Already Predicted Cooling Effects from Nuclear Fission before Carl Sagan
It should be noted that before Sagan, theorists had already been predicting cooling effects from nuclear fires. In 1982, Dr. Paul Crutzen of the Max Planck Institute and Dr. John Birks of the University of Colorado had already proposed such an effect. Sagan was just the one to bring it to public consciousness.
The Origin of the Term
Scientists had been investigating the atmospheric effects of nuclear weapons before, but the term wasn’t coined until the 80’s. Carl Sagan coined the term in 1983, when he, with 4 other co-authors, published the TTAPS study, which modeled the atmospheric effects of a nuclear war.
It should be noted that before Sagan, theorists had already been predicting cooling effects from nuclear fires. In 1982, Dr. Paul Crutzen of the Max Planck Institute and Dr. John Birks of the University of Colorado had already proposed such an effect. Sagan was just the one to bring it to public consciousness.
The Origin of the Term
Scientists had been investigating the atmospheric effects of nuclear weapons before, but the term wasn’t coined until the 80’s. Carl Sagan coined the term in 1983, when he, with 4 other co-authors, published the TTAPS study, which modeled the atmospheric effects of a nuclear war.
[History]
Early work
In June 1957, The Effects of Nuclear Weapons by Samuel Glasstone was published containing a section entitled "Nuclear Bombs and the Weather" (pages 69–71), which states: "The dust raised in severe volcanic eruptions, such as that at Krakatoa in 1883, is known to cause a noticeable reduction in the sunlight reaching the earth ... The amount of debris remaining in the atmosphere after the explosion of even the largest nuclear weapons is probably not more than about 1 percent or so of that raised by the Krakatoa eruption. Further, solar radiation records reveal that none of the nuclear explosions to date has resulted in any detectable change in the direct sunlight recorded on the ground."
In 1974, John Hampson suggested that a full-scale nuclear exchange could result in depletion of the ozone shield, possibly subjecting the earth to ultraviolet radiation for a year or more. In 1975, the United States National Research Council (NRC) reported on ozone depletion following nuclear war, judging that the effect of dust would probably be slight climatic cooling.
According to Dr. Vitalii Nikolaevich Tsygichko, a Senior Analyst at the Academy of Sciences, the author of the study, Mathematical Model of Soviet Strategic Operations on the Continental Theater, and a former member of the General Staff, military analysts discussed the idea of a "nuclear winter" (although they did not use that exact term) years before U.S. scientists wrote about it in the 1980s.
1982
In 1981, William J. Moran began discussions and research in the NRC on the dust effects of a large exchange of nuclear warheads. An NRC study panel on the topic met in December 1981 and April 1982.
As part of a study launched in 1980 by Ambio, a journal of the Royal Swedish Academy of Sciences, Paul Crutzen and John Birks circulated a draft paper in early 1982 with the first quantitative evidence of alterations in short-term climate after a nuclear war. In 1982, a special issue of Ambio devoted to the possible environmental consequences of nuclear war included a paper by Crutzen and Birks anticipating the nuclear winter scenario.[44] The paper discussed particulates from large fires, nitrogen oxide, ozone depletion and the effect of nuclear twilight on agriculture. Crutzen and Birks showed that smoke injected into the atmosphere by fires in cities, forests and petroleum reserves could prevent up to 99% of sunlight from reaching the Earth's surface, with major climatic consequences: "The normal dynamic and temperature structure of the atmosphere would therefore change considerably over a large fraction of the Northern Hemisphere, which will probably lead to important changes in land surface temperatures and wind systems." An important implication of their work was that a "first strike" nuclear attack would have severe consequences for the perpetrator.
1983
In 1982, the so-called TTAPS team (Richard P. Turco, Owen Toon, Thomas P. Ackerman, James B. Pollack and Carl Sagan) undertook a computational modeling study of the atmospheric consequences of nuclear war, publishing their results in Science in December 1983. The phrase "nuclear winter" was coined by Turco just prior to publication.[46] In this early work, TTAPS carried out the first estimates of the total smoke and dust emissions that would result from a major nuclear exchange, and determined quantitatively the subsequent effects on the atmospheric radiation balance and temperature structure. To compute dust and smoke impacts, they employed a one-dimensional microphysics/radiative-transfer model of the Earth's lower atmosphere (to the mesopause), which defined only the vertical characteristics of the global climate perturbation.
Around this time, interest in nuclear war environmental effects also arose in the USSR. After becoming aware of the work of the Swedish Academy and, in particular, papers by N.P.Bochkov and E.I.Chazov, Russian atmospheric scientist Georgy Golitsyn applied his research on dust-storms to the situation following a nuclear catastrophe.[48] His suggestion that the atmosphere would be heated and that the surface of the planet would cool appeared in The Herald of the Academy of Sciences in September 1983. Upon learning of the TTAPS scenarios, Vladimir Alexandrov and G. I. Stenchikov soon published a report on the climatic consequences of nuclear war based on simulations with a two-level global circulation model, which produced results consistent with the TTAPS findings.
