The J. Robert Oppenheimer biopic directed by Christopher Nolan has rekindled a morbid interest in nuclear weapons’ devastating potential. There are now 12,512 nuclear warheads, on average.
In a war where even a small portion of these weapons were dropped, blast waves and fires might instantaneously kill millions of people. The remaining population would be impacted for generations by the malignancies and genetic damage brought on by radiation.
But in the midst of the radioactive fallout, what kind of world would survive?
Computer simulations have been used over the past 40 years by scientists who study the Earth system to determine the answer.
In a brief study published in 1982, atmospheric scientists Paul Crutzen and John Birks suggested that a nuclear war would produce a smoke cloud so large that it would result in what is now known as a nuclear winter. They did this by drawing on their expertise in chemistry and climate modeling. They asserted that this would destroy agriculture and civilisation as a whole.
Scientists from the US and the Soviet Union initially verified, a year later, that nuclear weapons would really produce significantly more smoke and dust from towns and industrial complexes than from burning an equivalent amount of forest. In addition, this global layer of smog would prevent sunlight from reaching Earth’s surface, dramatically lowering temperatures and intensifying dryness and darkness.
According to climate modeling, the decreased sunlight would cause a 10-C global temperature drop for almost a decade. Mass famine would result from these cold circumstances, which would have disastrous effects on global food supply and less sunshine for plants to photosynthesize.
Compared to the models utilized in the 1980s, modern climate models are significantly more advanced. And while there are currently fewer nuclear weapons in operation, more recent computer simulation results indicate that the dire prognosis made by scientists forty years ago may have really been an underestimate.
In a recent publication, environmental scientists at Rutgers University in the US under the direction of Alan Robock contended that the nuclear winter theory contributed to putting a halt to the spread of nuclear weapons during the cold war. The initial moves toward a nuclear arms reduction were made in 1986 by President Ronald Reagan and General Secretary Mikhail Gorbachev, who cited the potential effects of a nuclear winter on all life on Earth.
Over 65,000 nuclear weapons were in existence at the height of the arms race in the middle of the 1980s. Some have questioned if the constrained climatic models employed in the 1980s had overstated the repercussions of a worldwide nuclear war in light of the decline in the nuclear arsenal to little over 12,000 (of which 4,000 are on operational standby).
The reverse is suggested by more recent and complex climate models, which are designed to predict future climatic changes brought on by the burning of fossil fuels.
New models predict that the ocean would cool so drastically following the greatest probable nuclear exchange between the US and Russia that the globe would enter a “nuclear little ice age” lasting thousands of years.
There are, of course, seven additional nuclear-armed nations: China, France, India, Israel, North Korea, Pakistan, and the UK. According to scientific simulations, even a limited nuclear conflict between India and Pakistan might result in the deaths of 130 million people and the food insecurity of 2.5 billion more for at least two years.
The threat remains
Without actually experiencing one, scientific modeling allows us to look into the abyss of nuclear war. A United Nations treaty banning nuclear weapons was adopted in 2017 as a result of forty years of scientific investigation into these possibilities. The pact was approved by the majority of nations, but not by the nine nuclear-armed states.
The international movement to abolish nuclear weapons received the Nobel Peace Prize in that same year for its efforts in bringing attention to the tragedy that any use of nuclear weapons would cause.
However, the conflict in Ukraine has rekindled long-buried anxieties. A single launch may turn into a regional or even global exchange, plunging billions of people into a world so terrifying we can hardly fathom it, as Russian President Vladimir Putin has warned a limited use of nuclear weapons as part of the fight.
According to Robock, it is now “even more urgent” for scientists to investigate the effects of igniting nuclear weapons and make sure that the greatest number of people are aware of them. Additionally, to eventually work toward the abolition of these weapons.
The prospect of a nuclear ice age, which would end much of Earth’s life for millennia, and the threat of nuclear war remain.