The widespread adoption of technologies including augmented reality (AR), virtual reality (VR), and mixed reality (MR) is resulting in an immersive experience
In a total nuclear exchange where the entire worlds arsenals are used, how long would the nuclear winter last and would we survive?
Flashback to the 1980’s … Mutually Assured Destruction (MAD)
Note: For an updated and more complete answer please go here
A lot has changed…..
In 2016 a nuclear winter isn’t possible even in an all out nuclear war. This is because both the quantities and yield of the world’s nuclear arsenals has dropped precipitously from the all time high in 1986. The arsenals today are only 20% the size they were in 1986 and the total megatons available is less than 10% of the peak.
Surprisingly quietly, the USA and Russia have dismantled over 50,000 nuclear weapons over the past 30 years. The nuclear materials from these bombs and other stockpiles of weapons grade materials, was recycled and used in nuclear power generation over the past 20 years. A fact that few may be aware of, the situation actually crashed the uranium market in the early 2000’s. The glut of available fuel brought the open market trading value down from $20 dollars a pound to near $2 per pound at that time. So a lot has changed from the time when many of us can remember the very real threat of mutually assured destruction.
Multi Megaton Weapons Now Obsolete
What has changed that the world no longer is building megaton weapons? The need for multi-megaton weapons was the result of low accuracy of warhead deliver on target…. we needed a sledgehammer approach to take out hardened targets and the way that was done was through very high yield bombs >=5 mt typically. The average nuclear weapon size today in 2016 is about 443kt at full yield but a large portion of those bombs can be adjusted in the field to a very small fraction of their potential yield.
Today the accuracy of on target delivery has massively improved ..we hit what we aim for. This means we need less hammer to do the same job. In the 1980’s the development of earth penetrating rounds was another game changer. Not only were we on target but now we could penetrate hundreds of feet of earth and concrete before detonating the warhead. This allowed a 100 kt weapon to do the damage of a >1 mt surface detonation. This is the primary method now for targeting hardened targets and is the final driver for smaller yield bombs.
The net effect of the use of EPW’s (Earth Penetrating Weapons) is a reduction in the number of casualties as compared with the number of casualties from a surface burst. This is primarily due to a 96% reduction in the weapon yield needed using an EPW. The greater coupling of the released energy to the ground shock for a buried detonation is the same as a surface burst with 25 times the explosive energy. For rural targets, the use of a nuclear earth-penetrator weapon is estimated to reduce casualties by a factor of 10 to 100 relative to a nuclear surface burst of equivalent probability of damage.. 
The average warhead size in the USA arsenal is 330 kt. The Russian average is higher, but not enough to change this outcome. To cause a nuclear winter the debris clouds and smoke have to be elevated above the troposphere into the high stratosphere. Any debris or smoke that is released into the troposphere (below 70,000 feet) quickly rains out in the weather within a few days to a week or so max. Nuclear weapons yields do not affect the environment on a linear scale , that is to say that a 1 megaton bomb, even though it is 10 x more energy than 100 kt bomb, doesn’t mean it produces 10 x more destruction. Thermal radiation decays as the inverse square while blast decays as the inverse cube of distance from the detonation point. Much of that extra heat and energy goes straight up and drops off quickly as distance is increased from the point of detonation. With smaller yields the energy isn’t enough to breach the stratosphere, and for bombs that size the earth has its own protection mechanism for particles released in the troposphere called the weather, and it is extremely efficient.
The only way to get particles to stay aloft longer is to blast them considerably higher than 70,000 feet. **The reason this won’t happen today is that the world has eliminated megaton-size bombs almost completely, and shortly it will be complete as the last ones are dismantled. Russia and the US both have eliminated megaton size weapons from the high-alert strategic forces (ICBM’s & SLBM’s).
To get anything above 70,000 feet you need yields substantially above 1 megaton. The bombs deployed today will throw debris up 50,000 – 60,000 feet into the atmosphere and all of that will rain back down to the earth in hours and days later near the point of detonation.
