June 26, 2025 – 4pm (CET)
With more than 13,000 nuclear weapons in the world, states with nuclear weapons have embarked on plans to modernize or expand their nuclear arsenals. The presence of these weapons creates a risk that, technical or human failure, hackers or even unwise leaders will launch the weapons intentionally or unintentionally. In the event of a nuclear war, urban firestorms — which create and sustain their own wind systems — would loft soot into the upper troposphere and lower stratosphere. The resulting reduction of sunlight would lead to global cooling that could also trigger changes in the ocean system. Impacts of the cooling could include expansion of sea ice also into populated coastal areas and affect marine life. Any use of nuclear weapons would be catastrophic for humanity. Even a “limited” nuclear war involving only 250 of the 13,000 nuclear weapons, or tactical “small’’ nuclear weapons, in the world could kill hundreds of million people outright and cause global climate disruption leading to a nuclear famine, putting 2 billion people at risk. Some of the most conventionally armed countries are pushing the world closer to the brink of nuclear conflict as mounting distrust and divisions corrode the bedrock of international cooperation, driving the multilateral system towards gridlock and dysfunction. David Ellwood will provide a picture of the climatic and humanitarian effects of a limited nuclear exchange. Paolo Cotta Ramusino will provide a picture of the actual risks of such a limited nuclear exchange to happen in one of the current high tension areas in the world, such as India-Pakistan, Russia-Ukraine or the Middle East.
Programme
Moderated by Mieke Massink – CNR ISTI; CNR GI-STS
16:00 Opening
Fabio Recchia – President of Area della Ricerca CNR, Pisa (to be confirmed)
Giuliano Colombetti – CNR IBF; CNR GI-STS
16:15 Climate and Humanitarian Consequences of an even Limited Nuclear Exchange
David Ellwood – Council of the Pugwash Conferences on Science and World Affairs
16:45 The Actual Risks Nuclear War
Paolo Cotta Ramusino – Former Secretary General of Pugwash Conferences on Science and World Affairs
17:15 Discussion
