Table 2. Global summary of the simulated CH4 lifetime with respect to OH
.
| Pre-Ind |
LGM |
|||
|---|---|---|---|---|
| Control | Low-fire | Standard | +LGM humans | |
| Emissions-driven | ||||
| Offline photolysis | 10.4 | 11.1 (+6.5%) | — | — |
| Offline photolysis, PI lightning NOx | — | 9.9 | — | — |
| Offline photolysis, PI non-CH4 surf. fluxes | — | 13.5 | — | — |
| Offline photolysis, PI climate | — | 8.6 | — | — |
| Concentration-driven | ||||
| Offline photolysis | 10.5 | 10.7 (+2.3%) | 11.2 (+6.5%) | 11.3 (7.7%) |
| Fast-J photolysis | 7.3 | 7.3 (−0.2%) | — | — |
| Fast-J photolysis, +3% strat. O3 | — | 7.4 (+1.7%) | — | — |
| Fast-J photolysis, Murray et al.16 strat. O3 | — | 7.4 (+2.1%) | — | — |
For the three fire-emissions scenarios: (i) low-fire, (ii) standard (based on LPJ-LMfire) and (iii) standard with LGM human-induced fires at the LGM. The percentage change relative to the respective pre-industrial control simulation is given in brackets.