Environmental concerns and a Supreme Court mandate prompted the Environmental Protection Agency last week to issue a rule requiring a 30 percent reduction in carbon dioxide emissions by 2030. But economics have Pennsylvania ahead of the game.

The rule is partly the result of a long legal battle which culminated with a Supreme Court ruling in 2007 that greenhouse gases, including carbon dioxide, are pollutants and that EPA must regulate them under the Clean Air Act. In effect, the new rule means that operators of older coal-fired power plants will have to vastly diminish their emissions. It follows a rule issued last year that applies to new power plants, and which likely will contribute to few new coal-fired plants being built.

But coal-fueled power generation already is in decline, especially in Pennsylvania and elsewhere in the region, for economic reasons. Several generators have announced the impending closure of up to seven coal-fired plants not because of an inability to comply with environmental regulations, but because of the rise of natural gas.

That ascendancy was not envisioned by the power industry even 20 years ago, until the development of deep horizontal drilling technology provided access to vast stores of natural gas in the Marcellus and Utica shale formations that had been unreachable. Sudden availability of large amounts of relatively inexpensive natural gas has driven the exodus from coal generation. The economic advantages are compounded because gas, which also is a fossil fuel, produces from a quarter to a half of the greenhouse gas emissions produced by coal for a comparable amount of power generation.

Pennsylvania also has abundant other resources to help it continue the progression away from coal. It has abundant wind along its Appalachian ridges and, until the Corbett administration scrapped a state solar subsidy program, the state’s solar industry had experienced several years of steady growth. Now, with the federal emissions mandate and the cost of solar energy steadily declining, the state government should get the state back in that game. The coal industry is a significant political constituent for state politicians in Harrisburg and Washington, and coal will be part of the energy mix for a long time. But global warming is real and the new standards simply emphasize that coal is not the fuel of the future.

Pennsylvania should embrace the standards and use them to help make the state a leader in energy innovation and efficiency.