One of the Democratic Party’s top crusaders for environmental action is now backing former Vice President Joe Biden’s White House bid.

Washington state Gov. Jay Inslee's endorsement of the presumptive Democratic presidential nominee came during a guest appearance on the latest episode of Biden’s series of “Here’s the Deal” podcasts. And Inslee’s support was announced on the 50th anniversary of Earth Day, which is celebrated each year to demonstrate support for environmental protection.

BIDEN LANDS A MAJOR GREEN ENDORSEMENT

Inslee – a rival for the 2020 Democratic nomination who centered his campaign in combating climate change before ending his bid in August – had tangled with Biden over climate change at a presidential primary debate in Detroit in late July. But in the podcast, he emphasized that the former vice president’s campaign offers "a chance for survival of life as we know it.”

“The faster we get in harness together, the likelier it is we will remove a man who has dedicated himself to deceit and rejection of science,” Inslee added as he took a shot at President Trump.

The governor’s endorsement comes as his aides are working with the Biden campaign to discuss the environmental agenda. Those conversations were first reported by The New York Times and confirmed by Fox News.

Inslee told the Times that he was “convinced, beyond the shadow of a doubt,” that the issue of climate change “will be a major driving force” of a Biden administration.

“You're going to have a concrete plan for action within the next 10 years to develop a clean energy plan, so we just don't plan to 2050. I know that you have efforts to really do things in the next 10 years and I'm very excited about this,” Inslee told Biden during the podcast.

INSLEE: TRUMP 'FORMENTING DOMESTIC REBELLION'

Inslee’s national profile has been elevated the past two months, as Washington was the first state to deal with an outbreak of the coronavirus pandemic. This past weekend he grabbed the spotlight again as he argued that the president is urging “insubordination” and “illegal activity” by supporting demonstrators protesting stay-at-home orders in multiple states.

“To have an American president to encourage people to violate the law, I can’t remember any time in my time in America where we have seen such a thing,” the governor said in an appearance on ABC’s “This Week.”

And in the podcast, Inslee said to Biden, “I know that you have a willingness to follow science and really help us get us out of the COVID-19 crisis. You're going to bring a reasoned approach to that, rather than just ignoring doctors. You're going to follow their advice. You're going to be honest with us, which we don't have right now in the White House.”

Fox News' Madeleine Rivera contributed to this report.