A proposal from Washington Gov. Jay Inslee to have a presidential debate focused on climate change gained steam on Wednesday with backing from a rival 2020 candidate and a coalition of environmental groups.

Inslee on Tuesday called on the Democratic National Committee to host an all-climate debate during the 2020 primary campaign season. The governor, who is centering his presidential campaign around climate change, said in an email to supporters that the Democratic nominee selected to challenge President Donald Trump needed to have a “concrete plan to address” the phenomenon, and that American’s deserved to hear it in advance of the primaries.

“Climate change is at the heart of every issue that matters to voters, and voters deserve to hear what 2020 presidential candidates plan to do about it,” Inslee wrote in the email, first reported by The Daily Beast.

Most Democrats in the crowded field have made climate change a core tenet of their campaigns, in direct opposition to Trump’s climate-denying policies. The White House has dramatically rolled back many environmental regulations and moved to withdraw the U.S. from the landmark Paris Climate Agreement as Trump himself has mocked the science around the issue.

Inslee’s debate idea was quickly endorsed by Sen. Kirsten Gillibrand (D-N.Y.), who called climate change the “greatest threat to humanity today.”

“A DNC debate focused on climate change would show the world that America intends to lead again on this issue, and would be a smart place to discuss the key tenets of the Green New Deal — infrastructure, green jobs and clean air and water — and how to put a price on carbon,” Gillibrand said in a statement to The Daily Beast.

But it’s unclear how far those conversations will go.

The DNC’s communications director declined to commit to Inslee’s proposal, simply saying that the party was “eager to put forward solutions to combat climate change” and that future debates would “absolutely have these discussions during the 2020 primary process.”

“The DNC is currently ironing out the details for all 12 debates and will work with the networks to ensure that Democrats have a platform to discuss these issues directly with the American people,” the spokesperson, Xochitl Hinojosa, told Axios.

A coalition of 11 environmental and progressive groups, including Greenpeace USA and 350 Action, released a petition shortly after Inslee’s proposal, calling on the DNC to back his plan.

“We need to know that whoever is nominated to take on Trump in 2020 has what it takes to stand up to the fossil fuel industry and fight for bold solutions to the climate crisis,” the coalition said in a statement. “That’s why we need a full debate focused specifically on climate change, so an informed moderator can press candidates beyond platitudes, seek out specific details, and hold them accountable to what the science says is necessary.”