The world has been firing on two cylinders over recent years: commodities and credit. These did not quite deliver soaring growth, but were enough to keep things sputtering along. The tank, however, is running dry. Asia is especially exposed. While this need not portend imminent financial stress, growth is bound to disappoint for a while.

Consider the big picture. With the collapse of demand in the West following the global financial crisis, China has been holding up the roof. Its contribution to world growth occurred mainly through commodities. True, China imported everything, from German cars and French handbags to Japanese excavators, but it was its appetite for raw materials that powered the world.

Exporters from Latin America to Africa, and South-east Asia to Australia, New Zealand and Canada enjoyed soaring incomes, driving up consumption and investment. Even economies that do not possess natural riches benefited. South Korea, for example, which sends 60 per cent of its exports to emerging markets, got a lift from global mining investment and rising consumer demand in developing countries.

The boom, unfortunately, has come to an end. It is not so much that China stopped buying commodities, but that its slowdown sent prices tumbling and put many projects on ice. Even a rebound in China construction, the principal driver for raw material demand, might not deliver a fix. Such is the growth in supply that prices are unlikely to recover to their earlier, lofty levels.

This leaves the world with an awkward problem. Commodity exporters, with their high propensity to spend, have suffered. Meanwhile, commodity importers, China above all but also the West and Japan, are not able to translate their savings into greater demand. Usually, a tumble in commodity prices, after a short delay, would be self-correcting, prodding importers to spend. This time it is not: The debt overhang is delaying the adjustment.

Take the United States consumer. Falling energy prices should ordinarily have spurred household purchases. But this time, most of the gains have been saved rather than spent as consumers deleverage. Balance sheet repair takes time, leaving the world short of demand in the meantime.

But it is not just commodities. Robust growth in emerging markets, particularly Asia, was also fuelled by cheap credit. That driver, too, is fading: not so much because funding costs are climbing again, but because many borrowers have already extended themselves to uncomfortable levels. With the Federal Reserve set to tighten, and currencies in emerging markets feeling the pinch, credit will no longer provide the customary fuel.

A bleak picture, then, and one for which no obvious solution exists. Few economies are in a position to provide sufficient stimulus to boost demand. China, to be sure, still has ammunition, and looks ready to use it. But without a recovery in commodity prices, many exporters will be left short of income.

The good news, at least, is that none of this needs to push the world to the brink again. Weaker growth is the most likely result, at least in Asia. As long as interest rates remain low, credit is bound to slow rather than contract. And with emerging markets limping along, inflation is unlikely to rise sharply. That, in turn, should keep the largest central banks in accommodative mode, with interest rates anchored long enough to prevent calamity.

But all this points to a more uncomfortable truth: that credit and commodities were not going to fuel the world indefinitely was always plain to see. Sustained growth requires gains in productivity. Public policy plays a critical role in raising efficiency, and it is here where too little has happened: reforms must be adopted to refill the tank.

In Asia, the list is long, and the work has barely begun. State-owned enterprises, not just in China, need to be revamped. Despite the region's export success, local economies remain too sheltered from foreign competition. Labour markets are too rigid. At the same time, parts of the region lack the infrastructure to encourage manufacturing.

This is not a purely liberalising agenda: social security, education and healthcare need an urgent overhaul as well. Hope remains that the latest financial turmoil in Asia will provide the necessary reminder that the engine needs retooling.

• The writer is co-head of Asia Economics Research, HSBC.