(CNN) - Al Gore, environmental activist and former vice president, said he was "very pleased" to hear President Barack Obama pledge to combat climate change in his inauguration speech. He urged the president to "follow through" on his commitment.
"There are some actions he can take that do not require congressional approval," Gore said in an interview that aired Sunday on CNN's "Fareed Zakaria GPS."
Gore argued the president should expand current Environmental Protection Agency regulations, saying such action would be protected by the Supreme Court.
"There is a law on the books that requires the EPA to regulate pollution. The Supreme Court has agreed with the obvious interpretation that global warming pollution is pollution," he said. "It's been applied to new coal plants. It should be applied to all facilities."
Environmental groups like the Sierra Club and the Natural Resources Defense Council have also called on the president to keep his distance from Congress on climate change.
They argue Obama can take executive actions such as curbing carbon emissions among existing power plants, not just new plants, and mandating high efficiency standards for larger trucks and longer haul vehicles.
In 2011, the EPA issued new standards on toxic pollutants and mercury emissions from coal power plants. Obama also finalized regulations requiring that passenger cars and trucks nearly double their fuel efficiency by 2025.
While Obama made some environmental changes in his first term, he signaled his second term would be more focused on the issue, a topic he rarely touched upon during his re-election campaign.
"We will respond to the threat of climate change, knowing that the failure to do so would betray our children and future generations," he said in his inauguration speech last month. "Some may still deny the overwhelming judgment of science, but none can avoid the devastating impact of raging fires and crippling drought and more powerful storms."
Gore said he thinks Obama should "move boldly on the agenda," arguing that the president is already taking big steps on other issues he wants to champion, such as gun control and overhauling immigration laws.
"I think that you already see a greater depth and sophistication in his approach," he said. "One thing that I think President Obama has demonstrated is an ability to reach across the aisle, to try to invite more cooperation. But he's now tempering that with a new firmness … that I think will serve him in good stead."
- CNN's Dan Merica contributed to this report.