Future atmospheric methane concentrations in the context of the stabilization of greenhouse gas concentrations

Tropospheric CH4 concentration depends, according to modeled tropospheric p rocesses, on many factors, including emissions of CH4 as well as NOx and CO . Illustrative analyses of the relation between emissions and CH4 concentra tion give some guidance on the role of CH4 in the stabilization of greenhou se gas concentrations. The contribution of CH4 to radiative forcing at the time of stabilization is expected to be modest, provided CH4 and CO emissio ns do not go far beyond current rates. However, in cases leading to stabili zation the potential mitigation of increases in radiative forcing by methan e control could be comparable to that of CO2 control over the next century. Whether or not this potential is realized will depend partially on the cos t of deep reductions of CH4, NOx, CO, or CO2 missions over the next century , which is not known.