Senate Majority Leader Chuck Schumer vowed Monday to hold the line and deliver sweeping climate change action in Democrats' party-line social spending bill — though he offered no concrete plans for winning over centrists who’ve expressed reservations.

Flanked by a half-dozen climate hawks during a sweltering afternoon press conference, Schumer said his caucus was doing “everything” it could to meet or exceed President Joe Biden’s goal of curbing U.S. emissions 50 percent by 2030 from 2005 levels.

“The bottom line for all of us is: We can't let this moment pass us by,” Schumer said at the event, hosted by the environmental groups League of Conservation Voters and Climate Power. “The Senate will act in a way that's commensurate with the magnitude of the climate crisis.”

Left unsaid is how the Democrats would allay the concerns of moderates like Sen. Joe Manchin (D-W.Va.) who’ve chafed at the overall price tag of the $3.5 trillion package, and the contents of climate change provisions specifically, in Manchin's case. Nonetheless, Schumer's comments amount to significant leadership buy-in as green activists and Democrats push corporate America to back their climate efforts in the reconciliation package.

Manchin on Sunday appeared cool to a centerpiece of Democratic plans to address climate change, a national clean electricity proram that would pay utilities for steadily expanding their portfolio of clean electricity while penalizing those that fail to do so.

“It makes no sense to me at all to take billions of dollars and pay utilities for what they’re going to do as the market transitions,” he said on CNN.

Schumer has previously argued to his Democratic colleagues that the electricity program, formally dubbed the Clean Electricity Payment Program, and a series of clean energy tax credits would be responsible for more than 40 percent of the total emissions reductions envisioned under the Democratic plan.