170
sumption of more plant based foods (Stehfest et al. 2009; Pierrehumbert and Eshel
2015). The RCP 4.5 scenario (Thomson et al. 2011) projects a CH 4 mixing ratio of
1.80 ppm in 2060 (Table 4.2; Fig. 4.12), close to today’s value. The RCP 4.5 design
entails the use of a market pricing mechanism to stabilize global emissions of CH 4
(and CO 2 , as well) at close to present level. Finally, the RCP 8.5 projection has
atmospheric CH 4 at 2.7 ppm in 2060 and continuing to rise, unabated, until end of
century (Fig. 4.12).
As noted in the introduction, the transition of production of electricity from coal
to natural gas
32
is touted by many as being climate friendly because combustion of
32 We use natural gas and methane interchangeably, but we are well aware that the mixture of gas
burned in a so-called natural gas facility does contains trace amounts of hydrocarbons other than
methane. Indeed, the association of ethane with methane in atmospheric samples can help distinguish whether a pulse of methane is due to ruminants or industry.
a
b
c
Fig. 4.12 Impact of CH 4 on EM-GC projections using RCP 4.5. (a) Time series of atmospheric
CH 4 from observations (Dlugokencky et al. 2009), RCP 4.5 (blue, lowest curve) (Thomson et al.
2011) and RCP 8.5 (red, highest curve) (Riahi et al. 2011) as well as various other “blended” scenarios for CH 4 that are linear combinations of RCP 4.5 and RCP 8.5; (b) probability that the rise
in ΔT in 2060 stays below 1.5 °C (gold diamonds) and 2.0 °C (blue squares) relative to preindustrial, computed using RCP 4.5 combined with one of the blended CH 4 scenarios and plotted
as a function of CH 4 in 2060; (c) same as (b), except for year 2100
4 Implementation
sumption of more plant based foods (Stehfest et al. 2009; Pierrehumbert and Eshel
2015). The RCP 4.5 scenario (Thomson et al. 2011) projects a CH 4 mixing ratio of
1.80 ppm in 2060 (Table 4.2; Fig. 4.12), close to today’s value. The RCP 4.5 design
entails the use of a market pricing mechanism to stabilize global emissions of CH 4
(and CO 2 , as well) at close to present level. Finally, the RCP 8.5 projection has
atmospheric CH 4 at 2.7 ppm in 2060 and continuing to rise, unabated, until end of
century (Fig. 4.12).
As noted in the introduction, the transition of production of electricity from coal
to natural gas
32
is touted by many as being climate friendly because combustion of
32 We use natural gas and methane interchangeably, but we are well aware that the mixture of gas
burned in a so-called natural gas facility does contains trace amounts of hydrocarbons other than
methane. Indeed, the association of ethane with methane in atmospheric samples can help distinguish whether a pulse of methane is due to ruminants or industry.
a
b
c
Fig. 4.12 Impact of CH 4 on EM-GC projections using RCP 4.5. (a) Time series of atmospheric
CH 4 from observations (Dlugokencky et al. 2009), RCP 4.5 (blue, lowest curve) (Thomson et al.
2011) and RCP 8.5 (red, highest curve) (Riahi et al. 2011) as well as various other “blended” scenarios for CH 4 that are linear combinations of RCP 4.5 and RCP 8.5; (b) probability that the rise
in ΔT in 2060 stays below 1.5 °C (gold diamonds) and 2.0 °C (blue squares) relative to preindustrial, computed using RCP 4.5 combined with one of the blended CH 4 scenarios and plotted
as a function of CH 4 in 2060; (c) same as (b), except for year 2100
4 Implementation