The U.S. and other nuclear powers should rapidly stop nuclear proliferation, researchers at Rutgers University said Wednesday as they released a study showing that a nuclear war between India and Pakistan could kill 125 million people instantly before causing global mass starvation.

"When nuclear weapons come into play, what happens in South Asia won't stay in South Asia. You won't see the mushroom clouds, but you can look forward to years of climate disruption, draught, famine and death. Or we could just get rid of them."

—Derek Johnson, Global Zero

Published in the journal Science Advances, the new research shows that rapidly growing nuclear stockpiles in India and Pakistan, which are currently in conflict over Kashmir, could release 16 million to 35 million tons of soot, or black carbon, into the atmosphere if the two countries escalated their standoff into nuclear strikes by 2025.

"Such a war would threaten not only the locations where bombs might be targeted but the entire world," said Alan Robock, co-author of the study and a professor of environmental sciences at Rutgers.

The only way to avoid such an outcome, said Robock, is to eliminate nuclear weapons.

"Nuclear weapons cannot be used in any rational scenario but could be used by accident or as a result of hacking, panic, or deranged world leaders," he said. "The only way to prevent this is to eliminate them."

According to a new study, as many as 125 million people would die within days if a nuclear war erupts between India & Pakistan. As co-author @AlanRobock states, the only way to prevent this is to eliminate nuclear weapons. https://t.co/MzBYgwmhZW — Global Zero (@globalzero) October 3, 2019

The findings of Robock and other researchers are Rutgers represent an update to research published a decade ago by groups including Physicians for Social Responsibility (PSR) and International Physicians for the Prevention of Nuclear War, which found that 22 million people could die immediately the event of nuclear war in the region and two billion could starve as a result.

Growing urban populations and nuclear arsenals in countries including India, Pakistan, and the U.S. would make such action even more deadly.

"Nine countries have nuclear weapons, but Pakistan and India are the only ones rapidly increasing their arsenals," Robock said. "Because of the continuing unrest between these two nuclear-armed countries, particularly over Kashmir, it is important to understand the consequences of a nuclear war."

In the event of nuclear war, black carbon's spread across the globe over a matter of weeks would result in the absorption of solar radiation, slashing the sunlight that reaches Earth by 20 to 35 percent. Precipitation and vegetation growth would be reduced by up to 30 percent, and the planet would take more than a decade to recover as the soot would remain in the upper atmosphere for years.

As Derek Johnson, chief executive of the anti-nuclear group Global Zero, tweeted, "You won't see the mushroom clouds, but you can look forward to years of climate disruption, drought, famine, and death."

When nuclear weapons come into play, what happens in South Asia won't stay in South Asia. You won't see the mushroom clouds, but you can look forward to years of climate disruption, draught, famine and death. Or we could just get rid of them. #globalzero https://t.co/9VU8zBuYbk — Derek Johnson (@derekjGZ) October 3, 2019

The estimates were based on the possibility that India could use 100 weapons and Pakistan could use 150; by 2025, the researchers expect the two countries to have between 400 to 500 nuclear weapons combined.

The prediction that nuclear war could kill 125 million people immediately could be applied to any region or country with densely-population urban areas.

PSR noted that the research was released months after U.S. President Donald Trump announced the development of a new so-called "low-yield" nuclear weapon.

"Not to be overlooked, at this moment, the United States wants to deploy so-called 'low-yield' nuclear weapons, which are touted as 'more usable,'" PSR Iowa coordinator Maureen McCue said in a statement. "The world cannot afford the impacts on public health, the environment and our climate that would result from any use of nuclear weapons. They must be eliminated before they eliminate us."

Warning that "the world can't afford to ignore the disturbing findings of the study," the group urged policymakers to work to end nuclear proliferation in the U.S. and elsewhere to avoid catastrophic, long-lasting damage.

"Nuclear weapons make us less, not more, safe, and as this study highlights, nuclear war poses one of the gravest threats to human health and survival," said Jeff Carter, executive director of PSR. "Given the current climate of withdrawal from vital international arms agreements, increased tensions that heighten the risk of nuclear conflict, and the escalation of a new nuclear arms race, there is no better time for the UnitedStates to assert leadership among its fellow nuclear-armed states by establishing an official policy never to use nuclear weapons first and prohibit funding for so-called 'low-yield' nuclear weapons."