Fire and Ice

There's no such thing as a limited nuclear war.

When President Trump warned North Korea this week not to underestimate America’s resolve, he wasn’t bluffing. You don’t double-park three of the U.S. Navy’s carrier battle groups off the coast of the Korean peninsula if you’re not prepared to use them.

A showdown over North Korea’s accelerating nuclear weapons program may be looming. Pundits with military credentials, most of them retired generals, are popping up on all of the talking-head shows offering their seat-of-the-pants assessments of how a military confrontation between the U.S. and North Korea might play out. They’re also speculating on how much firepower it would take to destroy Kim Jong Un’s nuclear ambitions. The words “preemptive strike” are being given serious consideration.

Unfortunately, North Korea’s ballistic missiles are not a fixed target, like the aging land-based ICBMs we keep on 24-hour alert in hardened silos in the heartland of America. Little Rocket Man’s favorite toys are attached to mobile launchers (launch pads carried by huge trucks) that are easy to conceal (they can be hidden in tunnels dug into the sides of mountains). Kim’s missiles can be deployed and fired in less than 10 minutes, and it’s impossible to know where most of them are.

The Pentagon admitted this week that even a first-strike nuclear bombardment of North Korea might not prevent Kim from launching a devastating counterattack with the 20 or so warheads he’s believed to have in hand (including a few hydrogen bombs). The DOD quietly issued a statement declaring that the only sure-fire method of eliminating North Korea’s nuclear threat would be a ground invasion.

But a half-century of war-games analysis by the Pentagon’s top strategic thinkers always has led to the same conclusion: conventional war between two nuclear powers escalates very quickly into nuclear war. In every scenario for such a conflict, the DOD’s supercomputers always predict the blooming of hideous mushroom clouds.

So we’re forced to think the unthinkable: what would the world look like after a nuclear exchange between the U.S. and North Korea?

You might think that the effects of a nuclear war on the Korean peninsula would be limited to a relatively small quadrant of Asia, but you’d be wrong. There’s no such thing as a limited nuclear war. The above-ground detonation of as few as 50 nukes has the potential to create a global environmental catastrophe that could make climate change seem like a picnic by comparison.

Which brings us to Carl Sagan, an astronomer who became a celebrity in the early 1980s by explaining science to the masses in his popular TV series Cosmos. At the height of the Cold War, as President Reagan’s Strategic Defense Initiative sparked fevered discussions of preemptive nuclear war, Sagan used his celebrity status to inform us of a phenomenon he called “The Nuclear Winter.”

In an article published in the tabloid newspaper insert Parade Magazine in 1983, Sagan warned that the smoke, dust and debris (much of it radioactive) hurled into the atmosphere during a nuclear war would circle the earth and form an atmospheric layer of soot that would block the rays of the Sun, sending global temperatures plunging below freezing and destroying our ability to grow food crops or raise livestock. The Nuclear Winter wouldn’t be permanent, Sagan said, but it could last long enough to threaten the survival of the human race.

Because he chose a newspaper tabloid to unveil his theory, preempting the publication in a leading academic journal of his scientific paper (called The Global Atmospheric Consequences of Nuclear War, based on research by Sagan and a team from NASA’s Ames Research Center), Sagan opened the door to ridicule from the U.S. government, which didn’t want us to scrutinize the danger from the “second-hand smoke” that could be generated by a nuclear exchange.

But the science behind Sagan’s Nuclear Winter theory was substantial, based on meteorological models derived from the study of volcanoes to calculate the effects on light and temperature of different kinds and numbers of nuclear explosions, factoring in the dust, smoke and soot produced by the burning of cities (some of the data also came from a Mariner satellite analysis of dust storms on Mars).

Here’s a Cliff Notes synopsis of the theory: scientists have measured the impact on the global atmosphere of volcanic eruptions. The soot from even a single large volcano produces a measurable effect on global temperatures as it circles the Earth. Scientists have warned for years that the eruption of any of the handful of “super-volcanoes” known to be on Earth (Yellowstone National Park is on top of one) could render an entire continent uninhabitable.

The average yield of a small strategic warhead is 2 megatons, the explosive equivalent of 2 million tons of TNT (which also is equivalent to the cumulative explosive force of all of the conventional bombs dropped in WWII). Here’s the bottom line: the detonation in the atmosphere of 50 nuclear weapons is roughly the equivalent of up to 10 super-volcanoes blowing up.

Here’s how Dr. Sagan put it:

“Perhaps the greatest surprise in our work was that even small nuclear wars can have devastating climatic effects. We considered a war in which a mere 100 megatons exploded, less than one percent of the world arsenals, and only in low-yield airbursts over cities. This scenario, we found, would ignite thousands of fires and the smoke from these fires alone would be enough to generate an epoch of cold and dark almost as severe as in the 5,000-megaton scenario. The threshold for The Nuclear Winter is very low.”

So as we wrestle with the best method of separating a crazed dictator from his growing nuclear stockpile, the stakes could not be higher. We may be standing on the threshold of a war in which everyone loses.

nuclear war


  1. Who writes these things? Sagan has been gone a very long time and was mostly less than a scientist and more a polemicist in his time. To be correct, we have seen a limited nuclear war, the bombings of Hiroshima and Nagasaki and those events ended WW II. To fear the bizarre pronouncements of despots in North Korea is a certain way to ensure conflict. To arm chair military capability and tactics of the most sophisticated military in the world, is less than astute.

    • The Editor responds:
      This post is about what may happen if two nuclear powers go to war. To be correct, Japan was not a nuclear power when we dropped A-bombs on Hiroshima and Nagasaki, and therefore WWII was not a nuclear war. Just because Carl Sagan is no longer with us doesn’t mean his theory should be ignored or his scientific credentials denigrated. As we noted in our post, Sagan’s scientific paper on nuclear winter might have had more impact had he not chosen to preempt it with a tabloid article. Nobody fears Kim Jong Un and we can all agree the world will be better when he’s gone, hopefully soon. Perhaps Kim’s friends in China can provide us with his home address, so we can adjust our target coordinates with precision.

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