172
leakage rates given in Table 4.4 (Brandt et al. 2014). Quantification of leakage of
CH 4 from production facilities will continue for quite some time, as will the debate
regarding which leakage rate threshold should be used, as the community attempts
to obtain consensus on whether fracking is friend or foe to climate. In some sense,
we’d prefer to use GWP over a ~45-year time horizon, since our primary focus is
projection of global warming out to 2060. We also direct the interested reader to a
critique of the concept of GWP that suggests alternative metrics (Pierrehumbert
2014), which should be considered by those assessing CH 4 leakage from fracking.
Here we use another approach to assess the impact of CH 4 on the Paris Climate
Agreement. The future projections of CH 4 offered by RCP 4.5 (Thomson et al.
2011) and RCP 8.5 (Riahi et al. 2011) are vastly different. Figure 4.12a compares
these two projections along with various “blended” scenarios, which are linear combinations of the two extremes. Simulations of the future rise in ΔT have been conducted in the EM-GC framework for the six CH 4 scenarios shown in Fig. 4.12a; all
other GHG and aerosol precursor values are based on RCP 4.5. Not only do these
calculations provide a means for assessing the importance of controlling CH 4 leakage, but they also serve as a surrogate for quantifying the importance of future
release of CH 4 from Arctic permafrost (Koven et al. 2011) (provided, of course, that
atmospheric CH 4 stays bounded by the two extremes shown in Fig. 4.12a). As noted
in Chap. 1, the present source of CH 4 from Arctic permafrost is small on a global
scale (Kirschke et al. 2013), but this could change due to feedbacks in the climate
system (Koven et al. 2011).
Figures 4.12b, c quantify the impact of future levels of atmospheric CH 4 on
achieving the Paris thresholds. Figure 4.12b shows the cumulative probability that
ΔT in year 2060, ΔT 2060 , will remain below the Paris target of 1.5 °C (gold diamonds) or the Paris upper limit of 2.0 °C (blue squares). Figure 4.12c shows similar
projections, but for 2100. Results are plotted as a function of the atmospheric mixing ratio of CH 4 for the respective end year. Otherwise, the calculations are calcuTable 4.4 Estimates of % of CH 4 leakage relative to production in the US, selected studies
Leakage (%) Region
Method
Citation
4.2–8.4
Bakken Shale, North Dakota
Aircraft sampling
Peischl et al. (2016)
1.0–2.1
Haynesville Shale, Louisiana
and Texas
Aircraft sampling
Peischl et al. (2015)
1.0–2.8
Fayetteville Shale, Arkansas
0.18–0.41
Marcellus Shale, Pennsylvania
9.1 ± 6.2
Eagle Ford, Texas
Satellite sampling
Schneising et al.
(2014)
10.1 ± 7.3
Bakken Shale, North Dakota
0.42
190 production sites including
Gulf Coast, Rocky Mountain,
and Appalachia
In situ within facility
grounds
Allen et al. (2013)
6.2–7.7
Unitah County, Utah
Aircraft sampling
Karion et al. (2013)
2.3–7.7
Julesburg Basin, Denver,
Colorado
Tall tower and ground
level mobile sampling
Pétron et al. (2012)
4 Implementation
leakage rates given in Table 4.4 (Brandt et al. 2014). Quantification of leakage of
CH 4 from production facilities will continue for quite some time, as will the debate
regarding which leakage rate threshold should be used, as the community attempts
to obtain consensus on whether fracking is friend or foe to climate. In some sense,
we’d prefer to use GWP over a ~45-year time horizon, since our primary focus is
projection of global warming out to 2060. We also direct the interested reader to a
critique of the concept of GWP that suggests alternative metrics (Pierrehumbert
2014), which should be considered by those assessing CH 4 leakage from fracking.
Here we use another approach to assess the impact of CH 4 on the Paris Climate
Agreement. The future projections of CH 4 offered by RCP 4.5 (Thomson et al.
2011) and RCP 8.5 (Riahi et al. 2011) are vastly different. Figure 4.12a compares
these two projections along with various “blended” scenarios, which are linear combinations of the two extremes. Simulations of the future rise in ΔT have been conducted in the EM-GC framework for the six CH 4 scenarios shown in Fig. 4.12a; all
other GHG and aerosol precursor values are based on RCP 4.5. Not only do these
calculations provide a means for assessing the importance of controlling CH 4 leakage, but they also serve as a surrogate for quantifying the importance of future
release of CH 4 from Arctic permafrost (Koven et al. 2011) (provided, of course, that
atmospheric CH 4 stays bounded by the two extremes shown in Fig. 4.12a). As noted
in Chap. 1, the present source of CH 4 from Arctic permafrost is small on a global
scale (Kirschke et al. 2013), but this could change due to feedbacks in the climate
system (Koven et al. 2011).
Figures 4.12b, c quantify the impact of future levels of atmospheric CH 4 on
achieving the Paris thresholds. Figure 4.12b shows the cumulative probability that
ΔT in year 2060, ΔT 2060 , will remain below the Paris target of 1.5 °C (gold diamonds) or the Paris upper limit of 2.0 °C (blue squares). Figure 4.12c shows similar
projections, but for 2100. Results are plotted as a function of the atmospheric mixing ratio of CH 4 for the respective end year. Otherwise, the calculations are calcuTable 4.4 Estimates of % of CH 4 leakage relative to production in the US, selected studies
Leakage (%) Region
Method
Citation
4.2–8.4
Bakken Shale, North Dakota
Aircraft sampling
Peischl et al. (2016)
1.0–2.1
Haynesville Shale, Louisiana
and Texas
Aircraft sampling
Peischl et al. (2015)
1.0–2.8
Fayetteville Shale, Arkansas
0.18–0.41
Marcellus Shale, Pennsylvania
9.1 ± 6.2
Eagle Ford, Texas
Satellite sampling
Schneising et al.
(2014)
10.1 ± 7.3
Bakken Shale, North Dakota
0.42
190 production sites including
Gulf Coast, Rocky Mountain,
and Appalachia
In situ within facility
grounds
Allen et al. (2013)
6.2–7.7
Unitah County, Utah
Aircraft sampling
Karion et al. (2013)
2.3–7.7
Julesburg Basin, Denver,
Colorado
Tall tower and ground
level mobile sampling
Pétron et al. (2012)
4 Implementation