Biden rejoins Paris climate pact. Environmental advocates hope the best is yet to come. - NBC News

Hours after Joe Biden was sworn in as the 46th president of the United States on Wednesday, his first actions in the White House included signing two executive orders related to climate change — a move that environmental activists say heralds an administration that is ready to take bold steps to undo the damage done over the past four years.

That the executive orders came on the day of his inauguration signals that Biden is serious about the commitments made on the campaign trail to prioritize climate action, said Andrea Marpillero-Colomina, a clean transportation advocate for GreenLatinos, a nonprofit organization that focuses on environmental and conservation issues that affect the Latino community.

But the realities of climate change demand urgent action, particularly in the wake of Donald Trump's presidency, when climate change was rarely addressed or even acknowledged, Marpillero-Colomina said.

Rejoining the Paris Agreement will help restore the country's credibility, but Biden will also have to set an example by pushing for even more aggressive emissions targets to avert the most damaging impacts of climate change.

Marpillero-Colomina said Biden's inclusion of leaders from the environmental justice movement gives her hope that those who work with Black and Latino communities that are disproportionately affected by climate change will have their voices heard.

Biden is also assembling climate experts for positions throughout the government, beyond just the standard appointments in the EPA and the Energy Department, which Mann said suggests an appreciation that climate action should be interwoven with efforts in all agencies and departments

"When you look across all of the appointments, there's a clear theme: There's a recognition that climate impacts every sector of society, and so climate action has to be incorporated in every sector of society," Mann said

For Melissa Miles, executive director of the New Jersey Environmental Justice Alliance, that means showing a commitment to engaging disadvantaged communities in climate action

Equally important, she said, is crafting solutions that address the inequalities and the root causes of climate change and their direct health implications

"What I've seen so far shows that Biden was listening to front-line climate justice and environmental justice leaders, but now we have to see his plan," she said