The world isn’t mining enough minerals to reach a future that runs on clean energy, according to a new report by the International Energy Agency (IEA). Minerals like lithium, cobalt, and nickel are the building blocks for clean energy economies. Countries can’t meet their new climate goals without them. If supply chains can’t meet skyrocketing demand, mineral shortages could mean clean energy shortages.

Many of the world’s biggest economies have set goals to nearly eliminate climate pollution from fossil fuels in the next few decades. Leading climate scientists have found that greenhouse gas emissions need to reach net zero globally by around 2050 to stave off the worst effects of climate change.

Hitting that 2050 target would require six times more critical minerals than are produced today, the IEA found. For some minerals, the gap between supply and predicted future demand is way bigger. Demand for lithium, for example, is expected to grow 70 times over the next couple decades. But the supply from existing lithium mines and projects under construction can only meet about half the projected demand this decade.

“This mismatch is something that worries us,” Fatih Birol, the executive director of the IEA, said at a press conference today. “Our numbers show that the critical minerals are not a sideshow in our journey to reach climate goals. It’s a part of the main event.”

Batteries for electric vehicles (EVs) and renewable energy storage are the biggest factor driving the potential mineral shortage. An EV requires six times more mineral resources than a car that runs on fossil fuels. Cobalt, nickel, graphite, and manganese are essential for batteries, too.

Wind and solar power generation are also mineral-hungry industries. Wind turbines need rare earth minerals for magnets, while solar panels are made with copper, silicon, and silver. An increase in renewable energy is also spurring the need to modernize electrical grids, which can’t be done without more copper and aluminum.

Existing supply chains for these minerals are already vulnerable, the IEA notes. Mining for certain minerals tends to be concentrated in a few places — sometimes in just one country. About seventy percent of the world’s cobalt came from the Democratic Republic of Congo in 2019, while some 60 percent of rare earth minerals were mined in China.

Relying on a single source for these minerals means that the whole world could be affected by otherwise localized disasters like flooding, drought, or conflict. It can also breed human rights, labor, and environmental abuses. Major tech companies and Tesla have already faced a lawsuit over children killed while mining cobalt in the DRC.

Leaders will need to grapple with these problems as they work to transition their economies to clean energy. Designing technologies that minimize the use of these minerals could help alleviate some of the pressure on supply chains, according to the IEA. So could more recycling of EV batteries, solar panels, and wind turbines.

Even with that kind of progress, the IEA expects a shortfall unless new mineral deposits are tapped. Production of new critical minerals isn’t ramping up fast enough because investors aren’t convinced that world leaders are fully committed to their climate goals, according to Birol.

“If they get from the governments unmistakable signals that clean energy technologies are the technologies of tomorrow, then I believe this investment will flow,” he says. Until then, limited supplies of critical minerals will loom large over any global action on climate change.