Deadly tensions between India and Pakistan are boiling over in Kashmir, a disputed territory at the northern border of each country.
A regional conflict is worrisome enough, but climate scientists warn that if either country launches just a portion of its nuclear weapons, the situation might escalate into a global environmental and humanitarian catastrophe.
For that reason, climate scientists have modeled how an exchange of nuclear weapons between the two countries – what is technically called a limited regional nuclear war – might affect the world.
Though the explosions would be local, the ramifications would be global, that research concluded. The ozone layer could be crippled and Earth’s climate may cool for years, triggering crop and fishery losses that would result in what the researchers called a “global nuclear famine.”
“The danger of nuclear winter has been under-understood – poorly understood – by both policymakers and the public,” Michael Mills, a researcher at the US National Center for Atmospheric Research, told Business Insider. “It has reached a point where we found that nuclear weapons are largely unusable because of the global impacts”.
The model suggested those explosions would release about 5 million tons of smoke into the air, triggering a decades-long nuclear winter.
The effects of this nuclear conflict would eliminate 20% to 50% of the ozone layer over populated areas. Surface temperatures would become colder than they’ve been for at least 1,000 years.
The bombs in the researchers’ scenario are about as powerful as the Little Boy nuclear weapon dropped on Hiroshima in 1945, enough to devastate a city. But that’s far weaker than many weapons that exist today. The latest device North Korea tested was estimated to be about 10 times as powerful as Little Boy. The US and Russia each possess weapons 1,000 times as powerful.
The fine black soot in the stratosphere would prevent some sun from reaching the ground. The researchers calculated that average temperatures around the world would drop by about 1.5 degrees Celsius over the five years following the nuclear blasts.
In populated areas of North America, Europe, Asia, and the Middle East, changes could be more extreme (as illustrated in the graphic above). Winters there would be about 2.5 degrees colder and summers between 1 and 4 degrees colder, reducing critical growing seasons by 10 to 40 days. Expanded sea ice would also prolong the cooling process, since ice reflects sunlight away.
“It’d be cold and dark and dry on the ground, and that’d affect plants,” Robock said. “This is something everybody should be concerned about because of the potential global effects.”