Far North Science

Imagine a sky so filled with soot that spring comes 10 days late and winter two weeks early.

Imagine the failure of the world wheat crop. Soybeans that die. Shriveled stalks of corn. Windrows of yellowed leaves in August. Livestock sickens. The birds have disappeared.

Famine sweeps the Third World. A billion people flee across borders. Vast regions become abandoned. Governments fall. Hundreds of millions die.

This is the future that might overwhelm the planet if any of the eight nuclear-armed countries — or the 35 other countries with enough weapons-grade fuel build their own bombs — start blasting their enemy’s cities with low-yield nuclear weapons.

An analysis published March 2 in the journal Science predicts that an exchange of 50 Hiroshima-sized bombs would kill up to 21 million people instantly and trigger enough ecological damage to shorten growing seasons for years and cause climate shifts that might continue for decades.

“The world has reached a crossroads,” writes Owen B. Toon and five co-authors in a policy forum article, Consequences of Regional-Scale Nuclear Conflicts. “Having survived the threat of global nuclear war between superpowers so far, the world is increasingly threatened by the prospects of regional-scale nuclear war. The consequences of regional-scale nuclear conflicts are unexpectedly large, with the potential to become global catastrophes.”

Even the Doomsday Clock of the Bulletin of Atomic Scientists has clicked closer to midnight for the first time in years.
The board explained why:

We stand at the brink of a second nuclear age. Not since the first atomic bombs were dropped on Hiroshima and Nagasaki has the world faced such perilous choices. North Korea’s recent test of a nuclear weapon, Iran’s nuclear ambitions, a renewed U.S. emphasis on the military utility of nuclear weapons, the failure to adequately secure nuclear materials, and the continued presence of some 26,000 nuclear weapons in the United States and Russia are symptomatic of a larger failure to solve the problems posed by the most destructive technology on Earth.

As in past deliberations, we have examined other human-made threats to civilization. We have concluded that the dangers posed by climate change are nearly as dire as those posed by nuclear weapons. The effects may be less dramatic in the short term than the destruction that could be wrought by nuclear explosions, but over the next three to four decades climate change could cause drastic harm to the habitats upon which human societies depend for survival.

This deteriorating state of global affairs leads the Board of Directors of the Bulletin of the Atomic Scientists–in consultation with a Board of Sponsors that includes 18 Nobel laureates–to move the minute hand of the “Doomsday Clock” from seven to five minutes to midnight.

Toon is peculiarly qualified for the discussion. Along with co-author Richard Turco, he was one of the key scientists who worked with Carl Sagan in the early 1980s in studies that predicted Nuclear Winter. That a global nuclear apocalypse would lead to a sort of Nordic hell became an idea so vivid and horrible that it helped end the arms race between the United States and the Soviet Union. Because dust and soot thrown up by a nuclear exchange would block the sun for a generation, even winning a nuclear exchange meant killing the Earth.

There’s been a call in different journals over the past few years for updated analysis of just how bad it would get, especially in light of breakthroughs in climate modeling and atmospheric sciences. Adding urgency is the spread of weapons to other countries, and the ambitions for weapons in dozens more.

While the United States and Russia may be much less likely to lob missiles into each other’s heartland, the chances of a regional nuclear conflict using much smaller weapons has dramatically increased, Toon and coauthors argue.

“A de facto nuclear arms race has emerged in Asia between China, India and Pakistan and could expand to include North Korea, South Korea, Taiwan and Japan,” they write. “In the Middle East, a nuclear confrontation between Israel and Iran would be fearful. Saudi Arabia and Egypt could also seek nuclear weapons to balance Iran and Israel.”

It’s relatively easy to build dozens of 15-kiloton bombs and stockpile them, similar in yield to Hiroshima. Plans can be found on the Internet. The bombs are small enough to be delivered by truck, car, boat, small plane. “The only serious obstacle to constructing a bomb is the limited availability of purified fissionable fuels,” they write.

So how bad could it be?

If 100 small nuclear bombs blasted cities and set them on fire, 1 to 5 million tons of soot, particles and smoke would spread into the sky. It would impact the atmosphere and darken the sky more than a huge volcanic eruption like Pinatubo in 1991. This would cut growing seasons by 10 to 30 days — especially hitting the Russian Arctic, central Europe and the heartland of North America.

Southcentral Alaska — where most people in the state live and the focus of the Alaska’s small agricultural industry — would lose 20 days of growing season.

And that’s not all. The authors speak of “climate anomalies” threatening the world in unexpected ways. Droughts, freezes, shifts in storm tracks, heat waves.

The threat of such a conflict “may constitute one of the greatest dangers to the stability of society since the dawn of humans,” they conclude.