1986
In 1984 the WMO commissioned Georgy Golitsyn and N. A. Phillips to review the state of the science. They found that studies generally assumed a scenario that half of the world's nuclear weapons would be used, ~5000 Mt, destroying approximately 1,000 cities, and creating large quantities of carbonaceous smoke - 1–2×1014 g being mostly likely, with a range of 0.2–6.4×1014 g (NAS; TTAPS assumed 2.25×1014). The smoke resulting would be largely opaque to solar radiation but transparent to infra-red, thus cooling by blocking sunlight but not causing warming from enhancing the greenhouse effect. The optical depth of the smoke can be much greater than unity. Forest fires resulting from non-urban targets could increase aerosol production further. Dust from near-surface explosions against hardened targets also contributes; each Mt-equivalent of explosion could release up to 5 million tons of dust, but most would quickly fall out; high altitude dust is estimated at 0.1-1 million tons per Mt-equivalent of explosion. Burning of crude oil could also contribute substantially.
The 1-D radiative-convective models used in these studies produced a range of results, with coolings up to 15–42 °C between 14 and 35 days after the war, with a "baseline" of about 20 °C. Somewhat more sophisticated calculations using 3-D GCMs (Alexandrov and Stenchikov (1983); Covey, Schneider and Thompson (1984); produced similar results: temperature drops of between 20 and 40 °C, though with regional variations.
All calculations show large heating (up to 80 °C) at the top of the smoke layer at about 10 km; this implies a substantial modification of the circulation there and the possibility of advection of the cloud into low latitudes and the southern hemisphere.
The report made no attempt to compare the likely human impacts of the post-war cooling to the direct deaths from explosions.
In 1987 P. M. Kelly of the University of East Anglia Climatic Research Unit stated that "although there are a handful of vociferous critics, the atmospheric community is united in its conclusion that the threat of nuclear winter is genuine".
1990
In 1990, in a paper entitled "Climate and Smoke: An Appraisal of Nuclear Winter," TTAPS give a more detailed description of the short- and long-term atmospheric effects of a nuclear war using a three-dimensional model:
First 1 to 3 months:
- 10 to 25% of soot injected is immediately removed by precipitation, while the rest is transported over the globe in 1 to 2 weeks
- SCOPE figures for July smoke injection:
*. 22 °C drop in mid-latitudes
*. 10 °C drop in humid climates
*. 75% decrease in rainfall in mid-latitudes
*. Light level reduction of 0% in low latitudes to 90% in high smoke injection areas
- SCOPE figures for winter smoke injection:
*. Temperature drops between 3 and 4 °C
Following 1 to 3 years:
- 25 to 40% of injected smoke is stabilised in atmosphere (NCAR). Smoke stabilised for approximately 1 year.
- Land temperatures of several degrees below normal
- Ocean surface temperature between 2 and 6 °C
- Ozone depletion of 50% leading to 200% increase in UV radiation incident on surface.
Early work
In June 1957, The Effects of Nuclear Weapons by Samuel Glasstone was published containing a section entitled "Nuclear Bombs and the Weather" (pages 69–71), which states: "The dust raised in severe volcanic eruptions, such as that at Krakatoa in 1883, is known to cause a noticeable reduction in the sunlight reaching the earth ... The amount of debris remaining in the atmosphere after the explosion of even the largest nuclear weapons is probably not more than about 1 percent or so of that raised by the Krakatoa eruption. Further, solar radiation records reveal that none of the nuclear explosions to date has resulted in any detectable change in the direct sunlight recorded on the ground."
In 1974, John Hampson suggested that a full-scale nuclear exchange could result in depletion of the ozone shield, possibly subjecting the earth to ultraviolet radiation for a year or more. In 1975, the United States National Research Council (NRC) reported on ozone depletion following nuclear war, judging that the effect of dust would probably be slight climatic cooling.
According to Dr. Vitalii Nikolaevich Tsygichko, a Senior Analyst at the Academy of Sciences, the author of the study, Mathematical Model of Soviet Strategic Operations on the Continental Theater, and a former member of the General Staff, military analysts discussed the idea of a "nuclear winter" (although they did not use that exact term) years before U.S. scientists wrote about it in the 1980s.
1982
In 1981, William J. Moran began discussions and research in the NRC on the dust effects of a large exchange of nuclear warheads. An NRC study panel on the topic met in December 1981 and April 1982.
