The spike in COVID-19 cases has short-term economic trends heading down, but if the metals market is any indication, the long-term prospects for the economy are looking up.

“Prices for copper have risen to their highest level in almost eight years,” The Wall Street Journal reports. “Other raw materials, such as aluminum and zinc, have added roughly 15 percent since the end of September and 40 percent or more since mid-May.”

Commodities such as metals and fuels are often good economic predictors. When growth slows, so does the demand for metals, which are necessary in building materials, infrastructure and tech. But when investors are driving up the price of these commodities, it means they expect an economic rebound, with more manufacturing, production and sales in the future.

In recent years, the U.S. mining sector suffered as commodity prices dropped. So any increase in future prices for metals — such as copper and iron ore — is likely to stimulate the mining industry. The industry analyst IBISWorld writes that it “expects improving macroeconomic conditions and rising commodity prices to buoy most of the industries comprised within the mining sector over the next five years.”

The price increases could be good for the American mining industry.

“Whether it’s manufacturing, infrastructure reinvestment or advanced energy-focused stimulus, all of these things are built on a foundation provided by metals and mining,” says Conor Bernstein with the National Mining Association.

“These near-term trends coupled with the soaring longer-term demand we know is coming from electrification and the electric vehicle revolution means that demand is only going to go up. The World Bank recently found that the production of key energy metals — everything from copper and lithium, to nickel and cobalt — could jump 500 percent by 2050. The analysts at Wood Mackenzie estimate that $1 trillion in investment in mining will be needed in just the next 15 years.

“Mining is rightfully being recognized as a sector poised for growth,” Bernstein said.

And, as the Journal reports, “mines in producing nations like Peru shut for part of the year due to the pandemic and labor strikes,” leaving American producers in a stronger position.

Metals are also benefitting from the fact that investors have fewer places to park their money. Stocks are surging even during the pandemic, with the S&P 500 Index up more that 14 percent so far this year. That makes investing in companies pricy.

For example, the stock of one company, Tesla, is up an amazing 600 percent. That company in particular uses a lot of metal in its cars and batteries. So if investors are right about Tesla’s future, they’re also right to think that metals prices will continue to increase.

Meanwhile, the Federal Reserve has driven interest rates about as low as they can go, and it vows to keep them near zero at least into 2023. That means that bonds and government bills are returning no interest, or even negative interest, meaning people must pay to lend their money to the government. That’s no way to make money.

All this leaves people who have money to invest scrambling to find places that provide a good return. Metals seem like a good bet. As the Journal notes, even with the recent price increases, the costs for raw materials “remain well below their historic peaks.”

Many people have more money to invest than they usually would at this time of year. Because so many stayed home for months, they didn’t spend big on vacations, entertainment or dining out. They need to do something with those savings, and with banks paying such low interest rates on savings accounts, they’re looking for returns by investing in commodities.

Finally, as the Journal points out, China is a major user of metals. For now, China seems to have COVID-19 under control, and is enjoying solid economic growth, up almost 5 percent between July and September. If that growth continues, it could signal an international boom as manufacturing ramps back up, and that manufacturing would require a steady stream of metals like copper and iron ore.

Commodities are typically leading indicators of economic activity. Rising metal prices are a positive sign for the American economy in 2021.