The Ile Saint-Louis is illuminated with the lettering reading 'The Paris accord is done' in Paris, Nov. 4, 2016, to celebrate the first day of the application of the Paris COP21 climate accord.
FILE - The Ile Saint-Louis is illuminated with the lettering reading 'The Paris accord is done' in Paris, Nov. 4, 2016, to mark the first day of the enforcement of the Paris COP21 climate accord.

U.S. President Joe Biden warned Friday that climate change is a “global existential crisis” that must be addressed, as the United States rejoined the 2015 Paris Climate Agreement.   

“We will all suffer — we will all suffer — the consequences if we fail,” Biden told leaders at a virtual gathering of the Munich Security Conference. 

“We have to rapidly accelerate our commitments to aggressively curb our emissions and to hold one another accountable for meeting our goals and increasing our ambitions,” he said. “That’s why as president I immediately rejoined the Paris Agreement, and as of today, the United States is officially once again a party to the Paris Agreement, which we helped put together.” 

Biden’s move reverses a Trump administration decision to leave the climate pact aimed at cutting greenhouse gas emissions. The former president was a supporter of the fossil fuel industry and often mocked clean renewable forms of energy, such as wind. 

In 2017, then-president Donald Trump announced the U.S. would pull out of the landmark agreement, saying it was in America’s “economic interest to do so.” But terms for leaving the accord meant his decision did not go into effect until November 4, 2020 – one day after the U.S. presidential election won by Biden.   

FILE - President Joe Biden signs a series of executive orders, in the Oval Office of the White House, in Washington, Jan. 28, 2021.

The 2015 Paris agreement, signed by virtually every country in the world, aims to reduce global greenhouse gas emissions and limit the planet’s temperature increase during this century to 2 degrees Celsius, while working to limit the increase even further to 1.5 degrees.   

On January 20, shortly after being sworn in, Biden signed a stack of executive orders, including the instrument to rejoin the Paris Agreement. It was sent to the United Nations, where treaties and agreements are “deposited” with the secretary-general, and now, after a 30-day wait, the U.S. officially becomes a party to the agreement once again.   

FILE - U.N. Secretary-General Antonio Guterres.

At a virtual event to mark Washington’s return to the accord, U.N. Secretary-General Antonio Guterres said it is a “day of hope,” and good news both for the United States and the world. 

“For the past four years, the absence of a key player created a gap in the Paris Agreement; a missing link that weakened the whole,” he said of the Trump years when the U.S. did not engage on climate action.  

“This is the race of our lifetimes,” Guterres added. “We must go much faster, and much farther.” 

Biden has committed to ambitious targets, including the U.S. achieving a 100% clean energy economy and reaching net-zero emissions no later than 2050. 

He appointed former U.S. Secretary of State John Kerry – who helped negotiate the Paris deal in 2015 – as the first-ever presidential envoy on climate and made him a part of his National Security Council.   

Kerry joined the U.N. chief on Friday, declaring that “failure is not an option” and noting that emissions have continued to rise globally in the years since Paris. He said this means the transition away from fossil fuels to renewable energy has to happen faster. 

“Everything has to be done with a greater sense of urgency, with the determination that we have to win this fight,” Kerry said. “Can we do that? Can we win it? Absolutely my friends, we can!” 

He said that would require the largest emitters, including China, the United States, India, Japan and the European Union, to be realistic about what they need to do in the next 10 years to meet net-zero targets and keep the Earth from warming more than 1.5 degrees Celsius. Anything over 1.5 degrees “will have catastrophic implications around the globe,” he said. 

On April 22 — Earth Day — the Biden administration will hold a Leaders Climate Summit to drive more ambitious action among top emitters, including in the United States.