The inauguration of Joe Biden

President Joe Biden just swore in presidential appointees from the White House in a virtual ceremony.

Biden told the administration staffers they shouldn't be working for him unless they were serious about forcing change.

"We have a chance to change things. That's the reason I got involved in politics," he said. "I really mean it. So you shouldn't be doing this unless you feel it."

Biden also told his team they were "engaged in and working with the most decent government in the world" and that he was counting on them to help "restore the soul of this country."

"People don't work for us, we work for the people. I work for the people. They pay my salary. They pay your salary. They put their faith in you. I put my faith in you. And so we have an obligation," Biden continued.

Biden ticked through some of his upcoming challenges, calling efforts to distribute the coronavirus vaccine the most "consequential" logistical challenge in US history.

He said Americans' "blinders" had been lowered when it came to systemic racism, and cited specifically the death of George Floyd in saying racial justice needed to come to America.

Biden said the US "can meet this existential threat" of climate change, and cited a past conversation with Chinese President Xi Jinping by saying his definition for the country was the single word: "possibility."

The President signed his first round of executive actions a bit ago, including an order requiring masks on federal property, one meant to ensure racial equality and another rejoining the Paris climate accord.

Here's a look at the events that will come next:

Watch the moment:

President Joe Biden warned new staff members he would terminate them if he found them trashing one another.

Making explicit he wanted to break with the toxic environment that pervaded the West Wing during the previous administration, Biden said he wanted his staff governed by collegiality and respect.

He said he wanted his staff to treat each other with decency, something he said had "been missing a big way the past four years."

Earlier in the ceremony, Biden said he wanted his staff to treat everyone with "dignity."

"History measures us and our fellow Americans…by how decent, honorable and smart we have been in looking out for their interests," he said.

Just moments after President Joe Biden signed an executive order, beginning the process of re-engaging with the World Health Organization, CNN's Dr. Sanjay Gupta said it was "an important step" in "the global vaccination effort."

"One thing we keep getting reminded of is that an infection anywhere in the world is an infection everywhere in the world," Gupta told CNN's Erin Burnett. "So the idea of being a part of a program that helps support vaccination efforts especially in low-income countries is really important. The goal is to get 2 billion vaccines to low-income countries by the end of next year."

More context: The Trump administration's notice of withdrawal from WHO was supposed to go in effect July 6, 2021.

President Joe Biden just completed signing the 15 executive actions and two agency actions, an administration official tells CNN.

What we know: Biden signed an order requiring masks on federal property, one meant to ensure racial equality and another rejoining the Paris climate accord.

Biden signed these three executive orders meant as early signs of his priorities and the start of an effort to erase his predecessor's agenda.

Sen. Tom Cotton, a Republican from Arkansas, dropped his hold on Avril Haines to be director of national intelligence, announcing on the floor that she had answered his outstanding questions.

Democratic and GOP senators expect she will be confirmed tonight with a big bipartisan vote.

President Joe Biden will then have one of his nominees on Inauguration Day; former President Trump had two, while former President's Barack Obama and George W. Bush had even more.

Hours after he was sworn in, President Joe Biden sent notice to the United Nations that the US will reenter the Paris climate accord, the landmark international agreement signed in 2015 to limit global warming, a sign of Biden's urgency to address the climate crisis.

The US abandoned the agreement late last year on former President Trump's orders. Trump spent much of his time in office weakening many of the country's bedrock climate and environmental guardrails.

Experts say that rejoining Paris is a significant step by the Biden administration to reverse the climate policies of the last four years.

Now comes the hard work: As he takes the reins of the executive branch, the challenges that Biden faces rival any confronted by his 45 predecessors — an out-of-control pandemic, a sputtering economy and the threat of right-wing extremist violence stoked by viral misinformation.

Biden's action on Paris sends a strong message that the US is prepared to cooperate in the fight against climate change and seek to reclaim the leadership role it once held, experts say. Under the agreement, countries are expected to enhance their commitments to curb greenhouse gas emissions every five years.

In 30 days, the US will be back in the agreement. From there, experts expect the pressure on the Biden administration to ratchet up.

President Joe Biden, on camera, signed three executive orders Wednesday meant as early signs of his priorities and the start of an effort to erase his predecessor's agenda.

Biden signed an order requiring masks on federal property, one meant to ensure racial equality and another rejoining the Paris climate accord.

Biden said they would be the first of many during his first days in office.

"As we indicated earlier we’re going to be signing a number of executive orders over the next several days to week," he said.

"Some of the executive actions that I’m going to be signing today are going to help change the course of the Covid crisis and combat climate change in ways we haven’t done so far," he went on.

He called the moves "starting points" that fulfilled his promises during the campaign.

"There’s a long way to go. These are just executive actions," he went on. "But we’re going to need legislation for a lot of these we’re going to do."

CNN reported that Biden plans to take 17 executive actions during his first hours in office, moving faster and more aggressively to dismantle his predecessor's legacy than any other modern president.

Sen. Mitch McConnell spoke on the Senate floor for the first time as Senate minority leader of the 117th Congress.

McConnell praised President Joe Biden for his speech today, specifically for emphasizing his call for unity and finding common ground.

He also congratulated Harris for her historic role.

“This groundbreaking achievement elicits national pride, it transcends politics. All citizens can applaud the fact that this new three-word phrase 'Madam vice president' is now a part of our American lexicon,” McConnell said.

As she was leaving the Capitol after presiding in the Senate, Vice President Kamala Harris was asked how it felt to take the chair as the now-president of the Senate. 

Earlier today, Harris swore in three senators: Georgia’s Jon Ossoff and Raphael Warnock, as well as Harris’ replacement in California, Alex Padilla.

With the swearing-in of three Democratic senators, the party breakdown of the Senate will be 50-50. Harris wields power as the Senate's crucial tie-breaking vote.