When it comes to the extraordinary threat posed by nuclear weapons, complacency is inadmissible.

It is a fact that nuclear weapons have not been exploded in the proximity of cities since the destruction of Hiroshima and Nagasaki in August 1945. It is undeniable that the risk of a crisis escalating into nuclear exchange between Russia and the United States has diminished substantially since the end of the Cold War. The longer these positive trends prevail, the safer we all are. But this relative safety must never lead to complacency.

The danger is still unacceptably high and there are also negative trends.
There is credible evidence that terrorists are actively seeking the knowledge and materials for nuclear weapons; there is also a risk of theft. More countries are gaining the capacity to develop nuclear weapons and some appear determined to exercise that capacity. Since the signing of the Comprehensive Nuclear Test Ban Treaty in 1996, three countries have announced their acquisition of nuclear weapons with test explosions. This increases the number of possible interstate conflicts that could escalate into nuclear war. And throughout, there is the remote but not zero chance of an exchange of the nuclear weapons on alert due to a ‘false-positive´ failure of the early warning systems.

Cities are at risk in all three scenarios, but the impact would be global.

The effect of a nuclear attack

A Rand study showed that an improvised nuclear device smuggled into Long Beach / Los Angeles Harbor and detonated there would cause tens of thousands of deaths, a trillion dollars in property damage and business losses. But it would also destroy the supply of fuel for transportation on the West Coast bringing the regional economy to a standstill. And it would severely disrupt the just-on-time delivery system upon which the national economy has come to depend, triggering an economic depression that would likely envelop the global economy.

A study using the same climatic modeling program used to predict global warming has shown that firestorms in one hundred cities would lead to reduced sunlight reaching the Earth’s surface for more than a decade. Firestorms burn hundreds of degrees hotter than normal line fires. They generate powerful updrafts that loft tons of soot particles high into the atmosphere, far above rainclouds that might otherwise wash them out. The soot blocks sunlight, causing temperatures to drop and killing frost to come late into the Spring and early in the Fall. Worldwide crop failures would lead to mass starvation. Famine would weaken resistance to pandemics. Within the decade, there would be over one billion deaths, over and above the one hundred million immediate deaths. It would be equivalent to all the catastrophes experienced in human history packed into one single decade.

The same study, if extended from a ‘limited’ nuclear war, to an accidental exchange of all the nuclear powers weapons on alert would trigger a new Ice Age. Civilization as we know it would cease to exist. The Earth’s natural system would be irreversibly damage.

The mere existence of nuclear weapons is an invitation to disaster. Cities would be the immediate victims, but also the agents (through firestorm incineration) of global catastrophe.