In his State of the Union address Tuesday night, President Barack Obama renewed his call to curb US carbon emissions and promised a shift toward cleaner energy production practices in the US.

Obama cited the need to continue reducing carbon emissions produced by burning fossil fuels, an echo from the State of the Union address a year ago when he promised he would start tackling climate change with, or without, the help of Congress.

"Over the past eight years, the United States has reduced our total carbon pollution more than any other nation on Earth," Obama said. (Read a full transcript of the 2014 State of the Union address here.)

"But we have to act with more urgency - because a changing climate is already harming western communities struggling with drought, and coastal cities dealing with floods. That's why I directed my administration to work with states, utilities, and others to set new standards on the amount of carbon pollution our power plants are allowed to dump into the air.

"The shift to a cleaner energy economy won't happen overnight, and it will require tough choices along the way," Obama said. "But the debate is settled. Climate change is a fact. And when our children's children look us in the eye and ask if we did all we could to leave them a safer, more stable world, with new sources of energy, I want us to be able to say yes, we did."

One of the main ways Obama can legislatively achieve his goal of carbon emissions reduction is through a systematic closure of old coal-fired power plants.

The oldest and dirtiest coal-fired power plants are already on their way to closing, facing pressure from the EPA on one side and and natural gas and renewable energy sources on the other, Ryan Cooper wrote in a Washington Post blog.

"With a bit of luck, and if the president keeps up the pressure, by the time he hands off to his successor coal will be on a permanently downward trajectory," Cooper said.

The EPA is expected to issue a ruling in June regarding carbon pollution from existing coal-fired power plants, which will likely dig the graves of the oldest and filthiest of those still in operation.

Once shuttered, the coal-fired plants will likely be replaced with natural gas plants, so-called "clean coal" plants or, in some cases, solar energy plants.

Natural gas - if extracted safely - Obama said, is "the bridge fuel that can power our economy with less of the carbon pollution that causes climate change."

"Businesses plan to invest almost $100 billion in new factories that use natural gas," Obama said. "I'll cut red tape to help states get those factories built, and this Congress can help by putting people to work building fueling stations that shift more cars and trucks from foreign oil to American natural gas.

"My administration will keep working with the industry to sustain production and job growth while strengthening protection of our air, our water, and our communities.

Frances Beinecke, president of the Natural Resources Defense Council, an influential non-profit group, lauded Obama's call to curb carbon pollution.

"Power plants account for 40 percent of our carbon pollution, and President Obama tonight underscored why we must move quickly to impose limits on them, as we do now for other pollutants," Beinecke said in a statement. "His Climate Action Plan points the way to using the Clean Air Act to allow even our most coal-dependent states to cut their emissions without economic impact."

Ending his more-than-hour-long speech's segment on climate and carbon, Obama added that he will use his executive authority to "protect more of our pristine federal lands for future generations."

Obama was presumably referring to the Antiquities Act, which allows the President to set aside certain valuable public natural areas as park and conservation land.

This authority can be used strategically, as Cooper pointed out, to lock up coal reserves inside a federally protected park, which is what President Bill Clinton did in 1996 when he declared a coal-rich area in Utah's Kaiparowitz Plateau as part of a National Monument, forever sealing the coal away from developers.