Wednesday, December 8, 2021

Nuclear War Analysis

What this item makes clear is that hte devastation of Nuclear War is overstated.  To start with, any form of fire storm is unlikely.  Yet it is typically a point blast at best and we are looking at Earthquake type damage.  Yet modern buildings will largely survive that.

The vulnerable target is dense populatioon.  We do have a few of that.  Yet again a percentage will die in this worst case scenario.  A few miles away,you can survive as happened in Japan.

We are not dropping big ones much either.  We need military targets and those are best handled by smaller bombs.  Nucleur winter is unlikely.

Nuclear War Analysis

December 4, 2021 by Brian Wang

The current nuclear arsenal will not kill all humans and the pattern of nuclear explosions for a nuclear war between the largest nuclear powers will not destroy civilization, let alone kill all people or even half of all people. The greatest risks from a total nuclear war are from fire and starvation and not from the radiation or the blasts.

Note: it is not automatic and not even easy to start a firestorm in modern cities. Nagasaki did not have a firestorm. Nuclear winter was predicated on the assumption that there would be firestorms in every city hit by a nuclear bomb.

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 seems to be that the cities will be targeted and the cities will burn in massive firestorms.

The Steps needed to prove nuclear winter:
1. Prove that enough cities will have firestorms (the claim here is that does not happen)
2. Prove that when enough cities in a sufficient area have firestorms that enough smoke and soot gets into the stratosphere (trouble with this claim because of the Kuwait fires)
3. Prove that condition persists and effects climate as per models (others have questioned that but this issue is not addressed here

Nuclear war is definitely to be avoided but we can be precise about effects for proper planning, policy and civil defence.

The same amount of fire damage caused by a nuclear weapon could have instead been produced by smaller total yield of thousands of incendiary bombs; however, World War II experience supports this assertion. For example, although not a perfect clone of the city of Hiroshima in 1945, in the conventional bombing of Dresden, the combined Royal Air Force (RAF) and United States Army Air Forces (USAAF) dropped a total of 3441.3 tons (approximately 3.4 kilotons) of ordnance (about half of which was incendiary bombs) on the night of 13–14 February 1945, and this resulted in “more than” 2.5 square miles (6.5 km2) of the city being destroyed by fire and firestorm effects according to one authoritative source, or approximately 8 square miles (21 km2) by another. In total about 4.5 kilotons of conventional ordnance was dropped on the city over a number of months during 1945 and this resulted in approximately 15 square miles (39 km2) of the city being destroyed by blast and fire effects. During the Operation MeetingHouse firebombing of Tokyo on 9–10 March 1945, 279 of the 334 B-29s dropped 1,665 tons of incendiary and high-explosive bombs on the city, resulting in the destruction of over 10,000 acres of buildings—16 square miles (41 km2), a quarter of the city.

In contrast to these raids, when a single 16-kiloton nuclear bomb was dropped on Hiroshima, 4.5 square miles (12 km2) of the city was destroyed by blast, fire, and firestorm effects. Similarly, Major Cortez F. Enloe, a surgeon in the USAAF who worked with the United States Strategic Bombing Survey (USSBS), said that the 21-kiloton nuclear bomb dropped on Nagasaki did not do as much fire damage as the extended conventional airstrikes on Hamburg.

Hiroshima had a lot of paper-walled houses and wood and charcoal cooking stoves.

Nuclear weapons also do not add any fuel to a city, and fires are entirely dependent on what was contained in the city prior to bombing, in direct contrast to the incendiary device effect of conventional raids. One undeniable advantage of nuclear weapons over conventional weapons when it comes to creating fires is that nuclear weapons undoubtedly produce all their thermal and explosive effects in a very short period of time.

A citywide firestorm needs several conditions to occur according to the WW2 analysis.

