Page 23 - Managing Global Warming

18 Managing Global Warming

emitted. The amounts of these gases and their dilution in the atmosphere create a
sociopolitical and engineering challenge of unprecedented proportions. Climatically
relevant scale is orders of magnitude greater than industrial scale, and the
interdependence of the options available to policymakers means that portfolios of
individually plausible policies may not be plausible in aggregate.
This chapter does not promote any particular net emissions technology (NET) to
deliver greenhouse gas removal (GGR). Instead, it treats them as a generic set of tech-
nologies that have in common the capture and permanent sequestration of atmospheric
CO 2 . The question addressed here is how much GGR will be required, not which
NETs will deliver it [1].
Solar radiation management (SRM) can assist in meeting the temperature targets by
reducing net insolation, thereby allowing a more gradual path to zero emissions, but it
cannot contribute to reducing greenhouse gases (GHGs), a necessary element of any
long-term sustainable climate policy. SRM is therefore outside the scope of this chapter.
The chapter uses outputs from a calculator designed to show how the
interdependent policy variables affecting energy consumption and emissions combine
to produce future consumption and emissions scenarios extrapolated to 2100. The core
assumptions and relationships that define the algorithms behind the calculations are
described in Section 2.2.
A critical challenge for policymakers is to decide which of the infinite range of
possible futures are policy relevant. The chapter deploys the complexity theory con-
cept of plausibility to define the feasible range of policy options and assess the extent
to which they rely upon zero emissions energy (ZEE) and GGR. The concept of plaus-
ibility is explained in Section 2.3.In Section 2.4, the interconnectedness of the input
parameters and their relative sensitivities are discussed without considering their feas-
ibility. In Section 2.5 plausibility is used to discard infeasible policy options, and
Section 2.6 looks at the policy implications of a range of feasible policy portfolios,
ranked according to their dependence on GGR. In Section 2.7, the plausibility of
meeting the demand for ZEE is assessed. The chapter closes with conclusions in
Section 2.8.
Notation used in this chapter follows the conventions set out in Box 2.1.

2.2 Methodology

This analysis is based on global aggregates without reference to geographic or national
distributions of energy consumption or production. It relies on three core axioms.
First, total final energy consumption (TFC) can be met either from fossil fuels (FF)
or from ZEE (biomass, nuclear, solar, wind, geothermal, tidal, and hydro). Second,
in a heterogeneous market-based global economy, global energy consumption is
market driven and cannot be determined by government fiat. Third, public policy
can influence the rate and direction of change in energy consumption, its primary
sources, and energy efficiency.
The analysis also makes the assumption that the climatic effect of a unit of GHG
removed is the same as a unit not emitted. However, the reduction in atmospheric
aerosols resulting from reduced FF combustion may generate countervailing net