President Barack Obama speaks about his Clean Power Plan on Monday in the East Room at the White House in Washington. The president is mandating even steeper greenhouse gas cuts from U.S. power plants than previously expected, while granting states more time and broader options to comply. (AP/Susan Walsh)

President Obama delivered a passionate plug for his Clean Power Plan to cut carbon emissions from electricity plants, saying "there is such a thing as being too late when it comes to climate change."

The White House sought to hit back at those who have said that the plan unveiled formally today by the Environmental Protection Agency would kills jobs in the coal industry and raise costs to consumers of electricity. “We’ve heard these same stale arguments before,” Obama said in remarks to supporters in the East Room of the White House Monday afternoon.

Earlier at the daily press briefing, White House spokesman Josh Earnest asserted that there were more coal industry jobs lost under Presidents Reagan and Clinton than under Obama.

[New EPA rule on greenhouse gases the latest blow to King Coal]

"Coal states have been losing jobs for decades," Obama said. He said that mining industry workers would benefit from his healthcare and job retraining programs. "I want to help them, not use them as a partisan football," the president said.

The president said he was going "off script" at one point and recalled arriving in Los Angeles to go to college and feeling the effects of pollution.

"I had a lot of pent up energy and wanted to take a run. And suddenly in five minutes I got this weird feeling like I couldn’t breathe," said Obama. He said "some of the characters" who are criticizing the Clean Power Plan were criticizing earlier efforts to stem air pollution, but that government and industry were able to reduce pollution. "The kind of cries you hear are excuses for inaction," he said.

[Clean-energy debate pitted ambition against legal worries]

Obama appeared to get emotional when describing the Earth as a "blue marble" in NASA photographs from space that "belongs to all of us." He said "I don’t want my grandkids to not be able to swim in Hawaii or climb a mountain or see a glacier because we didn’t do something about it. That would be shameful of us. This is our moment to get something right." He added, "There is no Plan B."