Nuclear Winter Theory is Wrong as It Assumes Super Flammable Cities

In 2010, I had written about the reason why Alan Robock and Brian Toons 2007 paper was wrong that an India and Pakistan nuclear war would trigger a nuclear winter and mass famine. Everyone knows that a nuclear war would be very bad and would cause a lot of casualties. There is no reason to create a fiction of more deaths from a nuclear winter that will not happen.

Alan Robock et al have written a new paper in Nature that again makes the case that an India -Pakistan nuclear war would trigger a nuclear winter and mass famine that would kill 2 billion people.

During WW2, the US used fire to destroy the equivalent of 60 nuclear weapons worth of Japan’s cities. The two atomic bombs destroyed 1372 hectares and regular firebombing set fires that destroyed 46000 hectares. This occurred over 6 months. The nuclear winter theorists assume that soot in the stratosphere lasts at least 8 months. There was not measurable temperature or climate impact after the war.

Robock and the nuclear winter proponents again reference their 2007-2008 papers for the conclusion that 100 nuclear weapons exchanged between India and Pakistan would produce 5 Trillion grams (5 million tons) of soot into the stratosphere.

Nuclear war opponents target the nuclear weapons and military assets of the other side. There will only be a fraction of the weapons used against the other side cities.

During WW2, the US and its allies intentionally set city-wide firestorms using incendiaries. Japan’s cities were very prone to fire because they were made of paper and wood. Japan had charcoal burners that they commonly used for cooking. City firestorms require over half of the buildings to catch fire. India and Pakistan have mostly burnt brick buildings that are much harder to start burning. There has been a drastic reduction of paper inside houses with few books and virtually no newspapers or magazines.

Alan Robock cites the 2017 Canada wildfires where 1.2 million hectares of forest was burned and injected 0.006-0.02 teragrams of soot into the stratosphere. This is 250 times less than the threshold that Robock asserts would happen from a 100 nuclear weapon war. Hiroshima had 1300 hectares of burnt city. Forest fires burned far more area than fires that would be set by nuclear bombs. It is not just the area of the fires it has to be exceptionally intense fires to send the soot into the stratosphere.

Between 3 February and 9 August 1945, an area of 461 square kilometers (46100 hectares) in 69 Japanese cities, including Hiroshima and Nagasaki, was burned during the U.S. B-29 Superfortress air raids, producing massive amounts of smoke. Most of the burning was not from the atomic bombs but fires set in Tokyo and other cities. There was no cooling effect from the burnt cities during and after WW2. Only 3% of the burned area of Japanese cities in WW2 was from the two atomic bombs.

I looked at nuclear winter and city firestorms in 2009 and 2010. I will summarize the case I made then in the next section. There is significant additions based on my further research and email exchanges that I had with Prof Alan Robock and Brian Toon in 2010.

The Steps needed to prove nuclear winter:
1. Prove that enough cities will have firestorms with big and intense fires. This does not happen based on WW2 firestorm analysis. Prove that nuclear weapons will set these extra intense fires.

2. Prove that when enough cities in a sufficient area have big and intense enough to send large amounts of smoke and soot gets into the stratosphere. Robock does not provide this evidence.

3. Prove that the condition persists and affects climate as per models. Others have questioned that but this issue is not addressed here. If the fires are not big and intense to the level indicated then nothing happens and there is no famine.

The nuclear winter case is predicated on getting 150 million tons (150 teragram case) of soot, smoke into the stratosphere and having it stay there. The assumption seemed to be that the cities will be targeted and the cities will burn in massive firestorms. Alan Robock assumes city firestorms based on the radius of ignition from the atmospheric blasts.

However, in the Scientific American article and in their 2007 paper the stated assumptions are:

assuming each fire would burn the same area that actually did burn in Hiroshima and assuming an amount of burnable material per person based on various studies.

The implicit assumption is that all buildings react the way the buildings in Hiroshima reacted on that day.

Therefore, the results of Hiroshima are assumed in the Nuclear Winter models.
* 27 days without rain
* with breakfast burners that overturned in the blast and set fires
* mostly wood and paper buildings
* Hiroshima had a firestorm and burned five times more than Nagasaki. Nagasaki was also a fire prone city. Nagasaki had the same wood and paper buildings and high population density.

