Opinion: How fear of nuclear winter has helped save the world, so far

Robock, Alan; Xia, Lili; Harrison, Cheryl S.; Coupe, Joshua; Toon, Owen B.; Bardeen, Charles G.

doi:https://doi.org/10.5194/acp-23-6691-2023

Articles | Volume 23, issue 12

https://doi.org/10.5194/acp-23-6691-2023

© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Special issue:

20 years of Atmospheric Chemistry and Physics

https://doi.org/10.5194/acp-23-6691-2023

© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 23, issue 12

Opinion

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19 Jun 2023

Opinion | Highlight paper |

| 19 Jun 2023

Opinion: How fear of nuclear winter has helped save the world, so far

Alan Robock, Lili Xia, Cheryl S. Harrison, Joshua Coupe, Owen B. Toon, and Charles G. Bardeen

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Final revised paper (published on 19 Jun 2023)
Preprint (discussion started on 10 Jan 2023)

Interactive discussion

Status: closed

RC1: 'Comment on acp-2022-852', Alexander Kmentt, 30 Jan 2023

This is a very important overview of the history of the nuclear winter research and the political significance of it. In the current situation of heighened nuclear risks (the Doomsday Clock stands at an unprecedented 90 seconds before midnight), this is a crucial contribution. It is particulalry important to highlight that there is a lot of very "new" research that goes beyond the knowledge of nuclear winter of the 1980s. This "new" research thus merits a reassessment of the arguments around the sustainability of an approach to international security that is based on the premement threat of inflicting mass destruction with the risk of causing nuclear winter. This knowledge needs to be further promulgated and form the basis of policy decisions regarding nuclear weapons.

Below are some specific comments and recommendations on the text linked to specific lines in the manuscript:

line	comment
1	Fear of nuclear winter is not the only reason why the « world has been saved » so far and nuclear war has not happened in the past 8 decades. It is a major contribution but many other factors have played a role. Suggest: How Fear of Nuclear Winter has Helped Save the World, So Far.
46	Suggest: ,for which the International Campaign to Abolish Nuclear Weapons (ICAN) received the 2017 Nobel Peace Prize
47	See comment re title: Nuclear winter is but one reason.
49	Possible technical errors go beyond computer and sensor malfunctions
51	In addition to Russia’s threats it is maybe worth highlighting that nuclear deterrence doctrines (of all nuclear-armed states) are based on the capability and readiness to use nuclear weapons
55 pp	This whole section is really important as a background and history of the nuclear winter research. It may be useful to explain a bit more in detail (lines 117 pp) how exactly progress in computing and climate modelling contributed to “new” knowledge. This is against the background that some nuclear-armed states claim that there is nothing “new” and that they knew about the humanitarian consequences and nuclear winter all along. A bit more detail here could be helpful in clarifying that the situation regarding nuclear winter research is fundamentally different and “new” compared to the 1980s.
210	Factual correction: ICAN did not organise the 3 international conferences. These were organised by Norway, Mexico and Austria as governmental expert conferences. ICAN and other NGOs as well as academic experts were invited to participate. ICAN organised separate civil society events in the margins of the three governmental conferences. Furthermore, ICAN campaigned for states to attend. Other than that, ICAN did not have any responsibility in the organisation of the governmental conferences.
220	Factual correction: The process to obtain a negotiation mandate in the UN General Assembly was led by four countries Austria, Ireland, Mexico and South Africa – and this group was later expanded to include Brazil, Costa Rica, Indonesia, New Zealand, Nigeria and Thailand. These states submitted resolutions in the General Assembly which garnered the necessary support from States. ICAN successfully campaigned all along for states to support this process but it is important to be clear that this was a state-led process.
224	Important not to omit the crucial role of the International Committee of the Red Cross (ICRC)
242 pp	I would suggest not to make too much of the attendance as observers. As welcome as it is, these states have stated their intention not to join the treaty. The transformational strength of the TPNW does not come from this. It is the normative pressure through increasing ratifications and signatories and the political pressure that comes from the TPNW underlying arguments on the humanitarian consequences and risks of nuclear weapons. This is a dicoursive process that has both a legal and a political dimension.
304	It is not just the increasing instability in South Asia. I would suggest “In view of today’s high level of nuclear risks”
329 pp	It might be worthwhile to reference the fact that the impact of such famine scenarios on social structures, likely societal collapse, infrastructure, mass migratory movements, psychological impact etc. are not considered in these studies but that would have to be included in any comprehensive attempt to understand the full scale impact of such scenarios.
368	Factual correction: The presentation was actually made at the 2022 Vienna Conference on the Humanitarian Impact of Nuclear Weapons (www.HINW22vienna.at ), which was organised by Austria on the day before the First Meeting of States Parties
388	While the G20 statement is very important, its link to nuclear winter argument is not really clear. The reference to “inadmissible” is more a reference to the legal/prohibitive aspect of nuclear weapons use.
394	See above: nuclear deterrence depends on the readiness and capability to use nuclear weapons.