(1) More than 8 pounds of fuel per square foot (40 kg per square metre) of ground area. Hence firestorms occurred in wooden buildings, like Hiroshima or the medieval part of Hamburg. The combustible fuel load in London is just 24 kg/m2, whereas in the firestorm area of Hamburg in 1943 it was 156 kg/m2. The real reason for all the historical fire conflagrations was only exposed in 1989 by the analysis of L. E. Frost and E.L. Jones, ‘The Fire Gap and the Greater Durability of Nineteenth-Century Cities’ (Planning Perspectives, vol.4, pp. 333-47). Each medieval city was built cheaply from inflammable ‘tinderbox’ wooden houses, using trees from the surrounding countryside. By 1800, Britain had cut down most of its forests to build wood houses and to burn for heating, so the price of wood rapidly increased (due to the expense of transporting trees long distances), until it finally exceeded the originally higher price of brick and stone; so from then on all new buildings were built of brick when wooden ones decayed. This rapidly reduced the fire risk. Also, in 1932, British Standard 476 was issued, which specified the fire resistance of building materials. In addition, new cities were built with wider streets and rubbish disposal to prevent tinder accumulation in alleys, which created more effective fire breaks.

(2) More than 50% of structures ignited initially.

(3) Initial surface winds of less than 8 miles per hour.

(4) Initial ignition area exceeding 0.5 square mile.

Background Science on Nuclear War

Fallout modeling.

Even if the bomb hit a nuclear reactor after one year gamma radiation levels are not life threatening.

A U.N. scientific committee has estimated that the cumulative per capita dose to the world’s population up to the year 2000 as a result of atmospheric testing through 1970 (cutoff date of the study) will be the equivalent of 2 years’ exposure to natural background radiation on the earth’s surface. For the bulk of the world’s population, internal and external radiation doses of natural origin amount to less than one-tenth rad annually. Thus nuclear testing to date does not appear to pose a severe radiation threat in global terms. But a nuclear war releasing 10 or 100 times the total yield of all previous weapons tests could pose a far greater worldwide threat.

A threat in that it would have health effects, but it would not be fatal to all people who were not already hit by the bombs other effects (blast, fire etc…) It seems 10,000 megatons of air exploded nuclear bombs are needed to double the annual background radiation. 50,000 megatons is needed to get the annual radiation up to one rad annually. Ramping up the megatonnage to kill all humans is possible, but it is more a matter of optimally targeting and using blast, fires and starvation in the immediate and relatively short few years after.

How may megatons to make a biosphere lifeless ? We can start going up the scale of volcanos, super-volcanos and asteroids.

The energy that the Mount Saint Helens eruption generated was equal to 27,000 Hiroshima-sized nuclear weapons. Ivy Mike, 10-12 megaton fusion bomb test, was only 430 times more powerful that the Hiroshima bomb. The Tsar Bomba, 50 megatons, was the single most physically powerful device ever produced. The Tsar-bomba design was capable of 100 megatons. the largest weapon ever produced by the United States, the now-decommissioned B41, had a predicted maximum yield of 25 MT, and the largest nuclear device ever tested by the US (Castle Bravo) yielded 15 megatons (due to a runaway reaction; the design yield was approximately 5 Mt).

The Yellowstone super volcano has erupted three times with a force up 2,500 times the Mount Saint Helens eruption. Super-volcano force of 60,000 megatons. Mt. St. Helens released 24 megatons of thermal energy, 7 of which as a direct result of the blast. With this type of power, the super volcano can cause a kind of nuclear winter since the ash can block all sunlight.

We know that 200 million megatons is not enough , which is 20,000 times bigger than a 10,000 megaton war. The asteroid that killed the dinosaurs was 200 million megatons.

Sixty-five million years ago a huge asteroid several kilometers across slammed into the Yucatan Peninsula in Mexico. This is the event that caused the extinction of the dinosaurs (and many other species). The explosion was the equivalent of about 200 million megatons of dynamite, about the equivalent of all 20 pieces of Shoemaker-Levy. The blast turned the air around it into plasma — a material so hot electrons are ripped from the atomic nucleus and molecules cannot exist. This is the stuff the Sun is made of. Enormous quantities of red-hot materials were thrown into space, most of which rained down worldwide burning literally the entire planet to a crisp. Anything not underground or underwater was killed. This scenario has been repeated over and over, perhaps once every 100 million years or so. Each collision killed up to 95% of all species on Earth.

