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Animation of smoke lofting from 5 Tg of soot from an India-Pakistan nuclear war, drawn by Mike Mills, from this paper.

Climatic Consequences of Nuclear Conflict
Nuclear Winter is Still a Danger

 

Alan Robock

Department of Environmental Sciences

Rutgers University

robock@envsci.rutgers.edu

+1-848-932-5751 (work)

Animation of smoke distribution from 5 Tg of soot from an India-Pakistan nuclear war, drawn by Luke Oman, from this paper.



 News   TEDx Talks   Publications   PowerPoint Presentations   Movies   Figures   Short Summaries

News:

What Happens AFTER Nuclear War?, by Kurzgesagt – In a Nutshell, February 20, 2024

Alan Robock appeared on Science Friday on National Public Radio on November 3, 2023
discussing "40 Years Of Sounding The Alarm On Nuclear Winter"

National Academies Independent Study on Potential Environmental Effects of Nuclear War
(Click on Past Events on February 23, June 22, and June 26, 2023, to see presentations from our group.)

New $4,000,000 Nuclear Winter research program, supported by Future of Life Institute

Here's How Bad a Nuclear War Would Actually Be, by Max Tegmark,
Time Magazine, June 29, 2023, including 4-minute video

Nowhere to Hide: How a nuclear war would kill you — and almost everyone else.
by François Diaz-Maurin, Bulletin of the Atomic Scientists, October 20, 2022

Alan Robock, Brian Toon, Richard Turco, and Georgiy Stenchikov win the 2022 Future of Life Award, August 6, 2022

What nuclear war looks like from space, YouTube by Max Tegmark, August 15, 2022

Putin’s Nuclear Threat – Global Implications and Options webcast, March 3, 2022
with Andy Revkin, Paul and Anne Ehrlich, Alan Robock, and Brian Toon

Robock, Alan, and Stewart C. Prager, 2021: Geoscientists can help reduce the threat of nuclear weapons,
Eos, 102, doi:10.1029/2021EO210633. Published on 2 December 2021.

Join the Physicists Coalition for Nuclear Threat Reduction

Treaty on the Prohibition of Nuclear Weapons Enters into Force, January 22, 2021

Congressional Mandate for a Study on Environmental Effects of Nuclear War
Section 3171 of the Fiscal Year 2021 U.S. National Defense Authorization Act

Congressional Mandate for a Study on Nuclear Policy
Section 1674 of the Fiscal Year 2020 U.S. National Defense Authorization Act

Witze, Alexandra, 2020: How a small nuclear war would transform the entire planet
Nature, 579, 485-487, https://www.nature.com/articles/d41586-020-00794-y  PDF file

International Campaign to Abolish Nuclear Weapons (ICAN) wins the 2017 Nobel Peace Prize. Read the Nobel Lecture here.  

Treaty on the Prohibition of Nuclear Weapons, adopted July 7, 2017  

January 10, 2017 Huffington Post Blog: My Advice to President-Elect Trump on Nuclear Weapons

December 23, 2016 United Nations General Assembly votes to launch negotiations in 2017 on a treaty prohibiting nuclear weapons

Nukemap [see the consequences in your neighborhood]

Global Warming Gives Science Behind Nuclear Winter a New Purpose, New York Times, April 3, 2016

Retro Report on Nuclear Winter in New York Times, April 3, 2016

February 11, 2016 New York Times Op-ed, Let’s End the Peril of a Nuclear Winter

September 1, 2015 Huffington Post Blog: A Modest Proposal

December 1, 2014 Huffington Post Blog: Nuclear Weapons Are Much More Dangerous Than Global Warming

March 22, 2014 Huffington Post Blog: Ukraine and Nuclear Weapons

February 20, 2014 Huffington Post Blog: Ban Nuclear Weapons; Saving Money and Saving the World

TEDx presentations of the message:

  TEDx talk by Brian Toon on "I've studied nuclear war for 35 years - you should be worried," Denver, Colorado, November, 2017 (15 minutes)

  TEDx talk by Alan Robock on "Nuclear winter - still possible but preventable," in Hoboken, New Jersey, June 28, 2013 (18 minutes)

Brief (12 minutes) presentation of the message:

