Updated: Sept. 23, 2014 at 6:39 p.m.

From 61st to 86th streets along Central Park West in New York City, more than 100,000 people gathered Sunday to march in the largest climate demonstration in U.S. history, shutting down Manhattan as they moved from Columbus Square through downtown.

The People’s Climate March brought together businesses, labor unions and social justice groups – with messages ranging from curbing carbon emissions to LGBT rights – hoping to prove that both the marginalized and the political elite have a stake in environmental justice.

And 2012 alumnus Evan Feeney, a senior campaigner for the year-old divestment lobby DC Divest, was one of thousands advocating for sweeping energy divestment legislation.

“It’s not just environmentalists that care about this,” Feeney said. “It’s religious groups and labor groups and neighborhood networks.”

Though he was never an environmentalist during his time at GW, Feeney and DC Divest are now spearheading a campaign to push D.C. to divest from fossil fuels. They are looking to use the momentum from the historic march to pressure the city to sell its holdings in the top 200 least environmentally friendly energy companies.

DC Divest and other divestment organizations are targeting the $35 million worth of fossil fuel investments made from the District’s $6.5 billion teacher, police and firefighter pension fund, Feeney said.

Last November, Feeney attended a series of D.C. Council hearings to testify in support of a divestment bill that Chairman Phil Mendelson had introduced on behalf of DC Divest. Ward 4 Council member and Democratic mayoral candidate Muriel Bowser co-sponsored Mendelson’s bill.

The challenge for DC Divest is locking up the votes of Council members who could swing either way, though Feeney said independent mayoral candidate David Catania recently threw his support behind the bill. He said DC Divest aims to next enlist Ward 5 Council member Kenyan McDuffie, with lobbyists trying to start conversations with the Council member’s grassroots donors and advisers.

“We now have both mayoral candidates in support and a theoretical vote count of 10 Council members in favor of the bill, with no Council members directly voicing opposition so far,” said Feeney, who will lead a rally in front of the Council’s Pennsylvania Avenue office on Tuesday.

Still, the past summer proved unremarkable for the divestment effort: The Council took a two-month recess without any legislative progress. Because of what Feeney called a “very nasty and protracted” budget fight between the Council and mayor’s office, legislators never looked at the bill that was originally scheduled for markup this summer.

Mendelson is now blocking the divestment initiative from moving to a markup after the District’s retirement board testified in opposition to the bill at a hearing last fall.

“This past spring, a lot of oxygen was sucked out of the room from the budget process,” Feeney said. “But when the Council members show up at 10 a.m. for the legislative meeting of this session, they will be greeted by all of these D.C. citizens asking them to take concrete and direct action on climate change.”

Jessica Jacobs, Mendelson’s legislative assistant for divestment, called the bill a “slippery slope.”

“It’s obviously been something [Mendelson] has been struggling with since he’s the one who introduced the bill. But if you politicize certain issues, what’s to say another Council member won’t choose another pet issue and try to divest based on that?” Jacobs said.

Looking forward, Feeney said DC Divest is focused on “allaying the concerns” that Mendelson has developed by connecting him with divestment leaders from cities like San Francisco and Seattle, as well as financial officers and former Securities and Exchange Commission commissioner Bevis Longstreth. Many were in New York for the People’s Climate March over the weekend.

To extend the impact of the People’s Climate March, the event’s logistics team comprised of environmental justice organizations in New York and New Jersey, planned it to coincide with the United Nation’s climate summit in New York City on Sept. 22.

Kyla Lang, a junior and the president of Fossil Free GW, said 50 GW students attended the march.

“The idea behind the march is climate justice. It’s not just a bunch of hippie environmentalists who really enjoy going to protests and holding signs and waving their fists. We can make this stand together,” said Lang, whose year-old group is looking to strong-arm the University into removing the top 15 most environmentally unfriendly companies from its investment portfolio.

About 150 other countries planned climate demonstrations on the same day.

“When they see people numbering in the millions, collectively, throughout London and Rio and Johannesburg and Tokyo, just every major city with a major climate demonstration, it’ll be clear to them that this isn’t some fringe movement,” Feeney said.