The worrying collapse in global trade

April 11, 2014, 1:00 PM UTC

FORTUNE — Chinese imports and exports fell off a cliff in March, and the Chinese economy isn’t the only one dealing with lagging trade figures.

Chinese exports plunged by 6.6% over the last 12 months ending in March, and they were flat in the year ended in December. This was well below the 4% increase in exports many economists had expected. True, data from China can be volatile and difficult to interpret. Some are attributing the drop to a crackdown on Chinese companies using exports as a means to evade capital controls. Andrew Tilton, an economist at Goldman Sachs in Asia, called this the “main reason” for the plunge, according to the Wall Street Journal.

Markets in Asia did seem to shrug off the report initially, perhaps buying the explanation that the dip was due to bad Chinese data, but Carl Weinberg, chief economist at High Frequency Economics, isn’t so optimistic.

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He argues that the data out of China is just the latest in a series of worrying signs that global trade is slumping. Weinberg points to an anomaly in trade data, pictured in the chart below, which shows “an obvious historic correlation between global industrial output and the volume of world trade.”

The problem is, while export growth hasn’t really recovered to pre-crisis levels, industrial production has somehow stayed strong. This doesn’t make a lot of sense, as producers need to sell their products somewhere in order to keep up economic activity. “That means we have to expect the anomaly to reverse, and we are worried that it will happen through a retracement of the pace of production,” Weinberg writes.

In other words, the above chart could be a sign that industrial production is about to fall off a cliff, and the data out of China on Thursday is just another warning sign that this will happen soon.

So where else is trade suffering? Mostly in Europe, where both Britain and France announced disappointing export figures this week. The main outlier is Germany, which recently reported a 4.6% year-over-year growth in exports. But this might simply be a sign that Europe is failing to rebalance its own economy — away from an over-reliance on German exports — as the European economy gains strength.

What to do about this slumping trade? Weinberg suggests stimulus, writing

The policy response is simple: Boost economic growth. Growing economies import more, boosting the exports of other economies. It’s just that simple. As long as fiscal policy in much of the world remains committed to austerity and monetary policy remains tapped out, global demand will be weak and trade will not flourish.

That’s easier said than done, of course. Britain and France are both struggling under large amounts of government debt. Meanwhile, China appears to be moving forward with plans to make its economy more open and liberal, which means it won’t be able to resort to its usual stimulative tactics like currency depreciation and pumping cheap money into its economy without facing destabilizing consequences.