Five years to the day after world leaders signed the Paris Agreement, President Joe Biden is hosting a summit on Thursday with fellow heads of state to stimulate efforts to tackle climate change also with the aim of making the United States the leader in addressing the issue.

The two-day virtual event is set to begin on Thursday, Earth Day, with the leaders of some 40 countries among the world’s largest economies – including Chinese President Xi Jinping, Japanese Prime Minister Yoshida Suga, German Chancellor Angela Merkel and Indian Prime Minister Narenda Modi.

The White House said Biden plans to announce an “ambitious” 2030 emissions target ahead of the meeting, possibly Wednesday, which comes as the new administration attempts to reassert itself as a world leader in efforts to limit global warming to 1.5 degrees Celsius above pre-industrial levels.

Former U.S. Secretary of State John Kerry joined some 195 signatories to the Paris pact during a ceremony in New York City on April 22, 2016. But the framework was little more than a year old when the next administration delivered a notice to the United Nations announcing the United States’ withdrawal.

Former President Donald Trump called the agreement “unfair” to the United States, saying it undermined the U.S. economy and was a bad deal for American workers.

On the first day of his administration in January, Biden immediately sought to reverse Trump’s efforts to downplay climate change and announced his intention to rejoin the pact.

John Podesta, founder of the Center for American Progress, said this week’s climate summit will be Biden’s chance to undo some of the Trump administration’s environmental policies.

“[Biden] comes into this summit with the need to repair U.S. credibility after four years of a president who denied the existence of climate change and did everything in his power to undermine the programs in the U.S. that were attempting to reduce emissions,” Podesta said, according to Vox.

David Waskow, International Climate Initiative director at the World Resources Institute, told a television show that Biden could set the standard by which other countries will act with his announcement of a new emissions target.

“Certainly China is looking to see what the United States is going to do,” he said. “We know that some of these other countries – Japan, South Korea, Canada, India — are watching to see how the United States will move.”

The White House said the summit will include discussions about how to utilize public- and private-sector finance, and technology to drive the transition to net-zero emissions, as well as the economic benefits of climate action.

The summit on Thursday follows a report by the International Energy Agency this week that says global carbon emissions could decrease by nearly 5 percent in 2021,  wiping out most of the decline that was seen in 2020 due to Covid-19-related shutdowns. The IEA said in its Global Energy Review 2021 that if the carbon increases continue as projected, this year would see the greatest growth of emissions since 2010 and would be the second-largest rise in history.

A World Meteorological Organization report earlier this week said the pandemic-related shutdowns failed to slow the drivers of climate change.

“This report shows that we have no time to waste,” United Nations Secretary-General António Guterres said.

“Countries need to commit to net zero emissions by 2050. They need to submit … ambitious national climate plans that will collectively cut global emissions by 45 percent compared to 2010 levels by 2030. And they need to act now to protect people against the disastrous effects of climate change.”