(KXAN) — Electric vehicles are the the forefront in the battle against climate change — and they’re top of mind for many as Tesla relocates its headquarters to Austin.

Yet, these cars still need resources to power their lithium-ion batteries.

And that resource? Nickel — and lots of it.

NBC News tracked nickel mining from the the Philippine rain forest all the way to Tesla the U.S. and found this mining is shrinking the rain forest and polluting the waters.

“Right now they [electric vehicles] account for maybe 4% of vehicles on the road in the United States but by the year 2025, the estimate is that could be as high as 30%,” NBC News correspondent Jacob Ward told KXAN News. “That is, of course, good news from the perspective of people who want to cut down on carbon emissions from our tailpipes but our nearly years-long investigation showed that there is a tremendous environmental cost.”

Last year, around 2.5 million metric tons of nickel were produced, Statistica reports. The majority of nickel mining happens in Indonesia, Philippines and New Caledonia. In 2020, the largest company producing nickel in the world is Tsingshan Holding Group in Wenzhou City, China.

High-grade nickel ore found in New Caledonia (Robin Smith via Getty Images)

But nickel production is likely to only ramp up.

As NBC News reports, electric vehicle popularity hit a record high in 2020. But many climate change advocates worry about the tradeoff between improved carbon emissions and the environmental toll of mining.

“I think it’s a really difficult ethical dilemma,” Gillian Galford, a professor in the Rubenstein School of Environment and Natural Resources at the University of Vermont, told NBC News. “On one hand, we have a very promising technology that can help us address our fossil fuel dependence. But on the other hand, we have lots of environmental harms that can go into getting us to that point.”

Ward said NBC’s investigation found that nickel mining in the Philippines is causing untold and possibly totally irreparable damage to one of the world’s rainforests — which is one of the keys to fighting climate change.

“We have always believed that doing away with normal emission vehicles was going to solve the climate problem… but it is basically the case that anything we build is going to come at some environmental cost… “[All of the factors in nickel mining] make the electric vehicle future much more complicated and much less environmental innocent than we understood.”