The development of oil and gas has a 150-year history in the US, with wells stretching across the nation from California to Texas to Pennsylvania. We continue to reap the benefits of the infrastructure we built in earlier eras. But the downside to this long history comes in the form of millions of abandoned, poorly documented wells scattered throughout the country.

Recently, a team of researchers examined some of the abandoned wells in Pennsylvania to build a better picture of how this history continues to impact us today. Measurements of methane emissions revealed that abandoned wells may still be a significant source of methane to the atmosphere.

Methane is one of the more common greenhouse gases, and its warming potential is 86 times greater than carbon dioxide over a 20-year period. So limiting methane emission is an important strategy to curb global warming. Unfortunately, little is known about the ways old wells contribute to methane emissions because they are outside of our greenhouse gas emission inventory system.