Recommendations Build only with non-combustible materials (cement and brick that is made fire resistant or specially treated wood). Make the roofs, floors and shingles non-combustible. Add fire retardants to any high volume material that could become fuel loading material. Look at city planning to ensure less fire risk for the city. Have a plan for putting out city wide fires (like controlled flood from dams which are already near cities.)

Fire and Details

If there are not multiple citywide firestorms then there is no trigger for nuclear winter even if the later modeling (which is still uncertain) would even need to be considered.
– The Material of the Houses in India and Pakistan do not appear to be Right for Firestorms (mostly burnt brick and mud)

Firestorms have always required at least 50% of buildings to be ignited. High percentage of builtupness is also necessary Hiroshima had most fires from overturned breakfast charcoal braziers.

References that provide the basis of my case Problems of Fire in Nuclear Warfare, Jerome Hill, Rand, 1961
– Nagasaki had no firestorm

4.4 square miles Hiroshima actual burned area

0.9 square miles Nagasaki

13.5 square miles maximum theoretical.

India building census indicates that most of the buildings are made from Burnt Brick, mud which are non-combustible.
Exploratory Analysis of Fire Storms, Stanford Research Institute, 1965

The frequency of rain in India or Pakistan is important because of the effect of recent rain on burning of cities.

Quantitive – seasonal rainfall patterns for India and Pakistan

Fire Factors

“Mass fires and Fire Behaviors” which studies fires in cities and other places indicates that combustible roofing material is a major cause of fires spreading in cities. This document also discusses how to reduce fire risks and lessen spreading of fires. The usual vegetation management that is commonly mentioned for LA fires and having non-combustible roofing materials and gaps between buildings. These anti-fire measures would apply to lessoning fires ignited by nuclear bombs too.

Steps to Reduce Damage

Simple civil defense and building improvements would reduce damage from nuclear war and from hurricanes and earthquakes. Haiti and New Orleans show the importance of building better to greatly reduce problems.

Hurriquake nails, outside paint that reflects heat and other cheap retrofits would reduce the damage radius and roofing material that does not burn.

Further improvement for buildings
Fighting Fires with Water From Behind Dams

There are also some basic counter measures against city wide fire.

More than 2,000 dams near population centers are in the United States are in need of repair, according to statistics released this month by the Association of State Dam Safety Officials. There are more dams near population centers which do not need repair. The water could be released in an emergency to more effectively fight any large area of fire.

25 thoughts on “Nuclear Winter Theory is Wrong as It Assumes Super Flammable Cities”

  1. Another reasonable analogy might be the huge forest/bush fires in Australia of 2020 (? or was it ’19?). About 18 million hectares burned, the amount of smoke, ashes, soot, etc. must have been enormous. Has anyone done some comparative calculations? I know that the amount of CO2 released was about equal to Germany’s in a whole year, but how about soot etc.?
    The same for the Siberian forest and peat fires of 2021.

    • Ok, I did some research myself, found some papers: the Australian bushfires of 2019/20 released about 1 million (metric) tonnes of soot/black carbon into the lower stratosphere. So, that is about 1/5th of what the authors of the quoted study on India-Pakistan nuclear exchange considered enough for nuclear winter. And yet the (direct) impact of this, plus the equally large Siberian wildfires the next year, plus the North American and European wildfires, on the global atmosphere and climate was negligible.

  2. As many people above mentioned, each weapon of today is 100 times more powerful than the devices used against Japan. And instead of a 6 month campaign, these hundreds of powerful bombs detonate in the space of a single one hour period.
    The blast would destroy your water towers, fire trucks, and emergency personnel. So your water pressure, equipment, and personnel are gone.
    Also, instead of wafting out over the vast Pacific Ocean, the soot may hover over crop growing areas for weeks. I hope this remains an academic debate.

    • India tested its first nuclear weapon in 1974, becoming the sixth country to detonate a nuclear weapon. The country’s arsenal carries weapons with estimated average yields ranging from 12 to 40 kilotons, though exact yields are unknown.

