Modeled sources and sinks of CH_4 show that there is scope to affect radiative forcing of climate by reduction of emissions of CH_4 and the alteration of emissions of other gases which deplete tropospheric OH. For example, if anthropogenic CO, NO_x, CH_4 and CO_2 emissions rates were reduced over the next century by the same relative extent, an extent leading to stabilization of CO_2 concentration at levels from 450 to 750 ppmv along specified time-pathways, then radiative forcing of climate would be reduced from that resulting from an emissions growth baseline scenario (IPCC scenario IS92a); in these cases the reduction of radiative forcing due to changes in CH_4 concentration would be at least 27
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