Climatic Consequences of Nuclear Conflict (download), invited presentation; AGU Fall Meeting, San Francisco, California, December 5-9, 2011.  This was the December 7, 2011, session to honor new AGU Fellows, and I presented it in a tuxedo.  (12 minutes)

For a quick summary of the results:

Why You Should Care About Nukes, with Max Tegmark (3 minutes)

Stumbling in the dark, reaching for the light, by Tilman Ruff (July 25, 2013) 

No such thing as a safe number of nukes, by Ira Helfand and Alan Robock, CNN (June 20, 2013)  

Self-assured destruction: The climate impacts of nuclear war, Bulletin of Atomic Scientists  (September, 2012)

Nuclear Famine: A Billion People at Risk, by Ira Helfand (April, 2012)

Scientific American 12 Events That Will Change Everything, Made Interactive, Click on mushroom cloud, then click on "Interview with Alan Robock." (May 21, 2010)

Regional Nuclear War and the Environment, by Eben Harrell in Time Science (Jan. 22, 2009)

Nuclear Winter article in Encyclopedia of Earth (July 21, 2008)

One Page Summary: Congressional Briefing (June 12, 2008)

 

For an illustrated 8-page summary of the results:

Local nuclear war, global suffering.  Scientific American (January, 2010)

 

PowerPoint Presentations:
Global Famine After Nuclear War (340 Mb)  (by Alan Robock; has many hidden slides that you are free to use, updated December, 2023)

Future of Life Project (52 Mb)  (by Brian Toon, with data on targets, smoke emissions, and work still to do, April 8, 2024)

Publications:

  1. Robock, Alan, Lili Xia, Cheryl S. Harrison, Joshua Coupe, Owen B. Toon, and Charles G. Bardeen, 2023: Opinion: How nuclear winter has saved the world, so far. Atm. Chem. Phys., 23, 6691-6701, doi:10.5194/acp-23-6691-2023.   PDF file

  2. Coupe, Joshua, Cheryl Harrison, Alan Robock, Alice DuVivier, Elizabeth Maroon, Nicole S. Lovenduski, Scott Bachman, Laura Landrum, and Charles Bardeen, 2023: Sudden reduction of Antarctic sea ice despite cooling after nuclear war. J. Geophys. Res. Oceans, 128, e2022JC018774, doi:10.1029/2022JC018774.  PDF file

  3. Xia, Lili, Alan Robock, Kim Scherrer, Cheryl S. Harrison, Benjamin Leon Bodirsky, Isabelle Weindl, Jonas Jägermeyr, Charles G. Bardeen, Owen B. Toon, and Ryan Heneghan, 2022: Global food insecurity and famine from reduced crop, marine fishery and livestock production due to climate disruption from nuclear war soot injection. Nature Food, 3, 586-596, doi:10.1038/s43016-022-00573-0.  PDF file

  4. Harrison, Cheryl S., Tyler Rohr, Alice DuVivier, Elizabeth A. Maroon, Scott Bachman, Charles G. Bardeen, Joshua Coupe, Victoria Garza, Ryan Heneghan, Nicole S. Lovenduski, Philipp Neubauer, Victor Rangel, Alan Robock, Kim Scherrer, Samantha Stevenson, and Owen B. Toon, 2022: A new ocean state after nuclear war. AGU Advances, 3, e2021AV000610, doi:10.1029/2021AV000610.    PDF file

  5. Hochman, Gal, Hainan Zhang, Lili Xia, Alan Robock, Saketh Aleti, Dominique Y. van der Mensbrugghe, and Jonas Jägermeyr, 2022: Economic incentives modify agricultural impacts of nuclear war. Env. Res. Lett., 17, 054003, doi:10.1088/1748-9326/ac61c7.    PDF file

  6. Yu, Pengfei, Sean M. Davis, Owen B. Toon, Robert W. Portmann, Charles G. Bardeen, John E. Barnes, Hagen Telg, Christopher Maloney, Karen H. Rosenlof, 2021: Persistent stratospheric warming due to 2019-20 Australian wildfire smoke, Geophys. Res. Lett., 48, e2021GL092609, doi:10.1029/2021GL092609.   PDF file

