More than a billion people worldwide could starve if India and Pakistan unleash nuclear weapons because even a 'limited' nuclear war would cause major climate disruptions, a study warned.
In addition to clouds of radiation which could contaminate farmland far from the center of the blasts, the study found soot released into the atmosphere would devastate crop yields by cooling global temperatures and reducing rainfall worldwide.
The study provides hard data to back up dire warnings of the global -- and unintended -- consequences of nuclear weapons, said author Dr. Ira Helfand of the International Physicians for the Prevention of Nuclear War.
"It is not just the arsenals of the US and Russia that pose a threat to the whole world," Helfand told AFP.
"Even these smaller arsenal pose an existential threat to our civilization, if not to our species. It would certainly end modern society as we know it."
The study, set to be published in the peer-reviewed journal Climate Change, was released at the World Summit of Nobel Peace Laureates in Chicago.
It found that corn production in the United States would decline by an average of 10 percent for an entire decade and soybean production would drop by about 10 percent with the most severe decline occurring five years after the nuclear war.
It also determined that rice production in China would drop by an average of 21 percent of the first four years and 10 percent next six years.
Significant losses would also likely occur with other crops and in other countries, Helfand said in an interview on the sidelines of the summit.
And the actual crop losses could be much worse than predicted since the conservative model did not account for increases in UV light and the likelihood that global cooling would also result in sudden, crop-killing frosts.
"Even with what we are able to show, the consequences for human nutrition and human life are really profound," Helfand said.
The resulting increase in food prices and agricultural shortfalls would almost certainly lead to panic and hoarding on an international scale, further reducing access to food.
Given that some 925 million people worldwide already suffer from malnutrition according to the latest UN study, the study found that mass famine deaths would likely be unavoidable.
That would further deepen social unrest and could lead to armed conflicts both within and between nations. Mass famine is also often by major epidemics of infectious diseases like cholera and dysentery, which could further raise the death toll.
Those consequences would pale in comparison to the Nuclear Winter which would devastate the globe should the United States or Russia unleash even a small portion of their arsenal, Helfand said.
"The US and Russia are not likely to start a war with each other, but we know of at least five times when the US or Russia prepared to launch a nuclear attack because it believed it was under attack," Helfand said.
Until the bulk of the arsenal is disarmed and hair-triggers are removed, Helfand said only "luck" will prevent the next computer glitch or communication failure to result in total nuclear war.
Mikhail Gorbachev, who as president of the Soviet Union helped end the Cold War and open Russia's communist regime to democracy, said the study offers further proof of the need to abolish nuclear weapons.
"Over twenty-five years ago, (US) President Ronald Reagan and I ended our summit meeting in Geneva with a joint statement that 'nuclear war cannot be won and must never be fought,'" Gorbachev, who founded the summit of peace laureates, said in a statement.
"This new study underscores in stunning and disturbing detail why this is the case and why we must discard Cold War-style plans for the possible use of these weapons and move rapidly to eliminating them from the world's arsenals."