How close are we to the end of the world?

The president of the United States stepped up the sabre-rattling earlier this week at the United Nations General Assembly. 

Of course, this is nothing new. 

When news broke in August that North Korea had a nuclear warhead that would fit inside an intercontinental ballistic missile, Mr. Trump threatened that North Korea would be "met with fire and fury like the world has never seen."

Most experts agree this overheated rhetoric is little more than a negotiating tactic — an effort to enlist China and Russia in attempts to rein in North Korean leader Kim Jong Un.

Still, the spectre of a nuclear war, no matter how unlikely, is terrifying. 

Not that it'll make you feel any better, but there is a measure of the degree and severity of the nuclear threat — it's known as the Doomsday Clock. 

By December 1991, the Cold War was over. The United States and the Soviet Union agreed to dismantle and decommission a significant portion of their nuclear stockpiles. Almost giddy with optimism, the Bulletin of the Atomic Scientists announced it would reset the Doomsday Clock to 17 minutes before midnight … midnight meaning nuclear annihilation. 

Still perhaps a little too close for comfort, but it appeared to signal the end of the waking nuclear nightmare that had gripped the world ever since the Soviet-American arms race kicked in after the Second World War.

Since that hopeful moment more than 25 years ago, the Doomsday Clock has ticked its way ever closer back toward midnight. In late January of this year, the Bulletin's board of directors moved the clock another 30 seconds forward to two and a half minutes before midnight. The minute hand hasn't been this close to that fateful hour since 1953.

It isn't just the flagging momentum of nuclear disarmament that worries the keepers of the Clock. 

They also cite a number of other complex threats to human life — a global failure to meaningfully address climate change, powerful technologies that threaten to spiral beyond human control, rising nationalist movements around the world.

And they cite the election of Donald Trump, who has mused openly about encouraging nuclear proliferation and restarting a nuclear arms race. 

Sharon Squassoni is a member of the Science and Security Board of The Bulletin of the Atomic Scientists. She's also the director of the Proliferation Prevention Program at Center for Strategic and International Studies and formerly worked for the Arms Control and Disarmament Agency and with the Congressional Research Service at the Library of Congress. 

She spoke to Michael on our program in March of this year. 

Click 'listen' above to hear the full interview.