Some rights reserved by Light Brigading

Noah’s ark lurched and started. An inflatable mosque and Hin­du temple bounced alongside it as pagan drums sounded and Hare Krishnas danced. More than 10,000 people of faith were huddled together off Colum­bus Circle in Manhattan on September 21, waiting to join in the largest-yet show of public will to address climate change.

Many came in response to Bill Mc­Kibben’s “call to arms” in Rolling Stone magazine. “This is an invitation,” he wrote, “to anyone who’d like to prove to themselves, and to their children, that they give a damn about the biggest crisis our civilization has ever faced.” The UN would be meeting once again to begin climate talks, and people from “every corner of our society” needed to come together to demand real action. By “every corner” McKibben meant trade union members, Superstorm Sandy survivors, health-care workers, and “clergy and laypeople from synagogues and churches and mosques, now rising in record numbers to say, ‘If the Bible means anything, it means that we need to care for the world God gave us.’”

That world has already warmed 1.4 degrees Fahrenheit above preindustrial levels, and the rate of this warming has been sharply increasing. The past 20 years were the hottest in at least 400 years. These rising temperatures are having an effect. California is burning and devastated by drought. Last year in the Philippines, Typhoon Haiyan killed 7,000 people—and produced the strongest winds ever recorded on land. This is only the beginning. The Intergovernmental Panel on Climate Change, an international group of 1,300 climate scientists, predicts that the next century will see a further increase of 2.5 to ten degrees. Whether we reach the low or the high end of that range has everything to do with whether we curb our greenhouse gas emissions now.

So 400,000 of us went to New York to demand that the world’s governments do more than offer nice talk and toothless resolutions, that they show the same enthusiasm for preventing the planet from burning that they do for suing each other over trade issues. And as so many other movements have done, we put our bodies in the streets.

There were 30,000 of us at the interfaith service and 5,000 representing faith communities in another section of the march. Almost a tenth of the 400,000 marchers were there, at least in part, to recognize the sacredness of this earth our world seems set on desecrating. As GreenFaith executive director Fletcher Harper told me, climate change “undoes the kind of work our faith communities have done for centuries.”

Before the march I spoke with Stephanie Johnson, an Episcopal priest who brought a full bus of people from New England. With their bishop’s approval, they celebrated the Eucharist together on the road. Johnson highlighted the eucharistic dismissal: “Go forth to love and serve the Lord.” She commented, “What better way to go forth than with 10,000 other people of faith to witness to our care for God’s creation?”

For Johnson, this particular witness has a great deal to do with hope in the face of the dire news around climate change. “Because of Jesus,” she said, “I’m a hopeful person who knows that I am loved by God. My theology tells me that I must be hopeful.”

For all the dire warnings, the atmosphere at the interfaith service also had a hint of hopeful celebration. “We will overcome,” broke out in an impromptu chorus somewhere. Pessimists don’t tend to gather for marches in the streets. The people gathered knew that something can and must be done.

Caleb Pusey, a Wake Forest Univer­sity School of Divinity grad, was dressed in a T-shirt with a stole. “I believe in resurrection,” he said, “and yet I also sometimes have trouble with hope, so the very fact that I can bear witness to something hopeful is inspiring.”

It was a common sentiment—people showing up to be inspired. But inspiration can’t stay on the mountaintop. “The hope I see for resurrection,” said Pusey, “are the conversations that begin here and the skills for organizing that can be brought back to our local communities.”

Such conversations were beginning quickly. Pusey and I soon found ourselves talking to organizers from the Interfaith Power and Light group, an organization that began with efforts by northern California churches to purchase renewable energy together. It now has chapters spanning 38 states.

The faith community was supposed to join the main march at 12:30, but it was past 1 p.m. and no movement had started. We knew this was good news: the crowd was very large, far exceeding the 100,000 people expected by organizers.

Suddenly a tall, elderly black man made his way toward the IPL contingent, wearing a suit, a white fedora, and a medal with Martin Luther King’s face etched on it. “This is the ‘I have a dream’ medal,” he told me. “Coretta Scott King gave it to me. There are only 20 of these in existence!” This was Gerald Durley, a Baptist minister whose name appears on the Civil Rights Walk of Fame.