      Land-based Missiles
      Name Number of launchers Range (KM) Warhead x yield (kilotons)
      Prithvi-II ~24 350 1 × 12
      Agni-I ~20 700+ 1 × 40
      Agni-II ~8 2,000+ 1 × 40
      Agni-III ~8 3,200+ 1 × 40
      Agni-IV n.a. 3,500+ 1 × 40
      Agni-V n.a. 5,200+ 1 × 40
      Sea-based Missiles
      Name Number of launchers Range (KM) Warhead x yield (kilotons)
      Dhanush 2 400 1 x 12
      K-15 (12) 700 1 x 12
      K-4 (4) 3,500 1 x ?

      About the same as the 20kt yield of Hiroshima.

      India and Pakistan made more smaller nukes. Making 10 small nukes instead of one bigger nuke. US and Russia have gone from big nukes as accuracy of missiles increased. It is an efficiency thing.

  3. Germany had the first firestorm in Hamburg 1943 and many more until May 1945, and its cities were not made of paper and wood.
    The Japanese cities example was never the actual basis of thermonuclear firestorm modelling.

    The people who modelled thermonuclear wars were no idiots.

    There’s no way of knowing for sure without a full-scale practical experiment.

    • In Hamburg. Coal and coke supplies stored for the winter in many houses caught fire and could only be extinguished weeks later.

      (3) Major-General Kehrl, report on the firestorm in Hamburg in August, 1943.
      Before half an hour had passed, the districts upon which the weight of the attack fell were transformed into a lake of fire covering an area of twenty-two square kilometres. The effect of this was to heat the air to a temperature which at times was estimated to approach 1,000 degrees centigrade. A vast suction was in this way created so that the air “stormed through the streets with immense force, bearing upon it sparks, timber and roof beams and thus spreading the fire still further and further till it became a typhoon such as had never before been witnessed, and against which all human resistance was powerless.” Trees three feet thick were broken off or uprooted, human beings were thrown to the ground or flung alive into the flames by winds which exceeded 150 miles an hour. The panic-stricken citizens knew not where to turn. Flames drove them from the shelters, but high-explosive bombs sent them scurrying back again. Once inside, they were suffocated by carbon-monoxide poisoning and their bodies reduced to ashes as though they had been placed in a crematorium, which was indeed what each shelter proved to be.
      d. During the

      following nights, until 3rd August 1943, the British returned and dropped on the almost defenceless city about 3,000 block-busters, 1,200 land-mines, 25,000 H.E., 3,000,000 incendiaries, 80,000 phosphorus bombs and 500 phosphorus drums; 40,000 men were killed, a further 40,000 wounded and 900,000 were homeless or missing.

      ww2dbaseThe bombing methods used by the Allied were to encourage total destruction of buildings: the high explosive bombs first expose the wood frames of buildings, then the incendiary bombs ignite the wood, and finally followed by various explosives to hamper the firefighting efforts. The results were devastating. 24,866 out of 28,410 houses in the inner city of Dresden were destroyed, many of them schools, hospitals, and churches. Estimate of deaths range from 25,000 to more than 60,000 (the official German report stated 25,000 estimated with 21,271 registered burials).

      Mostly wood buildings.

  4. This analysis leaves off so many catastrophic effects it’s impossible to list them all here.
    But since I live, and would die instantly, in NYC, let me focus just a bit on what the loss of cities would do. 50% of U.S. GDP comes from just the 25 top cities:
    In October, 2012, hurricane Sandy caused $65b worth of damage just in the U.S., most of that concentrated in or near NYC:
    It was only a category 1 hurricane when it hit the NY/NJ area, boosted by unusually high tides that night. Manhattan from 38th downtown was completely without power for nearly a week. Tunnels were so badly damaged that they have still not been fully repaired (PATH train tubes, F train under East River). Whole communities along the shores were wiped away – those flimsy wooded houses again.
    The wind speed of a nuclear bomb is significantly higher – 158mph vs. 115 for hurricane Sandy at its highest: Assuming it is suddenly released over the center of major cities like NYC, most if not all, major towers would collapse in the street (not pancake down like the internally created fires produced by 9/11 plane strikes that brought down the twin towers and #7 WTC). Most, if not all, first responders would become inoperative or cease to exist. All wooden piers, ships, cars, trucks, buses etc. would be subject to incineration, if not from the blast, then from chain reactions that no one would be around to stop. Most buildings here are powered by natural gas for cooking and still most for heating/cooling. Natural gas fires are a regular occurrence. Lately, 100s of apartment fires have been caused by poorly designed and/or maintained e-bike batteries too. There is a lot of wood in doors, floors, and other interior things within the brick walls of buildings that can catch fire from NG and gasoline (garages etc.) chain-reacted fires. Transformers shorted out & caught fire during hurricane Sandy too, which is why power went out.
    This comment is already too long to continue but shows only a tiny fraction of the damage expected in dense, high net worth cities like NYC, and doesn’t show most of the lingering disruption from food chain collapse, road and utility loss, personnel loss etc.
    Modern civilization is very delicate – as shown by the Covid supply chain problems when even a relatively few businesses were shut down. We have shifted from just in time to just in case supply chains, not entirely successfully so far, just from Covid, and that’s taken years, with a fraction of the loss – mostly old, retired people – expected from a nuclear bomb. It goes on and on…