Also, messing up the atmosphere and ozone for a few years or decades to mess up survival.

The biological effects of all forms of ionizing radiation have been calculated within broad ranges by the National Academy of Sciences. Based on these calculations, fallout from the 500-plus megatons of nuclear testing through 1970 will produce between 2 and 25 cases of genetic disease per million live births in the next generation. This means that between 3 and 50 persons per billion births in the post-testing generation will have genetic damage for each megaton of nuclear yield exploded. With similar uncertainty, it is possible to estimate that the induction of cancers would range from 75 to 300 cases per megaton for each billion people in the post-test generation.

If we apply these very rough yardsticks to a large-scale nuclear war in which 10,000 megatons of nuclear force are detonated, the effects on a world population of 5 billion appear enormous. Allowing for uncertainties about the dynamics of a possible nuclear war, radiation-induced cancers and genetic damage together over 30 years are estimated to range from 1.5 to 30 million for the world population as a whole. This would mean one additional case for every 100 to 3,000 people or about 1/2 percent to 15 percent of the estimated peacetime cancer death rate in developed countries. As will be seen, moreover, there could be other, less well understood effects which would drastically increase suffering and death.

United States and Russian Arsenals

As of 2017, the US has an estimated 4,018 nuclear weapons in either deployment or storage. This figure compares to a peak of 31,225 total warheads in 1967 and 22,217 in 1989, and does not include “several thousand” warheads that have been retired and scheduled for dismantlement.

The Start treaty of 8 April 2010 reduced the number of active nuclear weapons from 2,200 to 1,550. Obama also revised U.S. policy on the use of nuclear weapons in a Nuclear Posture Review required of all presidents, declaring for the first time that the U.S. would not use nuclear weapons against non-nuclear, NPT-compliant states.

Of 500 “tactical” “nonstrategic” weapons, around 100 are Tomahawk cruise missiles and 400 are B61 bombs.

B83 bombs can get up to 1.2 megatons This is the largest US nuclear bomb in active service.

The 1600-2000 active nuclear weapons for the United States has a total tonnage of about 700
megatons. Russia has the same number of weapons but about double the megatonnage.

Russia’s nuclear arsenal.

Russia was estimated to have around 6,800 nuclear weapons with about 1600 active strategic nuclear warheads in its arsenal.

Strategic nuclear forces of Russia include:

1. Land based Strategic Rocket Forces:like SS-18 Satan, and mobile delivery systems, like SS-27 Topol M.
3. Strategic Aviation: 237 bombers(16 Tu-160,63 Tu-95,and 158 Tu-22m) with a few hundred cruis missiles.

The SS-18 has some large megatonnage.

* The Mod 1 and Mod 2 were single nuclear re-entry vehicles of 18 and 25 megatons of TNT yield respectively.

* The Mod 4 was a three-warhead MIRV payload.

The Russians has higher mega-tonnage because of less accuracy in their missiles. They might not get it as close (to an enemy silo) so they made them bigger. Bombers, cruise missiles and submarines do not have large warhead devices because the devices must be smaller and lighter.

The scenarios for a total nuclear war between the United States and Russia are now reduced. However, war between any other countries and Russia or any other country and the United States would involve far fewer nuclear weapons. If there were a war between those two countries not all nuclear weapons would be launched. Presumably, one country is striking first and the other is responding while weapons are detected and in the air. Most of the bomber force of the non-first striking side would probably not get launched.

A total nuclear exchange between the USA and Russia is almost exclusively has targets in those two countries. One of the references indicates that any global radiation would be 20 times less in the southern hemisphere.

Nuclear winter
The first nuclear winter study was mostly discredited. Some of the same scientists have tried to update their studies with new computer climate models. Climate models have not been proving to be uncontroversial or highly accurate.

