In 2001, India and Pakistan came close to nuclear blows over Kashmir.
Two new studies find that even such a regional nuclear war could kill 20 million people, trigger a crop-killing nuclear winter, and destroy enough of Earth’s protective ozone layer to make skin cancer far more deadly.
“The results of these studies are quite surprising, considering the relatively small number and yields of the weapons,” said Brian Toon, an atmospheric scientist at the University of Colorado at Boulder.
Twenty years ago, Toon and other scientist found that after a global nuclear war between the U.S. and Soviet Union superpowers, a “nuclear winter” would descend on the planet.
Scientists now report that if two emerging nuclear powers detonated 100 “small” nuclear bombs in one region, the consequences also would be global and devastating.
Eight countries have known nuclear weapons, and 32 have the fissile material necessary for building them, Toon said. India and Pakistan apparently each have 50 bombs about the size of those the U.S. dropped on Hiroshima and Nagasaki during World War II.
“At this point, we believe the world’s scientific community and world governments have got to evaluate this more,” Toon said before the American Geophysical Union meeting in San Francisco, where he and his colleagues presented their research Monday.”What happens if arsenals are allowed to build up everywhere?” Toon asked. “We’re moving toward a nightmare.”
The new papers describe consequences of a regional nuclear war in which 100 15-kiloton bombs – Hiroshima-sized – targeted major cities:
Twenty million people would be killed in blasts, in subsequent fires and by radiation.
Fires would send 5 million metric tons of dark soot high into the upper atmosphere, where it could remain for a decade or more.
Soot would shade the planet from the sun, dropping temperatures by several degrees Fahrenheit and reducing growing seasons by a month.
A hotter upper atmosphere – from the sunlight-absorbing soot – would eat away at ozone, creating a “hole” over much of the planet.
“The effects last much longer than we ever thought,” said Alan Robock, a professor of environmental sciences at Rutgers University in New Jersey. “It would be the largest climate change in recorded human history.”
But another researcher who studied nuclear winter 20 years ago said he suspects the chill from a regional conflict, though serious, would last just two years.
“This (study) is very timely. It’s important to keep in mind there is an arsenal out there,” said Steve Gahn, an atmospheric scientist with the Pacific Northwest Laboratory in Richland, Wash.
“But they chose in their simulations … an upper range of plausibility,” Gahn said.
Back in 1983, when Toon, Richard Turco, James Pollack, Thomas Ackerman and Carl Sagan were studying nuclear winter, John Endicott was a nuclear-targeting officer in the Air Force.
Now a professor of political science at the Georgia Institute of Technology’s Sam Nunn School of International Affairs, Endicott said military brass were reading the science.
“We looked at it rather closely when were were doing our nuclear planning,” he said.
Today, Endicott works closely with officials in India and other Asian countries on lessening the risk of nuclear war.
Because India and Pakistan “came very close to blowing each other to smithereens in 2001,” he said, they’re less inclined to detonate nuclear bombs today.
Kennette Benedict, executive director of the Bulletin of the Atomic Scientists, said she worries most about U.S. and Russian arsenals because both countries still have nuclear bombs ready to launch with a few minutes’ notice.
“We haven’t really stood down,” Benedict said.
Both countries’ launch systems may be vulnerable to hacking, she said, citing a classified 1979 incident in which someone broke into the U.S. system.
“We know enough to know it was serious,” Benedict said. “So, yeah, there’s a lot to be worried about.”
Staff writer Katy Human can be reached at 303-954-1910 or khuman@denverpost.com.
