June 23, 2026 Experts gather at UW–Madison to accelerate research on nuclear war effects Written By: Lili Sarajian Departments: Nuclear Engineering & Engineering Physics Categories: Event|Faculty|Research Blue summer skies and the shimmering waves of Lake Mendota made for a striking contrast to the subject at hand: the potentially catastrophic effects of nuclear war. From June 2-6, 2026, researchers, physicists, policy analysts, professors, students, and security experts gathered at the University of Wisconsin–Madison for the Workshop on Nuclear War Effects: Scenarios and Modeling. Organized by Sébastien Philippe, an assistant professor in the Department of Nuclear Engineering and Engineering Physics, the workshop brought together leading experts from universities, national laboratories, nonprofit organizations, and policy institutions to better understand what a nuclear war would mean for people, societies, and the planet. Sébastien Philippe, UW–Madison assistant professor of nuclear engineering and engineering physics, introduces the inaugural Workshop on Nuclear War Effects: Scenarios and Modeling The meeting supports broader ongoing international efforts to reassess the consequences and risks of nuclear war, including the work of the United Nations independent scientific panel on the effects of nuclear war, to which Philippe was appointed by the UN Secretary-General in 2025. “Over the past decade, there has been renewed scientific and policy interest in reassessing the consequences of nuclear war,” says Philippe. “This effort has gained urgency amid intensified military competition and arms racing, the collapse of arms control, technological change, ongoing wars involving nuclear-armed states, and repeated threats of nuclear weapon use.” Even as political tensions have heightened, the world has become increasingly interdependent, indicating complex, cascading effects in the event of nuclear war. “Global trade and economic crises, climate change, mass migration and COVID all reveal how humanity and nature are now more tightly bound in world-spanning circuits that push up against planetary boundaries,” says Zia Mian, one of the workshop participants, in his 2024 Scientific American article, “We Need a U.N. Study on the Effects of Nuclear War.” Zia Mian, physicist and co-director of Princeton University’s Program on Science and Global Security, discusses the current approach to nuclear war planning and targeting in India and Pakistan. Steve Fetter, professor in the School of Public Policy at the University of Maryland, breaks down the global economic impacts of nuclear war. The consequences of nuclear war extend far beyond the blast zone. Researchers today study everything from radioactive fallout and infrastructure damage to climate effects, food shortages, public health impacts, and disruptions to global trade and the economy. “Our understanding of the consequences of nuclear war is fundamental for nuclear policy and central to many debates about nuclear policy,” said Steve Fetter, a professor of public policy at the University of Maryland who previously served in the White House Office of Science and Technology Policy. The complexity of these questions requires expertise from many disciplines. To that end, the workshop brought together a select group of 28 experts spanning nuclear engineering, physics, atmospheric science, agriculture, economics, international affairs, political science, arms control, and global security. “To develop realistic nuclear war scenarios, you need people who understand military doctrine and targeting, people who model fallout and climate effects, people who study food systems and economic impacts,” says Philippe. “Bringing everyone into the same room allowed us to connect those pieces together and test assumptions collectively rather than in isolation.” Mackenzie Knight-Boyle, Senior Research Associate for the Nuclear Information Project at the Federation of American Scientists, overviews the status of world nuclear forces. Fiona Cunningham, Assistant Professor of Political Science at the University of Pennsylvania, briefs participants on China’s current approach to nuclear war strategy and targeting. The program began with a series of briefings on the world’s major nuclear-armed states, including their nuclear arsenals, military doctrines, and approaches to war planning and targeting. Experts in the United States, Russia, China, Europe, South Asia, and North Korea discussed how these countries might approach a nuclear conflict, providing the foundation for a collaborative scenario-building exercise. Working in groups, participants developed a range of plausible nuclear war scenarios informed by current geopolitical tensions, military capabilities, and nuclear doctrines. Rather than attempting to predict a specific future conflict, the exercise explored how different assumptions about escalation, targeting, and decision-making could shape the course and consequences of a nuclear war. Those scenarios were then translated into computer simulations that estimated immediate and longer-term impacts, including fatalities, radioactive fallout, infrastructure damage, urban fires, and climatic effects. The exercise highlighted both the progress scientists have made and the challenges that remain. Researchers today can model many aspects of nuclear war in far greater detail than was possible even a decade ago. At the same time, participants identified important uncertainties related to urban fire behavior, infrastructure resilience, food-system adaptation, economic disruption, and the ways governments might make decisions during a rapidly escalating crisis. Professor Sharon Weiner, Associate Professor at the School of International Service at American University, shares her perspective with other workshop participants in a nuclear war scenario design exercise. Lili Xia, Assistant Research Professor with the Atmospheric Science Group in the Department of Environmental Sciences at Rutgers University, summarizes key research findings regarding the agricultural and food impacts of nuclear war. John Wolfsthal, Fellow for U.S. Nuclear Policy with PAX Sapiens, discusses DPRK nuclear strategy with other workshop participants during a group exercise to construct and assess plausible nuclear war scenarios. Gerson Esquivel Garcia, PhD student in the Department of Nuclear Engineering and Engineering Physics at the UW–Madison, discusses coupling the Nuclear War Simulator with the Global Change Analysis Model to generate more accurate nuclear war effects models. One recurring theme throughout the workshop was that the consequences of nuclear war would not be confined to the countries directly involved. Participants discussed how disruptions to food production, trade networks, energy systems, public health, and the global economy could reverberate across the world, affecting millions if not billions of people far from any battlefield. The workshop concluded with discussions on future collaborations, data sharing, and opportunities to better connect nuclear-war modeling with nuclear threat reduction efforts. For Philippe, one of the workshop’s most important outcomes was the opportunity to strengthen a growing community of researchers working to understand and reduce nuclear risks. “Understanding the effects of nuclear war is one of the most challenging interdisciplinary problems we face,” he said. “The better we understand those effects—and the better we communicate them—the better equipped policymakers and the public will be to make informed decisions about addressing one of humanity’s greatest collective threats.”