A Japanese organization made up of survivors of the Hiroshima and Nagasaki atomic bombs is getting well-deserved attention with its selection to receive the 2024 Nobel Peace Prize. The group, called Nihon Hidankyo, does work that is bold and essential. It has made a powerful case for the “nuclear taboo,” the consensus that nations with nuclear weapons must never use them.

The survivors are direct witnesses to the awesome power of nuclear weapons, and their numbers are shrinking as we approach the 80th anniversary of the bombings. As the Nobel Committee said, they “help us to describe the indescribable, to think the unthinkable, and to somehow grasp the incomprehensible pain and suffering caused by nuclear weapons.”

The Nobel Prize award is also a timely reminder that the nuclear threat is still very real. Because nuclear weapons haven’t been used again in combat, it’s easy to imagine they won’t be. We can’t afford to downplay the risk. Only skillful diplomacy, a patchwork of arms-control treaties, and sheer luck have prevented a nuclear catastrophe so far.

The 1945 bombings caused the death of an estimated 140,000 people in Hiroshima and another 74,000 in Nagasaki by the end of 1945, according to the International Campaign to Abolish Nuclear Weapons. In Hiroshima, the atomic bomb leveled and incinerated about 70 percent of the city’s buildings. In Nagasaki, ground temperatures reached over 7,000 degrees Fahrenheit and radioactive rain fell from the sky.

The death and destruction may seem justified, as the bombings were followed by a quick end to World War II, the deadliest conflict in human history. But that was little consolation for the Japanese people, most of them civilians, who were victims of the bombs. Many survivors died prematurely from leukemia and other cancers caused by radiation exposure. Others bore permanent scars from burns. Many were stigmatized and shunned for years.

The bombs dropped on Hiroshima and Nagasaki had the explosive power of 15 to 25 tons of TNT. Just a few years later, the United States and Soviet Union were testing hydrogen bombs that were about 1,000 times more powerful than that. Nuclear weapons haven’t been used again in warfare, but we have come close, notably in the Cuban Missile Crisis.

Nuclear powers, primarily the U.S. and the USSR, possessed more than 70,000 nuclear warheads at the height of the Cold War. Those numbers have declined significantly thanks to arms-control agreements and efforts like the Nunn-Lugar initiative to dismantle nuclear stockpiles. But the number of nations with nuclear weapons has grown to nine. Experts say the most serious risk isn’t that one will use a Hiroshima-style bomb but that combatants will use smaller tactical nuclear weapons, igniting a conflagration that will escalate.

Some countries are modernizing and expanding their nuclear arsenals. Vladimir Putin has warned that Russia may use nuclear arms if other countries intervene in its war with Ukraine. Kim Jong Un wants to make North Korea a nuclear superpower. In the volatile Middle East, Israel has nuclear weapons, and Iran may aspire to have them. Adversaries India and Pakistan are nuclear powers.

Early this year, a disturbing and thoroughly researched series in the New York Times spelled out the horrifying consequences of nuclear war. Nuclear war may seem unimaginable, the Times said, but the problem is that we don’t imagine it enough. We choose to ignore the risk.

I have long believed that the possibility of a nuclear disaster is the greatest threat to humanity. Japan’s nuclear survivors know this firsthand, and they have borne witness to this fact for decades. We owe them our gratitude and attention. The Nobel Peace Prize is a fitting honor for them and a warning for the rest of us.      

Lee Hamilton, 93, is a senior advisor for the Indiana University (IU) Center on Representative Government, distinguished scholar at the IU Hamilton Lugar School of Global and International Studies, and professor of practice at the IU O’Neill School of Public and Environmental Affairs. Hamilton, a Democrat, was a member of the U.S. House of Representatives for 34 years (1965-1999), representing a district in south-central Indiana.