North Korea's fourth nuclear test, claimed on state TV to be its first of a hydrogen bomb, leaves little room for doubt that North Korea is progressing its development of nuclear weapons.

While the UN's Comprehensive Test Ban Treaty Organisation has yet to definitively confirm another nuclear test, this seems virtually certain.

The nature of the explosion, at 10am local time on January 6, however, is less certain. At 5.1, the associated tremor was similar to that of North Korea's last nuclear test in February 2013. It is only if fallout products can be detected outside North Korea that the type of nuclear explosion can be verified.

What is clear, however, is that the means to produce nuclear weapons are accessible to any determined government. North Korea's continuing nuclear developments have surprised the international community before — for example in 2010, when it acquired (from Pakistan) the capacity to enrich uranium to weapons-grade, in addition to extracting plutonium from spent nuclear fuel produced by its Yongbyon reactor.

Hydrogen (or thermonuclear) weapons work by the fusion of isotopes of hydrogen — the main process powering stars like our sun — which occurs only under extreme heat and pressure.

In a weapon these conditions are created by a fission nuclear bomb "primary". These use the explosion created by a runaway chain reaction of atomic splitting in a greater than critical mass of highly enriched uranium (HEU) and/or plutonium (known as fissile materials). Both processes release vast amounts of energy. Most modern nuclear weapons utilise HEU, plutonium and hydrogen isotopes.

Hydrogen bombs can be built of almost limitless size — the largest exploded was by Russia in 1960. At 50 megatons, this single weapon released about five times more explosive power than all explosive weapons used in all previous wars throughout human history.

Whether this latest explosion was or wasn't a hydrogen bomb, a determined North Korea can in time acquire hydrogen bombs, produce more fissile material, build more nuclear weapons, miniaturise them to mount on missiles, and develop the guidance and re-entry capabilities for long-range missiles to carry a nuclear warhead.

It could also deliver nuclear weapons by other means — aircraft, ship or submarine, or create nuclear mayhem through its investment in cyber-warfare capability. And it could continue to assist other states to acquire the means to produce fissile materials and build nuclear weapons, as it assisted the construction of an undeclared nuclear reactor in Syria.

All this is reprehensible and deserving of condemnation. However, the context and enabling factors for the North Korean regime, desperate to foment a climate of external threat to keep its brutal grasp on power domestically and demand attention internationally, are key to turning around the existential threat that all nuclear weapons pose to all humanity every single day.

Nuclear expertise

North Korea's nuclear weapons program began out of the Korean War, 1950-53, when the US made explicit threats to use nuclear weapons. There is still no treaty, 63 years later, formalising the end of that war.

North Korean scientists and engineers gained nuclear expertise and a research nuclear reactor from the Soviet Union. They built the Yongbyon reactor to extract plutonium from the spent fuel, based on the 1950s design of the British Magnox reactors. Under the inadequate nuclear Non-Proliferation Treaty (NPT), countries can withdraw from the treaty after giving three months notice, as North Korea did.

While other nuclear-armed states have stopped nuclear test explosions, they conducted more than 2000 nuclear tests between 1945 and 1998, including over 500 in the atmosphere, spreading enormous amounts of radioactive fallout over the globe, causing millions of long-term cancer deaths.

And most of the other nuclear-armed states only stopped nuclear tests when they had perfected the computer and laboratory means to continue to develop and test new nuclear weapons without needing to blow them up.

The Comprehensive Test Ban Treaty (CTBT), to ban all nuclear test explosions, was negotiated 20 years ago but has not yet entered into force because eight states who must ratify it have not yet done so. This includes nuclear-armed China, India, Israel, Pakistan and the US, in addition to North Korea. Nor have a number of these committed to end nuclear testing or dismantled their test sites.

While all of the nine nuclear-armed countries are legally obliged to dismantle their nuclear arsenals, none of them is walking the talk. All are investing massively, to the tune of over US$100 billion each year, in modernising their nuclear arsenals, with long-range plans to keep nuclear weapons into the indefinite future.

The US Congressional Budget Office estimates that the US alone will spend US$348 billion on its nuclear forces to 2024; and US$1 trillion over the next 30 years.

While any nuclear weapons pose a catastrophic humanitarian danger, North Korea's estimated arsenal of less than 10 warheads comprises less than 0.1% of the current global total of 15,800.

More nuclear duplicity and inconsistency, what South Africa has characterised as global apartheid, more of failing business as usual, will not achieve the eradication of nuclear weapons that is the only guarantee against their otherwise inevitable eventual use.

For some to possess and thereby threaten use of nuclear weapons does not enhance security and stability for anyone, and inevitably provokes others to acquire them. And as North Korea shows us, that cat is out of the bag. What we need for nuclear weapons is one law for all, similar to the treaties that ban and provide for the progressive elimination of other unacceptable weapons — biological and chemical weapons, landmines and cluster munitions.

Governments that are serious about freeing our world of the worst of all terror weapons — nuclear weapons — will not only condemn North Korea's nuclear test and program, they will ratify the CTBT, renounce any reliance on nuclear weapons, and use the UN Working Group that will convene in Geneva next month to prepare to negotiate a treaty to outlaw and provide for the global elimination of nuclear weapons.

Banner image: North Korean Victory Day, July 2013. Picture: Stefan Kraskowski/Flickr