Methane leaks from city pipes in local natural gas distribution systems have fallen significantly over the past two decades, according to a study conducted by researchers at Washington State University.

The findings, published in a peer-reviewed article in the journal Environmental Science & Technology, show that methane emissions are 36 to 70 percent lower (depending on region) than current government estimates.

According to the WSU news release (emphasis mine):

Researchers found dramatically lower emissions at metering and regulating stations. In fact, because of the significant differences they saw from the early 1990s data, the researchers revisited nine sites from the previous study. They measured 10 times fewer emissions than 20 years ago.

They also measured lower emissions from individual pipeline leaks compared to earlier studies. The improvements are the result of both regulatory changes and increased investment in leak prevention by utilities.

This Houston Chronicle story notes that lead researcher Brian Lamb was “surprised” by the results, since they demonstrated decreasing methane emissions despite a 44 percent increase in natural gas distribution pipeline mileage over the period in question.

Perhaps not surprisingly, a small number of sources are responsible for a large share of the leaks that do occur. That presents a golden opportunity for utilities and distribution companies to make improvements to further the trend in methane emissions reductions.

This is just the latest bit of good news to come out about methane emissions and natural gas.

The Environmental Protection Agency recently issued its draft inventory of greenhouse gas emissions, showing that methane emissions from natural gas production have fallen 35 percent since 2007.

That decline in overall emissions from natural gas production is astonishing when you consider that domestic natural gas production has soared 22 percent in that time.

In January, the Obama administration announced its intention to roll out a slew of new regulations on oil and natural gas development as a way to cut down on methane leaks.

Since leaks are already decreasing – and quite significantly – it’s not clear what target the White House is taking aim at.