The 'doomsday scenario', executed by retreating Iraqi troops in February 1991 in setting the Kuwaiti oil fields alight, was meant as a modern version of Kahn's ultimate deterrent - an idea that failed. Two climate modeling responses, from the United Kingdom Meteorological Office and the Max Planck Institute for Meteorology, denied an attenuating impact on the Indian monsoon (a concern that had been expressed before). Successors of their GCMs did correctly represent the major Asian rainbelts as part of a planetary system, and their seasonal migration, but not the seasonal mean distribution, to say nothing about intraseasonal activity. Just those 30-60-day active-break monsoon cycles, including realistic motions of the major Asian systems, were now found in the Berlin version ('CCAS-B') ofthe CCAS GCM in an own Kuwait oil well fire study. This GCM version is a completely regenerated, flexible tool of dynamic systems analysis. Its boreal summer monsoons turned out indeed to be part of an interhemispheric, oscillatory seasonal climate regime between critical transitions in June and September. The Kuwait oil fire smoke caused a regional lower-
troposphere heating anomaly, and thus an 'exciting' disturbance that fanned the GCM's dynamics in a way not dissimilar to the observed 1991 season. Such a type of monsoon climate may thus be the 'playing ground' for martial adventures seizing the source regions of the atmospheric water cycle. Its structural robustness is unknown.
The theme is again put on the agenda by recent studies into the climatic effects of a potential regional nuclear conflict of 1.5 Mt 'size' in Southeast Asia, using the full atmosphere-ocean GCM with high vertical resolution of NASA's Goddard Institute of Space Studies (GISS), which has been successfully applied to study the climatic impact of volcanic eruptions. The GISS model shows extremely long smoke residence times, up to a decade, due to efficient lofting into the upper stratosphere, all year round in these latitudes. The surface air temperature drop is much less than in the 'nuclear winter' case, of course, but still considerable if compared with the climate record: a global cooling from 1.25 to 0.5 K over a decade, with minima of several kelvin (degrees centigrade) over large areas of North America and Eurasia. A 10% weakening of the global precipitation is concentrated in the Tropics, but substantial (seasonal mean) reductions of the Asian subtropical summer monsoons are also found, with potentially serious human impacts.
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