Despite South Korean and US emphasis on the defensive nature of THAAD, Beijing is suspicious of the capacity that the system's radars have to monitor China's own missiles.

Will China's coal ban hurt North Korea?

Whatever the precise reasons for China's announcement, a more important question in gauging the likely impact of the measures, is to what extent the China's new restrictions on coal imports from North Korea will be implemented on the ground.

Though coal exports remain North Korea's single largest exported item, the slowdown in the Chinese economy since 2014 has already led to decreased demand for the mineral. Instead, economic exchange between the two countries has been increasing in other areas.

For example, Chinese clothing companies have increasingly outsourced production to North Korean trading companies as a result of rising wages in China and low-cost labor in North Korea. In recent years, there has also been the increasing dispatch of North Korean workers to Chinese border cities such as Dandong, Hunchun and Yanji.

As such, limitations on coal exports will no doubt have some impact on North Korea's earning of foreign exchange, but will be partly offset by growth in other sectors.

Will the ban curb Pyongyang's nuclear program?

The scope for China's restrictions on coal imports to impact upon North Korea's foreign exchange earnings certainly exists, and for sanctions advocates, this may offer a ray of hope that the sanctions regime may yet work. This is likely to be wishful thinking, however.

For a country that regards its external environment as irredeemably hostile and places the survival of the regime above all other goals, it is hard to see that the deprivation of foreign exchange will be significant enough to have any direct impact on Pyongyang's willingness to finance its nuclear and missile programs.

Livelihood exemptions within the international sanctions regime notwithstanding, an arguably more realistic scenario is that China's enforcement of sanctions may produce widespread hardship that results in social unrest and potential regime change from within.

Contrary to oft-made predictions concerning the country's impending collapse, however, it seems that the paradox of the North Korean regime is not its instability but its resilience.

Even during the time of the famine of the 1990s, long before North Korea's mineral export boom, there was a distinct lack of any overt actions of resistance amongst the North Korean populace. In addition, sanctions are widely regarded as ineffectual if there are no existing splits amongst elites or opposition movements within the country. North Korea is notably lacking in either.

China finds itself in a dilemma, however. Beijing has repeatedly expressed skepticism that North Korea can be persuaded to abandon its nuclear program through force, yet it is under intense pressure to enforce existing international sanctions against the country.

Whether or not China is correct on this point, it is nonetheless unrealistic to expect that Beijing is either willing or able to exert enough pressure on Pyongyang to induce it to change course.

Given this reality, there seems to be little evidence that Beijing has ceased in its calls for the resolution of the North Korean issue through negotiations.

Given the poor prospect of sanctions achieving their stated goals, perhaps it is time the world should listen.