  7. Bardeen, Charles G., Douglas E. Kinnison, Owen B. Toon, Michael J. Mills, Francis Vitt, Lili Xia, Jonas Jägermeyr, Nicole S. Lovenduski, Kim J. N. Scherrer, Margot Clyne, and Alan Robock, 2021: Extreme ozone loss following nuclear war resulting in enhanced surface ultraviolet radiation. J. Geophys. Res. Atmos., 126, e2021JD035079, doi:10.1029/2021JD035079.   PDF file

  8. Redfern, S., Lundquist, J. K., Toon, O. B., Muñoz-Esparza, D., Bardeen, C. G., & Kosović, B, 2021: Upper troposphere smoke injection from large areal fires. J. Geophys. Res. Atmos., 126, e2020JD034332, doi:10.1029/2020JD034332.   PDF file

  9. Coupe, Joshua, and Alan Robock, 2021: The influence of stratospheric soot and sulfate aerosols on the Northern Hemisphere wintertime atmospheric circulation. J. Geophys. Res. Atmos., 126, e2020JD034513, doi:10.1029/2020JD034513.   PDF file

  10. Coupe, Joshua, Samantha Stevenson, Nicole S. Lovenduski, Tyler Rohr, Cheryl S. Harrison, Alan Robock, Holly Olivarez, Charles G. Bardeen, and Owen B. Toon, 2021: Nuclear Niño response observed in simulations of nuclear war scenarios. Communications Earth & Environment, 2, 18, doi:10.1038/s43247-020-00088-1.     PDF file

  11. Frishcosy, Christopher Cole, Yao Wang, and Yunping Xi, 2021: A novel approach to estimate fuel energy from urban areas. Energy and Buildings, 231, 110609, doi:10.1016/j.enbuild.2020.110609.  PDF file

  12. Scherrer, Kim J. N., Cheryl S. Harrison, Ryan F. Heneghan, Eric Galbraith, Charles G. Bardeen, Joshua Coupe, Jonas Jägermeyr, Nicole S. Lovenduski, August Luna, Alan Robock, Jessica Stevens, Samantha Stevenson, Owen B. Toon, and Lili Xia, 2020: Marine wild-capture fisheries after nuclear war.  Proc. Nat. Acad. Sci., 117(47), 29,748-29,758, doi:10.1073/pnas.2008256117.   PDF file

  13. Jägermeyr, Jonas, Alan Robock, Joshua Elliott, Christoph Müller, Lili Xia, Nikolay Khabarov, Christian Folberth, Erwin Schmid, Wenfeng Liu, Florian Zabel, Sam S. Rabin, Michael J. Puma, Alison C. Heslin, James Franke, Ian Foster, Senthold Asseng, Charles G. Bardeen, Owen B. Toon, and Cynthia Rosenzweig, 2020: A regional nuclear conflict would compromise global food security. Proc. Nat. Acad. Sci., 117, 7071-7081, doi:10.1073/pnas.1919049117.    PDF file

  14. Lovenduski, Nicole S., Cheryl S. Harrison, Holly Olivarez, Charles G. Bardeen, Owen B. Toon, Joshua Coupe, Alan Robock, Tyler Rohr, and Samantha Stevenson, 2020: The potential impact of nuclear conflict on ocean acidification. Geophys. Res. Lett., doi: 10.1029/2019GL086246.    PDF file

  15. Robock, Alan, Owen B. Toon, Charles G. Bardeen, Lili Xia, Hans Kristensen, Matthew McKinzie, R. J. Peterson, Cheryl Harrison, Nicole S. Lovenduski, and Richard P. Turco, 2019: How an India-Pakistan nuclear war could start–and have global consequences. Bull. Atomic Scientists, 75:6, 273-279, doi:10.1080/00963402.2019.1680049.  PDF file

  16. Toon, Owen B., Charles G. Bardeen, Alan Robock, Lili Xia, Hans Kristensen, Matthew McKinzie, R. J. Peterson, Cheryl Harrison, Nicole S. Lovenduski, and Richard P. Turco, 2019: Rapid expansion of nuclear arsenals by Pakistan and India portends regional and global catastrophe. Science Advances, 5, eaay5478, doi:10.1126/sciadv.aay5478.    Full paper and PDF file

  17. Robock, Alan, Owen B. Toon, and Charles G. Bardeen, 2019: Comment on “Climate impact of a regional nuclear weapons exchange: An improved assessment based on detailed source calculations” by Reisner et al. J. Geophys. Res. Atmos., 124, 12,953-12,958, doi:10.1029/2019JD030777.    PDF file