Citation: https://doi.org/10.5194/acp-2022-852-RC1

RC2:
'Comment on acp-2022-852', Anonymous Referee #2, 03 Feb 2023
This opinion piece addresses a very important topic, which has, unfortunately, become very timely again in the current political situation. The paper provides a comprehensive overview on the history of research performed on the climatic effects of a nuclear war, and how this research affected global politics. While the basic scientific findings regarding the climatic consequences of a nuclear conflict have been robust over the years, more recent studies go beyond the climate response and highlight the dramatic humanitarian impacts of a nuclear winter. I agree with the authors that the disastrous threat from nuclear weapons to human mankind can never be stressed enough.
Below a few more specific comments.
I find the title a bit confusing and misleading. In my view, the term “nuclear winter” describes not only the theory behind, but the occurrence. Luckily, the world has not yet experienced nuclear winter so far, so how could nuclear winter have saved the world . The title of the paper became only clear to me after I had read the abstract.

The paper focuses mainly on nuclear winter and its consequences on world agriculture as indirect effects of a nuclear war that would also affect other regions than those directly involved in the war. This is in a way understandable as it is the research topic of the authors, but how about effects on regions further away from the combat zone from the long-range transport and fallout of radioactive material?

L61: Do you mean “The smoke cloud would spread …”. Otherwise, either “could” or “would”, but not both.

L80-82: I find this sentence a bit weird. I assume the authors want to highlight the gap in published articles on the nuclear winter topic between the 1990s and the 2000s, but I do not get the point about the launch of ACP.

L114: “… and they outlined…” ?

L129: “The basic conclusion…”

L151-153: I am not sure that the sentence makes sense as is. Maybe: “Observations of firestorms, that pumped smoke into the stratosphere after the August 6, 1945 atomic bombing of Hiroshima and the April 18, 1906 San Francisco earthquake, are evidence…”
Citation: https://doi.org/10.5194/acp-2022-852-RC2
AC1: 'Comment on acp-2022-852', Alan Robock, 08 Mar 2023

The comment was uploaded in the form of a supplement: https://acp.copernicus.org/preprints/acp-2022-852/acp-2022-852-AC1-supplement.pdf

Citation: https://doi.org/10.5194/acp-2022-852-AC1

Peer review completion

AR: Author's response | RR: Referee report | ED: Editor decision | EF: Editorial file upload

AR by Alan Robock on behalf of the Authors (08 Mar 2023) Author's response Author's tracked changes Manuscript

ED: Referee Nomination & Report Request started (27 Mar 2023) by Rolf Müller

RR by Alexander Kmentt (17 Apr 2023)

ED: Publish as is (25 Apr 2023) by Rolf Müller

ED: Publish as is (11 May 2023) by James Allan (Executive editor)

AR by Alan Robock on behalf of the Authors (17 May 2023)

Executive editor

The term "nuclear winter" was commonly used in the 1980s and represented a scenario where a nuclear war could profoundly alter the earth's climate through injection of aerosols into the stratosphere, which could be considered a highly extreme example of human activity altering the earth system. Paul Crutzen, in his Nobel Prize speech, said that this concept is politically important as it "magnifies and highlights the dangers of a nuclear war and convinces me that in the long run mankind can only escape such horrific consequences if nuclear weapons are totally abolished by international agreement". While nuclear war is hopefully something that we will never experience, it is highly interesting to return to this topic four decades later, after the major advancements in the science of aerosol-climate interactions that have occurred in the meantime (partly motivated by an exploration of geoengineering concepts), and improvements in our abilities to model the agricultural and economic impacts of climate change. The conclusions of the paper by Robock et al. offer a sobering reminder of the manifold dangers of this type of warfare to the earth system and society.