The global impact of nuclear war—in perception and reality—took a significant, unprecedented and highly negative turn in the summer of 2017 with North Korea’s acquisition of a thermonuclear weapon.

Those of us in the field of emergency preparedness shudder with the realization that a growing number of nations are joining the global thermonuclear arms race.
This reality is fraught with consequences that most people do not recognize, and frankly do not want to know.
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In a nutshell, thermonuclear weapons, colloquially known as H-bombs, produce much larger yields of destructive power than the nuclear weapons that countries tested in the early days of nuclear weapon development.  
For example, the nuclear bombs that the U.S. dropped on Japan in 1945 were in the 15 to 20 kiloton yield. This means that they had the destructive power of an equivalent of 15,000 to 20,000 tons of dynamite.
In addition to killing about 100,000 people, these weapons cause thousands of traumatic injuries, thousands of radiation injuries and hundreds of thermal burn victims.
Compare that to a thermonuclear weapon which is in the range of 75 to 49,000 kilotons of destructive power. Used on a densely populated urban center like New York City or Tokyo, just one weapon would kill millions of people and produce millions of casualties.
Those numbers are devastating enough, but the real nightmare is that the number of thermal burn casualties greatly multiply with a thermonuclear weapon relative to a simple nuclear weapon.  
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6th November 1952: A mushroom cloud begins formation after the first H-Bomb explosion (US) at Eniwetok Atoll in the Pacific. Three Lions/Getty
A typical serious thermal burn injury in a well staffed hospital takes three to four medical personnel per patient to provide adequate care. When we have hundreds of thousands of surviving burn patients due to an urban thermonuclear detonation, we are not going to be able to treat even a tiny fraction of them.
Until now, only wealthy and advanced nations – the United States, Russia, China, the United Kingdom, France and Israel – were able to produce these massively destructive thermonuclear weapons.
Now, with poor and unstable North Korea joining the thermonuclear club, other small nations may realize that this previously difficult threshold may be within their technical reach.
Even worse, nations around the world know that the Earth is getting to be a much more dangerous place when a nation like North Korea has such weapons, and many will perceive that their national safety now depends on procuring these terrible devices as well.
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In academic journals and in the media, there is talk of India acquiring thermonuclear weapons on the fast track, which will pressure Pakistan to do the same. The sense of urgency is even touching nations that previously eschewed the development of nuclear weapons.
Even Japan – which by its constitution is significantly restricted in its armaments and has no nuclear weapons at all –  could use its enormous stockpile of nuclear waste to rapidly develop an equally enormous stockpile of thermonuclear weapons.
Despite repeated headlines about the growing possibility of nuclear war, most people, curiously, avoid thinking or talking about it. In over a thousand lectures on nuclear war medical response, I find even medical audiences do not want to address the issue.
In fact, I recently published an assessment of U.S. and Asian emergency medical responders’ hypothetical response to a nuclear event which found a striking lack of knowledge about patients affected by radiation after nuclear war and a strong reluctance to treat them, even though it is far less dangerous than treating infectious disease patients.  
This fear of radiation is just as pronounced in the general population. We had a very hard time getting the medical and public health community to adequately address this issue even when we were focused on the smaller, Hiroshima-sized weapons, where it is feasible to mount a credible response. Now, we have to discuss the grim prospect of responding to the global thermonuclear arms race that we are now in – and currently losing.  
While nuclear nonproliferation remains a top priority, the preparation for responding to the actual use of these terrible weapons is now a regrettable necessity that we must confront.

Cham Dallas is the director of the Institute for Disaster Management at the University of Georgia.