“It doesn’t indicate that we love everything. It indicates where we think we have the best chances of pushing our agenda,” 350 Action Executive Director May Boeve told POLITICO in an interview. “We’ve already seen movement and we’re going to keep pushing.”

Background: The group, which rose to prominence opposing the Keystone XL oil pipeline and led the “Keep It In The Ground” movement to halt fossil fuel extraction, hoped its support would galvanize environmentally minded voters who had backed Biden rival Sen. Bernie Sanders (I-Vt.) in the primary and are considering sitting out the election. Other progressive greens, like the youth-led Sunrise Movement, have also begun speaking positively about Biden after dogging him in the primary. Biden's campaign, too, has deepened outreach to the party's left flank.

“If they got excited about Bernie they should get excited about so much of that platform getting absorbed into this one,” 350 Action North America Director Tamara Toles O’Laughlin told POLITICO. “It’s actually quite staggering how people who are so involved, who care about these issues, feel like they have not been spoken to.”

Sanders and Sen. Elizabeth Warren (D-Mass.), another progressive favorite, both called for national fracking bans. To the dismay of some progressives, Biden has said several times he does not support a national fracking ban. Several progressive green groups have slammed Biden for consulting with policy insiders they contend are too cozy with fossil fuel companies.

What's next: Boeve and Toles O’Laughlin said they believed progressives could push Biden into more aggressive action on fracking and other climate policies if he wins the White House.

“Our own transformation is proof that that’s possible,” Toles O’Laughlin said. “As a group of people who pride ourselves on being really skeptical, it’s super important for us to recognize when the needle has moved."