Kim Jong-un thinks Trump is bluffing – does the world face an accidental nuclear war?

Could war break out between the United States and North Korea? Tensions have certainly escalated between the world's most powerful country and the rogue nation.

North Korea fired ballistic missiles over over Japan and threatened to strike the US pacific island of Guam, while a war of words broke out between the country's respective leaders, President Donald Trump and Kim Jong-un.

Never one to shy away from an altercation, Trump called the North Korean dictator "rocket man". He even went as far as to say "only one thing will work", suggesting military action is on his mind as the solution for stopping North Korea's rapidly advancing nuclear weapons programme.

But could fiery rhetoric soon erupt into a devastating conflict? Dr John Nilsson-Wright, a senior research fellow at Chatham House, tells IBTimes UK he believes conflict is still a last choice and "because of that Kim Jong-un is emboldened".

"He has taken the measure of Trump and I think he thinks he's bluffing," Nilsson-Wright said.

This dangerous game is, however, what Nilsson-Wright thinks could get the two countries into trouble: "If Kim decided to follow through on his boast that he would be willing to fire long range missiles in the direction of American forces on Guam - not in an attempt to attack American forces but to demonstrate his capacity to threaten American territory - [and] that challenges the carefully drawn red lines that Trump has kept to, then the president may feel like he has no choice but to respond. So you can easily imagine the escalation dynamic."

So in the worst case scenario, what would conflict with North Korea look like?

'Devastating for both North and South Korea'

Based on the predictions given to US President Bill Clinton in the 1990s, Nilsson-Wright says war on the peninsula would be "devastating for the residents of both South and North Korea".

Back then, one million people were at risk of dying. Today, 10 million live in South Korea's capital Seoul, a city only 30 miles from North Korea's artillery pieces, not to mention its army of over one million men and potentially up to 30 nuclear devices. North Korea has the fourth largest military in the world.

China

There are also other factors to consider. China has had strong relations with North Korea since the Korean war in 1951 when it sent in troops to help its neighbour against the South and its allies.

Like everybody else, China wants to avoid conflict in the Korean Peninsula. Foreign Ministry Spokesperson Hua Chunying recently asked the various powers involved to stop "provoking each other."

Ultimately, though, China would intervene. Not only because of its obligation to an ally, but in fear for its own territory, too.

"China I think would worry that a conflict would create a security vacuum, north of the DMZ (Korean Demilitarised Zone), that would be filled by the United States and its South Korean ally, posing a security risk to China," Nilsson-Wright says.

'North Korea cannot win'

In spite of North Korea's military strength and any assistance from China, conflict would most likely see the end of the Kim regime.

"Undoubtedly the United States and its South Korean ally would prevail," Nilsson-Wright said. "North Korea cannot win this conflict. That's what in the past has deterred it from taking these sorts of provocative steps."

For now, it's stalemate between the US and North Korea. But with no parties willing to sit down and talk amid rising hostility, and no viable options currently on the table, Nilsson-Wright warns there could be conflict "by accident rather than by design".