There’s a good reason why the US nuclear posture isn’t determined by trigger-happy civilians eager to immolate enemy nations in radioactive hellfire. More than two decades of not having to think about nuclear annihilation seem to have created a bizarrely casual attitude about the, well, for lack of a better word, fallout from using nukes.
Trump seems unable to grasp the real world consequences of deploying humanity’s deadliest invention on a whim.
Nuclear weapons are not just big bombs that create huge fireballs and level a large territory. On top of the terrifying geopolitical implications, they come with some very nasty side-effects that are impossible to contain, especially if they’re ever used in bulk.
After the initial burst of gamma rays created by the blasts, the heavy elements from the fission primary, the uranium spark plug, casing, and tamper, will mix with the air currents generated by the heat of the nuclear fireballs and come down as a black, sticky rain after about 40 minutes to an hour. This is exactly what happened in Hiroshima, but that was just one bomb, one explosion
The combined soot and heat from 100 blasts would be like a massive volcanic eruption, except it would also be far, far deadlier. Depending on the weather conditions, it’s not out of the question to see black rainstorms across the entire region.
And herein lays the problem. The affected region would include China, Russia, Japan and South Korea. Radioactive particles will spread across the Northern Hemisphere, ending up in Hawaii, Alaska, Washington, Oregon, California, and the Canadian Pacific Coast.
The fish many nations around the Pacific Rim rely on for food would be killed or contaminated. Tens of millions will be poisoned or sickened, and even several generations down the line, there will be numerous birth defects and cases of aggressive cancers as lower intensity fallout takes its toll.
Even worse, about 100 bombs like this, are more than enough to start nuclear winter. Yes, that’s right, things are about to get worse. As the radioactive soot travels across the world, carried by currents high in the atmosphere, it begins to blot out the sun, cooling the planet.
While this could temporarily stop global warming, it will also collapse countless food chains, and guarantee failure of harvests blighted with the unstable isotopes raining from the sky, then denied sunlight, even after replanting and disposing of the contaminated soil to start rebuilding.
US enemies may be dead and dying, but the US and it's allies will also have to deal with the fallout, the nuclear winter’s decade or so of hungry years, and the long term residual effects of being irradiated. Over 371.8 million people live in the region in question, and a tens of millions more could also feel the effects of the fallout and food shortages.
A smaller strike would stave off nuclear winter and lessen the possible long term casualties from the disruption of the food supplies. However, given the population density of the region, the death toll would still be in the tens of millions and spread to our allies.
That is even if China and Russia do not retaliate and nuke the US, which considering the impact such an attack on North Korea would cause on their nations is highly unlikely.