Methane accounts for more than one-quarter of the anthropogenic radiative imbalance since the pre-industrial age. Its largest sources include both natural and human-mediated pathways: wetlands, fossil fuels (oil/gas and coal), agriculture (livestock and rice cultivation), landfills, and fires. The dominant loss of methane is through oxidation in the atmosphere via the hydroxyl radical (OH). Apart from its radiative effects, methane impacts background tropospheric ozone levels, the oxidative capacity of the atmosphere, and stratospheric water vapor. As such, changes in the abundance of atmospheric methane can have profound impacts on the future state of our climate.