The second implication, related to the first, is that the widely feared economic "hard landing" for China would have a devastating global impact. Every decline in Chinese GDP growth of one percentage point knocks close to 0.2 percentage points directly off world GDP; including the spillover effects of foreign trade, the total global growth impact would be around 0.3 percentage points.

Defining a Chinese hard landing as a halving of the current 6.7 percent growth rate, the combined direct and indirect effects of such an outcome would consequently knock about one percentage point off overall global growth. In such a scenario, there is no way the world could avoid another full-blown recession.

Finally (and more likely in my view), there are the global impacts of a successful rebalancing of the Chinese economy. The world stands to benefit greatly if the components of China's GDP continue to shift from manufacturing-led exports and investment to services and household consumption.

Under those circumstances, Chinese domestic demand has the potential to become an increasingly important source of export-led growth for China's major trading partners－provided, of course, that other countries are granted free and open access to rapidly expanding Chinese markets. A successful Chinese rebalancing scenario has the potential to jump-start global demand with a new and important source of aggregate demand－a powerful antidote to an otherwise sluggish world. That possibility should not be ignored, as political pressures bear down on the global trade debate.

All in all, despite all the focus on the US, Europe, or Japan, China continues to hold the trump card in today's weakened global economy. While a Chinese hard landing would be disastrous, a successful rebalancing would be an unqualified boon. That could well make the prognosis for China the decisive factor in the global economic outlook.

While the latest monthly indicators show China's economy stabilizing at around the 6.7 percent growth rate recorded in the first half of 2016, there can be no mistaking the headwinds looming in the second half of the year. In particular, the possibility of a further downshift in private-sector fixed-asset investment could exacerbate the ongoing pressures associated with deleveraging, persistently weak external demand, and a faltering property cycle.

But, unlike the major economies of the advanced world, where policy space is severely constrained, the Chinese authorities have ample scope for accommodative moves that could shore up economic activity. And, unlike the major economies of the developed world, which constantly struggle with a trade-off between short-term cyclical pressures and longer-term structural reforms, China is perfectly capable of addressing both sets of challenges simultaneously.

To the extent that the Chinese leadership is able to maintain such a multi-dimensional policy and reform focus, a weak and still vulnerable global economy can only benefit. The world needs a successful China more than ever.

The author is a faculty member at Yale University and a former chairman of Morgan Stanley Asia, and author of Unbalanced: The Codependency of America and China. Project Syndicate