Presidential candidate Michael Bloomberg took the stage at the COP25 climate conference in Madrid, Spain, on Tuesday to lead former Secretary of State John Kerry and former Vice President Al Gore in jeering at U.S. President Donald Trump’s climate policies.

The three climate activists attacked Trump on the world stage one week after Nancy Pelosi flew 3,700 miles with 12 other Democrats to the same venue to say that even though Trump has withdrawn the U.S. from the flawed 2015 Paris climate accord, to her mind the country is still in it. She said:

This is a mission, this is a passion, this is a scientifically based approach to all of it in – *clears throat* – and we’re here to say to all of you on behalf of the House of Representatives in the Congress of of the U.S. we’re still in it.

Bloomberg, who launched his 2020 presidential campaign less than three weeks ago, spoke as the official U.S. delegation was forced to look on in silence from the sidelines.

As other Democratic candidates have done, Bloomberg vowed to immediately rejoin the Paris accord if he gains the White House.

“The first thing you do, Day One, is you say we’re going back in,” he said. “That’s a no-brainer.”

He touted his own report that said non-federal actors representing more than two-thirds of the U.S. economy are on course to cut the nation’s emissions 37 percent by 2030 compared with 2005 levels. If the next administration joins in, that figure could rise to 49 percent, bringing the U.S. roughly in line with the Paris treaty, according to the report.

“Americans are willing to continue to work, even with a climate change denier in the White House,” the 77-year-old businessman told a packed room.

Gore and Kerry, for their part, said the absence of any high-profile representative from the White House at the talks “speaks for itself.”

“It’s an absence of leadership, it’s a tragedy,” Kerry lamented at an event that has attracted 25,000 attendees to fly to the Spanish capital in the name of nature, an act of hypocrisy in itself, as Breitbart’s own James Delingpole reported:

Al Gore also took his turn at attacking Donald Trump, saying politicians that ignored climate warnings are liable to face future criminal proceedings.

“It is criminally negligent for the generation of leaders in power today to stick their heads in the sand and ignore what the scientists are telling us in ever more dire terms,” he told the Thomson Reuters Foundation.

“We have to stop using the sky as an open sewer for heat-trapping pollution. It threatens the future of human civilisation,” said Gore, who won a Nobel Peace Prize in 2007.

He then urged the world to heed “mother nature.”

“Mother Nature has become the most powerful advocate for new policies to limit the impacts of the climate crisis,” Gore said.

Trump has started the process to withdraw his country from the Paris accord – but it cannot leave until the day after the November 2020 presidential elections.