 introduced an exceptionally stringent standard to protect humans from such nightmarish consequences.
Known as the Linear No-Threshold (LNT) assumption, it was a radical departure from any similar safety standard. Humans can tolerate poisons - the challenge lies in finding the threshold dose above which poisonous effects appear. But the LNT assumption singled out radiation as being so uniquely nasty that there is no threshold dose: the only safe dose of radiation is no radiation.
Back in the 1950s, this seemed entirely reasonable: no-one wanted to see a repeat of the genetic horrors of atomic bombing. But the doctors monitoring the hibakusha - those people 'affected' by the explosion within a mile or so of Ground Zero of the two bombs - soon noticed something odd. Babies were indeed being born with genetic abnormalities, but the rate was the same as it had ever been.
In 1994, the UN expert committee on radiation also found no extra cancer risk to survivors exposed to levels deemed utterly |
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| Humans can cope with hefty doses of radiation without ill-effects |
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unacceptable on the basis of the LNT assumption.
In short, the A-bomb survivors have proved the LNT is simply wrong: humans can cope with hefty doses of radiation without ill-effects. This is more than good news for nuclear workers and radiologists. It has profound implications for the debate about nuclear power, which many scientists insist has a key role in combating global warming.
Nuclear power has a reputation for being lethal even if the reactors don't explode. The demand to protect us all from even the minutest radiation from accidental discharges and disposal of its waste has made nuclear power punitively expensive.
Yet through their survival, the hibakusha are telling us that the LNT is nonsense - and that we are spending huge sums to protect ourselves from non-existent risks.
Unless we recognise the significance of their survival, nuclear power will remain under a mushroom-shaped cloud - and be unable to help save millions from the all-too-real effects of climate change. 
FIRST POSTED AUGUST 9, 2007
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Nuclear - for when the wind stops blowing
Pros and cons
Swimming pools for nuclear waste
