123
sumption of fossil fuel, which has had two distinct growth spurts (1860–1910;
1950–1973) and appears to be entering a third period of growth.
The Paris INDCs focus on reducing the emission of the UNFCCC basket of
GHGs, expressed in terms of CO 2 -eq (Sect. 3.1). Release of CO 2 by the combustion
of fossil fuel is the most important contributor to this total GHG emission burden.
Total anthropogenic emission of CH 4 , which is released to the atmosphere by many
aspects of our industrialized world (Sect. 1.2.3.3), is the second largest contributor.
The release of CO 2 by land use change (CO 2
LUC
) and the emission of N 2 O (Sect.
1.2.3.4) make additional contributions, nearly equal in magnitude, that must be considered when examining the Paris INDCs.
Figure 3.2a shows a time series of CO 2 -eq emission of GHGs. The four most
important terms are included: CO 2
FF
, CO 2
LUC
, CH 4 , and N 2 O. Global population is
also shown in Fig. 3.2a. The per-capita emission of GHGs in the Paris INDC
relevant metric, CO 2 -eq, is shown in Fig. 3.2b. The quotient of CO 2 -eq emissions
divided by global population, which reflects the globally averaged contribution to
global warming by the world’s population, is termed pC
EQ-GL
.
Figure 3.3 shows the breakdown of anthropogenic release of CH 4 and N 2 O, in
CO 2 -eq units. Figure 3.3a shows emission estimates for CH 4 and N 2 O from the same
source, RCP (Meinshausen et al. 2011), which has been the resource used for global
0
10
20
30
40
50
Emission
(Gt CO
2
−eq yr
−1
)
CO
2
LUC
CH 4 + N
2
O
CO
2
FF
Population
a
0
2
4
6
8
10
Population
(Billion)
1825
1850
1875
1900
1925
1950
1975
2000
0
2
4
6
8
10
Per−Capita Emission
(t CO
2
−eq ppy)
Steel Manufacture
WWI
Market Crash
Great Depression
WWII
US−USSR−Europe Growth
1st Oil Shock
2nd Oil Shock
80s Recession
China Growth
b
Fig. 3.2 Total global emission of atmospheric CO 2 , CH 4 , and N 2 O. (a) Emission of CO 2 from
combustion of fossil fuels (CO 2
FF
; same as Fig. 3.1), anthropogenic emission of CH 4 plus N 2 O
expressed as CO 2 -equivalent (CO 2 -eq) (blue), and emission of CO 2 from land use change (CO 2
LUC
,
red); global population (green) is also shown; (b) per-capita emission of CO 2
FF + CO 2
LUC + CH 4 +
N 2 O, termed pC
EQ-GL
, expressed in metric tons of CO 2 -eq per person, per year (t CO 2 -eq ppy).
World events associated with changes in pC
EQ-GL are noted. See Methods for further information
3.2 Prior Emissions
sumption of fossil fuel, which has had two distinct growth spurts (1860–1910;
1950–1973) and appears to be entering a third period of growth.
The Paris INDCs focus on reducing the emission of the UNFCCC basket of
GHGs, expressed in terms of CO 2 -eq (Sect. 3.1). Release of CO 2 by the combustion
of fossil fuel is the most important contributor to this total GHG emission burden.
Total anthropogenic emission of CH 4 , which is released to the atmosphere by many
aspects of our industrialized world (Sect. 1.2.3.3), is the second largest contributor.
The release of CO 2 by land use change (CO 2
LUC
) and the emission of N 2 O (Sect.
1.2.3.4) make additional contributions, nearly equal in magnitude, that must be considered when examining the Paris INDCs.
Figure 3.2a shows a time series of CO 2 -eq emission of GHGs. The four most
important terms are included: CO 2
FF
, CO 2
LUC
, CH 4 , and N 2 O. Global population is
also shown in Fig. 3.2a. The per-capita emission of GHGs in the Paris INDC
relevant metric, CO 2 -eq, is shown in Fig. 3.2b. The quotient of CO 2 -eq emissions
divided by global population, which reflects the globally averaged contribution to
global warming by the world’s population, is termed pC
EQ-GL
.
Figure 3.3 shows the breakdown of anthropogenic release of CH 4 and N 2 O, in
CO 2 -eq units. Figure 3.3a shows emission estimates for CH 4 and N 2 O from the same
source, RCP (Meinshausen et al. 2011), which has been the resource used for global
0
10
20
30
40
50
Emission
(Gt CO
2
−eq yr
−1
)
CO
2
LUC
CH 4 + N
2
O
CO
2
FF
Population
a
0
2
4
6
8
10
Population
(Billion)
1825
1850
1875
1900
1925
1950
1975
2000
0
2
4
6
8
10
Per−Capita Emission
(t CO
2
−eq ppy)
Steel Manufacture
WWI
Market Crash
Great Depression
WWII
US−USSR−Europe Growth
1st Oil Shock
2nd Oil Shock
80s Recession
China Growth
b
Fig. 3.2 Total global emission of atmospheric CO 2 , CH 4 , and N 2 O. (a) Emission of CO 2 from
combustion of fossil fuels (CO 2
FF
; same as Fig. 3.1), anthropogenic emission of CH 4 plus N 2 O
expressed as CO 2 -equivalent (CO 2 -eq) (blue), and emission of CO 2 from land use change (CO 2
LUC
,
red); global population (green) is also shown; (b) per-capita emission of CO 2
FF + CO 2
LUC + CH 4 +
N 2 O, termed pC
EQ-GL
, expressed in metric tons of CO 2 -eq per person, per year (t CO 2 -eq ppy).
World events associated with changes in pC
EQ-GL are noted. See Methods for further information
3.2 Prior Emissions