Carbon monoxide

Carbon monoxide (CO) is a very weak Direct greenhouse gas although it has important indirect implications. CO levels vary strongly around the world and throughout the year, ranging from 30 parts per billion (ppb) to 200 ppb. It is estimated that about half of annual CO emissions are man-made and are mainly attributed to fossil fuel and biomass combustion.

=Environmental effects= CO reacts with hydroxyl (OH) radicals in the atmosphere reducing their abundance. OH acts to reduce the lifetime of Strong greenhouse gases such as Methane and so the indirect effects of CO increase its global warming potential.