Impact of a global warming on biospheric sources of methane and its climatic consequences

Abstract

Most of atmospheric methane originates by bacterial processes in anaerobic environments withinthe soil which are found to become more productive with increases in ambient temperature. Awarming of climate, due to increasing levels of industrial gases resulting from fossil fuel burning, is thus likely to increase methane abundance within the atmosphere. This may lead to furtherheating of the atmosphere, since both methane and ozone (which is generated in the tropospherefrom reactions of methane) have greenhouse effects. We have explored this feedback mechanismusing a coupled climate-chemical model of the troposphere, by calculating the impact of thepredicted global warming due to iricreased emissions of carbon dioxide and other industrial gaseson the biospheric sources of methane. Although we find this climate feedback to be, by itself, relatively minor, it can produce measurable increases in atmospheric CH₄, concentration, aquantity which should additionally increase as a consequence of increasing anthropogenicemissions of CO and CH₄, itself. It would thus seem useful to carefully monitor futureatmospheric CH₄, concentrations