Note: it is not automatic and not even easy to start a firestorm in modern cities. Nagasaki did not have a firestorm. Nuclear winter was predicated on the assumption that there would be firestorms in every city hit by a nuclear bomb.

There were many analysis of nuclear war on climate. They had global maps of temperature reductions and reduced growing season. Things could still be grown even if these scenarios were correct. The reason for doubting these scenarios is that they are based on smoke from burning cities staying in the high atmosphere and reducing sunlight. Yet, there were large scale fires with dark smoke like oil fires in Kuwait and there is more material placed into the air from volcanoes.

There would be some starvation, but even in the worst cases the climate change would not kill all people, let alone all animals and plants even in the worst-hit areas. Australia, New Zealand and a lot of South America would be able to ride out the weather and agricultural problems.

Environmental Effects

The National Academy of Sciences report concludes that in 20 years the ecological systems would have essentially recovered from the increase in ultraviolet radiation–though not necessarily from radioactivity or other damage in areas close to the war zone. However, a delayed effect of the increase in ultraviolet radiation would be an estimated 3 to 30 percent increase in skin cancer for 40 years in the Northern Hemisphere’s mid-latitudes.

Much of our knowledge of the production and distribution of radionuclides has been derived from the period of intensive nuclear testing in the atmosphere during the 1950’s and early 1960’s. It is estimated that more than

500 megatons of nuclear yield were detonated in the atmosphere between 1945 and 1971, about half of this yield being produced by a fission reaction. The peak occurred in 1961-62, when a total of 340 megatons were detonated in the atmosphere by the United States and Soviet Union.

Half Life of Fallout

In bomb fallout, a large amount of short-lived isotopes such as Zr are present.
Most of the bomb-produced radionuclides decay rapidly. Even so, beyond the blast radius of the exploding weapons there would be areas (“hot spots”) the survivors could not enter because of radioactive contamination from long-lived radioactive isotopes like strontium-90 or cesium-137, which can be concentrated through the food chain and incorporated into the body.

Strontium-90 is a beta emitter (546 KeV, no gammas) with a half-life of 28.1 years (specific activity 141 curies/g). So 70 some halvings over 2000 years, translation there is 1000 times less after 281 years and one million times less after 562 years.

Cesium-137 is a beta and gamma emitter with a half-life of 30.0 years (specific activity 87 Ci/g). So 60 some halvings over 2000 years, translation there is 1000 times less after 300 years and one million times less after 600 years.

Carbon-14 has a long halflife but because of carbon exchange between the atmosphere and ocean it has a half life of only 6 years in the atmosphere.

Carbon-14 is also a weak beta emitter (156 KeV, no gamma), with a half-life of 5730 years (4.46 Ci/g). Atmospheric testing during the fifties and early sixties produced about 3.4 g of C-14 per kiloton (15.2 curies) for a total release of 1.75 tonnes (7.75×10^6 curies). For comparison, only about 1.2 tonnes of C-14 naturally exists, divided between the atmosphere (1 tonne) and living matter (0.2 tonne). Another 50-80 tonnes is dissolved in the oceans. Due to carbon exchange between the atmosphere and oceans, the half-life of C-14 residing in the atmosphere is only about 6 years. By now the atmospheric concentration has returned to within 1% or so of normal. High levels of C-14 remain in organic material formed during the sixties (in wood, say, or DNA).

Radioactive Fallout Would Not Be the Main Problem After 2000 Years

Expending the current level or even the highest nuclear arsenals that we have ever had would do nothing to the long-term survival of the biosphere based on radiation and fallout. The world is too big. The stuff settles out and the most dangerous stuff has a short life. The long life stuff is long lived because it is giving off low energy level of radiation.

That is why the long-term debate about nuclear war is about altering the climate or ozone in a lasting way. Plenty of atmospheric big nuclear tests have been done and the biosphere can take it. Killing a biosphere with nukes would take lot more nukes and radiation would not be the main and lasting problem ever after 2000 years.

For all of the people to die, it has to be from a big enough war that the climate and ecology is disrupted long enough that the survivors starve or do not have water or cannot last until conditions improve.

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