The Environmental Defense Fund (EDF) has prepared an information page about methane an how harmful it is to our air. https://www.edf.org/climate/methane-other-important-greenhouse-gas
The EDF information also included a link to their map of methane leaks so you can see if there is one near you.
Methane is 84 times more potent as a greenhouse gas in the first 2 decades after it is released, compared to carbon dioxide. EDF estimates that 25% of climate change can be attributed to methane.
Methane comes from natural (bogs, etc.) and man-made sources (oil and gas production, leaks in pipelines, agriculture). In 2016 the EPA established a methane rule that requires oil and gas companies to capture methane leaks as they are drilling and producing oil.
We need the 2016 methane rule to stay in place and not be weakened.