[4][5] When developing computer models of nuclear-winter scenarios, researchers use the conventional bombing of Hamburg, and the Hiroshima firestorm in World War II as example cases where soot might have been injected into the stratosphere,[6] alongside modern observations of natural, large-area wildfire-firestorms.
Mills et al., published in the Proceedings of the National Academy of Sciences, found that a nuclear weapons exchange between Pakistan and India using their current arsenals could create a near-global ozone hole, triggering human health problems and causing environmental damage for at least a decade.
[69] The implications for civil defense of numerous surface bursts of high yield hydrogen bomb explosions on Pacific Proving Ground islands such as those of Ivy Mike in 1952 and Castle Bravo (15 Mt) in 1954 were described in a 1957 report on The Effects of Nuclear Weapons, edited by Samuel Glasstone.
[74][79] In 1975, Hampson's hypothesis "led directly"[11] to the United States National Research Council (NRC) reporting on the models of ozone depletion following nuclear war in the book Long-Term Worldwide Effects of Multiple Nuclear-Weapons Detonations.
[63][80] However, independent of the computer models presented in the 1975 NRC works, a paper in 1973 in the journal Nature depicts the stratospheric ozone levels worldwide overlaid upon the number of nuclear detonations during the era of atmospheric testing.
Martin describes views about potential ozone loss and therefore increases in ultraviolet light leading to the widespread destruction of crops, as advocated by Jonathan Schell in The Fate of the Earth, as highly unlikely.
[87] The first published suggestion that cooling of the climate could be an effect of a nuclear war, appears to have been originally put forth by Poul Anderson and F. N. Waldrop in their story "Tomorrow's Children", in the March 1947 issue of the Astounding Science Fiction magazine.
[90] Similarly in 1985 it was noted by T. G. Parsons that the story "Torch" by C. Anvil, which also appeared in Astounding Science Fiction magazine, but in the April 1957 edition, contains the essence of the "Twilight at Noon"/"nuclear winter" hypothesis.
In the story, a nuclear warhead ignites an oil field, and the soot produced "screens out part of the sun's radiation", resulting in Arctic temperatures for much of the population of North America and the Soviet Union.
Crutzen and Birks' calculations suggested that smoke particulates injected into the atmosphere by fires in cities, forests and petroleum reserves could prevent up to 99 percent of sunlight from reaching the Earth's surface.
After the publication of "Twilight at Noon" in 1982,[100] the TTAPS team have said that they began the process of doing a 1-dimensional computational modeling study of the atmospheric consequences of nuclear war/soot in the stratosphere, though they would not publish a paper in Science magazine until late-December 1983.
calculations show large heating (up to 80 °C) at the top of the smoke layer at about 10 km (6.2 mi); this implies a substantial modification of the circulation there and the possibility of advection of the cloud into low latitudes and the southern hemisphere.
[122] 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.
Mills (at the US National Center for Atmospheric Research, NCAR), et al., published "Multi-decadal global cooling and unprecedented ozone loss following a regional nuclear conflict" in the journal Earth's Future.
[131] The authors used computational models developed by NCAR to simulate the climatic effects of a soot cloud that they suggest would be a result of a regional nuclear war in which 100 "small" (15 Kt) weapons are detonated over cities.
The model had outputs, due to the interaction of the soot cloud: ...global ozone losses of 20–50% over populated areas, levels unprecedented in human history, would accompany the coldest average surface temperatures in the last 1000 years.
[144][145] Another paper published that year, from the Tohoku University Earth science scholar Kunio Kaiho, compared the impact of nuclear winter scenarios on marine and terrestrial animal life with that of historical extinction events.
[151] A major criticism of the assumptions that continue to make these model results possible appeared in the 1987 book Nuclear War Survival Skills (NWSS), a civil defense manual by Cresson Kearny for the Oak Ridge National Laboratory.
[12] The TTAPS authors responded that, amongst other things, they did not believe target planners would intentionally blast cities into rubble, but instead argued fires would begin in relatively undamaged suburbs when nearby sites were hit, and partially conceded his point about non-urban wildfires.
In the Alan Robock et al. 2007 paper, they write that, "because of the use of the term 'nuclear autumn' by Thompson and Schneider [1986], even though the authors made clear that the climatic consequences would be large, in policy circles the theory of nuclear winter is considered by some to have been exaggerated and disproved [e.g., Martin, 1988].
[12] Russell Seitz, Associate of the Harvard University Center for International Affairs, argues that the winter models' assumptions give results which the researchers want to achieve and is a case of "worst-case analysis run amok".
[169] Following his investigation into the Siberian fire of 1915, Seitz criticized the "nuclear winter" model results for being based on successive worst-case events: The improbability of a string of 40 such coin tosses coming up heads approaches that of a pat royal flush.
[149]Seitz cited Carl Sagan, adding an emphasis: "In almost any realistic case involving nuclear exchanges between the superpowers, global environmental changes sufficient to cause an extinction event equal to or more severe than that of the close of the Cretaceous when the dinosaurs and many other species died out are likely."
