Nuclear weapons today are many times more destructive than those used against Hiroshima and Nagasaki in 1945. A single nuclear weapon could destroy a city and kill most of its people. We invite you to visit Nukemap for an illustration of the destruction of a nuclear bomb dropped on your city. In addition to the loss of lives and property, a nuclear detonation would likely result in profound social, economic and political disruption (See ICRC: Humanitarian impacts and risk of use of nuclear weapons). This could also stimulate further military action including nuclear retaliation. Indeed, if a nuclear armed country was conducting a first strike, they would probably launch multiple nuclear weapons, not just one, in order to destroy military and economic targets, and to try to pre-empt a retaliatory attack against them. Several nuclear explosions against targets in, or close to, modern cities would kill tens of millions of people and could generate climatic consequences that dwarf the climate change we are currently experiencing from carbon emissions. When US President Reagan and Soviet President Gorbachev became aware of the risks and catastrophic consequences of nuclear weapons being used, they jointly announced that ‘a nuclear war cannot be won and must never be fought’. This understanding was reflected by the 192 States parties to the Non-Proliferation Treaty (including five nuclear armed States China, France, Russia, UK and USA) in 2010 when they agreed that ‘any use of nuclear weapons’ would have ‘catastrophic humanitarian consequences.’ The next step is to ensure that a nuclear war is never fought, through no-first-use commitments.