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The effects of nuclear weapons |
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Nuclear weapons have been used twice, on the Japanese cities of Hiroshima and Nagasaki in August 1945. Atmospheric nuclear testing and nuclear power accidents have also contributed to our now well- documented knowledge of the effects of nuclear weapons. Modern nuclear weapons generally have much greater explosive power than those first two bombs but the effects would only differ in scale.
The effects on human beings can most easily be understood as a sequence of overlapping categories: instantaneous, near-immediate, short term and long term:
Instantaneous
The heart of a nuclear explosion reaches a temperature of several million degrees centigrade. Over a wide area the resulting heat flash literally vaporises all human tissue. At Hiroshima, within a radius of half a mile, the only remains of most of the people caught in the open were their shadows burnt into stone.
Near-immediate
Beyond this area all people caught in the open will be killed by the heat and blast waves. People inside buildings or otherwise shielded will be indirectly killed by the blast and heat effects as buildings collapse and all inflammable materials burst into flames. The immediate death rate will be over 90%.
The many individual fires combine to produce a fire storm as all the oxygen is consumed. As the heat rises, air is drawn in from the periphery at or near ground level. This both results in lethal, hurricane force winds and perpetuates the fire as the fresh oxygen is burnt. (Such fire storms have also been produced by intense, large scale conventional bombing in cities such as Hamburg and Tokyo).
Even people in underground shelters who survive the initial heat flash will die as all the oxygen is sucked out of the atmosphere.
Outside the area of total destruction there will be a gradually increasing percentage of immediate survivors. However most of these will suffer from non-survivable burns, will be blinded, bleeding from glass splinters and will have suffered massive internal injuries. Many will be trapped in collapsed and burning buildings.
Even those with possibly survivable injuries will die since almost all rescue and medical services will have been destroyed and personnel killed.
The death rate among the seriously injured will approach 100%. Survival rates among the potential survivors will depend on the extent of rescue and medical services that can be brought in from outside. Many of the medical services needed such as specialist burns units are in strictly limited supply. The sheer scale of the casualties would overwhelm any state’s medical resources even in peace time.
Most casualties would receive at best minimal, palliative treatment. The best they could hope for would be to die in as little pain as possible.
Short Term
Many survivors, either uninjured or with survivable injuries will be affected within a matter of days by radioactive fall-out.
The amount and extent of fall-out will vary according to whether the nuclear explosion was an air-burst (as at Hiroshima) or a ground-burst. While the former emphasises the heat/blast effects, the latter will throw up much larger quantities of radioactive debris into the atmosphere.
The area covered by fall-out is determined by wind speed and direction. The heavier particles of radioactive material will fall in the immediate or close vicinity. Finer particles will be wind blown over longer distances before they descend. Very fine particles may be blown very long distances before they combine with water vapour and fall as radioactive rain. (In the aftermath of the Chernobyl nuclear power explosion and fire in the Ukraine in 1986, radioactive rain fell over the next few days in a wide arc across Northern Europe, including Scandinavia and then Scotland, North Wales and Cumbria. North Wales is over 1000 miles from Chernobyl.)
The effects of exposure to high levels of radioactive fall-out (radiation sickness) include hair loss, bleeding from the mouth and gums, internal bleeding and haemorrhagic diarrhoea, gangrenous ulcers, vomiting, fever, delirium and terminal coma. There is no effective treatment and death follows in a matter of days.
At lower levels of exposure, while there is an increasing chance of at least short term survival, the death rate remains high. Even where long term survival is probable, pregnant women are likely to miscarry or give birth to babies with a range of disabilities.
Healing from injuries is often slow, leaving distinctive scar tissue. Damage to the immune system is probable.
Long Term
Radiation-induced cancers will affect many survivors, often twenty or more years later. Certain cancers such as thyroid cancer in children are particularly associated with exposure to radiation. There are statistically higher than normal birth abnormalities and leukaemia rates in the children of exposed survivors.
Because of the long period between exposure and eventual cancer it is difficult to attribute a particular cancer to a particular cause. The correlation is described as epidemiological, rather as the connection between smoking and lung cancer was statistically established before the medical links had been uncovered.
Accurate estimates of long term fatalities at Hiroshima are not possible given the large scale destruction of records, population movements and a general censorship on nuclear effects by the US occupation regime. However the generally used minimum figure for immediate and short term deaths is 140,000.
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