  5. Your analysis ignores the following factors:

    1) The bombs today are extraordinarily more powerful than anything previously used on Japan and the models for fallout would be closer to the Bikini Atoll tests, which will incinerate far more material – especially dirt underneath ground zero. The size of the blast craters will simply be huge. That material goes straight up into the atmosphere – and burning cinders spread the fire far and wide, particularly with drought increasing world wide.

    2) Material wealth has improved and technologies have progressed since 1945, populating cities with a large amount of exotic metals in cars and semiconductors (TVs, phones, etc…), neither of which were being mass produced or consumed in Japan in 1945. Building materials are denser and heavier – e.g., steel, concrete – all of which will aerosolize with stronger bombs (not to mention what’s in all the landfills). It’s these heavy metals in the dirt and modern manufactured goods that makes forest fires so toxic today.

    3) In the most likely strategic scenarios, most or all of the weapons are likely to detonate. Geographically, Pakistan has less strategic depth, which makes them more paranoid about not surviving a first strike and thus more tempted to launch first. Having more depth, India has more time to detect a launch and more opportunity to retaliate. This was one of the first dangers that strategists noticed about the nuclear armament of these nations when it was formally announced. I know because I sat around a seminar table discussing it with other graduate students at the time. Constant satellite surveillance may have diminished the first strike temptation Pakistan has, but it’s only made detection of a launch more likely, not less so – and hence it has increased the odds of a full exchange.

    4) I don’t know enough about modeling on a supercomputer with differential equations to tell if the nuclear winter hypothesis is likely or not, but historically speaking I do know what animates the ideological fight over it: money. Throughout recent American history, formal political attacks on both nuclear winter and global warming have been exclusively funded by right-wing financiers who make money off of selling us nuclear bombs and gasoline. They’re “talking their book,” as Wall Street says, downplaying the risks of their products and relying on the same “Merchants of Doubt” lobbyists who promoted the “health benefits” of tobacco, flame retardant chemicals added to couches (that were actually highly flammable, not to mention toxic) and the cardiovascular “protections” of sugar and transfats. The individuals you bump into who express these views are either directly involved in the money train or ideologically prone to believing the gaslighting. In a world where it’s impossible to conduct an experiment about the “safety” of a nuclear war that incinerates a billion people, I will play the odds and assume those promoting it are as wrong as they have been about more mundane issues directly related to biology and chemistry where I do know enough to understand that they’re lying. It was obvious to Weston Price in the 1960s that the saturated fat hypothesis about heart disease was wrong and many of the leaders who worked for the Orwellian-named American Heart Association at the time in fact died of heart disease after selling Congress on the benefits of artery-clogging margarine (which they all had patents on, unlike real butter). Nutritionists knew sugar caused diabetes in the 1930s but the sugar lobby destroyed them again and again until around 2005 when Lustig repeated this and the sugar lobby tried one more time but couldn’t destroy him. By then nobody had enough money to bury a fact instantly obvious to any lab in the country with rats, time and a soda machine – not once gene arrays became cheap enough to tell you exactly what’s happening to metabolism. Yet even today, when we cover a terrorist shooting supposedly because we treasure life, these same reporters fail to discuss the astronomically higher death toll from toxic chemicals like junk food, tobacco, gasoline, sugar, transfats, palm oil, Vioxx, etc… BECAUSE THEY ARE MAKING MONEY ADVERTISING THEM or have in the past. Understand the pattern here, know the side you’re on, protect your personal reputation and pick your fights carefully over “bad” science.

