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Greenhouse gas removal and zero emissions energy production 61

2.6.3 GGR of 5Gt(C)/yr

GGR starting in 2025 and growing to 5Gt(C)/yr within 26 years provides even greater
flexibility for policymakers. For example, the 1.8°C target could be delivered with
emissions peaking in 2025 and falling to 4Gt(C)/yr by 2065 while allowing TFC
growth to follow its long-term trend (Scenario 17).
Even the 1.5°C target can be achieved although it requires emissions to stabilize at
only 3Gt(C)/yr by 2056 and requires help from REC (20% in 20 years) and CIR (15%
in 25 years). However, in this scenario, the carbon budget is breached in 2030 and is
gradually brought back on target through the remainder of the century (Scenario 18).
There is no combination of plausible policies that would avoid breaching the 1.5°C
carbon budget.
If the commencement of GGR is deferred until 2040, the 1.8°C target would require
emissions to settle 5 years earlier at the lower level of 3Gt(C)/yr. This overshoots the
carbon budget in 2042. No combination of plausible policies can eliminate this over-
shoot. For the less demanding 2°C target, emissions could be reduced to 5Gt(C)/yr by
2058 and if GGR grows to 5Gt(C)/yr over 26 years starting in 2040, there would be no
overshoot of the carbon budget (Scenario 19). The ZEE Index remains high at 13.
Reducing TFC by 20% in 20 years from 2018 reduces the ZEE Index to 10 and reduces
marginally the requirement for GGR to 4.7Gt(C)/yr. This is a world in which GGR
removes atmospheric CO 2 as fast as FF consumption puts it there.

2.6.4 GGR of 10Gt(C)/yr
This set of scenarios describe a world in which FF energy production is much as it is
today, and as fast as the GHG emissions are produced, they are captured and perma-
nently sequestered. At this level of GGR, policymakers have great freedom to manage
the transition from FF to ZEE. One scenario that delivers the 1.5°C target with
10Gt(C)/yr of GGR reached within 41 years from 2025, is for emissions to peak
by 2028 and be reduced to 7Gt(C)/yr by 2062 together with a contribution of 15%
in CIR delivered over 20 years to 2037 (Scenario 20). Without any REC, this still pro-
duces a ZEE Index of 13, although this can be reduced to 10 with the maximum plau-
sible REC; this also reduces the requirement for GGR to 9.5Gt(C)/yr. In this scenario,
there is a significant overshoot of the carbon budget that peaks in 2050 and is gradually
recovered during the remainder of the century.
For 1.8°C there is even more latitude with emissions peaking in 2018 and then
returning to today’s level of 10Gt(C)/yr within 10 years and GGR commencing in
2025 and reaching 10Gt(C)/yr by 2065; no assistance is required from CIR or
REC. Alternatively, emissions could peak in 2030 and take 26 years to stabilize at
8Gt(C)/yr, together with GGR commencing in 2025 and taking 45 years to reach
10Gt(C)/yr (Scenario 21). Here there is a modest overshoot and the ZEE Index with-
out REC is 12. With 20% REC, the ZEE Index reduces to 9 and the requirement for
GGR reduces to 9.1Gt(C)/yr.