[177] In 1986 Seitz also contends that many others are reluctant to speak out for fear of being stigmatized as "closet Dr. Strangeloves"; physicist Freeman Dyson of Princeton for example stated "It's an absolutely atrocious piece of science, but I quite despair of setting the public record straight.
"[152] MIT meteorologist Kerry Emanuel similarly wrote in a review in Nature that the winter concept is "notorious for its lack of scientific integrity" due to the unrealistic estimates selected for the quantity of fuel likely to burn, the imprecise global circulation models used.
[190] In 1985, Time magazine noted "the suspicions of some Western scientists that the nuclear winter hypothesis was promoted by Moscow to give anti-nuclear groups in the U.S. and Europe some fresh ammunition against America's arms buildup.
Former Soviet intelligence officer Sergei Tretyakov claimed that, under the directions of Yuri Andropov, the KGB invented the concept of "nuclear winter" in order to stop the deployment of NATO Pershing II missiles.
They are said to have distributed to peace groups, the environmental movement and the journal Ambio disinformation based on a faked "doomsday report" by the Soviet Academy of Sciences by Georgii Golitsyn, Nikita Moiseyev and Vladimir Alexandrov concerning the climatic effects of nuclear war.
[208] Although it is accepted that the Soviet Union exploited the nuclear winter hypothesis for propaganda purposes,[207] Tretyakov's inherent claim that the KGB funnelled disinformation to Ambio, the journal in which Paul Crutzen and John Birks published the 1982 paper "Twilight at Noon", has not been corroborated as of 2009[update].
These include natural-gas-digesting bacteria, the most well known being Methylococcus capsulatus, that is presently used as a feed in fish farming;[211] bark bread, a long-standing famine food using the edible inner bark of trees, and part of Scandinavian history during the Little Ice Age; increased fungiculture or mushrooms such as the honey fungi that grow directly on moist wood without sunlight;[212] and variations of wood or cellulosic biofuel production, which typically already creates edible sugars/xylitol from inedible cellulose, as an intermediate product before the final step of alcohol generation.
Simulation of a nuclear war between Russia and the US based on Xia et al.
[
15
]
and others: Over 80% of the global population would starve to death unless they succumbed to other causes sooner. The death toll in the US, Russia, Europe, and China would be approximately 99%, with over 90% of fatalities occurring in countries not directly involved in the nuclear exchange.
Picture of a
pyrocumulonimbus cloud
taken from a commercial airliner cruising at about 10 km. In 2002, various sensing instruments detected 17 distinct pyrocumulonimbus cloud events in
North America
alone.
[
22
]
Smoke rising in
Lochcarron
,
Scotland
, is stopped by an overlying natural low-level inversion layer of warmer air (2006).
Diagram obtained by the
CIA
from the
International Seminar on Nuclear War
in Italy 1984. It depicts the findings of Soviet 3-D computer model research on nuclear winter from 1983, and although containing similar errors as earlier Western models, it was the first 3-D model of nuclear winter. (The three dimensions in the model are longitude, latitude and altitude.)
[
52
]
The diagram shows the models predictions of global temperature changes after a global nuclear exchange. The top image shows effects after 40 days, the bottom after 243 days. A co-author was nuclear winter modelling pioneer
Vladimir Alexandrov
.
[
53
]
[
54
]
Alexandrov disappeared in 1985. As of 2016, there remains ongoing speculation by friend,
Andrew Revkin
, of foul play relating to his work.
[
55
]
The
Kuwaiti oil fires
were not just limited to
burning oil wells
, one of which is seen here in the background, but burning "oil lakes", seen in the foreground, also contributed to the smoke plumes, particularly the sootiest/blackest of them.
[
107
]
Smoke plumes from a few of the
Kuwaiti Oil Fires
on April 7, 1991. The maximum assumed extent of the combined plumes from over six hundred fires during the period of February 15 – May 30, 1991, are available.
[
107
]
[
108
]
Only about 10% of all the fires, mostly corresponding with those that originated from "oil lakes" produced pure black soot filled plumes, 25% of the fires emitted white to grey plumes, while the remaining emitted plumes with colors between grey and black.
[
107
]
This satellite photo of the south of
Britain
shows black smoke from the 2005
Buncefield fire
, a series of fires and explosions involving approximately 250,000,000
litres
of
fossil fuels
. The plume is seen spreading in two main streams from the explosion site at the apex of the inverted 'v'. By the time the fire had been extinguished the smoke had reached the
English Channel
. The orange dot is a marker, not the actual fire. Although the smoke plume was from a single source, and larger in size than the individual
oil well
fire plumes in Kuwait 1991, the Buncefield smoke cloud remained out of the stratosphere.
Percent of the world's population dead from a nuclear war per simulations by Xia et al. (2022, see esp. their Table 1)
[
15
]
with models fit thereto. The vertical axis is the percent of the world's population expected to die within a few years after a one-week long nuclear war that injects between 1.5 and 150 Tg (teragrams = million metric tons) of smoke (soot) into the stratosphere, shown on the top axis.
