Effects of nuclear weapons

Hiroshima and Nagasaki, Japan, in August, 1945. The energy yields were equivalent to 12 500 tonnes and 20 000 tonnes of high explosive. Yields from thermonuclear weapons (H-bombs) range up to several megatons (Mt). Between 1945 and the signing of the Comprehensive Test Ban Treaty in 1996, over 2000 nuclear tests were carried out by the USA, USSR, Britain, France and China, plus one by India. More than 500 of these were above-ground tests; the largest, by the USSR, had a yield of over 50 Mt. Concern about radioactive fallout led to the Partial Test Ban Treaty of 1963 which only drove testing underground. Stockpiles rose to over 69 000 in 1985, but have fallen to around 32 000 today. Nevertheless, there will still be over 20 000 in about 2007, with a combined yield of some 10 000 Mt. Many missiles can be launched within minutes of an alert, which could be an error—indeed accidental nuclear war remains a serious risk. The economic crisis facing the Russian military undermines the Russian system of command and control, with more danger of an unauthorised military strike. In January, 1996, a rocket was launched from Norway to explore the aurora borealis. Notification of the launch was given but the information was not passed on, and President Yeltsin’s aides opened the “football” containing Russia’s nuclear launch codes. If a single Russian submarine had been ordered to fire its missiles, nearly 7 million people in US cities might have died from the resulting firestorms. The Non-Proliferation Treaty of 1970 obligates nuclear weapon states to achieve nuclear disarmament by negotiation, though their commitment is questionnable. April 24 saw the start, in New York, of a review of this treaty and many nonnuclear states and non-governmental organisations will be pressing for genuine progress. This is the best, and perhaps the final, chance to advance to a nuclear-weapon-free world. The review ends on May 15, 2000.