Reliance on nuclear weapons as a deterrent "is becoming increasingly hazardous and decreasingly effective," the bipartisan group said in a commentary.
The authors were former Secretary of State Henry A. Kissinger, former Secretary of State George P. Shultz, former Defense Secretary William Perry and former Senate Armed Services Committee Chairman Sam Nunn.
"North Korea's recent nuclear test and Iran's refusal to stop its program to enrich uranium — potentially to weapons grade — highlight the fact that the world is now on the precipice of a new and dangerous nuclear era," they said.
They also expressed alarm at the likelihood that nonstate terrorists will get their hands on nuclear weapons.
If nuclear weapons states would band together to end reliance on nuclear weapons, the commentary said, it "would lend additional weight to efforts already under way to avoid the emergence of a nuclear-armed North Korea and Iran."
Iran and many other non-nuclear countries have long complained about the "double standard" of nuclear powers in possessing atomic weapons while demanding that others refrain from having them.
The most notable of the four experts is Kissinger, 83, who has achieved elder statesman status since his service as national security adviser and secretary of state under presidents Richard Nixon and Gerald Ford three decades ago. He is an unofficial adviser on Iraq policy to President George W. Bush.
Shultz also served in Nixon's cabinet and was President Ronald Reagan's secretary of state for more than six years. Perry was President Bill Clinton's defense secretary for three years and later advised Clinton on North Korea policy. Nunn was chairman of the Senate Armed Services Committee from 1991-97 and currently is co-chairman of the Nuclear Threat Initiative, which works to reduce international threats from weapons of mass destruction.
The essay noted that the concept of a nuclear-free world is not revolutionary, pointing out that the Non-Proliferation Treaty (NPT) envisions that nuclear weapons states divest themselves of such armaments over time.
The essay expressed concern that the increasing number of potential nuclear enemies worldwide could dramatically increase the risk that nuclear weapons will be used.
New nuclear states do not have the benefit of years of Cold War-era safeguards that prevented nuclear accidents, misjudgments or unauthorized launches, it said.
"Will new nuclear nations and the world be as fortunate in the next 50 years as we were during the Cold War?" it asked.