“Right now we are fighting for the freedom for young children to breathe,” he went on, “the freedom for old people to walk around in healthy air, the freedom to eat food that is not filled with toxins from fracking up the ground.” His voice boomed as he continued: “We are going to have to do two things: risk and sacrifice.”

This was what we were in the streets calling for as the world’s leaders gathered at the UN. We need risk and sacrifice on a scale typically called for only as part of a war effort. Carbon dioxide is overflowing the earth’s natural receptacles, warming the atmosphere, and killing off coral reefs. The Union of Concerned Scientists has called for an 80 percent reduction in U.S. emissions between 2000 and 2050. Yet greenhouse gas emissions rose 20 percent globally between 2000 and 2010, and they’ve kept on rising ever since.

Without risk and sacrifice, all this spells disaster. It is going to take serious changes in our current ways of life if we are going to continue to live on a planet that supports human flourishing.

As I walked I caught up with Fred Bahnson, director of the Food, Faith, and Religious Leadership Initiative at Wake Forest Divinity School. Bahnson is a quiet guy who likes to be in his garden in North Carolina. He joined the throng in New York because, he said, “I want to put my body where my beliefs are. . . . It is clear that our leaders are not going to take action unless we make them.” I asked Bahnson what role a march like this can play for the church. “I hope this catalyzes within the church the idea that the ecological crisis is not some side issue, something some people are into, like youth ministry or altar guild, but is at the heart of our faith,” he said. “The dome in the midst of the waters, spoken of in Genesis, is under threat from our own hand. If we really believe that Christ will redeem the cosmos, then we need to stop thwarting and start joining with Christ in that redemptive work now.”

As the march moved into the heart of Times Square, the word began to spread that we would be asked to leave the march before reaching the planned endpoint. The crowd was too big, and the police were asking us to disperse.

I spotted Ben Stewart, a liturgical theologian at the Lutheran School of Theo­logy at Chicago, and wondered what a liturgist might think of a march like this.

“I talk with my students about processions as prayers with feet,” Stewart said. “This is a kind of prayer.”

He’d come to New York on the “Climate Train,” an Amtrak train filled with activists. “Someone rewrote the song, ‘People Get Ready, There’s a Train a-Comin.’ It was this symbol that participated in the reality to which it pointed: we were on this train hurtling toward New York City with people singing, ‘there’s a train a-coming.’ It was really powerful.”

Stewart’s comments recalled a lecture I’d recently heard by ethicist Willis Jenkins of the University of Virginia. Jenkins believes we stand little chance of significantly addressing a problem like climate change by simply being the moral voice or trying to change someone’s worldview. He writes in The Future of Ethics that we need instead a “view of culture in which morality is learned in bodies, carried by practices, and formed into repertories that teach agents how to see and solve problems.” There is more hope, then, in our liturgies, our songs, and our works of charity than in any finger-wagging or attempts at the moral conversion of oil company executives. This is part of the reason I ended up in seminary rather than a school of public policy.

Soon we turned into a street with live hip-hop music, booths from various or­ganizations, and a mercifully long row of portable toilets. As I turned toward the subway that would start my journey home, liturgical words of sending echoed in my head: “Our service has now ended, and our service to the world begins.” This march, this processional service of dire lament and raucous hope, was over. But this was no end in itself. It was a place we’d come, as Stewart said to me, “to remind ourselves who we are.” Now it was time to go to work for the changes that have to happen: advocating for bike lanes on our city streets, blockading the next oil pipeline that goes through our town, gathering to fast and pray for change.

I’ll be joining in future climate actions and inviting others to as well. But I’ll also be processing every Sunday, singing hymns, proclaiming the gospel, and joining around the common meal of the one who came to reconcile all creation. Through this I hope to participate in the practices necessary for us to find our way forward—to develop the hope and courage to take the risks and make the sacrifices now required.

This article originally mispelled Caleb Pusey's name. It was corrected on October 27, 2014.