    5) Even if you’re correct about soot falling out of the atmosphere rapidly, where do you think that goes? It goes into our lungs. Then the survivors get to eat food grown in contaminated soils and drink contaminated water – and not just the radiation is a problem. Think about those exotic metals and microplastics raining down.

    • Average yield of a deployed warhead today is 450kt. Blast radii (and associated effects) increase at the cube root of yield. So a 450kt weapon does not cause 22.5x as much damage as the bomb dropped on Nagasaki. It’s closer to 3x.

      Also masonry buildings between the are relatively unaffected outside of the 20psi overpressure radius. They might be damaged but they certainly won’t be “vaporized” as you state.

      Fireball radius for a 450kt weapon is ~.7km. For Fat Man (Nagasaki bomb) it was ~.23km.

      You don’t need to have a Ph.D in mathematics to see that the inputs for the “nuclear winter” models were and are intentionally wrong.

  6. Agree, but a key factor, convection, is sensitive to speed of release, i.e. thermonuclear near instantaneous versus months of fire bombing. So the WW2 and gulf war data is misleading.

  7. How long will areas remain irradiated? It’s strange how Hiroshima and Nagasaki are habitable but Chernobyl isn’t. Different types of radiation?

    • The weapons used in Japan contained around 200 lbs of high enriched uranium and a significantly less amount of plutonium. Less than 5 grams of matter was converted into energy with significantly more fission products released. However modern weapons use less than ~ 5 lbs of plutonium. Fukushima and Chernobyl reactors contain tons of uranium and plutonium which has been burned for several years prior to release. Virtually all of the low melting point metals and all of the noble gasses are released faulted fuel pins during a fuel melt which can contaminate thousands of acres down wind.
      With modern nuclear weapons, contamination is much less. Hiroshima and Nagasaki were rebuilt due to the wide dispersion of a relatively small mass of fission products which have a relatively short half life.
      Two factors to remember, The solution to pollution is dilution, and The dose makes the Poison !

    • Air burst of a bomb, vs a reactor actually catching fire and its contents being dispersed over the area.

    • Nuclear weapons are single instantaneous reaction with radiation. Fission nuke reactors are a smaller but ongoing reaction, that is contained in a concrete and water radiator to hold. Chernobyl breached the container when it failed and Russians literally sent waves of men to their death to basically bury it to re-contain. To this day it is still a running reaction emitting radiation.

    • For an airburst it’s safe to go outside after about a week. Today’s nuclear weapons are vastly “cleaner” than what was dropped on Hiroshima or Nagasaki.

  8. This article is going to get a lot of pushback but it is correct. The nuclear winter scenarios are not plausible:

    -Insufficient fuel load in modern cities. Cladding inparticular is usually non-combustible material such as concrete, steel, fiber-cement, etc.
    -We *know* how thermal radiation will affect various building materials from the operation Tea Pot tests. These results are commonly ignored by nuclear winter models.
    -Weapon yields are too low to eject substantial amounts of ash into the stratosphere.
    -Atmospheric residence times for soot has been shown to be on the order of weeks, not months or years (as the nuclear winter models assert)

    Also, the oil fires from Gulf War I, which ejected the ash equivalent of ~300 400kt nuclear weapons into the atmosphere, were predicted to cause “major global cooling” by Sagan et al. The measured effect was zero.

    A general nuclear exchange would kill tens of millions and be a very dark day for humanity but it would not be the end of humanity. It’s up to the reader whether that is more or less scary.

    • I never bought nuclear winter. Now folks think a limited nuclear exchange in a Pakistan/India war would doom us. But how many test nukes were set off in the Cold War?

      Maybe someone could write Naftali a letter

  9. Kurt Vonnegut penned a character who founded ‘Poets and Artists for Immediate Nuclear War.’ Not sure if there’s a branch in Moscow – or Islamabad.

  10. Well done. ^_^
    Of course, I would hope that everyone is a nuclear war opponent. 🤣 Too much to hope for, though.

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