I wake up every day thinking about nuclear weapons.

But when the credits rolled on Christopher Nolan’s Oppenheimer, the disquiet of the Trinity test—the first-ever detonation of an atomic bomb—refused to let go of me. “The culmination of three hundred years of physics,” a pillar of fire and cloud reaches into the heavens, the utter silence of it stretching for two full minutes before its thunderclap rolls over distant scientists and soldiers bearing witness. Through the eyes of J. Robert Oppenheimer, it is a moment of awe and terror: the power of human resolve pushing past preconceived limits, a door we were never meant to open swinging wide.

The Manhattan Project was a marvel of scientific innovation and industrial might, synonymous in the United States with what can be achieved when we set aside limiting beliefs about what’s possible. “It is a matter of life and death,” Oppenheimer tells his skeptics, “I can perform this miracle.” In just three years, equipped with ample resources, a brilliant cross-disciplinary team, and belief in the absolute imperative of success, that is precisely what he did.

There are holes in Nolan’s story and critiques that bear repeating, from the short shrift given to women to the untold legacy of suffering caused by the nuclear weapons complex. Still, Oppenheimer moved me in ways I did not expect, and called me back to the central tenet of my career: All things are possible; the world is change.

For more than a decade, I’ve worked on the front lines of the international Global Zero movement to expose nuclear dangers and advance disarmament. I spend a lot of time talking to people—experts, government officials, total strangers on the Internet—about the harm these weapons have carried into the here and now, the extraordinary risks we’re running, and all the things we must do to change course. (As you can imagine, I am loads of fun at parties.)

“The genie,” I am often told, “cannot be put back in the bottle.” Nuclear weapons are regrettable, but immutable; a law of the universe we must learn to accept.

It is the worst kind of wishful thinking. If all of human history were compressed into a single year, the nuclear era would make up not even the last four hours. Humanity has barely survived half the night with these capabilities, and there have been dozens of close calls and near-misses in the meantime. The notion that we can carry on like this indefinitely is as naive as it is dangerous.

Oppenheimer was a genius, but he didn’t rewrite the laws of the universe. He built a new and terrible weapon, and in so doing opened a door to a world of intolerable risk. The question is, are we willing to do what it takes to escape it?

When the Soviet Union collapsed, most assumed that nuclear weapons and the dangers they posed were on their way out. For years, this lack of public awareness and concern was the fundamental challenge to disarmament. Leaders in government felt no heat whatsoever to have a position on this issue, let alone a plan.

It’s impossible to ignore these weapons now. Last year, Russia’s invasion of Ukraine brought the specter of nuclear war roaring back into public consciousness. Polling showed 82 percent of Americans worried about nuclear conflict. Rightly so: the iconic Doomsday Clock sits at just 90 seconds to proverbial midnight, the closest it has ever been to global catastrophe.

And yet at the very moment the world is being pushed from so many directions to consider this danger anew, the tiny community of experts and activists dedicated to preventing nuclear catastrophe is on life support. Funding for policy work, never mind advocacy and movement-building, is drying up. Major foundations who long understood the need for sustained focus on nuclear weapons have shifted their priorities or walked away entirely. The field is bleeding talent, and several critical efforts face existential threats.

As Alex Toma and Istra Fuhrmann noted in Chronicle of Philanthropy, “Less than 1 percent of last year’s peace and security funding went toward nuclear issues, according to data from the Peace and Security Funding Map. Nearly 60 percent of these philanthropic funds came from the John D. and Catherine T. MacArthur Foundation, which plans to stop investing in nuclear-related programs—dealing a huge blow to nonprofits that had long depended on its support.”

Even Global Zero, a Nobel-nominated initiative backed by hundreds of world leaders, has been forced to dramatically scale back. Just days before Oppenheimer came to the big screen, the bulk of my staff—one of the most diverse teams in the field, and some of its best and brightest young minds—collected their severance checks. It is a maddening retrenchment at a time we should be thinking big and moving fast to meet the fierce urgency of now. Meanwhile, defense contractors are raking it in as the United States spends $126,000 every minute on a whole new generation of nuclear weapons.

In the final scene of Oppenheimer, years after Trinity, Nolan revisits an interaction between Oppenheimer and Einstein that we observe earlier from a distance but can’t hear. We discover that it refers back to another conversation between the two men, in the midst of the Manhattan Project, about speculation that a nuclear test could ignite Earth’s atmosphere.

“When I came to you with those calculations,” Oppenheimer tells Einstein, “we thought we might start a chain reaction that could destroy the entire world.”

“What of it?” Einstein asks.

“I believe we did,” Oppenheimer says.

The screen leaps forward to massive modern-day nuclear armaments, even one of which can carry the equivalent destructive force of all the bombs detonated in World War II combined—including the two atomic bombs that killed 200,000 Japanese civilians. An entire world war’s worth of ruin in the cone of a single missile.

At the height of the Cold War, the planet was bristling with nuclear weapons. Cynics and hard-liners were absolutely certain that a disarmament agenda would go nowhere. Few could have imagined that in just a few short decades, 80 percent of the global nuclear stockpile would be on the scrap heap.

We can continue—in fact, must expand and accelerate—efforts to rein in these weapons, from a peak of 70,000 to fewer than 13,000 today. There are no ideal conditions to wait for and no time to waste. Oppenheimer’s chain reaction relentlessly advances. There’s only one way it ends for a nuclear-armed world; the math on this is unforgiving.

The obstacles we face are not the scientific or technological barriers the Manhattan Project sought to overcome. Today, they are political and diplomatic problems—no less formidable, no less solvable. It will require new approaches and diverse capacities. What miracles might we work, equipped with ample resources, a brilliant cross-disciplinary team, and belief in the absolute imperative of success?

The greatest danger to human civilization and the planet is the inability to believe that tomorrow can be different, the idea that we are individually powerless in the face of colliding existential threats. This is the main front in the story war on nuclear weapons: not whether disarmament is preferable, because of course it is, but whether disarmament is possible. A world beyond the Bomb is seen as utopian fantasy only because we are not projecting an audacious vision of the future and sustaining its pursuit.

Human ingenuity and resolve, brought into searing focus in the stolen tribal lands we call Los Alamos, opened the door to a terrible future. It is not too late to muster the courage and conviction to close it.

All things are possible; the world is change.