152
projected to supply only 5.7 % of world energy needs.^7 We do not allow nuclear energy
to grow to accommodate achievement of the RCP 4.5 emissions of CO 2. As such, if
global emissions of CO 2 are to meet their RCP 4.5 target, there needs to be a more rapid
transition to renewable energy than Thomson et al. ( 2011 ) had envisioned.
Examination of the present state of affairs for renewables casts this challenge in
stark terms. Figure 4.4a shows a breakdown of supply of energy from renewables
for the EIA business as usual projection from two categories: combustion of bio-
mass (dark green) and all other sources (light green). Although it is not commonly
appreciated, the primary source of energy from renewables throughout the world
happens to be combustion of biomass (Kopetz 2013 ). Much of the developing world
heats and cooks using energy derived by burning wood. Energy produced in this
manner is classified as renewable, by EIA and others, because the carbon in the
(^7) EIA bookkeeping has nuclear energy supplying 4.64 % of total, global consumed energy in 2012
and projects supply of 5.64 % in 2040.
Coal
Natural Gas
Liquid Fuels
RCP 8.5
RCP 4.5
b
34.0%
29.8%
36.2%
1990 2000 2010 2020 2030 2040 2050 2060
10
20
30
40
50
60
70
World Energy Consumption and CO 2 Emissions, Modified to Meet RCP 4.5 in 2030
History
Nuclear
Renewables
Coal
Natural Gas
Liquid Fuels
a
5.7%
49.2%
11.1%
16.9%
(^100) 17.2%
200
300
400
500
600
700
800
900
1000
Energy Consumption (quad BTU)
Gt CO
yr 2
-1
Fig. 4.3 World energy consumption and CO 2 emissions, modified to meet RCP 4.5. Same as Fig.
4.2, except the sum of CO 2 emissions from coal, natural gas, and liquid fossil fuels has been modi-
fied to match RCP 4.5 (Thomson et al. 2011 ) starting in year 2030. For point of comparison, global
energy demand used in the design of RCP 4.5 is shown by the four black circles on the top panel.
The gap between the EIA-based projection of energy demand and that which can no longer be
provided by the combustion of fossil fuels under has been allocated to renewable sources that
presumably do not release GHGs. See Methods for further information
4 Implementation