One previously unforeseen consequence of an Indo-Pakistani nuclear war will be global climate change beyond anything “experienced in recorded history”. Among other things, says a study led by Alan Robock of Rutgers University, there will be 10 per cent less rain around the world. The monsoon everywhere will be badly affected.
Robock’s team used climate-change models, but applied them to the giant smoke clouds that would be created by nuclear explosions on large cities. Assuming an exchange of 100 Hiroshima-sized atom bombs (each of them a relatively small 15 kilotons) in a subtropical climate, the study concluded the war would produce “large and long-lasting” climate change.
The impact would be worsened by a strong sun which will heat the smoke and drive it higher. Though the paper does not mention the time of year, Robock says his simulation assumed an Indo-Pakistan nuclear exchange in May. “The plume would be marginally less high if a war took place in the winter,” he said.
Among the results
The smoke cloud produced would see surface global temperatures fall by 1.25 degrees Centigrade for several years. This would result in “large climatic effects” occurring “in regions far removed from the target areas”. Places as far apart as central Africa, Australia, the Deccan and Canada could see even summer temperatures fall by four degrees C. Says Robock, “A severe disruption of global agricultural production would be inevitable.”
The cooling would “weaken” the global hydrological cycle. Rainfall, snow and other forms of precipitation would drop by about 10 per cent. This would include “large reductions of the Asian summer monsoon”. Says Robock of the latter, “More models would be needed, but the one that we did showed sharp drops in rain in Cambodia, Thailand as well as Pakistan.” One beneficiary: the Sahel region of Africa would get more rain.
Robock’s team included two new observations into their calculations. One was “fuel-loads”. A lesson learnt from watching the effect of Canadian forest fires is that concentrations of flammable material result in very large amounts of smoke and lifts them higher into the atmosphere.
Large cities, like forests, have sizeable quantities of material that burn well, including fuel, plastic and wood. After a nuclear hit these would throw up huge smoke clouds.
The other new factor was the impact of subtropical temperature. Because the subcontinent is warm, the smoke clouds will be driven “high into the stratosphere” and persist in the atmosphere for years on end. firstname.lastname@example.org