from CooperativeIndividualism Website
A more or less typical strategic warhead
has a yield of 2 megatons, the explosive equivalent of 2 million
tons of TNT. But 2 million tons of TNT is about the same as all the
bombs exploded in World War II - a single bomb with the explosive
power of the entire Second World War but compressed into a few
seconds of time and an area 30 or 40 miles across...
There are now more than 50,000 nuclear
weapons, more than 13,000 megatons of yield, deployed in the
arsenals of the United States and the Soviet Union - enough to
obliterate a million Hiroshimas.
There are some who think that a nuclear war can be "contained," bottled up before it runs away to involve much of the world's arsenals. But a number of detailed analyses, war games run by the U.S. Department of Defense, and official Soviet pronouncements all indicate that this containment may be too much to hope for: Once the bombs begin exploding, communications failures, disorganization, fear, the necessity of making in minutes decisions affecting the fates of millions, and the immense psychological burden of knowing that your own loved ones may already have been destroyed are likely to result in a nuclear paroxysm.
Many investigations, including a number
of studies for the U.S. government, envision the explosion of 5,000
to 10,000 megatons - the detonation of tens of thousands of nuclear
weapons that now sit quietly, inconspicuously, in missile silos,
submarines and long-range bombers, faithful servants awaiting
An additional 1.1 billion people would suffer serious injuries and radiation sickness, for which medical help would be unavailable.
It thus seems possible that more than 2 billion people - almost half of all the humans on Earth - would be destroyed in the immediate aftermath of a global thermonuclear war. This would represent by far the greatest disaster in the history of the human species and, with no other adverse effects, would probably be enough to reduce at least the Northern Hemisphere to a state of prolonged agony and barbarism.
Unfortunately, the real situation would be much worse. In technical studies of the consequences of nuclear weapons explosions, there has been a dangerous tendency to underestimate the results. This is partly due to a tradition of conservatism which generally works well in science but which is of more dubious applicability when the lives of billions of people are at stake.
In the Bravo test of March 1, 1954, a 15-megaton thermonuclear bomb was exploded on Bikini Atoll. (below image)
It had about double the yield expected, and there was an unanticipated last-minute shift in the wind direction.
As a result, deadly radioactive fallout
came down on Rongelap in the Marshall Islands, more than 200
kilometers away. Most all the children on Rongelap subsequently
developed thyroid nodules and lesions, and other long-term medical
problems, due to the radioactive fallout.
Soon it became clear what had happened:
Afterwards, I and my colleagues, James B. Pollack and Brian Toon of NASA's Ames Research Center, were eager to apply these insights to the Earth. In a volcanic explosion, dust aerosols are lofted into the high atmosphere.
We calculated by how much the Earth's
global temperature should decline after a major volcanic explosion
and found that our results (generally a fraction of a degree) were
in good accor4 with actual measurements. Joining forces with
Richard Turco, who has studied the effects of nuclear weapons
for many years, we then began to turn our attention to the climatic
effects of nuclear war. [The scientific paper, "Global
Atmospheric Consequences of Nuclear War," was written by
R. P. Turco, 0. B. Toon, T. P. Ackerman, J. B. Pollack and Carl
Sagan. From the last names of the authors, this work is generally
referred to as "TTAPS."]
Our work was further spurred by Paul Crutzen of the Max Planck Institute for Chemistry in Mainz, West Germany, and by John Birks of the University of Colorado, who pointed out that huge quantities of smoke would be generated in the burning of cities and forests following a nuclear war.
The amount of dust and soot generated depends on the conduct of the war, the yields of the weapons employed and the ratio of ground-bursts to airbursts. So we ran computer models for several dozen different nuclear war scenarios.
Our baseline case, as in many other studies, was a 5000-megaton war with only a modest fraction of the yield (20 percent) expended on urban or industrial targets.
Our job, for each case, was to follow
the dust and smoke generated, see how much sunlight was absorbed and
by how much the temperatures changed, figure out how the particles
spread in longitude and latitude, and calculate how long before it
all fell out in the air back onto the surface. Since the
radioactivity would be attached to these same fine particles, our
calculations also revealed the extent and timing of the subsequent
The oceans, a significant heat reservoir, would not freeze, however, and a major ice age would probably not be triggered. But because the temperatures would drop so catastrophically, virtually all crops and farm animals, at least in the Northern Hemisphere, would be destroyed, as would most varieties of uncultivated or domesticated food supplies.
Most of the human survivors would
However, the radioactivity carried into the upper atmosphere (but not as high as the stratosphere) seems to have been largely forgotten.
We found for the baseline case that
roughly 30 percent of the land at northern mid-latitudes could
receive a radioactive dose greater than 250 rads, and that about 50
percent of northern mid-latitudes could receive a dose greater than
100 rads. A 100-rad dose is the equivalent of about 1000 medical
X-rays. A 400-rad dose will, more likely than not, kill you.
Synthetics burned in the destruction of the cities would produce a wide variety of toxic gases, including carbon monoxide, cyanides, dioxins and furans.
After the dust and soot settled out, the
solar ultraviolet flux would be much larger than its present value.
Immunity to disease would decline. Epidemics and pandemics would be
rampant, especially after the billion or so unburied bodies began to
thaw. Moreover, the combined influence of these severe and
simultaneous stresses on life are likely to produce even more
adverse consequences - biologists call them synergisms - that we are
not yet wise enough to foresee.
The Southern Hemisphere would
experience effects that, while less severe than in the Northern
Hemisphere, are nevertheless extremely ominous. The illusion with
which some people in the Northern Hemisphere reassure themselves -
catching an Air New Zealand flight in a time of serious
international crisis, or the like - is now much less tenable, even
on the narrow issue of personal survival for those with the price of
We considered a war in which a mere 100
megatons were exploded, less than one percent of the world arsenals,
and only in low-yield airbursts over cities. This scenario, we
found, would ignite thousands of fires, and the smoke from these
fires alone would be enough to generate an epoch of cold and dark
almost as severe as in the 5000 megaton case. The threshold for what
Richard Turco has called The Nuclear Winter is very
The carrying of dust and soot from the
Northern to the Southern Hemisphere (as well as more local
atmospheric circulation) will certainly thin the clouds out over the
Northern Hemisphere. But, in many cases, this thinning would be
insufficient to render the climatic consequences tolerable - and
every time it got better in the Northern Hemisphere, it would get
worse in the Southern.
What else have we overlooked?
On the other hand, it is also possible-and, from previous experience, even likely-that there are further adverse effects that no one has yet been wise enough to recognize.
With billions of lives at stake, where
does conservatism lie-in assuming that the results will be better
than we calculate, or worse?
The delicate ecological relations that bind together organisms on Earth in a fabric of mutual dependency would be torn, perhaps irreparably. There is little question that our global civilization would be destroyed. The human population would be reduced to prehistoric levels, or less. Life for any survivors would be extremely hard.
And there seems to be a real possibility
of the extinction of the human species.
There is no more important or more