The bombings of Hiroshima and Nagasaki 60 years ago were stunning and sobering events. They brought World War II to an end, and everyone was thankful for that. Not too many of us stopped to think about the full implications of those bombs for our future. We were too busy celebrating the end of that terrible war.

One of the people who had it absolutely right at the very beginning about the meaning of Hiroshima was the great French writer Albert Camus. He wrote in a French resistance newspaper: “Our technological civilization has just reached its greatest level of savagery. We will have to choose, in the more or less near future, between collective suicide and the intelligent use of our scientific conquests.” We are still facing that choice.

Both the US and the USSR tested nuclear weapons in the atmosphere until the early 1960s, while they continued to create more efficient weapons. It didn’t take either country long to get those weapons on intercontinental ballistic missiles and then submarine-launched ballistic missiles. They created a situation in which the world could be destroyed in a matter of minutes. This threat of a massive nuclear exchange was thought to provide an ad hoc policy to prevent nuclear war. It was called the policy of Mutually Assured Destruction, for which the acronym was M.A.D. or MAD. Never was an acronym more accurately descriptive.

We came very close to a nuclear exchange between Washington and Moscow in 1962 with the Cuban Missile Crisis. It was a very frightening time, and we can all be thankful that sanity managed to prevail. There were high-ranking US officials at the time who were pressing for bombing Cuba, which would have meant a nuclear war with the Soviet Union. That was one of many close calls during the Cold War.

With the end of the Cold War, there seemed to be a real chance again to put nuclear dangers behind us, and once again the opportunity was largely missed. Today, in the 60th year of the Nuclear Age, we still have some 30,000 nuclear weapons in the world, and some 4,000 of these are on hair-trigger alert. You have to wonder about a species that seems so incapable of eliminating the greatest danger to its own survival. Not so incidentally, the United States has more nuclear weapons in its arsenal than any other nation.

There has been much emphasis in the news about the dangers of nuclear proliferation in such countries as North Korea. All countries should abide by the Non-Proliferation Treaty. Few Americans are aware, however, that the treaty also provides that the US and other nuclear-weapons states must reduce their numbers of nuclear weapons. Unfortunately, disarmament by nuclear-weapons states receives limited attention in news reporting, at least within the United States. I think this might be because the continuing existence of our own vast arsenal doesn’t seem to Americans, even if they are aware of it, to be nearly as dangerous as the threat of new nations acquiring the ghastly weapons.

The survivors of Hiroshima and Nagasaki — the hibakusha — have continually warned, “Nuclear weapons and human beings cannot coexist.” In the end, I believe this is the most important lesson of Hiroshima. We must eliminate nuclear weapons before they eliminate us.

The best security, perhaps the only security, against nuclear weapons being used again, or getting into the hands of terrorists, is to eliminate them. Most of the people of the world already know this. Now it is up to the world’s people to impress the urgency of this situation upon their governments. We must act now. The future depends upon us.

Anything less would be to abandon our responsibility to future generations.

Walter Cronkite is an eminent broadcast journalist and serves on the Nuclear Age Peace Foundation’s Advisory Council. He was anchor of the CBS Evening News from 1962-1981, and currently hosts “Lessons from Hiroshima, 60 Years Later,” now airing on public radio stations nationwide.