A nuclear war between the United States and Russia could produce a nuclear winter, with catastrophic consequences for global food supplies. Smoke from fires ignited by nuclear weapons exploded on cities and industrial targets would block out sunlight, causing dark, cold, and dry surface conditions, with surface temperatures below freezing even in summer for years. Crops would die and massive starvation could kill most of humanity. Even a nuclear war between new nuclear states, such as India and Pakistan, could produce climate change unprecedented in recorded human history and massive disruptions to the world’s food supply, with famine killing one to two billion people. The existence of nuclear weapons means that they can be used, by unstable leaders or because of an accident, computer malfunction, sensor malfunctions, human error, or by terrorism. Because nuclear weapons cannot be used without the danger of escalation and a global humanitarian catastrophe, their existence threatens Sustainable Development Goal 2 (Zero Hunger). It is urgent for scientists to speak truth to power and work for the elimination of nuclear weapons. A first step is urging all nations to sign and ratify the UN Treaty on the Prohibition of Nuclear Weapons.

The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)