Did you know that greenhouse gas emissions in the United States are falling? Last year energy-related carbon dioxide emissions were 13 percent lower than in 2005. We’re talking about levels not seen since the mid-1990s.

This is an environmental success story, with a number of characters playing significant roles.

As it happens, the lead role has been turned in by the oil and natural gas industry.

That’s the principal conclusion of a new study showing that the U.S. oil and gas industry was the single largest investor in technologies and efforts to reduce greenhouse gas emissions between 2000 and 2012.

According to the study, compiled by T2 & Associates for the American Petroleum Institute, “the U.S.-based oil and gas industry invested $165.4 billion … in end-use, fuel substitution, non-hydrocarbon, and enabling technologies” that helped reduce emissions.

That $165.4 billion contributed by petroleum companies is nearly half of the total of $336.3 billion that was invested by government, the oil and gas industry, and various other industries to tackle greenhouse gas emissions.

I should note that the $165.4 billion figure includes money spent on shale gas development. But even if you didn’t count those investments, oil and gas companies still spent $81 billion on emission-reducing technologies such as efficiency improvements, carbon capture and storage and advanced technology vehicles.

That’s more than the federal government – which spent $80 billion – or any other single industry invested on greenhouse-gas reduction efforts over the same time period.

Last year the Energy Information Administration noted that the “decline in coal-related emissions is due mainly to utilities using less coal for electricity generation as they burned more low-priced natural gas.”

Marty Durbin of America’s Natural Gas Alliance took to the Huffington Post the other day to describe this as “the quiet revolution behind your light switch.”

He’s right, and the technological story behind this revolution – in particular the oil and gas industry’s role in driving it – is one that deserves to be told far and wide.