Peering into its magician's hat and seeing just one rabbit remaining, a key bellwether of Asian industry may be dropping the curtain without an encore.

South Korea's POSCO (NYSE:PKX) has performed feats of sheer magic by making margin pressures disappear and levitating earnings to dazzle even the disbelievers in the crowd. For its final trick, the company managed a 40% increase in profits for the third quarter despite indications of a sharp reversal of fortune for the steelmaking industry.

Judging by the 24% sell-off in shares as we speak today, that profit windfall is clearly yesterday's news, as concerns over the state of demand growth from China and other emerging markets now hogs the spotlight of investor concerns. POSCO issued a stark warning in the earnings release, where it cited a "tougher" outlook for the upcoming quarter. The company said "the global financial crisis will slow steel demand growth from the auto and construction sectors, while higher input costs and a tumbling won currency will add further pressure."

A chorus of backup singers appears to be singing the same note. Just weeks after industry leader ArcelorMittal (NYSE:MT) announced major production cuts, mining conglomerate Rio Tinto (NYSE:RTP) today noted a "marked reduction in Chinese commodity demand growth."

All of the industrial commodity sectors are suffering from similar uncertainty, and as a result, the iShares S&P GSCI Commodity-Indexed Trust (NYSE:GSG) has shed 46% just over the past three months. Copper miner Freeport-McMoRan (NYSE:FCX) has been forced to review its cost structures as copper prices have plummeted, and several Chinese aluminum producers, including Aluminum Corporation of China (NYSE:ACH), have reduced output until prices improve.

Now that every imaginable backstop has been hurled at the global financial crisis, investor focus will undoubtedly shift to tracking earnings results and tracking growth forecasts for emerging economies such as China. Since this activity may foster a return to greater rationality in calculating company valuations, I am hopeful that the dramatic sell-offs experienced so far in these sectors will be seen to have some significant demand destruction already priced in.

More importantly, although evidence is mounting for a near-term shock to the growth engines of BRIC countries and other emerging markets, I hope that Fools will keep their eyes on the long-term prize. In fact, POSCO's proven management team is diving deep into the shipbuilding business precisely because, long-term, the fundamental picture for global commodity demand growth remains intact.

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Fool contributor Christopher Barker captains yachts and writes about stocks. He can also be found blogging actively and acting Foolishly within the CAPS community under the username TMFSinchiruna. He owns shares of Freeport-McMoRan and Aluminum Corporation of China. POSCO ADR is a Motley Fool Income Investor recommendation. The Motley Fool has a disclosure policy.