At the end of January, the keepers of the Doomsday Clock announced that the world was 89 seconds to midnight, a metaphor for our proximity to extinction. That’s one second closer than we were for the past two years, and the nearest the clock has ever inched to global destruction by way of human-made risks, including nuclear weapons, climate change and new technologies like artificial intelligence.

The iconic clock is set by the Bulletin of the Atomic Scientists, an organization founded by American physicists at the dawn of the nuclear age, months after the United States detonated atomic bombs in Japan. On Monday, the Bulletin named Alexandra Bell, a nuclear affairs expert, as its new president and chief executive. She replaces Rachel Bronson, who served in the role for a decade.

Ms. Bell worked on arms control and nonproliferation issues in the U.S. State Department starting in the Obama administration, where she was involved in securing ratification of New START, the nuclear arms reduction treaty with Russia. She returned to the department as a deputy assistant secretary in 2021, promoting dialogue on nuclear issues with nations around the world. During the last two years of the Biden administration, she led the U.S. delegation of the P5 Process, currently the only forum where the United States, China and Russia discuss nuclear risk reduction.

In an interview last week, Ms. Bell discussed the ever-evolving threats of the day and the role she wants the Bulletin to play in preventing worldwide disaster. “It’s important to listen to the echoes of history,” she said, to be “informed by the past, but not shackled to it.”

The following conversation has been edited for brevity and clarity.

How does an 80-year-old organization like the Bulletin stay relevant in an ever-changing world?

When I entered the field, the Doomsday Clock was at five minutes to midnight. I remember being struck by the symbolism. The clock being at its closest point to midnight now is really a warning that we are running out of time. The fact that it ticked one second closer is an indication that every second counts.

We are living through an overload of crisis with a compounding nature of threats. The key is to understand those threats and make sure that we’re transitioning to solutions. It will take work and patience and persistence, and a broad demand from the public, to address these concerns.

Hopefully, the Doomsday Clock pulls people in to help them understand the urgency of the moment. There’s no single, neat solution. But there are things we can do to pull ourselves away from the edge.

How does this era of nuclear risk differ from the past?

Nuclear threats are on vivid display for the first time, really, since we pulled ourselves away from the edge of catastrophe in the Cuban Missile Crisis of 1962. The United States and Russia are not in a sustained dialogue about how to stabilize nuclear risk. China has embarked on an unprecedented expansion of their nuclear forces. Iran has the potential to create nuclear weapons, and North Korea continues to flout international law, threaten its neighbors and grow its nuclear arsenal.

We also have structures that we’ve spent the last 50 years building now crumbling under us. The Nuclear Nonproliferation Treaty, which has held back the tide of nuclear chaos, is under duress. The next steps that we were supposed to take in reducing nuclear threat, like the Comprehensive Nuclear Test Ban Treaty, haven’t come to pass yet.

I’m sure people living through the height of the Cold War would not have thought it was uncomplicated. But looking back, that was a bipolar conflict — it was the U.S. and the Soviet Union. Now, it’s more complex.

There are no quick fixes here. This time, it won’t just be the nuclear experts alone who come up with solutions. We have to be talking with experts in A.I., quantum, biotechnology and climate change. These risk areas are overlapping and require coordination we haven’t quite mastered yet. But that cross-pollination of expertise will be key to how we manage these threats.

The looming threat for most people these days seems to be climate change, rather than nuclear weapons.

You’re right, younger generations don’t think about nuclear threat as much. We did a good job of reducing that threat, but it never went away. In some ways, it’s become worse. It’s more complex, more diffuse, and there’s not as much attention on it.

The nuclear issue is a matter of minutes. Intercontinental ballistic missiles in the United States or Russia can reach anywhere in the world in about 33 minutes. If we get the nuclear problem wrong, nothing else matters.

Climate change is a longer-term problem. And the potential conflicts that could arise from it, like mass migration, can increase tension. More nuclear-armed states with climate-related conflicts means the likelihood of nuclear war increases. These threats are tied together. All the more reason to be thinking about both at the same time.

What are your thoughts so far on the direction of the new presidential administration?

I was pleased to see President Trump’s comments in Davos about reducing nuclear threats. That was encouraging. But he is also withdrawing from the Paris Agreement. That is a step in the wrong direction.

Hopefully, the administration will see that there are economic and security benefits to the U.S. pursuing a move to greener technology.

I hope there is an acknowledgment that climate change isn’t a matter of belief. This is happening. You can choose not to believe in it, but I guarantee that your insurance company believes in it. When that starts financially impacting people across the country, they will be looking to their leaders to do something about it.

In what ways do you hope to shape the work of the Bulletin in the years ahead?

The Bulletin is trying to facilitate a public reckoning with human-made existential risk. It’s been an increasingly exclusive conversation, and I don’t want it to be that. I want people anywhere to understand why this is so important, and why they have a part in it.

I am from Tuxedo, N.C. — a place with no stoplights. My folks’ house got 40 inches of rain in two days from Hurricane Helene. The havoc caused by a changing climate has now happened in a place like my hometown. How do we connect those people into the conversation about preventing this? It’s our job to make sure they are a part of it just as much as people in the Beltway are.

It can be easy to look at these challenges and go to a dark place. The harder thing is to let those challenges drive you. My mother is from Finland, and we always talk about this Finnish ethos of “sisu” — unstoppable grit in the face of extreme adversity. We need more sisu in this field. We’ve inherited a mess, and we have to work together to clean it up.