  18. Coupe, Joshua, Charles G. Bardeen, Alan Robock, and Owen B. Toon, 2019: Nuclear winter responses to global nuclear war in the Whole Atmosphere Community Climate Model Version 4 and the Goddard Institute for Space Studies ModelE. J. Geophys. Res. Atmos., 124, 8522-8543, doi:10.1029/2019JD030509.     PDF file

  19. Yu, Pengfei, Owen B. Toon, Charles G. Bardeen, Yunqian Zhu, Karen H. Rosenlof, Robert W. Portmann, Troy D. Thornberry, Ru-Shan Gao, Sean M. Davis, Eric T. Wolf, Joost de Gouw, David A. Peterson, Michael D. Fromm, and Alan Robock, 2019: Black carbon lofts wildfire smoke high into the stratosphere to form a persistent plume. Science, 365, 587-590, doi:10.1126/science.aax1748.     PDF file

  20. Robock, Alan, and Brian Zambri, 2018: Did smoke from city fires in World War II cause global cooling? J. Geophys. Res. Atmos., 123, 10,314-10,325, doi:10.1029/2018JD028922.     PDF file

  21. Toon, Owen B., Alan Robock, Michael Mills, and Lili Xia, 2017: Asia treads the nuclear path, unaware that self-assured destruction would result from nuclear war. J. Asian Studies, 76, 437-456, doi:10.1017/S0021911817000080.     PDF file

  22. Robock, Alan, 2015: Cloud control: Climatologist Alan Robock on the effects of geoengineering and nuclear war. Bull. Atomic Sci., 71(3), 1-7, doi:10.1177/0096340215581353.    PDF file

  23. Baum, Seth D., David C. Denkenberger, Joshua M. Pearce, Alan Robock, and Richelle Winkler, 2015: Resilience to global food supply catastrophes. Environment, Systems, and Decisions, 35, 301-313, doi:10.1007/s10669-015-9549-2.    PDF file

  24. Xia, Lili, Alan Robock, Michael Mills, Andrea Stenke, and Ira Helfand, 2015: Decadal reduction of Chinese agriculture after a regional nuclear war. Earth’s Future, 3, 37-48, doi:10.1002/2014EF000283.     PDF file

  25. Robock, Alan, 2015: A Modest Proposal, Huffington Post.     PDF file

  26. Mills, Michael J., Owen B. Toon, Julia Lee-Taylor, and Alan Robock, 2014: Multi-decadal global cooling and unprecedented ozone loss following a regional nuclear conflict. Earth’s Future, 2, 161-176, doi:10.1002/2013EF000205.    PDF file

  27. Xia, Lili, and Alan Robock, 2013: Impacts of a nuclear war in South Asia on rice production in mainland China. Climatic Change, 116, 357-372, doi:10.1007/s10584-012-0475-8.    PDF file

  28. Özdoğan, Mutlu, Alan Robock, and Christopher Kucharik, 2013: Impacts of a nuclear war in South Asia on soybean and maize production in the Midwest United States. Climatic Change, 116, 373-387, doi:10.1007/s10584-012-0518-1.   PDF file

  29. Robock, Alan, and Owen Brian Toon, 2012: Self-assured destruction: The climate impacts of nuclear war, Bull. Atomic Scientists, 68(5), 66-74, doi:10.1177/0096340212459127.  (Invited article)  PDF file

  30. Robock, Alan, 2011: Nuclear winter is a real and present danger. Nature, 473, 275-276.   PDF file

  31. Robock, Alan, and Owen Brian Toon, 2010:  Local nuclear war, global suffering.  Scientific American, 302, 74-81.  PDF file

  32. Robock, Alan, 2010: Nuclear winter. Wiley Interdisciplinary Reviews: Climate Change, 1, 418-427. (Invited paper)   PDF file

  33. Robock, Alan, 2010: New START, Eyjafjallajökull, and Nuclear Winter. Eos, 91 (47), 444-445, doi:10.1029/2010ES003201.   PDF file

  34. Mills, Michael J., Owen B. Toon, Richard P. Turco, Douglas E. Kinnison, and Rolando R. Garcia, 2008:  Massive global ozone loss predicted following regional nuclear conflict.  Proc. National Acad. Sci., 105, 5307–5312.   PDF file