As part of a study launched in 1980 by Ambio, a journal of the Royal Swedish Academy of Sciences, Paul Crutzen and John Birks circulated a draft paper in early 1982 with the first quantitative evidence of alterations in short-term climate after a nuclear war. In 1982, a special issue of Ambio devoted to the possible environmental consequences of nuclear war included a paper by Crutzen and Birks anticipating the nuclear winter scenario.[44] The paper discussed particulates from large fires, nitrogen oxide, ozone depletion and the effect of nuclear twilight on agriculture. Crutzen and Birks showed that smoke injected into the atmosphere by fires in cities, forests and petroleum reserves could prevent up to 99% of sunlight from reaching the Earth's surface, with major climatic consequences: "The normal dynamic and temperature structure of the atmosphere would therefore change considerably over a large fraction of the Northern Hemisphere, which will probably lead to important changes in land surface temperatures and wind systems." An important implication of their work was that a "first strike" nuclear attack would have severe consequences for the perpetrator.
1983
In 1982, the so-called TTAPS team (Richard P. Turco, Owen Toon, Thomas P. Ackerman, James B. Pollack and Carl Sagan) undertook a computational modeling study of the atmospheric consequences of nuclear war, publishing their results in Science in December 1983. The phrase "nuclear winter" was coined by Turco just prior to publication.[46] In this early work, TTAPS carried out the first estimates of the total smoke and dust emissions that would result from a major nuclear exchange, and determined quantitatively the subsequent effects on the atmospheric radiation balance and temperature structure. To compute dust and smoke impacts, they employed a one-dimensional microphysics/radiative-transfer model of the Earth's lower atmosphere (to the mesopause), which defined only the vertical characteristics of the global climate perturbation.
Around this time, interest in nuclear war environmental effects also arose in the USSR. After becoming aware of the work of the Swedish Academy and, in particular, papers by N.P.Bochkov and E.I.Chazov, Russian atmospheric scientist Georgy Golitsyn applied his research on dust-storms to the situation following a nuclear catastrophe.[48] His suggestion that the atmosphere would be heated and that the surface of the planet would cool appeared in The Herald of the Academy of Sciences in September 1983. Upon learning of the TTAPS scenarios, Vladimir Alexandrov and G. I. Stenchikov soon published a report on the climatic consequences of nuclear war based on simulations with a two-level global circulation model, which produced results consistent with the TTAPS findings.
1986
In 1984 the WMO commissioned Georgy Golitsyn and N. A. Phillips to review the state of the science. They found that studies generally assumed a scenario that half of the world's nuclear weapons would be used, ~5000 Mt, destroying approximately 1,000 cities, and creating large quantities of carbonaceous smoke - 1–2×1014 g being mostly likely, with a range of 0.2–6.4×1014 g (NAS; TTAPS assumed 2.25×1014). The smoke resulting would be largely opaque to solar radiation but transparent to infra-red, thus cooling by blocking sunlight but not causing warming from enhancing the greenhouse effect. The optical depth of the smoke can be much greater than unity. Forest fires resulting from non-urban targets could increase aerosol production further. Dust from near-surface explosions against hardened targets also contributes; each Mt-equivalent of explosion could release up to 5 million tons of dust, but most would quickly fall out; high altitude dust is estimated at 0.1-1 million tons per Mt-equivalent of explosion. Burning of crude oil could also contribute substantially.
The 1-D radiative-convective models used in these studies produced a range of results, with coolings up to 15–42 °C between 14 and 35 days after the war, with a "baseline" of about 20 °C. Somewhat more sophisticated calculations using 3-D GCMs (Alexandrov and Stenchikov (1983); Covey, Schneider and Thompson (1984); produced similar results: temperature drops of between 20 and 40 °C, though with regional variations.
All calculations show large heating (up to 80 °C) at the top of the smoke layer at about 10 km; this implies a substantial modification of the circulation there and the possibility of advection of the cloud into low latitudes and the southern hemisphere.
The report made no attempt to compare the likely human impacts of the post-war cooling to the direct deaths from explosions.
In 1987 P. M. Kelly of the University of East Anglia Climatic Research Unit stated that "although there are a handful of vociferous critics, the atmospheric community is united in its conclusion that the threat of nuclear winter is genuine".
1990
In 1990, in a paper entitled "Climate and Smoke: An Appraisal of Nuclear Winter," TTAPS give a more detailed description of the short- and long-term atmospheric effects of a nuclear war using a three-dimensional model:
First 1 to 3 months:
- 10 to 25% of soot injected is immediately removed by precipitation, while the rest is transported over the globe in 1 to 2 weeks
- SCOPE figures for July smoke injection:
*. 22 °C drop in mid-latitudes
*. 10 °C drop in humid climates
*. 75% decrease in rainfall in mid-latitudes
*. Light level reduction of 0% in low latitudes to 90% in high smoke injection areas
- SCOPE figures for winter smoke injection:
*. Temperature drops between 3 and 4 °C
Following 1 to 3 years:
- 25 to 40% of injected smoke is stabilised in atmosphere (NCAR). Smoke stabilised for approximately 1 year.
- Land temperatures of several degrees below normal
- Ocean surface temperature between 2 and 6 °C
- Ozone depletion of 50% leading to 200% increase in UV radiation incident on surface.