(** B-83 variable yield ≈ 20 kt – 1.2 mt slated for retirement in 2025. This is a gravity bomb and is also being considered as a reserve against an asteroid impact. Marshall Space Flight Center have developed designs for an array of asteroid interceptors wielding 1.2-megaton B83 nuclear warheads. 650 units in reserve but not alert status)
As we have all heard in the past that there were enough nuclear weapons to kill everyone several times over, let me put that myth to rest. Hypothetical scenario for maximum damage: Starting in an arbitrary corner of the USA (or if you prefer … Canada) take the entire world’s inventory of nuclear weapons (10,000 active and stockpiled) and place each one in its own circle covering 100 square miles. Using a world average yield size of 500 kt, this sets up the scenario for maximum destruction. If all the warheads are then elevated to 6000 feet, the height for maximum destruction and fatalities, and then detonated. Each bomb would make a 10 km radius of destruction from its center with 3rd & 2nd degree burns on the outskirts of this radius. The fallout would be minimal with only air bursts, most dangers would be gone within hours or days after the blasts. Using every bomb in existence today as laid out in this hypothetical scenario, the area of assured destruction would only amount to 1/3 of the USA’s total land mass. If it was Canada, many might not even notice. That’s it. On a global scale that isn’t hardly a scratch at 1/42 of the world’s total land mass.
Firestorms and other bad science that led to the wrong conclusions.
A lot of new knowledge on pyrocumulonimbus cloud formation and soot into the lower stratosphere is still being interpreted. Until the early 2000’s it was thought the boundary layer between the troposphere and stratosphere presented a greater barrier for smoke, however, smoke columns rising into the lower stratosphere have been observed. This indicates that there is a long term lasting effect, but to what extent is still unanswered.
A 2010 study by the American Meteorological Society is the first modern attempt to quantify these effects. In their report, they tracked the effects of 17 stratospheric smoke plumes in 2002. What they found is that the average time that the smoke plumes’ presence in the stratosphere was detectable, was only about 2 months. The report indicates that particles of carbon soot start to clump together at some point after interacting with sunlight and then drop out of the stratosphere quickly. This happens in weeks not in years, a major contradiction to the premise of nuclear winter theories. What isn’t known is there a tipping point of equilibrium that would keep the soot aloft if there was enough of it. So like many things, there is a certain element of the unknown in this.
What is known is that the TTAPS study, made famous by Carl Sagan and his team, used exaggerated volumes of soot and smoke in their model. Their assumptions for a nuclear winter were significantly off in their calculations. Key government studies since then have shown that the available combustible materials used in the models in TTAPS were significantly overstated and this has flawed all the studies since that have used the TTAPS study as the basis of their work.
The nuclear winter theory relies heavily on the worst case scenario of many of the events that would unfold during a nuclear exchange and as such exaggerates the effect dramatically.  A contemporary example of prediction not accurately modeling reality is the forecast effects of the Iraqis setting 600 oil rigs ablaze in 1991.
Following Iraq’s invasion of Kuwait and Iraqi threats of igniting the country’s 800 or so oil wells were made, speculation on the cumulative climatic effect of this, presented at the World Climate Conference in Geneva that November in 1990, ranged from a nuclear winter type scenario, to heavy acid rain and even short term immediate global warming.
As threatened, the wells were set ablaze by the retreating Iraqis in March of 1991 and the 600 or so successfully set Kuwaiti oil wells were not fully extinguished until November 6, 1991, eight months after the end of the war During this time they consumed an estimated six million barrels of oil daily at their peak intensity.
In articles printed in the Wilmington morning star and the Baltimore Sun newspapers of January 1991, prominent authors of nuclear winter papers — Richard P. Turco, John W. Birks, Carl Sagan, Alan Robock and Paul Crutzen —together collectively stated that they expected catastrophic nuclear winter like effects with continental-sized effects of “sub-freezing” temperatures as a result of the Iraqis going through with their threats of igniting 300 to 500 pressurized oil wells that could subsequently burn for several months.
Carl Sagan later conceded in his book The Demon-Haunted World that his predictions obviously did not turn out to be correct: “it was pitch black at noon and temperatures dropped 4–6 °C over the Persian Gulf, but not much smoke reached stratospheric altitudes and Asia was spared.”
The problems with the models that started the nuclear winter debate, the models used by Sagan and other teams of scientists at that time, is obvious when you look at the detail. The analysis was done at extremely low resolution and with no feedback loops. It was a 2D model, not a 3D model, so the volume and altitude of particles, heat flux, and fuel “mass loading” (the amount of fuel per square meter) were never actually calculated. The numbers were made uniform and plugged in as a single result for the entire world. So the heat flux, fuel “mass loading”, soot, smoke and debris was uniform no mater if the city was Fargo North Dakota or Los Angeles. It was inherently wrong and fatally flawed. 
