Electric vehicles are not as environmentally friendly as you may believe. This is why.

The transportation sector accounts for nearly a quarter of all direct carbon-dioxide emissions from fuel combustion. Passenger cars account for 45 percent of this total. The problem extends beyond what comes out of the tailpipe: every step in the production of a vehicle’s 20,000 to 30,000 parts, which involves thousands of tonnes of aluminum, steel, and other materials, emit emissions.

EVs were supposed to be the solution. However, while cleaner cars may eventually solve the tailpipe emissions problem, they do not address all of the environmental damage caused by their production. When compared to the traditional internal combustion engines, or ICE, vehicles, greenhouse gases released during the manufacturing process account for a greater portion of life-cycle emissions. As the EV hype grows, battery production and research are accelerating, and sales are increasing.

That means material emissions are going to rise to more than 60% by 2040 from 18% today, according to consultancy firm McKinsey & Co. 

“The importance of supply chain decarbonization cannot be ignored,” Greenpeace noted in a report published this week, which examines car companies’ commitments and actions. “Accounting for about 20% of the life cycle of [greenhouse gas] emissions, decarbonizing the production phase of a car is harder than the use phase.” 

Consider this: As technologists work to make better EV batteries, one issue is getting more energy into a smaller, lighter powerpack. In their current form, these units end up becoming heavy and increasing the total weight of the car, which in turn requires more energy to drive. To deal with this, carmakers have started turning to aluminum for light-weight body designs, with EVs using 45% more of the metal than traditional vehicles. Emissions from aluminum have started rising, too, because it’s energy-intensive to mine and produce.

To put it another way, the manufacturing of the body and chassis accounts for roughly half of the emissions produced from cradle-to-gate — that is, the carbon impact from raw material extraction to a completed vehicle. According to the Greenpeace report, the metals used in both ICE and battery-electric vehicles account for 53% and 47% of the carbon footprint of car manufacturing, respectively. Meanwhile, as companies strive to develop batteries that can propel cars further, they use nickel, cobalt, and manganese, which emit even more greenhouse gases.

Despite this, we rarely hear about the magnitude of supply chain emissions. If policymakers and automakers do not start focusing on this issue soon, they risk losing the battle with emissions targets entirely. It’s not that we weren’t aware of the risks — warnings have been issued in recent years — but that key players have effectively chosen to ignore them in favor of simpler rhetoric.

Big auto companies and EV upstarts aren’t under any pressure to divulge this information. Investors aren’t asking, so manufacturers aren’t telling – or may not even know. To gauge how much progress is being made (or not), these numbers should be made part of the mandatory disclosure.

None of this is to say we are doomed — there will always be emissions. But we now need to go beyond the big, lofty goals and get into the weeds of realistic solutions. These should also include battery recycling, prioritizing types that use less carbon-intensive materials, or emission caps on the battery and electric vehicle manufacturing process. Small companies like Nano One Materials Corp. and Euro Manganese Inc. are thinking about how to decarbonize supply chains for battery parts. Other, bigger players need to catch on, too. Without a sharper focus, we’ll just be chasing ambition in a much hotter world.