  35. Toon, Owen B., Alan Robock, and Richard P. Turco, 2008:  Environmental consequences of nuclear war.  Physics Today, 61, No. 12, 37-42.  PDF file

  36. Robock, Alan, 2008:  Time to bury a dangerous legacy – part II: Climatic catastrophe would follow regional nuclear conflict.  YaleGlobal Online

  37. Robock, Alan, 2008:  Nuclear winter. In: Encyclopedia of Earth. Cutler J. Cleveland, Ed. (Washington, D.C.: Environmental Information Coalition, National Council for Science and the Environment). [First published in the Encyclopedia of Earth July 21, 2008; Last revised July 22, 2008].  http://www.eoearth.org/article/Nuclear_winter

  38. Robock, Alan, 2007:  Climate effects of a regional nuclear conflict. IPRC Climate, 7, no. 1, 16-18.   PDF file

  39. Robock, Alan, Luke Oman, Georgiy L. Stenchikov, Owen B. Toon, Charles Bardeen, and Richard P. Turco, 2007a:  Climatic consequences of regional nuclear conflicts.  Atm. Chem. Phys., 7, 2003-2012.  PDF file   Supplement caption  Supplement   This paper supersedes the previous discussion version.  Russian translation (по русский)  (See below for most important figures.)

  40. Robock, Alan, Luke Oman, and Georgiy L. Stenchikov, 2007b:  Nuclear winter revisited with a modern climate model and current nuclear arsenals: Still catastrophic consequences.  J. Geophys. Res., 112, D13107, doi:2006JD008235.  PDF file  Russian translation (по русский)  Featured as a Research Highlight in Nature.

  41. Robock, Alan, Owen B. Toon, Richard P. Turco, Luke Oman, Georgiy L. Stenchikov, and Charles Bardeen, 2007c: The continuing environmental threat of nuclear weapons:  Integrated policy responses needed.  EOS, 88, 228, 231, doi:10.1029/2007ES001816.  PDF file

  42. Toon, Owen B., Richard P. Turco, Alan Robock, Charles Bardeen, Luke Oman, and Georgiy L. Stenchikov, 2007:  Atmospheric effects and societal consequences of regional scale nuclear conflicts and acts of individual nuclear terrorism.  Atm. Chem. Phys., 7, 1973-2002.  PDF file  This paper supersedes the previous discussion version.   Russian translation (по русский)

  43. Toon, Owen B., Alan Robock, Richard P. Turco, Charles Bardeen, Luke Oman, and Georgiy L. Stenchikov, 2007:  Consequences of regional-scale nuclear conflicts.  Science, 315, 1224-1225.  PDF file

Movies:

 

What nuclear war looks like from space, YouTube by Max Tegmark (Aug. 15, 2022)

 

5 Tg of smoke from a regional nuclear war between India and Pakistan (from Mills et al., 2014):

h3zm.soot.BW.10fps.gif is an animation of the vertical distribution of the smoke as it is spread around the world by the winds.  The smoke is heated by absorbing sunlight, lofted into the upper stratosphere, and blown into the Southern Hemisphere.  See Powerpoint for this figure with different layers of the atmosphere marked.
5 Tg of smoke from a regional nuclear war between India and Pakistan (from Robock et al., 2007a):

BCabsoptdaily.gif is an animation of the smoke distribution as it is spread around the world by the winds.  The smoke is heated by absorbing sunlight, lofted into the upper stratosphere, and blown into the Southern Hemisphere.  Animation drawn by Luke Oman.

BCabsopred.gif is the same animation as BCabsoptdaily.gif, but in red.  Animation drawn by Luke Oman.


BCabsoptdailyheight.gif contains the same animation as BCabsoptdaily.gif, but also includes a graph at the side that shows the vertical distribution of the smoke.  Within the first week the smoke in the troposphere, the lowest atmospheric layer, is lofted or washed out, and the remaining smoke is lofted well into the stratosphere, removed from weather where it can remain for years.  The black horizontal line at about 150 mb marks the boundary between the troposphere and stratosphere, at about 12 km (7 miles).  The top of the stratosphere (at 50 km or 30 miles) has a pressure of about 1 mb. (Updated June 14, 2008, to correct small errors.  If you downloaded this before June 14, 2008, please take this new one.)  Animation drawn by Luke Oman.

