Paris Climate Agreement Beacon of Hope

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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 con-
sidered 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 pCEQ-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

−eq yr 2

−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

−eq ppy) 2

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 pCEQ-GL, expressed in metric tons of CO 2 -eq per person, per year (t CO 2 -eq ppy).
World events associated with changes in pCEQ-GL are noted. See Methods for further information

3.2 Prior Emissions