051)
1773
(1303- 1860)
989
(794- 1306)
1160
(1033- 1627)

Cumulative carbon dioxide, land use (GtC)
1990-2100
61 (31- 69)
62 (31- 84)
31 (31- 62)
89 (49- 181)
-6 (- 22- 84)
4 (4- 153)

Cumulative carbon dioxide, total (GtC)
1990-2100
2189
(2127- 2538)
1499
(1301- 2073)
1068
(1049- 1113)
1862
(1352- 1938)
983
(772- 1390)
1164
(1164- 1686)

Sulfur dioxide, (MtS/ yr) 70.9
2020
87 (60- 134)
100 (62- 117)
60 (60- 101)
100 (66- 105)
75 (52- 112)
61 (48- 101)
2050
81 (64- 139)
64 (47- 120)
40 (40- 64)
105 (78- 141)
69 (29- 69)
56 (42- 107)
2100
40 (27- 83)
28 (26- 71)
20 (20- 27)
60 (60- 93)
25 (11- 25)
48 (33- 48)

Methane, (MtCH4 /yr) 310
2020
416 (415- 479)
421 (400- 444)
415 (415- 466)
424 (354- 493)
377 (377- 430)
384 (384- 469)
2050
630 (511- 636)
452 (452- 636)
500 ( 492- 500)
598 (402- 671)
359 (359- 546)
505 (482- 536)
2100
735 (289- 735)
289 (289- 640)
274 (274- 291)
889 (549- 1069)
236 (236- 579)
597 (465- 613)

Nitrous Oxide,
(MtN/ yr)
6.7
2020
9.3 (6.1- 9.3)
7.2 (6.1- 9.6)
6.1 (6.1- 7.8)
9.6 (6.3- 12.2)
8.1 (5.8- 9.5)
6.1 (6.1- 11.5)
2050
14.5 (6.3- 14.5)
7.4 (6.3- 14.3)
6.1 (6.1- 6.7)
12.0 (6.8- 13.9)
8.3 (5.6- 14.8)
6.3 (6.3- 13.2)
2100
16.6 (5.9- 16.6)
7.0 (5.8- 17.2)
5.4 (4.8- 5.4)
16.5 (8.1- 19.3)
5.7 (5.3- 20.2)
6.9 (6.9- 18.1)

CFC/ HFC/ HCFC (MtC equiv./ yr) b 1672
2020
337
337
337
292
291
299
2050
566
566
566
312
338
346
2100
614
614
614
753
299
649

PFC, (MtC equiv./ yr) b 32.0
2020
42.7
42.7
42.7
50.9
31.7
54.8
2050
88.7
88.7
88.7
92.2
42.2
106.6
2100
115.3
115.3
115.3
178.4
44.9
121.3

SF6 , (MtC equiv./ yr) b 37.7
2020
47.8
47.8
47.8
63.5
37.4
54.7
2050
119.2
119.2
119.2
104.0
67.9
79.2
2100
94.6
94.6
94.6
164.6
42.6
69.0

CO, (MtCO/ yr) 879
2020
1204
(1123- 1552)
1032
(978- 1248)
1147
(1147- 1160)
1075
(748- 1100)
751
(751- 1162)
1022
(632- 1077)
2050
2159
(1619- 2307)
1214
(949- 1925)
1770
(1244- 1770)
1428
(642- 1585)
471
(471- 1470)
1319
(580- 1319)
2100
2570
(2298- 3766)
1663
(1080- 2532)
2077
(1520- 2077)
2326
(776- 2646)
363
(363- 1871)
2002
(661- 2002)

NMVOC, (Mt/ yr) 139
2020
192 (178- 230)
222 (157- 222)
190 (188- 190)
179 (166- 205)
140 (140- 193)
180 (152- 180)
2050
322 (256- 322)
279 (158- 301)
241 (206- 241)
225 (161- 242)
116 (116- 237)
217 (147- 217)
2100
420 (167- 484)
194 (133- 552)
128 (114- 128)
342 ( 169- 342)
87 (58- 349)
170 (130- 304)

NOx , (MtN/ yr) 30.9
2020
50 (46- 51)
46 (46- 66)
46 (46- 49)
50 (42- 50)
40 (38- 59)
43 (38- 52)
2050
95 (49- 95)
48 (48- 100)
61 (49- 61)
71 (50- 82)
39 (39- 72)
55 (42- 66)
2100
110 (40- 151)
40 (40- 77)
28 (28- 40)
109 (71- 110)
19 (16- 35)
61 (34- 77)

a The uncertainties in the SRES emissions for non- CO2 greenhouse gases are generally greater than those for energy CO2 . Therefore, the ranges of non- CO2 GHG emissions provided in the Report may not fully reflect the level of uncertainty compared to CO2 , for example only a single model provided the sole value for halocarbon emissions.

b In the SPM the emissions of CFC/ HFC/ HCFC, PFC, and SF6 are presented as carbon- equivalent emissions. This was done by multiplying the emissions by weight of each substance (see Table 5- 8) by its global warming potential (GWP; see Table 5- 7) and subsequent summation. The results were then converted from CO2 -equivalents (reflected by the GWPs) into carbon- equivalents. Note that the use of GWP is less appropriate for emission profiles that span a very long period. It is used here, in the interest of readability of the SPM in preference to a more detailed breakdown by the 27 substances listed in Table 5- 7. The method here is also preferred over the even less desirable option to display weighted numbers for the aggregate categories in this table.

 

Table SPM- 3b : Overview of GHG, SO2, and ozone precursor emissions a in 1990, 2020, 2050, and 2100, and cumulative carbon dioxide emissions to 2100. Bold numbers show the value for the illustrative scenario and the numbers between brackets show the value for the range across 26 harmonized SRES scenarios in the six scenario groups that constitute the four families. Units are given in the table .
Family A1 A2 B1 B2

Scenario group 1990 A1FI A1B A1T A2 B1 B2

Carbon dioxide, fossil fuels (GtC/ yr) 6.0
2020
11.2
(10.7-14.3)
12.1
(8.7- 14.7)
10.0
(9.8- 10.0)
11.0
(10.3- 11.0)
10.0
(8.2- 13.2)
9.0
(8.8- 10.2)
2050
23.1
(20.6- 26.8)
16.0
(12.7- 25.7)
12.3
(11.4- 12.3)
16.5
(15.1- 16.5)
11.7
(8.5- 17.5)
11.2
(11.2- 15.0)
2100
30.3
(30.3- 36.8)
13.1
(13.1- 17.9)
4.3
(4.3- 8.6)
28.9
(28.2- 28.9)
5.2
(3.3- 7.9)
13.8
(13.8- 18.6)

Carbon dioxide, land use (GtC/ yr) 1.1
2020
1.5 (0.3- 1.8)
0.5 (0.3- 1.6)
0.3 (0.3- 1.7)
1.2 (1.1- 1.2)
0.6 (0.0- 1.3)
0.0 (0.0- 1.1)
2050
0.8 (0.0- 0.8)
0.4 (0.0- 1.0)
0.0 (- 0.2- 0.0)
0.9 (0.8- 0.9)
-0.4 (- 0.7- 0.8)
-0.2 (- 0.2- 1.2)
2100
-2.1 (- 2.1- 0.0)
0.4 (- 2.0- 2.2)
0.0 (0.0- 0.1)
0.2 (0.0- 0.2)
-1.0 (- 2.6- 0.1)
-0.5 (- 0.5- 1.2)

Cumulative carbon dioxide, fossil fuels (GtC)
1990-2100
2128
(2096- 2478)
1437
(1220- 1989)
1038
(1038- 1051)
1773
(1651- 1773)
989
(794- 1306)
1160
(1160- 1448)

Cumulative carbon dioxide, land use (GtC)
1990-2100
61 (31- 61)
62 (31- 84)
31 (31- 62)
89 (81- 89)
-6 (- 22- 84)
4 (4- 125)

Cumulative carbon dioxide, total (GtC)
1990-2100
2189
(2127- 2538)
1499
(1301- 2073)
1068
(1068- 1113)
1862
(1732- 1862)
983
(772- 1390)
1164
(1164- 1573)

