Figure 2. Last glacial maximum atmospheric CH₄ lifetime change relative to the pre-industrial (%) and estimates of the separate contributions to this change.

LGM minus pre-industrial relative CH₄ lifetime change (dark upper bar), and sensitivity experiments (perturbation minus LGM), light bars below. V: Valdes et al.⁸, K: Kaplan et al.⁷,¹⁴, L: Levine et al.¹⁵, S: Singarayer et al.¹⁰ and Murray et al.¹⁶, for which only warm-LGM simulations are included and where m denotes the low-fire scenario. The effects of physical climate changes on reaction rates were not accounted for by Kaplan et al.¹⁴ or by Singarayer et al.¹⁰ shown in blue. Note for the BVOC sensitivity tests, Valdes et al.⁸ only changed isoprene and terpene emissions, Levine et al.¹⁵ also changed CO, ethane, propane and acetone; while here soil NO_x was also included. Details of all of the lifetime results are given in Table 2.