Commodity traders like to say that when copper coughs, the global economy catches a cold. They call the metal “Dr. Copper” because its price is a pretty good way of diagnosing how the economy’s doing. And over the past six weeks or so, the price of copper has fallen more than 10% — looks like the economy is heading for a slowdown.

The story with copper, simply put, is too much supply and not enough demand. China, which uses half the world’s supply, is a big part of that story.

“They’ve been building real estate ferociously for decades, it seems like, and they simply have enough stock now,” said Chris Bataille, an adjunct research fellow at Columbia University’s Center on Global Energy Policy. He said as growth pulls back, “they don’t need to keep building infrastructure and all the wiring, everything that goes with that.”

Rising interest rates are contributing to weaker demand around the world. Traders are seeing that reflected in growing stockpiles of copper. Phillip Streible, chief market strategist at Blue Line Futures, has been keeping a close eye on them.

“For 23 consecutive days now, there has been an inflow of copper. So the inventories are building,” he said, adding that the market’s dour now, but he sees opportunity down the road.

“It could take months for a bottom to form. But we think ultimately, it’s going to take off to the upside,” he said. “There’s just so much infrastructure that needs to be replaced and improved on.”

Here in the U.S., that includes improvements to the grid as electrification takes off and renewables gain more market share.

Meanwhile, while China’s slowing down, India may be on its way up, according to Eli Tesfaye, a senior market strategist at RJO Futures. 

“Infrastructure is gonna be an investment area for Indian government,” he said. “Maybe they would be the catalyst for global economic improvement.”

That means the long-term prognosis for Dr. Copper could be looking up.