The Sierra Club and Tom Steyer's NextGen America, as well as veteran Democrat Rep. Earl Blumenauer (Ore.), are among the first backers of Rep. Alexandria Ocasio-Cortez's (D-N.Y.) upcoming resolution calling for a Green New Deal.

Where it stands: Ocasio-Cortez's office is circulating a "dear colleague" memo seeking more initial co-sponsors for the resolution that will call for a "national, social, industrial and economic mobilization at a scale not seen since World War II." It's slated to be introduced as early as this week.

Why it matters: The short memo her office is circulating seeking backers, obtained by Axios, provides an early look at support for the first formal — if non-binding — Green New Deal effort on Capitol Hill.

Democratic Sen. Edward Markey (Mass.) is working on a Senate companion.

Who they are: Other lawmakers listed as initial co-sponsors with Ocasio-Cortez are Democratic Reps. Brendan Boyle (Pa.), Joaquin Castro (Texas), Yvette Clarke (N.Y.), Pramila Jayapal (Wash.), Ro Khanna (Calif.), Ted Lieu (Calif.), Joe Neguse (Colo.), and Ayanna Pressley (Mass.).

The big picture: The memo lays out the broad framing of what the resolution will call for, including:

"Achieve net-zero greenhouse gas emissions through a fair and just transition for all communities and workers."

"Create millions of good, high-wage jobs and ensure prosperity and economic security for all."

"Promote justice and equity by preventing current and repairing historic oppression to frontline and vulnerable communities."

Details: The two dozen groups listed as endorsers include two units of the big Service Employees International Union, Working Families Party, People’s Action, Center for Popular Democracy, Justice First, Green For All, 350.org, CREDO Action, as well as the Sunrise Movement and Justice Democrats, which are the two groups at the forefront of the Green New Deal push.

Yes, but: All the groups in the memo are listed as endorsers "pending final resolution language."

The intrigue: What's actually in the resolution is unclear and apparently evolving. Per Axios' Amy Harder, Khanna said on NPR's "1A" on Monday that the resolution would not include provisions on a jobs guarantee and universal health care, something a congressional staffer also confirmed. But Ocasio-Cortez's chief of staff, Saikat Chakrabarti, called Amy later Monday to confirm that those proposals are in fact in the proposal.

Between the lines: These particular parts indicate the sweeping progressive nature of the policy, so their inclusion (or not) is notable.

Go deeper: 2020 pressure for Green New Deal

Editor's note: This story has been updated to include the latest information on what is likely to be in the forthcoming resolution.