The atmospheric scientist tasked with studying the atmospheric effect of the Kuwaiti fires by the National Science Foundation, Peter Hobbs, stated that the fires’ modest impact suggested that “some numbers (used to support the Nuclear Winter hypothesis)… were probably a little overblown.”
In a paper by the United States Department of Homeland Security finalized in 2010, fire experts stated that due to the nature of modern city design and construction, with the US serving as an example, a firestorm is unlikely after a nuclear detonation in a modern city. This is not to say that fires won’t occur over a large area after a detonation, but that the fires would not coalesce and form the all-important stratosphere punching firestorm plume that the nuclear winter papers require as a prerequisite assumption in their climate computer models. Additional recent studies on smoke columns indicate that nearly every possible fire scenario results in little to no stratospheric injection of smoke..
The nuclear bombing of Nagasaki for example, did not produce a firestorm. This was similarly noted as early as 1986-88, when the assumed quantity of fuel “mass loading” in cities underpinning the winter models was found to be too high and intentionally creates heat fluxes that loft smoke into the lower stratosphere, yet assessments “more characteristic of conditions” to be found in real-world modern cities, had found that the fuel loading, and hence the heat flux that results from burning, would rarely loft smoke much higher than 4 km.
The scenarios contributing to a firestorm are also dependent on the size of bombs being used. Only bombs in the 1-megaton range and higher would ignite a sufficiently large area for firestorms to coalesce crossing over from sparsely located high fuel-load areas into these lower fuel-loaded areas in a mixed city model, such as Nashville. 
Russell Seitz, Associate of the Harvard University Center for International Affairs, argues that the winter model’s assumptions give results which the researchers want to achieve and is a case of “worst-case analysis run amok”. Seitz criticized the theory for being based on successive worst-case events.
Notes from “Disaster Preparedness, An International Perspective”: “If the amount of smoke assumed in the “nuclear winter” report (Science, v222, 1983, pp1283-92) were decreased by a factor of 2.5, the climatic effect would probably be trivial. In considering the actual terrain that surrounds most likely targets, the probable type of explosions (ground bursts against hardened military facilities), the overlapping of targets, and conditions that could reduce the incendiary potential of the thermal pulse, critics of the report believe that the quantity of smoke from non-urban fires has probably been overestimated by at least a factor of ten (Cresson Kearny, Fire Emissions and Some of Their Uncertainties, Presented at the Fourth International Seminar on Nuclear War, Erice, Sicily, August 19-24, 1984). Rathjens and Siegel (Issues in Science and Technology, v1, 1985, pp123-8) believe there would likely be four times less smoke and eight times less soot from cities than estimated in the National Research Council study.”
Putting the fires of a nuclear war in another perspective. Every year on earth, wildfires consume 350,000,000 – 450,000,000 hectares of forests, grasslands and structures and results in an average of 339,000 deaths worldwide.  This is equal to 1,700,000 square miles burned every year worldwide, nearly half the size of the entire Unites States. Earlier in this document, I laid out a hypothetical scenario where every nuclear bomb in existence, excluding ones listed as retired, are spread out equally at a density of 1 bomb every 100 square miles (10,000 bombs x 100 square miles = 1,000,000 square miles). Under that scenario, the bomb coverage only extends over 1/3 of the land mass of the USA (the USA is 3,800,000 square miles). The world burns more already every year without sending the climate into a nuclear winter. This also is equal to half the CO2 released from burning fossil fuels annually. Wild fires release massive amounts of energy on a scale equivalent to nuclear weapons. The Chisholm Fire, a man-caused forest fire in Edmonton, Alberta, Canada in 2001 released the equivalent energy of 1200 Hiroshima atomic detonations. The firestorm after the bombing of Hiroshima released 200 times the energy of the atomic bomb itself.
