There aren’t enough nuclear weapons to end the world

By MUNGAI KIHANYA

The Sunday Nation

Nairobi,

16 July 2006

This week, members of a religious sect from Nyandarua district were reported in press to be preparing for the end of the world. Their leaders are preaching that an all-out nuclear conflict is imminent and that the war will break out on September 12 this year. They say that on this day, the world’s nuclear powers will unleash their weapons of mass destruction on each other and the ensuing fallout will result in the end of life on Earth. Is that possible? Can an all-out nuclear war wipe out life on Earth?

The explosive power of a bomb is measured in terms of the equivalent weight of the explosive chemical, TNT (trinitrotoluene). When exploded, one gram of TNT releases about 1,000 calories (cal) of energy. That is, enough to raise the temperature of one kilogram (or one litre) of water by one degree celcius. To bring this water to boiling point would require about 80,000cal

One kilogram of TNT will produce about 1,000,000cal and a tonne will release one billion calories. For comparison, the 1998 bomb in Nairobi was estimated to be about 250 kg of TNT. The explosive power of nuclear weapons is in the range of thousands of tonnes – so called kilotons (kt). The Hiroshima atomic bomb was about 15 kilotons.

The most powerful bomb ever constructed is the 50,000kt “Ivan” made by the USSR at the height of the cold war in the early 1960’s. Today however, the average nuclear warhead has a power of about 300kt. Such an explosive device can completely flatten all buildings (including city skyscrapers) within a one-kilometre radius. If dropped at the centre of Nairobi, everything in the CBD would be reduced to sand! Furthermore, it would cause severe damage to all houses within a 5km radius – that is, up to Umoja, Kangemi, Dagoreti Ruaraka etc. Deaths can be in hundreds of thousands.

Now, there are about 12,400 active nuclear warheads in the world today. Most of them (over 11,500) are held by Russia (5,830) and the USA (5,735) – and you thought America was the bigger power! At an average of 300kt each, their combined explosive power is over 3.7 million kilotons or 3,700 megatons (Mt) – 1,800 Mt with the Americans and another 1,800Mt in Russia.

If all the word’s nuclear warheads were dropped at one point, they would destroy everything within a radius of about 70km.That is quite small! Greater destruction would be achieved if the bombs were fired at different places. Each would clear a 5km radius – equal to 80 square km. The total combined area affected would be about one million square kilometres. But that is still much smaller than the 450 million square km surface area of the Earth. Clearly, there aren’t enough nuclear weapons in the world to wipe out life on Earth.

What about nuclear radiation? Well, that is a story for another day. But for now, it will suffice to note that its effects are much less than the destruction of the blast.