Over the last 20 years, as China ramped up heavy industry and grew at a torrid pace, the country consumed staggering quantities of raw materials. This chart by Jeff Desjardins of Visual Capitalist gives a sense of the sheer scale involved:

China now burns as much coal as the rest of the world combined, and accounts for roughly half the planet's aluminum, steel, and copper consumption, according to data from the Wall Street Journal. In the last three years alone, China poured more concrete than the United States did in the entire 20th century. This despite only making up 13 percent of global GDP.

China's vast appetite for raw materials is now slowing down — creating turmoil around the world

But now comes a major twist. China's economy has been sputtering of late. The old model of relying on investment — building endless factories, highways, airports — and growing at 10 percent each year seems to be hitting diminishing returns. China's growth rate has fallen sharply this year (official stats say 7 percent annual growth, but many analysts suspect the real number is far lower). The country is also trying to transition to a consumption-based economy, similar to what you see in the United States or Europe, which could entail smaller growth rates going forward.

That means China's vast appetite for raw materials is tapering off, which in turn has had outsized effects on global commodity markets. As China's economy has slowed, the price of oil has fallen by more than half over the past year, while commodities like iron ore, copper, and aluminum have seen drops of 20 percent or more since January.

That slowdown is having ripple effects around the globe. During the 2000s, China's industrial growth was a huge boon for commodity exporters like Brazil, Argentina, Australia, and even Canada. Now that Chinese demand for raw materials is sagging, many of those countries are struggling — particularly Brazil, which has tumbled into recession. Similarly, a big chunk of Africa's export growth since 2005 came from selling raw materials like copper and iron ore to China. Those countries are now taking a hit.

Not everyone loses out, mind you: If waning Chinese demand drives down the price of crude oil, that's a boon for petroleum consumers in places like the United States and Europe. Same goes for, say, users of industrial metals who would benefit from cheaper costs.

Meanwhile, China isn't going to disappear overnight. Even if slower growth becomes the norm, it will remain the world's biggest consumer of raw materials for years to come. And if China makes the switch to a consumption-based economic model, that will propel demand for other "soft" commodities — say, coffee instead of concrete. But as the chart shows, China is so vast that even small blips can reshape global markets, causing turmoil around the world.

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