Bearing in mind the special situations represented in the evidence from Japan, the Tribunal was anxious to establish the impact of a major nuclear attack on a modern and highly developed society using weapons currently existing in the arsenals of the major nuclear powers. Evidence was presented by Mr. Greene and Dr. Steadman of the Open University on the results of computer simulations of large scale nuclear attacks on the UK. Their evidence gave a detailed account of calculations of short-term effects, the numbers killed and injured, the extent of physical damage caused by blast and fire, and the extent of radioactive contamination by fall-out. These calculations are based primarily on direct evidence of the effects of modern weapons which are detailed in a recent joint US Department of Energy/Department of Defence report which provides the most comprehensive technical summary of nuclear explosion effects openly available 9. The US report is based principally on the results of a large number of nuclear tests carried out by the United States during the 1950s and 1960s. Notably, results from British nuclear tests are still not openly available.
The Steadman and Greene evidence focused on assumed attack levels of 219 megatons and 348 megatons which are based on attacks covering (i) all major nuclear and conventional military bases including command centres, as well as power stations, oil and gas refineries, ports and a few heavy industrial plants and (ii) as in (i) but with a few general urban-industrial targets added as well. These attacks are regarded as primarily counterforce and countervalue attacks aimed at eliminating military forces and reducing industrial/economic recovery. Steadman and Greene assume that one-third to one-quarter of the nuclear warheads available to the Soviet Union in its Eurostrategic arsenal would be allocated for use against the United Kingdom on account of its key role within NATO and the high density of military targets and American nuclear bases. However only about one third of these levels are used in their attack scenarios. Steadman and Greene also pointed out that up until 1981 the British Home Office made the assumption for the purposes of civil defence planning that an attack by the Soviet Union would be of roughly 200 megatons. More recently government spokesmen have been asserting that more limited attacks (e.g. of 50 megatons) are "more probable" than an all-out attack though this remains an issue of deep contention.
The effects of the two attack patterns presented by Steadman and Greene are given in Table 3-1. Both levels of attack which are not aimed principally at population centres generate substantial civilian casualty rates. The Tribunal interpret this as being indicative of the fact that it is impossible to distinguish between military and non-military targets with modern nuclear weaponry.
During his oral evidence, Dr. Steadman provided the Tribunal with estimates of the indirect effects of the attack scenarios on energy supply, agriculture, and the provision of food and water. He pointed out that the effects of blast damage, the electromagnetic pulse and radiation would seriously damage all public services and hamper if not eradicate all chance of post-attack recovery within a predictable or reasonable time-scale.
Mr. Greene was cross-examined at length on differences between their calculations and similar ones carried out by the UK Home Office which generated a casualty level of only 17 million. Mr. Greene pointed out that many independent scientists have been critical of assumptions in the Home Office models relating to the extent of blast damage and the radiation protection offered by damaged buildings.
The members of the Tribunal noted with some concern that there appears to be substantial disagreement within the scientific community vis a vis the extent of blast damage from nuclear explosions, the protection factors for modern housing stock, and LDSO values for radiation injury. Nevertheless the Tribunal accepted that even allowing for the most optimistic assumptions the consequences of any nuclear attack against a nation would be extremely dire and that there could be no effective civil defence for whole populations particularly when long-term effects are taken into account.
|Targets:||military plus a few industrial||military, industrial plus a few urban|
|Total yield:||219 MT||348 MT|
|Short-term casualties:||37.5 million killed (79% of population)||42.5 million killed (90% of population)|
|Fire zones||66,000 sq. km.||102,000 sq. km.|
|Area contaminated by:|
|>450 rads (human LD50)||120,000 sq. km.||120, 000 sq. km.|
|Blast damage zones:|
|>12 psi (total destruction)||7,000 sq. km.||13,000 sq. km.|
|>5 psi (severe damage)||18,000 sq. km.||34,000 sq. km.|
|>2 psi (light housing damage)||49,000 sq. km.||80,000 sq. km.(*)|
|Total housing stock damaged or destroyed:||60%||80%|
The Tribunal noted that the UK Home Office had not been prepared to send representatives to the Tribunal to explain its own calculations and assumptions.
Finally Steadman and Greene presented the Tribunal with a publication outlining a number of other attack scenarios on the UK. Two other recent publications on British assessments of the effects of nuclear attack were also made available to the Tribunal, one dealing with an attack on London, the other with the detailed consequences for the British housing stock.