The amount of methane in Earth's atmosphere has grown by about 160 percent since the Industrial Revolution began around 1750. Global levels climbed to 1866 parts per billion by 2019, representing an increase by a factor of 2.6 compared to pre-industrial times.
Methane acts as a powerful greenhouse gas with a global warming potential eighty-four times greater than carbon dioxide over a twenty-year timeframe. Over one hundred years this figure drops to about twenty-eight times greater than CO2 due to its shorter atmospheric lifetime.
About 60 percent of current methane emissions are human-caused contributing to the growth of atmospheric gas levels. Anthropogenic sources dominate the overall increase according to findings that fossil fuels agriculture and waste can each account for roughly half of the rise.
The most effective methane sink removes 90 percent of atmospheric methane through oxidation by hydroxyl radicals in the troposphere. This process reacts methane molecules to produce water vapor and carbon dioxide while another major natural sink occurs through methanotrophic bacteria residing within Earth's soils.
Scientists reported with very high confidence that current concentrations exceed any point in the last eight hundred thousand years based on ice core data collected between 1996 and 2004. The Global Carbon Project consortium updates the methane budget every few years working with over fifty international institutions to track these changes.