In the decades following the first successful detonation of a nuclear weapon on 16 July 1945, humanity quaked with fear at atomic weaponry. As the global nuclear arsenal swelled, so, too, did our dread of the breed of war we might unleash with it. As scientists researched the possible ramifications of such a conflict, a new term entered public vernacular: nuclear winter.
Since the 1980s, a nuclear winter has permeated our most dismal visions of the future: The sky suddenly blazes with the radiance of a thousand suns. Millions of lives burn to ash and shadows. Nuclear firestorms incinerate cities. Torrents of smoke ascend into the atmosphere to entomb the planet in clouds of ash. The result is noontime darkness and plummeting temperatures.
The theory of a nuclear winter is one of environmental collateral damage. The scenario assumes that if 100 or more firestorms follow the explosions of a nuclear war and loft large enough amounts of sooty smoke into the upper troposphere and lower stratosphere, it could have a profound and severe effect on the climate, causing cold weather and reduced sunlight for months or even years.
In an interview with Mikhail Gorbachev in 2000, the interviewer commented, “In the 1980s, you warned about the unprecedented dangers of nuclear weapons and took very daring steps to reverse the arms race.” Gorbachev responded, “Models made by Russian and American scientists showed that a nuclear war would result in a nuclear winter that would be extremely destructive to all life on Earth; the knowledge of that was a great stimulus to us, to people with honor and morality, to act in that situation.”
In the late 1980s, as the implications of a nuclear winter began to be taken more seriously, military analysts turned their attention to the development of nuclear warheads that would explode at low altitudes and cause less fires ignited by thermal radiation, thus reducing the likelihood of a nuclear winter.
Volcanic winters are similar in nature to the theoretical nuclear winter, although there have been a number of instances of volcanic ash and droplets of sulfuric acid obscuring the Sun and increasing the Earth’s reflection of solar radiation: the eruption of Mount Tambora in 1815, the explosion of Krakatoa in 1883, and more recently, the explosion of Mount Pinutubo in 1991.