After withdrawing from the Paris climate agreement under the Trump administration last year, the United States formally rejoined the international effort.

With a new administration, President Joe Biden signed an executive order for the United States to rejoin the Paris Agreement hours after being sworn in. Prior to assuming office, Biden promised to sign the necessary documents to rejoin the agreement on Inauguration Day.

“We can no longer delay or do the bare minimum to address climate change,” Biden said. “This is a global, existential crisis. And we’ll all suffer the consequences if we fail.”

Former President Donald Trump began the process of removing the United States from the agreement back in 2017 and the country did not officially exit until late last year. The United States was the first and only country out of almost 200 nations to exit the effort, according to NPR.

Rejoining the Paris Agreement is a very important step in the Biden administration’s plan to reverse Trump’s changes to existing climate policies in the past four years.

After Biden’s move was made official last month, Secretary of State Antony Blinken expressed his satisfaction with the United States rejoining the agreement on Twitter, guaranteeing the nation would “waste no time” in the fight against climate change, according to CNN.

“Now, as momentous as our joining the Agreement was in 2016 — and as momentous as our rejoining is today — what we do in the coming weeks, months, and years is even more important,” Blinken said in a statement.

Following the recent announcement of the country’s formal return to the agreement, world leaders rejoiced in Biden’s move, sending him celebratory and welcoming messages on social media.

“I warmly welcome @POTUS Joe Biden’s steps for the USA to re-enter the #ParisAgreement, the global roadmap to tackle the climate emergency,” Secretary-General of the United Nations António Guterres said. “With all countries fully engaged, we have a real opportunity to prevent climate catastrophe & embark on transformative #ClimateAction.”

Another celebratory message came from French President Emmanuel Macron, who excitedly labeled the formal announcement as a “significant day for the American people.”

“We are together. We will be stronger to face the challenges of our time. Stronger to build our future. Stronger to protect our planet. Welcome back to the Paris Agreement!” Macron said on Twitter.

Climate experts are also weighing in on Biden’s action, stating the move is a critical step in properly fighting the ongoing climate crisis.

“From Paris to Keystone to protecting gray wolves, these huge first moves from President Biden show he’s serious about stopping the climate and extinction crises,” Executive Director of the Center for Biological Diversity Kieran Suckling, said.

“These strong steps must be the start of a furious race to avert catastrophe.”

Many experts, however, still emphasize that there is still a lot that has to get done to get the United States back on track with the global effort against climate change.

“Rejoining is just table stakes,” John Morton, the former energy and climate director under the Obama administration, said.

“The hard work of putting the country on a course to becoming net zero emissions by midcentury begins now.”