[
141
]
The bottom axis is the total megatonnage (number of nuclear weapons used times average yield) simulated to produce the quantity of soot plotted on the top axis. "IND-PAK" marks a range of hypothetical nuclear wars between
India
(IND) and
Pakistan
(PAK). "USA-RUS" marks a simulated nuclear war between
the US
(USA) and
Russia
(RUS). "PRK" = a simulated nuclear war in which
North Korea
(the People's Republic of Korea, PRK) used their existing nuclear arsenal estimated at 30 weapons with an average yield of 17 kt
[
142
]
without nuclear retaliation by an adversary
.
[
143
]
The first nuclear bombing in history used a
16-kiloton nuclear bomb
, approximately 10 times as much energy as delivered onto Tokyo, yet due in part to the
comparative inefficiency of larger bombs
,
[
note 1
]
[
163
]
a much
smaller
area of building destruction occurred when contrasted with the results from Tokyo. Only 4.5 square miles (12 km
2
) of Hiroshima was destroyed by blast, fire, and
firestorm
effects.
[
164
]
Similarly, Major Cortez F. Enloe, a surgeon in the
USAAF
who worked with the
United States Strategic Bombing Survey
(USSBS), noted that the even more energetic
22-kiloton nuclear bomb
dropped on
Nagasaki
did not result in a firestorm and thus did not do as much fire damage as the
conventional airstrikes on Hamburg
which did generate a firestorm.
[
165
]
Thus, whether a city will firestorm depends primarily not on the size or type of bomb dropped, but rather on the density of fuel present in the city.
[
citation needed
]
Moreover, it has been observed that firestorms are not likely in areas where modern buildings (constructed of bricks and concrete) have totally collapsed. By comparison, Hiroshima, and Japanese cities in general in 1945, had consisted of mostly densely-packed wooden houses along with the common use of
shoji
paper sliding walls
.
[
164
]
[
166
]
The fire hazard construction practices present in cities that have historically firestormed are now illegal in most countries for general safety reasons, and therefore cities with firestorm potential are far rarer than was common at the time of World War II.
United States and Soviet Union nuclear stockpiles. The effects of trying to make others believe the results of the models on nuclear winter, does not appear to have decreased either country's nuclear stockpiles in the 1980s,
[
186
]
only the failing
Soviet economy
and the
dissolution of the country between 1989 and 1991
which marks the end of the
Cold War
and with it the relaxation of the "
arms race
", appears to have had an effect. The effects of the electricity generating
Megatons to Megawatts
program can also be seen in the mid-1990s, continuing the trend in Russian reductions. A similar chart focusing solely on quantity of warheads in the multi-megaton range is also available.
[
187
]
Moreover, total deployed US and Russian
strategic weapons
increased steadily from 1983 until the Cold War ended.
[
188
]
The 1951
Shot Uncle
of Operation
Buster-Jangle
, had a yield about a tenth of the 13 to 16 Kt Hiroshima bomb, 1.2 Kt,
[
193
]
and was detonated 5.2 m (17 ft) beneath ground level.
[
194
]
No thermal flash of heat energy was emitted to the surroundings in this shallow buried test.
[
193
]
The explosion resulted in a cloud that rose to 3.5 km (11,500 ft).
[
195
]
The resulting crater was 260 feet (79 m) wide and 53 feet (16 m) deep.
[
196
]
The yield is similar to that of an
Atomic Demolition Munition
. Altfeld and Cimbala argue that true belief in nuclear winter might lead nations towards building greater arsenals of weapons of this type.
[
197
]
However, despite being complicated due to the advent of
Dial-a-yield
technology, data on these low yield nuclear weapons suggests that they, as of 2012, make up about a tenth of the arsenal of the US and Russia, and the fraction of the stockpile that they occupy has diminished since the 1970–1990s, not grown.
[
198
]
A factor in this is that very thin devices with yields of approximately one kiloton of energy are nuclear weapons that make very inefficient use of their nuclear materials, e.g.
two-point implosion
. Thus a more
psychologically detering
higher efficiency/higher yield device, can instead be constructed from the same mass of
fissile material
.
An animation depicting a massive asteroid–Earth impact and subsequent
impact crater
formation. The asteroid connected with the extinction of the
Cretaceous–Paleogene extinction event
released an estimated energy of 100
teratonnes of TNT
(420
ZJ
).
[
220
]
corresponding to 100,000,000 Mt of energy, roughly 10,000 times the maximum combined arsenals of the US and Soviet Union in the Cold War.
[
221
]
This is hypothesized to have produced sufficient ground-energy coupling to have caused severe
mantle plume
(volcanism) at the
antipodal point
(the opposite side of the world).
[
222
]
Depending on the size of the meteor, it will either burn up high in the atmosphere or reach lower levels and explode in an air burst akin to the
Chelyabinsk meteor
of 2013, which approximated the thermal effects of a nuclear explosion.