Sabres are rattling again between Moscow and Washington, not to mention India and Pakistan, feuding over Kashmir. China鈥檚 nuclear arsenal is growing. Some still fear the nuclear intentions of Iran. North Korea is a nuclear power. The cold war may be over, but the weapons and geopolitical flashpoints are still there. Could nuclear war happen sometime in the next 60 years?
The world still possesses around 10,000 nuclear warheads, overwhelmingly in Russia and the US. But let鈥檚 assume these two nations do not press the button, and that tensions eventually explode between India and Pakistan.
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Most people away from South Asia might imagine such a conflict would not threaten them too much. Think again. The two countries have just over 200 relatively small nuclear warheads between them. Suppose they unleash half of them, a hundred 15-kilotonne weapons the size of Little Boy, dropped on Hiroshima in 1945.
The carnage from the blast, as well as firestorms and radiation in megacities like Karachi and Delhi, would kill millions. But that would be just the start, according to by Alan Robock of Rutgers University in New Jersey and Michael Mills at the National Center for Atmospheric Research in Boulder, Colorado.
The fires would send about 5 million tonnes of hot black smoke into the stratosphere, where it would spread round the world. This smog would cut solar radiation reaching Earth鈥檚 surface by 8 per cent 鈥� enough to drop average winter temperatures by a startling 2.5 to 6 掳C across North America, Europe and much of Asia, and not just for a few days. It would take around five years for the impacts to peak, and the repercussions would still be felt strongly after a decade.
Besides a nuclear winter, climate models predict that rainfall would be reduced as weather systems lost energy. The Asian monsoon would collapse: that鈥檚 two billion people with as much as 80 per cent less water. The Amazon basin and the already arid Southwestern US and western Australia would scarcely do better.
The smoke would heat the normally chilly stratosphere by around 30 掳C, unleashing nitrogen chemistry that would destroy much of the ozone layer. But skin cancer might be the least of our concerns. Near-ice-age temperatures would cause frosts capable of reducing the growing season in the world鈥檚 mid-latitude bread baskets by up to 40 days. This, combined with meagre rainfall and blistering UV, would cause crop yields to plummet. Nuclear winter would deliver global famine.
All this, remember, from a small regional war. Steven Starr of the University of Missouri has calculated that a could throw 150 million tonnes of smoke into the air. That would block 70 per cent of sunlight and cool much of the world by 20 掳C or more. Unable to grow food, most people would starve to death. One of the greatest geopolitical achievements of the past 60 years was to avoid a nuclear war. Fingers crossed for the next 60.
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This article appeared in print under the headline 鈥淲hat if鈥� There鈥檚 a nuclear war?鈥�
