An emerging Capitol Hill deal could give White House carbon-cutting goals a huge lift that looked all but impossible weeks ago.

Why it matters: President Biden's target under the Paris Agreement of cutting U.S. emissions 50% by 2030 could be within reach if Congress approves the new clean energy investments, analysts say — but it's not clear that it would have the votes to pass.

Catch up fast: Senate Majority Leader Chuck Schumer and Sen. Joe Manchin (D-W.Va.) have unveiled the details of a revenue-and-spending deal with $369 billion in "energy security and climate change" measures.

• If approved, it would be the biggest federal investment in clean energy yet made in the United States.
• Manchin's vote is needed to move the bill on a party-line vote.
• But Sen. Kyrsten Sinema (D-Ariz.) would have to vote for it too, and there's no guarantee that she will. "We do not have a comment, as she will need to review the text," a Sinema spokesperson told Axios' Alayna Treene and Hans Nichols Wednesday night.

Details: The bill would provide tax credits and other incentives to spur the development and deployment of clean energy and carbon abatement technologies.

• These include wind and solar power, so-called "clean hydrogen," as well as direct air capture.
• It also includes monetary incentives to help people buy clean cars, subject to certain income requirements.
• It would incentivize the increased domestic production of critical minerals used in batteries for electric vehicles.
• In a concession to Manchin, the bill would also force the Interior Department to reinstate Gulf of Mexico oil drilling leases from a 2021 auction that was vacated by a federal judge, and conduct new Gulf leasing as well.

Zoom in: A few takeaways on the bill's unexpected revival Wednesday evening...

1. It looks consequential. Schumer and Manchin jointly said it would cut U.S. emissions by 40% by 2030. Schumer's office confirms that's from 2005 levels, the same baseline as Biden's pledge.

• Ben King of the Rhodium Group, a research firm, tells Axios if the deal is consistent with the package they've previously modeled, it could "plausibly" put the U.S. on track for a 40% reduction.
• "Additional action by the Biden administration and states can help close the rest of the gap to the target of a 50-52% cut by 2030," he said via email.
• Princeton University energy expert Jesse Jenkins also tells Axios that the estimate from Schumer's office looks accurate.
• "It'll probably be at least 800 million tons and up to 1 billion tons of additional [emissions] reductions in 2030 relative to current policy baseline," he said via email, noting that's about two-thirds to three-quarters of what's needed to reach Biden's target.

2. It has global implications. Stronger U.S. climate efforts could prompt other big polluters to do more. Peer pressure matters in global climate diplomacy, since commitments under the Paris deal are voluntary.

3. The path forward looks very real. Several of the most outspoken lawmakers on climate — like Sens. Brian Schatz and Sheldon Whitehouse — applauded the deal.

• The House Progressive Caucus said it needs to evaluate the details of the overall package, but said it's a "promising" step.
• But it's certainly not a done deal. Every Senate Democrat must be on board to move the bill, while House Democrats can afford only a handful of defections.

4. Some lawmakers will have to grit their teeth. Manchin, whose state is a big coal and gas producer, backs fossil fuels more than most Democrats.

• In a statement, he said the deal invests in tech needed for all energy types — including fossil fuels — to be used as cleanly as possible.
• "This bill does not arbitrarily shut off our abundant fossil fuels," Manchin said.

What they're saying: University of California at Santa Barbara climate policy expert Leah Stokes said the bill would be "transformative" in terms of boosting clean energy jobs and manufacturing — and would be timely after the extreme weather events of recent weeks.

• "I think that the last two weeks have shown us what the price of failure is. That it is an unlivable planet," she said.

Go deeper:

Manchin announces support for climate, tax, health care deal

Washington waits for Sinema's verdict