Good Samaritans cleaned beaches, picked up trash from highways, and marched peaceably in many cities in support of battling climate change — mainly by reducing our consumption of fossil fuels. But a major milestone went unmentioned on Earth Day, namely that America’s greenhouse gas emissions, or GHGs, are lower today than they were 20 years ago even as the economy has expanded by more than half.

How was this accomplished? Not as a result of environmental regulations and mandates or the huge subsidies given to renewables like wind and solar, but rather by using more, not less, of a fossil fuel called natural gas.

It’s a well-known fact that natural gas burns a lot cleaner than coal or oil. The simple chemical composition of the gas lends itself to fewer impurities in combustion, and because it burns cleanly, carbon dioxide emissions are less than half that of coal and a third less than fuel oil, diesel or gasoline.

At the same time, thanks to the so-called “shale revolution,” natural gas is abundant and inexpensive, and likely to remain so for the foreseeable future.

Consequently, the power-generation sector, which is responsible for about 25 percent of GHGs in the U.S., has moved quickly to adopt natural gas. Electric utilities have shuttered more than 250 coal plants since 2010, and a dozen more will close this year.

A decade ago, coal-fired generation accounted for about 50 percent of the electrons coursing through the nation’s power grids, but by last year, that had dropped to 27 percent. No utility in the nation has plans to build a new coal plant in the future.

Opponents of fossil fuels acknowledge that gas has a smaller carbon footprint than coal but nonetheless object to its use because of the methane releases associated with its production and transportation. Because the heat-trapping characteristics of methane are 20 times greater than carbon dioxide, environmentalists have good reason to be concerned.

However, again they fail to acknowledge the tremendous progress that has been made in recent years to contain methane emissions.

According to data from the Environmental Protection Agency and the Energy Information Administration, methane emissions from onshore U.S. oil and natural gas production fell 24 percent between 2011 and 2017 even as production increased by almost 50 percent and 730,000 miles of new transmission and distribution pipelines were added.

What’s more, the Oil and Gas Climate Initiative, a coalition of global energy companies, has committed to cutting average methane intensity by at least 20 percent and total emission levels by one-third by 2025.

America’s natural gas boom is also helping reduce greenhouse gas emissions abroad. From virtually zero a few years ago, liquefied natural gas, or LNG, exports approached 800 billion cubic feet last year. With capacity expected to double by the end of this year, export volumes will continue to grow exponentially. Indeed, by 2024 the U.S. is projected to be the world’s second-largest exporter of LNG, after Qatar.

Countries such as China, India and Japan that still rely heavily on coal for power generation are among the largest purchasers of American LNG. To the degree they substitute our “clean gas” for their domestic or imported “dirty coal,” the air becomes cleaner while global greenhouse gas emissions are reduced.

Cheap natural gas, made available by hydraulic fracturing, has already made the U.S. the world leader in carbon emissions reduction.

Though President Donald Trump took us out of the Paris climate treaty, we will surely exceed the carbon reduction targets in that agreement, and well ahead of schedule.