The dropping of the atomic bombs on Hiroshima and Nagasaki ushered in a Nuclear Age. A race to develop nuclear weapons was amplified by tensions between the United States and the formed Soviet Union, leading to the creation of a hydrogen bomb with a destructive force 3,300 times greater than that of the atomic bomb used on Hiroshima.
Following a theory of nuclear deterrence, which states that powerful nuclear weapons will inhibit threats and attacks from an enemy nation, extensive nuclear force was accumulated on earth. Under the name of this nuclear deterrence, the number of countries posessing nuclear weapons increased, and the threat of nuclear war grew larger.
Nuclear tests continued, with over 500 atmospheric tests conducted by 1980. The fallout resulting from these tests fell across large ranges, affecting the environment and exposing many people living in the area, as well as military personnel, to radiation.
At the end of the Cold War, the United States and Russia conducted negotiations to discuss strategic arms reductions, yet even now there are still approximately 16,000 nuclear weapons in existence.
In the 1960s, France and China, in addition to the United States, Soviet Union and United Kingdom, began conducting their own nuclear tests and became nuclear powers. Fearing the spread of nuclear weapons, the United States and Soviet Union proposed a treaty, and in March 1970 the Nuclear Non-Proliferation Treaty (NPT) came into effect. This treaty limited the possession of nuclear weapons to five countries (the United States, the Soviet Union, the United Kingdom, France and China) and prohibited other countries from developing or posessing them. It also committed the countries to the discussion of nuclear disarmament.
As awareness of the negative effects of nuclear testing on humans and the environment increased, a treaty prohibiting nuclear testing was agreed upon. In September 1996, the Comprehensive Nuclear Test Ban Treaty (CTBT), prohibiting nuclear tests accompanied by nuclear explosions, was adopted by the United Nations General Assembly. However, because it was predicted that the treaty would not be ratifies by countries such as the United States, China, India and Pakistan, it has not yet been implemented. At the 2010 NPT Review Conference, a proposal was made to restart the negotiations on the nuclear weapons convention.
- Information signs at the Hiroshima Peace Museum