Taking all that into consideration and taking the available megatonnage in today’s arsenals and and adjusting the implied atmospheric load of carbon black soot you might end up with 5 teragrams aloft in the lower stratosphere resulting in a 2–3 °C drop for several months to, worst case, several years. Not quite a nuclear winter, barely a nuclear fall… and even that is debatable since evidence suggests a much shorter time of smoke suspension in the stratosphere and that the premise on uncontrolled fire storms is unfounded based upon actual observations of the bombs dropped in 1945. While Hiroshima did experience a firestorm Nagasaki did not. Nagasaki was a city with much more combustible material than most modern day cities. The great flaw with the original nuclear winter models is that it assumed the same high loading of fuel for all cities and that firestorms would occur at all those locations. A firestorm isn’t assured and is considered unlikely in modern cities, and thus the theory is flawed from top to bottom.
An interesting note about several major recent reports to the contrary of my conclusion, and even ones going back 10 years. None of these reports question the fuel loading and levels of atmospheric smoke generated. They all seem to use the original basis as put forth by Carl Sagan’s team, even though Sagan himself admitted his model did not work. The footnote here will take you to an example of the poor quality models still being pushed as real science. A Rutgers 2010 report that references the work by Sagan offers no explanation for the mechanism of smoke and soot transport into the stratosphere. Quality work is not guaranteed just because the sources are listed as a professionals in this field. Healthy skepticism is your friend, use it.
So nuclear winter was always a stretch because the science was unfounded and we never had enough high-yield bombs in reality to cause it ever, but for sure in 2016 because we don’t have any in the high-yield range required within the active arsenals of the nuclear nations at all (other than a small quantity of bombs held by China, around 50 and not enough to change these outcomes).
I have always been intrigued by the specter of nuclear weapons and the power of the atom. I have a not insignificant set of reference books I have collected over the years. The ones from the late 1940’s and early 1950’s are quite amusing; we did not know what we were really dealing with back then.
We have come a long way since the era of Dr. Strangelove.
I have come full circle in my understanding and no longer buy into the popular myths because the clear science is there that tells you otherwise. However, having this knowledge may not be a blessing. Knowing that nuclear weapons are not the end of mankind in 2016 isn’t necessarily a great truth to latch onto. The pain and suffering that would transpire from the use of these weapons should always remain a strong deterrent from their use.
Making the unthinkable thinkable, was there some sanity in the insanity of MAD?
In dismissing the notions of nuclear winter and MAD (mutually assured destruction), could we be making the use of these weapons more palatable as a tool of political and ideological foreign policy enforcement? A quick fix to the next ISIS where collateral damage is deemed acceptable? Is that something we can manage as a civilization? Are our values within society as a whole, strong enough to kill any temptation in the future if using these weapons seems like a quick fix for an immediate problem? Is a limited exchange something to be seriously considered? Or are we better off letting our imagination embrace a nightmare, a dark vision of reality, a nuclear winter, with complete conviction without regard to the truth?
Note: I make no claim that I am right… I only offer an analysis with considerations for details and data overlooked by others … sometimes intentionally. Please do your own due diligence and make an educated determination for yourself.
Additional Notes and Recommended Follow-on Reading
Obama committed to a major nuclear triad upgrade in order to get the Senate support of the New Start Treaty in 2010. This article does a good job questioning the reasons why we are planning to spend $1 trillion on nuclear weapons systems upgrades over the next couple of decades. It is a worthwhile read, and the access is free with registration.
and with unplanned yet uncanny timing …on 60 minutes tonight 9/25/2016
A well thought out and compelling Harvard report “The end of MAD” argues that America’s technological edge and the reduced nuclear arsenals are actually compelling the USA towards a first strike
This article makes three empirical claims. First, the strategic nuclear balance has shifted dramatically since the end of the Cold War, and the United States now stands on the cusp of nuclear primacy. Second, the shift in the balance of power has two primary sources: the decline of the Russian nuclear arsenal and the steady growth in U.S. nuclear capabilities. Third, the trajectory of nuclear developments suggests that the nuclear balance will shift further in favor of the United States in the coming years. Russia and China will face tremendous incentives to reestablish mutual assured destruction, but doing so will require substantial sums of money and years of sustained effort. If these states want to reestablish a robust strategic deterrent, they will have to overcome current U.S. capabilities, planned improvements to the U.S. arsenal, and future developments being considered by the United States. U.S. nuclear primacy may last a decade or more
If this becomes a trend, the nuclear winter bit might need another take: