Table 1. Current and projected annual greenhouse gas emission estimates for the scenarios (a) IS92a and (b) IS92c of the Intergovernmental Panel on Climate Change (IPCC). Extracted from Leggett et al.⁴²

(a) Includes both the anthropogenic and the natural components, the later being constant rates of 8Mt/yr of N for N₂O and 155 Mt/yr for CH₄
Greenhouse gas year Change
(%)
1990 2000 2005 2025 2050 2075 2100 1990-
2100
C02 (Gt C)
industrial 6.1 7.1 7.9 11.1 13.7 16.2 20.4 +230
land use 1.3 1.3 1.2 1.1 0.8 0.4 -0.1 -108
N₂O (Mt N)^a) 12.9 13.8 14.1 15.8 16.6 16.7 17.0 +32
CH₄ (Mt)^a) 506.0 545.0 568.0 659.0 785.0 845.0 917.0 +61
CFC-1l(kt) 289 168 137 94 85 16 2 -99
CFC-12 (kt) 362 200 161 98 110 22 1 -100
CFC- 113(kt) 147 29 22 21 24 0 0 -100
CFC-114 (kt) 13 4 3 3 3 0 0 -100
CFC-115 (kt) 7 5 4 1 1 0 0 -100
CC14 (kt) 119 34 15 19 21 0 0 -100
CH3CC13 (kt) 738 353 137 97 110 0 0 -100
HCFC-22 (kt) 138 275 329 568 1058 1232 1225 +788
H-1301 (kt) 4 4 4 2 1 1 0 -100
C0₂ Equivalent 20.3 19.4 20.2 24.2 28.9 30.6 35.3 +74
(GtC)^b

(b) Equivalent CO₂ emission rate defined as the product of the 100-year Global Warming Potential (Isaksen et al.⁴³) and the mass emission rate of the trace gases

Greenhouse gas				year				Change
								(%)
	1990	2000	2005	2025	2050	2075	2100	1990-
								2100
C02 (Gt C)
industrial	6.1	6.2	6.5	7.7	6.8	5.7	4.8	-23
land use	1.3	1.3	1.3	1.1	0.7	0.2	-0.2	-115
N₂0 (Mt N)^a)	12.9	13.6	13.8	15.0	15.0	14.2	13.0	+6
CH4 (Mt)^a)	506.0	526.0	540.0	589.0	613.0	584.0	546.0	+8
CFC- 11 (kt)	289	168	137	94	85	16	2	-99
CFC-12 (kt)	362	200	161	98	110	22	1	-100
CFC-113(kt)	147	29	22	21	24	0	0	-100
CFC-114 (kt)	13	4	3	3	3	0	0	-100
CFC-115 (kt)	7	5	4	1	1	0	0	-100
CC14 (kt)	119	34	15	19	21	0	0	-100
CH3CC13 (kt)	738	353	137	97	110	0	0	-100
HCFC-22 (kt)	138	275	329	568	1058	1232	1225	+788
H-1301 (kt)	4	4	4	2	1	1	0	-100
C02 Equivalent	20.3	18.3	18.4	19.9	19.7	16.3	14.9	-26
(GtC)b)