On Monday night, at the final stop on the Sunrise Movement’s “Road to a Green New Deal” tour across the United States, the group called for a mass, youth-led mobilization to pressure Democratic candidates to make the 2020 election a referendum on climate change. On July 30, the scheduled date for the second Democratic presidential debate, Sunrise hopes to bring tens of thousands of young people to Detroit to present all the Democratic contenders with three demands:

Sign the no fossil fuel money pledge .

Commit to making the Green New Deal a day one priority if elected president.

Pledge support for a presidential debate on climate change, so voters can hear where candidates stand on the issues.

Sunrise co-founder Varshini Prakash called it the “largest action our movement has organized to date for the Green New Deal.” Monday night’s event came exactly six months since Sunrise activists staged a protest in the office of Nancy Pelosi’s office before she became House speaker; they were joined by Rep. Alexandria Ocasio-Cortez, who had yet to be sworn into Congress.

Some 1,500 people turned up for the sold-out event in the Cramton Auditorium at Howard University to hear Ocasio-Cortez, Sens. Bernie Sanders and Ed Markey, policy writer Rhiana Gunn-Wright, and Intercept columnist Naomi Klein, among others. The event came just one week after a landmark U.N. report concluded that at least 1 million species are at risk of extinction due to human activity, and just days after carbon dioxide levels were recorded at the highest ever in human history.

“I wish as a public servant, I could tell you everything is going to be all right,” said Ocasio-Cortez, who was the final speaker of the evening. “But I can’t tell you that today, because I’m not interested in lying to you. … Frankly, there is no reason for us to be comfortable right now.”

Activists at Monday night’s event were nonetheless hopeful and spoke unapologetically about the need to center front-line and vulnerable communities in the policymaking process. While none said his name outright, multiple speakers blasted taking a “middle ground” approach to climate change, a reference to Joe Biden, who reportedly told Reuters last week that he sought a “middle ground” on global warming.

Ocasio-Cortez ripped “conservatives on both sides of the aisle,” drawing laughs and applause from the crowd skeptical of Democratic intransigence on the Green New Deal. “No middle ground!” a man shouted, drawing agreement from Ocasio-Cortez.

“I will be damned if the same politicians who refused to act then are going to try and come back today and say we need a middle-of-the-road approach to save our lives,” Ocasio-Cortez said. “That is too much for me.”

At a campaign stop in New Hampshire on Monday, Biden defended his record on climate and said he’d be releasing a detailed climate plan by the end of the month.