What is Nuclear Winter

Prior to 1968 the UK had a well-trained volunteer army ready to move in the event of disaster.  They were skilled in first aid, evacuation of threatened areas, rescue, communications, forward planning, catering, instructing the public to prepare fall-out shelters, estimating severity and extent of damage from various threats, building bridges, clearing roads and shoring up damaged buildings.

In the event of disaster or even nuclear attack, the British public was assured of the guidance and assistance of a benevolent and capable, Government sponsored, survival force.  They were assured that if they responded promptly to warnings, had emergency bags packed in the event of evacuation and a safe room designated in their own homes where they could shelter for up to 14 days until the worst of the fallout had decayed, the Government, safely holed up in deep bunkers underground, would instruct and assist them in rebuilding and getting back to normal.

In 1968, volunteers who had trained and held exercises for years, who knew just what could be done in their own areas, were sent polite letters of thanks by the Queen, and the Civil Defence was disbanded.  It had been decided that the likelihood of anyone surviving a massive nuclear attack on the UK was not worth gambling the expense of keeping up even a volunteer force.

There were a number of reasons for this.  The easing of the Cold War was the excuse.  But as Debora Mackenzie demonstrated in the New Scientist, research was beginning to show that immediate damage and short-term radioactive fallout was not the worst that could be expected after a nuclear attack. 

The largest assault the UK could be expected to survive was equivalent to a total of 2 million tons of TNT, the size of one average strategic warhead, equal to all the explosives detonated in World War II.  But they had reckoned without the long-term climatic effects of soot and dust released into the atmosphere by the fireball.

It was not until observers reported the effects of dust raised by storms on Mars in 1971, that models were made of the way in which this dust and soot would circulate in the atmosphere, rising and falling and travelling for thousands of miles before settling to earth.  It would blot out light for months and cause the theoretical Nuclear Winter in which temperatures would fall and no plant could grow.

There are currently 11 states with the capacity to deploy nuclear weapons.  If only two of them detonated 50 bombs each of the size used on Hiroshima, which was equivalent to approximately 15 thousand  tons of TNT, it would be enough to cause the worst  climactic disaster in human history. In theory this would be less than 0.03% of the estimated current global nuclear stockpile.

The psychological factors inherent in a nuclear war scenario would surely lead to the exchange of a greater proportion of the global nuclear stockpile, estimated at over 30 million megatons by Carl Saganin 1983 when he and his team wrote up the TAPPS  research on “Climate and Smoke: An Appraisal of Nuclear Winter”.

As explained by Alan Roebok in 2009, even a small outbreak would cause global damage to the ozone layer due to chemical reactions with hot nitrogen oxide “lofted” into the stratosphere by smoke plumes from burning cities, forests and fuel stores.  This alone would blind livestock and burn plants no longer protected from ultra-violet rays.

The smoke plumes would be depleted by 25% falling to earth in the first few weeks, but the rest would circulate the globe on both sides of the Equator for months and even years, causing up to 99% loss in sunlight reaching the earth.

This would result in darkness, causing green plants to starve for lack of photosynthesis: the ability to produce carbohydrates in the presence of sunlight. In turn, animals would also starve.  Cities would starve too as food reserves would be inadequate and distribution would be impossible to sustain life for years until food production recovered.

Lack of sunlight would lower land and ocean surface temperatures and alter the pattern of wind systems. Temperatures would plunge to below freezing, even in summer in temperate zones, threatening world food supplies.  The resulting climate change would bring about fierce wind storms, typhoons, hurricanes and floods.

In a larger nuclear war, it is estimated that billions of people, up to half the total world population, would be instantly vapourized or incinerated.  Most of the  rest would be injured, affected by radiation, exposure, starvation and psychological trauma.  Without access to medicine or treatment many of them would die.  The survivors would not be able to re-impose any form of stability and the human race would be reduced to primitive existence and it would probably be hundreds of years before the effects were overcome.

Any nuclear aggressor would clearly be in as much danger as the people under attack.

It was with this scenario in mind that in July 2009,  Mikhail Gorbachev said “Models made by Russian and American scientists showed that a nuclear war would result in a nuclear winter that would be extremely destructive to all life on Earth; the knowledge of that was a great stimulus to us, to people of honor and morality, to act in that situation.”  Accordingly, Russia and America agreed to step down the arms race. Their current nuclear stockpiles are now only a third of what they were in 1980, but still more than enough to destroy our planet.

There is apprehension, however, that smaller, more fanatical states could make pre-emptive strikes, or rebel minorities could use nuclear threats or retaliation to bring about the nuclear winter that the rest of the world fears.  As Roebok says, “ Only nuclear disarmament will prevent the possibility of a nuclear environmental catastrophe”.