Rep. Alexandria Ocasio-Cortez thinks former Vice President Joe Biden’s $5 trillion climate plan — one of the first major policies his campaign has released — is a “start,” albeit one that needs to be scaled up dramatically.

“I think what that has shown is a dramatic shift in the right direction, but we need to keep pushing for a plan that is at the scale of the problem,” Ocasio-Cortez, progressive superstar and co-sponsor of the Green New Deal, told reporters on Tuesday. (For the record, she thinks the plan that gets closest is Washington Gov. Jay Inslee’s, which she called the “gold standard.”)

But the very fact that Biden felt the need to release a climate plan near the start of his policy rollout shows the influence and success of Ocasio-Cortez and her allies in the climate movement. Five candidates, including Biden, Inslee, Sen. Elizabeth Warren, and former Reps. Beto O’Rourke and John Delaney have all released massive plans to combat climate change, ranging from $1.5 trillion to $3 trillion in federal investment over a decade. Candidates are factoring in the spur of private investments as well, hence the jump to $5 trillion in Biden’s plan.

“It’s a recognition of where the electorate is,” Monmouth University polling director Patrick Murray told Vox. “This popped out from the very beginning. Climate change and the environment in general was the No. 2 issue after health care for Democratic voters.

“I think it’s just becoming a zeitgeist for Democrats,” Murray added.

How climate change went from an “add-on” to a “zeitgeist”

Over the past eight months, climate change has shot up as a core Democratic issue in polls. Murray noted that while it certainly came up during the 2016 presidential primary and was discussed on the sidelines in 2018, this year marks a noticeable shift.

“If we look at 2016 and even 2018 among Democratic voters, there was a whole host of issues, and climate change was, ‘by the way, what do you think of that?’” Murray said. “It’s no longer an add-on, it’s become a core issue for many voters.”

Climate change is still trailing health care as the most important issue on Democratic voters’ minds; in an April Monmouth poll of Iowa voters, 51 percent of Iowa Democrats named health care as their top issue, followed by 17 percent who said climate change. But it’s also no longer an abstract concept. Iowa is currently dealing with severe flooding, with parts of towns underwater as heavy rain has caused rivers to swell.

“It shows that climate change is actually manifesting into a real political force,” Ocasio-Cortez told Vox on Tuesday, pointing to the widespread success of the climate-focused Green Party in recent European elections.

For Sen. Brian Schatz (D-HI), a longtime advocate of tackling climate change, the support can’t come soon enough. Schatz sees a direct correlation with the rising number of natural disasters like floods in Iowa and Missouri, deadly forest fires in California, and sweltering heatwaves across the world. In his home state of Hawaii, residents are watching as coral reefs bleach, beaches erode, and temperatures increase.

“Climate change is a hot issue for 2020 in a way that we’ve never seen before,” Schatz told me in an interview. “Democrats everywhere are puzzling through the challenge of turning out young voters. There’s a very simple way to motivate millennials to vote, and that’s demonstrating commitment to addressing climate change.”

While climate change is consistently a top issue for young voters, Murray insisted it’s increasingly becoming important for older voters as well.

Climate change’s sudden rise as an issue people care about isn’t coming out of nowhere. It’s been built on the work of climate activists, both from the relatively new youth activist group Sunrise Movement, as well as older organizations like 350.org, the US Climate Action Network, and others. Several of these groups have had viral moments, from a group of schoolchildren pressing Sen. Dianne Feinstein (D-CA) to support the Green New Deal, to Ocasio-Cortez encouraging climate protesters staging a sit-in in House speaker Nancy Pelosi’s office.

Sunrise Movement, which has worked closely with Ocasio-Cortez in the past, released a statement on Tuesday also calling Biden’s plan to decarbonize the US by 2050 a “good start.”

“Last month, we put the national spotlight on Joe Biden’s advisers talking about a ‘middle ground’ climate plan that included more fossil fuel development,” Sunrise spokesman Stephen O’Hanlon said in a statement. “We forced them to backtrack, and today, he put out a comprehensive climate plan that cites the Green New Deal and names climate change as the greatest challenge facing America and the world.”

To get an ambitious climate change plan passed, Democrats need more than the presidency

Schatz and Ocasio-Cortez said they’re glad to see presidential candidates releasing plans that go far beyond simply rejoining the Paris Climate Accord or taxing carbon.

But the reality is that even if Democrats win the White House in 2020, they face absolutely no chance of passing bold climate legislation if Republicans hang onto the Senate. Senate Majority Leader Mitch McConnell has special ire for the Green New Deal; he has vowed to be the “grim reaper” for the bill and other progressive legislation, and put the resolution up for a rare vote in the Senate to try to make Democrats take an uncomfortable show vote (none of them voted for it).

“Mitch McConnell will not schedule a climate bill as long as he controls the agenda,” Schatz told me. “Simply put, we need Democrats to run the Senate. It’s not enough to imagine that we have 49 votes and we capture two Republicans.”

With Republicans controlling the House and Senate for the first two years of Trump’s presidency, climate change wasn’t taken seriously on Capitol Hill at all — and barely mentioned.

“We weren’t even allowed to hold hearings on the issue or things that would contribute to carbon reduction,” said Rep. Peter DeFazio (D-OR), chairman of the House Transportation and Infrastructure Committee told Vox in February. “The Republicans were a total roadblock for us even talking about climate change. They don’t believe in it. Well, some of them do, but their leadership and the president certainly don’t.”

In order to reclaim even a bare majority in the Senate, Democrats need to hold onto the seats they have and pick up four more. Even though Senate Republicans are technically defending more territory in 2020, the map still doesn’t look great for Democrats because many of these states went for Trump in 2016. Acknowledging the challenge Democrats have before them, Schatz said he wishes some of the Democratic enthusiasm in the presidential race would trickle down to the Senate.

“I’m frankly a little worried that the excitement around the presidential race is causing people to not understand the importance of the Senate,” Schatz said.

Climate activists think the plans being proposed are all a great start, but their hopes hinge on Democrats having a great electoral year in the White House, Senate, and House of Representatives.

In other words, they have their work cut out for them.