Giant EVs aren’t perfect, but they can still help fight climate change.

But the scale of the differences between the conditions is quite eye-opening. Consider the difference between the worst-case scenario and what the study considers the “situation”. When it comes to lithium, with people driving as much as they do now, we’ll need 306,000 tons by 2050. With more batteries, that number could increase to 483,000 tons -50% more.

We don’t run out of materials to make batteries, but every mineral we need to build has consequences for people and the environment. Mining often causes pollution, especially waterways, and the industry is linked to human rights violations around the world. So big batteries mean big consequences.

Bigger cars also have a bigger climate impact. For a dramatic example, compare the EV Hummer to a gas-powered sedan.

Even though they don’t burn fossil fuels on board, EVs aren’t completely zero emissions. Building them, especially their batteries, requires energy. And the electricity that powers most EVs today comes from the grid, fueled at least in part by fossil fuels almost everywhere.

If you factor in the lifetime emissions from building a battery and charging the EV, an electric model of the same car will be better than a gas-powered version in almost every situation. But comparing different models can be a different story. A gas-powered Toyota Corolla is responsible for less greenhouse gas emissions per mile than an EV Hummer, according to Quartz study estimates. So now, that hummer is worse for the climate.

To be clear, I’m not saying we should all buy old gas-powered Corollas. EVs, even the giant ones, are getting cleaner. A 2040 grid-charged EV hummer should have more renewables in its power mix and have lower emissions than those hitting the roads today. And by then we hope to reduce the climate impact from mining and heavy industry.

So what now?

It would be nice if we could drive less overall. I live in a walkable city, so I don’t have a car, and I love it. It will be very soon if I never have to drive again. Policy measures could help more cities emulate mine, or at least support public transit and walking and cycling infrastructure to reduce car trips.