Page 91 - Managing Global Warming

62 Managing Global Warming

Finally, with GGR of 10Gt(C)/yr and maximum REC and CIR, emissions could
peak in 2030 and reduce to 8Gt(C)/yr by 2060 provided GGR commences in 2040
and peaks in 2090 (Scenario 22). However, even in this relatively fossil-fuel-friendly
world, the consumption of ZEE will be considerable with a ZEE Index of 9, implying
the need for a total of more than 38,000EJ of ZEE during the remainder of the century.
GGR of 10Gt(C)/yr is demonstrably capable of delivering the UNFCCC global
warming targets but at this scale is testing the limits of plausibility. In all these
scenarios, the GGR industry will rival global mining in size and resources and must
be developed alongside a rapidly growing ZEE sector. However, even with this rel-
atively undemanding target for the reduction of FF emissions, by 2100 the current pro-
portions of FF and zero emissions energy will need to be reversed with FF delivering
less than 20% of TFC and the annual consumption of ZEE being almost 17 times its
2014 figure.

2.7 Delivering ZEE

As already noted, never has a novel energy source resulted in less energy production
from legacy sources (Fig. 2.4 supra). In the decade to 2014, a period during which the
impetus toward green energy began to gather pace, the total amount of ZEE grew
annually by about 35% of the 2004 figure, reaching 66EJ by 2014. Fig. 2.8 shows
the relatively small contribution so far made by new ZEE technologies such as solar
and wind.
Fig. 2.9 shows the greatest likely annual and cumulative consumption of ZEE
assuming that TFC will continue to increase at its historical rate and that the transition
away from FF will be rapid. Even in this high growth scenario, it is apparent that some
80% of the ZEE necessary to meet demand during the balance of the century will not
be required until after 2050. From a policymaking perspective, this growth profile
would seem gradual enough that given the political will, sufficient ZEE could be
developed in a timely fashion.
A ZEE Index of 14 implies an aggregate ZEE demand between 2015 and 2100 of
more than 60,000EJ. In political, finance, and engineering terms, this is challenging
given that current annual ZEE isless than 70EJ. However, this increase in ZEE will
not occur proportionately across all ZEE sources. The scope for increasing biomass
(64% of ZEE in 2014) is very much less than that for solar and wind. Nuclear has
considerable growth potential but its political sensitivity and concerns about the dis-
posal of radioactive waste may be severe limiting factors [24]. The ZEE Index under-
states the challenge in scaling ZEE if most of the growth to about 1500EJ/yr by 2100 is
to come from solar and wind, which in 2014 delivered less than 5EJ (Fig. 2.8).
Novel technologies may have a role but the time from conception to global scale is
such that they are unlikely to have a major impact until the latter part of the century, by
which time those ZEE technologies currently at hand will have to have already
secured the delivery of our climate change targets.
While the virtual elimination of dominant legacy energy sources may be unprec-
edented, these figures suggest that it is plausible for the UNFCCC target to be