27 Tg of smoke from a regional nuclear war between India and Pakistan (from Toon et al., 2019):

Click here for an animation of the smoke distribution as it is spread around the world by the winds.  The smoke is heated by absorbing sunlight, lofted into the upper stratosphere, and blown into the Southern Hemisphere.  The panel on the left shows the horizontal distribution and the one on the right shows the zonal average vertical distribution.  Animation drawn by Chuck Bardeen.

 

Click here for an animation of the temperature changes, in degrees Celsius.  On the left are the surface air temperature changes and on the right is the zonal average vertical distribution. Animation drawn by Chuck Bardeen.

 

Click here for an animation of the temperature changes, in degrees Fahrenheit.  On the left are the surface air temperature changes and on the right is the zonal average vertical distribution.   Animation drawn by Chuck Bardeen.

50 Tg of smoke from a nuclear war between Russia and U.S. using 1/3 of the current arsenal (from Robock et al., 2007b):

BCdaily50tg.gif is an animation of the smoke distribution as it is spread around the world by the winds.  The smoke is heated by absorbing sunlight, lofted into the upper stratosphere, and blown into the Southern Hemisphere.  Animation drawn by Luke Oman.

150 Tg of smoke from a nuclear war between Russia and U.S. using the entire current arsenal (from Robock et al., 2007b):

BCdaily150tg.gif is an animation of the smoke distribution as it is spread around the world by the winds.  The smoke is heated by absorbing sunlight, lofted into the upper stratosphere, and blown into the Southern Hemisphere.  Animation drawn by Luke Oman.

Figures from Robock et al. (2007a):

 

Fig3TempPrecip.jpg  Time variation of global average net surface shortwave radiation, surface air temperature, and precipitation changes for the 5 Tg standard case.  The global average precipitation in the control case is 3.0 mm/day, so the changes in years 2-4 represent a 9% global average reduction in precipitation.  The precipitation recovers faster than the temperature, but both lag the forcing.  For comparison the global average net surface shortwave forcing from a model simulation of the 1991 Mt. Pinatubo eruption is shown.  By contrast, volcanic particle last for a much shorter time in the atmosphere, as they are not lofted by solar absorption.  Figure drawn by Luke Oman.

Fig5SummerTempMap.jpg  Surface air temperature changes for the 5 Tg standard case averaged for June, July, and August of the first year following the smoke injection.  Effects are largest over land, but there is substantial cooling over tropical oceans, too.  The warming over Antarctica is for a small area, is part of normal winter interannual variability, and is not significant.  Figure drawn by Luke Oman.

Fig9GISStemperatures.jpg  Global average surface air temperature change from the 5 Tg standard case (red) in the context of the climate change of the past 125 years.  Observations are from the NASA Goddard Institute for Space Studies analysis (Hansen et al., 2001, updated at http://data.giss.nasa.gov/gistemp/2005/).  Figure drawn by Alan Robock.

Fig10HockeyStick.jpg  Northern Hemisphere average surface air temperature change from 5 Tg standard case (red) in the context of the climate change of the past 1000 years.  Black curve is from Mann et al. (1999), and the blue curve is from the latest data from the Climatic Research Unit website (http://www.cru.uea.ac.uk/cru/data/temperature/).  Figure drawn by Alan Robock.

Fig11GrowingSeason.jpg  Change in growing season (period with freeze-free days) in the first year following the 5 Tg standard case smoke injection.    Figure drawn by Luke Oman.

References

 

Hansen, J. E., et al., 2001: A closer look at United States and global surface temperature change, J. Geophys. Res., 106, 23,947-23,963, doi:10.1029/2001JD000354.

 

Mann, M. E., R. S. Bradley, and M. K. Hughes, 1999: Northern Hemisphere temperatures during the past millennium: Inferences, uncertainties, and limitations, Geophys. Res. Lett., 26, 759-762.

 



 Prepared by Alan Robock (robock@envsci.rutgers.edu) - Last updated on July 7, 2024

 This work is partly supported by the U.S. National Science Foundation grants ATM-0313592, ATM-0351280, ATM-0730452 and AGS-1157525, the Open Philanthropy Project, and the Future of Life Institute.