The United States officially joined the Paris Agreement on Friday, the international treaty to avert catastrophic global warming.

President Biden said tackling the climate crisis was one of his top priorities and he signed an executive order re-committing the United States to the deal just hours after he took office last month.

“We can no longer delay the fight against climate change or do what is absolutely necessary,” said Biden on Friday. “This is a global existential crisis. And we will all face the consequences if we fail. “

It was a sharp rejection of the Trump administration, which had pulled the country out of the pact and appeared to be eager to undercut regulations to protect the environment.

“The Paris Agreement is an unprecedented framework for global action,” Foreign Minister Antony J. Blinken said in a statement on Friday. “We know because we helped design it and make it a reality.”

With around 189 countries joining the pact in 2016, it had broad international support, and Mr Biden’s move to rejoin the effort was welcomed by foreign leaders.

“Welcome back to the Paris Agreement!” Emmanuel Macron, the President of France, said in a Twitter message at the time.

The galvanizing idea of ​​the Paris Climate Agreement is that only global solidarity and collective action can prevent the ravages of climate change: hotter temperatures, rising sea levels, stronger storms or droughts that lead to food shortages.

President Biden has announced a plan to spend $ 2 trillion over four years to increase the use of clean energy in transportation, electricity and buildings while rapidly moving away from coal, oil and gas. His goal is to eliminate fossil fuel emissions from power generation by 2035 and has vowed to put the entire U.S. economy on the right track to become carbon neutral by mid-century.

Former President Trump announced in 2017 that the United States would withdraw from the Paris Agreement, but the withdrawal could not be made official until November 4th last year.

The United States was officially excluded from the agreement for 107 days.

On Friday, Blinken said the fight against climate change would once again be at the center of the US domestic and foreign policy priorities.

“Climate change and science diplomacy can never again be” add-ons “in our foreign policy discussions,” said Blinken.

But he added: “As significant as our accession to the agreement in 2016 was – and as significant as our re-entry is today – what we do in the weeks, months and years to come is even more important.”

Since the industrial age began, the United States has emitted more greenhouse gases than any other country. The way the United States uses its money and power has both a symbolic and a real impact on whether the world’s 7.6 billion people, and the poorest in particular, will be able to avert climate disasters.

There are two immediate signals to watch out for. First, how ambitious will the Biden government be with its emissions reduction targets? Stakeholders are under pressure to cut emissions by 50 percent by 2030 compared to 2005.

Second, how much money will the United States spend to help poor countries adapt to global warming disasters and turn their economies away from fossil fuels?

The answers to both questions are expected in the next few weeks, just in time for the virtual climate summit on April 22nd, which President Biden has announced.