Sulfur dioxide, (MtS/ yr) 70.9
2020
87 (60- 134)
100 (62- 117)
60 (60- 101)
100 (80- 100)
75 (52- 112)
61 (61- 78)
2050
81 (64- 139)
64 (47- 64)
40 (40- 64)
105 (104- 105)
69 (29- 69)
56 (44- 56)
2100
40 (27- 83)
28 (28- 47)
20 (20- 27)
60 (60- 69)
25 (11- 25)
48 (33- 48)

Methane, (MtCH4 /yr) 310
2020
416 (416- 479)
421 (406- 444)
415 (415- 466)
424 (418- 424)
377 (377- 430)
384 (384- 391)
2050
630 (511- 630)
452 (452- 636)
500 (492- 500)
598 (598- 671)
359 (359- 546)
505 (482- 505)
2100
735 (289- 735)
289 (289- 535)
274 (274- 291)
889 (889- 1069)
236 (236- 561)
597 (465- 597)

Nitrous oxide, (MtN/ yr) 6.7
2020
9.3 (6.1- 9.3)
7.2 (6.1- 9.6)
6.1 (6.1- 7.8)
9.6 (6.3- 9.6)
8.1 (5.8- 9.5)
2050
14.5 (6.3- 14.5)
7.4 (6.3- 13.8)
6.1 (6.1- 6.7)
12.0 (6.8- 12.0)
8.3 (5.6- 14.8)
2100
16.6 (5.9- 16.6)
7.0 (5.8- 15.6)
5.4 (4.8- 5.4)
16.5 (8.1- 16.5)
5.7 (5.3- 20.2)

CFC/ HFC/ HCFC (MtC equiv./ y) b 1672
2020
337
337
337
292
291
299
2050
566
566
566
312
338
346
2100
614
614
614
753
299
649

PFC, (MtC equiv./ yr) b 32.0
2020
42.7
42.7
42.7
50.9
31.7
54.8
2050
88.7
88.7
88.7
92.2
42.2
106.6
2100
115.3
115.3
115.3
178.4
44.9
121.3

SF6 , (MtC equiv./ yr) b 37.7
2020
47.8
47.8
47.8
63.5
37.4
54.7
2050
119.2
119.2
119.2
104.0
67.9
79.2
2100
94.6
94.6
94.6
164.6
42.6
69.0

CO, (MtCO/ yr) 879
2020
1204
(1123- 1552)
1032
(1032- 1248)
1147
(1147- 1160)
1075
(1075- 1100)
751
(751- 1162)
1022
(941- 1022)
2050
2159
(1619- 2307)
1214
(1214- 1925)
1770
(1244- 1770)
1428
(1428- 1585)
471
(471- 1470)
1319 (1180- 1319)
2100
2570
(2298- 3766)
1663
(1663- 2532)
2077
(1520- 2077)
2326
(2325- 2646)
363
(363- 1871)
2002
(1487- 2002)

NMVOC, (Mt/ yr) 139
2020
192 (178- 230)
222 (194- 222)
190 (188- 190)
179 (179- 204)
140 (140- 193)
180 (179- 180)
2050
322 (256- 322)
279 (259- 301)
241 (206- 241)
225 (225- 242)
116 (116- 237)
217 (197- 217)
2100
420 (167- 484)
194 (137- 552)
128 (114- 128)
342 (311- 342)
87 (58- 349)
170 (130- 170)

NOx , (MtN/ yr) 30.9
2020
50 (46- 51)
46 (46- 66)
46 (46- 49)
50 (47- 50)
40 (38- 59)
43 (38- 43)
2050
95 (49- 95)
48 (48- 100)
61 (49- 61)
71 (66- 71)
39 (39- 72)
55 (42- 55)
2100
110 (40- 151)
40 (40- 77)
28 (28- 40)
109 (109- 110)
19 (16- 35)
61 (34- 61)

a The uncertainties in the SRES emissions for non- CO2 greenhouse gases are generally greater than those for energy CO2 . Therefore, the ranges of non- CO2 GHG emissions provided in the Report may not fully reflect the level of uncertainty compared to CO2 , for example only a single model provided the sole value for halocarbon emissions.



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