North Korea claims it has performed a successful test of a hydrogen bomb, the most powerful class of nuclear weapon.
Or at least that's the word from an formal statement by North Korea's official news agency, The Korean Central News Agency.
The announcement comes after the US Geological Survey reported a 5.1 magnitude earthquake 30 miles from Punggye-ri, North Korea's chief nuclear test site around 10:30 a.m. local time. That's the same site of three previous nuclear tests from 2006 to 2013, all of which tested less powerful but still potentially devastating atomic bombs.
If this test was indeed a hydrogen bomb, or an "H-bomb" or "superbomb" — which experts are still skeptical about and could take weeks to confirm — there are a number of reasons to be concerned.
For one, this would mean that North Korea is one step closer to positioning itself as a formidable threat to global security.
Nuclear tests are extremely tricky, Jeffrey Lewis, director of the East Asia Nonproliferation Program at the Middlebury Institute of International Studies at Monterey in California, wrote in a post for 38 North, a website devoted to the analysis of North Korea.
They take a fine-tuned dance of mining and enriching the necessary materials, assembling a working detonation device, and then actually delivering the entire package on top of a conventional warhead.
H-bombs are even trickier to test than atomic bombs because they are much, much more powerful than atomic bombs. This is because H-bombs rely on fusion, rather than fission, to produce a devastating blast.
This is the same physical process that stars use to produce energy.
"Think what’s going on inside the sun," Takao Takahara, professor of international politics and peace research at Meiji Gakuin University in Tokyo, told The Indian Express. "In theory, the process is potentially infinite. The amount of energy is huge."
If it's revealed that North Korea has tested an H-bomb, it would mean that the nation has acquired the sophisticated technology and testing to become a serious threat.
But even if it was a less powerful nuclear bomb, there's still reason to be concerned.
"What is important is that North Korea isn't content to settle for a crude nuclear program," Jeffrey Lewis told Tech Insider via email. "They want an arsenal of relatively advanced nuclear weapons."
Even a limited, regional nuclear war would have devastating consequences globally.
A study published in April 2014 in the journal Earth's Future found that a nuclear war between proximally close nations — such as India and Pakistan detonating 50 small nukes each, for example — would cause a sudden cooling of temperatures on land and an intense heating of Earth's stratosphere.
This would cause about 20% to 50% loss of the protective ozone layer over populated areas, bringing about the coldest surface temperatures Earth has seen in the past 1,000 years and a 30% to 80% increase in UV exposure to midlatitudes, which could devastate human health, agriculture, and land-and-water-based ecosystems.
For this reason the US and other nations are taking the possibility of this test very seriously. The United Nations Security Council will hold an emergency meeting in New York to strategize the best response to the test, The Washington Post reports.
"We think of the country as impoverished, both in terms of economy and leadership," Lewis wrote in the 38 North post. "Well, that’s not how the government in North Korea sees itself. Pyongyang’s propaganda apparatus argues ... that North Korea is a technological powerhouse."
Still, that nation has a long way to go before it can actually deliver a warhead to the US or some other country.
"North Korea isn't about to nuke New York, or anywhere else for that matter," Armin Rosin wrote for Business Insider. "There's no smoking gun proving nuclear miniaturization. North Korea's intercontinental missile test in 2009 was a failure, as was a 2015 test of a submarine-based ballistic missile."
Most likely, their technologies might allow them to strike South Korea or Japan, but even then that would be an ill-advised move: The US has a strong presence in South Korea, plus nuclear-armed submarines, so an attack on anyone would prompt a swift and potentially cataclysmic response.
