The preamble of the treaty to ban nuclear weapons now under consideration at the UN will be greatly strengthened if it includes a summary of the long-term environmental consequences of nuclear war, as described by a series of peer-reviewed studies done by prominent scientists working at major US and Swiss Universities, as well as at the US National Center for Atmospheric Research. These studies are considered to be the most authoritative type of scientific research—subjected to criticism by the international scientific community before final publication in scholarly journals—and the findings of these studies remain unchallenged.

The research predicts that a nuclear war fought between emerging nuclear weapon states—with less than 1 percent of the explosive power contained in the global nuclear arsenals—can produce catastrophic long-term damage to global environment and weather. A war fought with 100 atomic bombs can result in the coldest average annual surface temperatures experienced in the last 1,000 years, and this prolonged cold (and drought) would last for several years before temperatures began to return to normal. Medical experts predict that this prolonged cold would lead to a global famine causing up to two billion people to starve to death. Climatologists also predict that such a war would cause major damage to the Earth’s protective stratospheric ozone layer, leading to a doubling of harmful UV-B radiation in the populated mid-latitudes.

The studies also forecast that a war fought with US and Russian strategic nuclear weapons would create post-war Ice Age weather conditions across the Northern Hemisphere in a matter of weeks. These catastrophic changes in weather would be the result of a global stratospheric smoke layer, produced by hundreds or thousands of nuclear firestorms, which would block up to 90 percent of sunlight over central North America and Eurasia.

The loss of warming sunlight would cause temperatures in these central regions to fall below freezing every day for one to two years. Because the stratospheric smoke layer could not be rained out, it would remain for a decade or longer, affecting both the northern and southern hemispheres. Growing seasons in the large agricultural zones would be eliminated for many years, dooming most humans and animals to starvation from nuclear famine.

Confusion: nuclear war or a nuclear weapon? To date, there has been an unfortunate avoidance (among both diplomats and nongovernmental organizations involved in the ban treaty) of any explicit discussion of the effects of nuclear war; instead the language of the general conversation has tended to focus on the effects of a nuclear weapon, in the singular. This is evidenced by the wording of the Humanitarian Pledge, which was issued on December 9, 2014 at the conclusion of the Vienna Conference on the Humanitarian Impact of Nuclear Weapons. Notice that the pledge states:

“Understanding that the immediate, mid- and long-term consequences of a nuclear weapon explosion are significantly graver than it was understood in the past and will not be constrained by national borders but have regional or even global effects, potentially threatening the survival of humanity.” (emphasis added)

This statement is technically incorrect, as a single nuclear weapon explosion cannot produce “global effects, potentially threatening the survival of humanity.” Only a nuclear war, fought with the strategic nuclear arsenals of the United States and Russia, is predicted to have the capacity to produce the catastrophic consequences capable of wiping out most peoples and nations. Likewise, scientists predict that a war fought with atomic bombs of the emerging nuclear weapon states can cause global weather changes that will likely lead to mass starvation. But a single nuclear detonation cannot produce such an effect.

The apparent confusion about the effects of a single nuclear weapon versus the effects of nuclear war were also reflected in the UN Resolution 70/47, titled “Humanitarian Consequences of Nuclear Weapons.” It was passed in December 2015 and contains this language:

“Welcoming the facts-based discussions on the effects of a nuclear weapon detonation that were held at the conferences on the humanitarian impact of nuclear weapons convened respectively by Norway in March 2013, Mexico in February 2014 and Austria in December 2014…” (emphasis added)

It is imperative to avoid any similar confusion of cause and effect within the text of the ban treaty now being written. The scientifically predicted consequences of nuclear war must be clearly distinguished from those likely be to be caused by a single nuclear weapon detonation.

Science should be part of the ban treaty. The best way to avoid confusion over the effects of nuclear weaponry on the world environment would be to include authoritative scientific predictions—detailing the likely consequences of a range of nuclear conflicts—as supporting evidence in the preamble of the ban treaty. The existential threats explained by these peer-reviewed scientific studies provide the most powerful arguments imaginable against the existence of nuclear weapons and nuclear arsenals.

A series of studies were conducted at the Laboratory for Atmospheric and Space Physics at the University of Colorado-Boulder, the Department of Environmental Sciences at Rutgers, the Department of Atmospheric and Oceanic Sciences at UCLA, the National Center for Atmospheric Research Earth System Laboratory, Boulder, Colorado, and ETH Zurich, which used a state-of-the-art computer modeling to evaluate the environmental consequences of a range of possible nuclear conflicts. The five peer-reviewed studies listed below evaluated the consequences of a war fought with atomic bombs:

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. Retrieved from (English): http://climate.envsci.rutgers.edu/pdf/acp-7-1973-2007.pdf (Russian): http://climate.envsci.rutgers.edu/pdf/acp-7-1973-2007Russian.pdf

Robock, Alan, Luke Oman, Georgiy L. Stenchikov, Owen B. Toon, Charles Bardeen, and Richard P. Turco, 2007: Climatic consequences of regional nuclear conflicts. Atm. Chem. Phys., 7, 2003-2012. Retrieved from (English): http://climate.envsci.rutgers.edu/pdf/acp-7-2003-2007.pdf (Russian): http://climate.envsci.rutgers.edu/pdf/acp-7-2003-2007Russian.pdf

Mills, Michael, Owen B. Toon, Richard P. Turco, Douglas E. Kinnison, Roland R. Garcia, 2007: Massive global ozone loss predicted following regional nuclear conflict. Proceedings of the National Academy of Sciences, Vol. 105 no. 14, doi: 10.1073/pnas.0710058105. Retrieved from http://www.pnas.org/content/105/14/5307.full

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. Retrieved from http://climate.envsci.rutgers.edu/pdf/MillsNWeft224.pdf

Stenke, Andrea, C. R. Hoyle, B. Luo, E. Rozanov, J. Gröbner3, L. Maag, S. Brönnimann, and T. Peter, 2013: Climate and chemistry effects of a regional scale nuclear conflict. Atmos. Chem. Phys., 13, 9713-9729, doi:10.5194/acp-13-9713-2013. Retrieved from http://www.atmos-chem-phys.net/13/9713/2013/

Another important peer-reviewed study describes the catastrophic long-term environmental consequences of a large-scale nuclear war fought with strategic nuclear weapons: