A new study in *Science* quantifies the climate advantages of retiring operational internal combustion engine vehicles (ICEVs) early rather than waiting for their natural end of life. Researchers conducted a comprehensive lifecycle assessment, comparing the cumulative greenhouse gas emissions of keeping an existing gasoline or diesel car on the road versus replacing it with a battery electric vehicle (BEV) today. The analysis accounts for the carbon debt of manufacturing a new BEV, including battery production, and the ongoing tailpipe emissions of the ICEV.

Results show that in most regions, retiring an ICEV immediately yields net emissions reductions within 3–5 years, even when the electricity grid is not fully decarbonized. The break-even point shortens dramatically as grids get cleaner. The study emphasizes that delaying replacement locks in avoidable emissions for decades, undermining 2030 climate targets. Policy incentives should therefore prioritize accelerating the turnover of the existing fleet, not just subsidizing new EV purchases.

The findings challenge the notion that extending vehicle lifespans is always environmentally optimal. By quantifying the "carbon payback period" for early retirement, the research provides a rigorous basis for scrappage schemes and feebate programs designed to shrink the global carbon budget overshoot from transport.