According to the International Atomic Energy Agency, the world's nuclear watchdog, there were 1,500 cases of nuclear material lost or stolen during 1993 to 2008, with an increase in smuggling.

Experts say that the world's stock of nuclear weapons can destroy the earth dozens of times and that worry has not proven to be an exaggeration, with the possible party responsible for such damage changing from sovereign nations to terrorists.

So far, no effective mechanism has been set up to monitor destructive nuclear weapons. Quite a few quasi-nuclear countries have not exercised forcible and effective protection for their nuclear facilities.

Since the end of the Cold War, the situation worldwide has experienced profound changes. Different from the security environment during the Cold War period, people across the globe now hear rising calls for nuclear safety in the international community.

In a globalized era, any country's safety is no longer based on the safety within its own territory, given that a free and cross-border movement of personnel, materials and wealth has made all members of the international community more interdependent in the pursuit of their security. It will be a worldwide disaster should destructive nuclear weapons fall into the hands of terrorist groups or incidents take place in some civilian nuclear facilities. The Chernobyl disaster is still a fresh, shuddering reminder of such a danger although more than 20 years have passed. The leakage in the Ukrainian nuclear plant in 1986 spread westward to Europe, creating a catastrophic impact on the continent's environment.

People who have long lived under the nuclear cloud hold high expectations that nuclear threats can be reduced to the minimum and nuclear weapons can be finally eliminated from the planet. The Washington summit made a good start to this process, but it is unrealistic to expect a summit to help world members reach complete consensus on this thorny and long-controversial matter.

Since humankind has created nuclear weapons, it is its responsibility to rid the world of such a threat.