A few years ago, environmental scientist Elliot Campbell went around asking people why they would, or would not, switch to an electric vehicle. A surprising number of them asked him a question in return: Because building an EV generates emissions, isn’t it better for the planet just to keep my gas car running for as long as possible?
Campbell, a professor at the University of California, Santa Cruz, didn’t know the answer, so he set out to find it. Turns out the old adage that the greenest car is the one in your driveway is a myth. In fact, his study, published today in the journal Science, finds that swapping even a two-year-old gas car for an EV leads to a lifetime emissions savings of roughly 50 percent.
Not everyone can afford to ditch a nearly new car, of course. It’s simply the most extreme example of the broader point his study revealed: The emissions saved by driving an EV very quickly compensate for the planet-warming gases generated by building it. Campbell said that finding consistently surprises his students, and goes against his own instincts.
“I like to repair things and keep them going,” he said. But, “we found there is a big advantage to retiring the gas vehicles early.”
Campbell designed the study to give internal combustion vehicles every possible advantage. “We really tipped the scales in favor of the gas vehicle,” he said. Most notably, it ignored the emissions that went into making the gas car, treating them instead as a sunk cost. EV still came out ahead, which suggests that climate-conscious drivers should make the switch as soon as it’s feasible.
“You’re just delaying the benefits longer and longer,” he said, noting that sidelining gas guzzlers off the road can improve air quality as well. This is especially true for cars that were built to less stringent standards, added David Reichmuth, a transportation sustainability expert at the Union of Concerned Scientists. “The magnitude of the benefits for getting an older gasoline vehicle,” he said, “can be much higher in terms of the air pollution.”
Reichmuth was not involved with Campbell’s study, but said it aligns with his own work on the issue. His analysis found that EVs reach an emissions break-even point at around 18,000 miles, which the average driver travels in about 18 months. That, however, depends on where a person lives and the source of their electricity.
The benefit is greatest where the grid is greenest. In upstate NY, which generates a lot of hydroelectric power, getting around in an EV is like driving a gas car that gets 219 mpg. But even in the Rockies, where coal and natural gas are the norm, an EV is better than anything getting less than 68 mpg.
Campbell’s study identified few exceptions to the conclusion that replacing a gas car with an electric one significantly reduces greenhouse gas emissions. Even moving away from high-efficiency vehicles and hybrids, like the Toyota Prius, is a climate win in the long-run. One case where it wouldn’t make sense, Campbell and his co-author found, is with plug-in hybrid electric vehicles, which have larger batteries and travel farther on electric power before switching to an internal combustion engine. Another is low mileage situations, such as with a second car that doesn’t get used that often.
“To me, this is the biggest factor,” said Moaz Uddin, senior electric vehicle policy specialist at the think tank Great Plains Institute, about mileage. He gave the example of a retiree who only drives their Prius a few thousand miles a year. “It’s good that the study considers that.”
The new research finds that in order to repay the carbon debt of making a new EV, it must be driven 4,400 miles if it’s a car and 6,700 miles each year if it’s a truck. That’s already well below the 12,500 miles the average driver travels in a year, and the benefits to making the switch are likely to grow.
As the United States increasingly relies on renewables, for example, charging an EV becomes even more environmentally appealing. Campbell and his co-author also point to improvements in battery recycling as a way of reducing the emissions involved with making an electric car.
One hole in this latest study is that it doesn’t consider the cost of going electric. While previous research has shown that EVs come with higher upfront costs but lower operating expenses, it’s a thread that Campbell hopes economists pull on. He would also like to see someone better account for the emissions generated while extracting oil and getting gasoline to the pump, rather than simply the burning. But, for now, he believes the study sends a clear message.
“We’re trying to show that there’s not an environmental motivation for extending the lifetime of a gas vehicle,” he said. “Electric vehicles are a very clear winner.”
The most direct policy interpretation of the study would be to give people money to scrap gas cars. There have been some efforts to do this, such as the 2009 federal Car Allowance Rebate System, also known as “cash for clunkers.” That gave people $3,500 to $4,500 if they upgraded to more efficient vehicles, and blew through its $3 billion budget in only a month. Reichmuth, though, says that the issue could be tackled earlier in the process.
“The obvious policy implication is don’t sell the gasoline car to begin with,” he said, with the corollary being that EVs need to be as attractive an alternative as possible. “Make sure there are more options, more support, for people to make that initial choice.”
This story was originally published by Grist with the headline Your gas car works fine. Consider an EV anyway, scientists say. on Aug 6, 2026.
