CO2 Emission Rise in U.K. Blamed on Diesel Backlash

The average carbon dioxide emission level of new cars sold in the U.K. last year rose by about 1 gram per kilometer—the first year-on-year increase since at least 2000.

The Society of Motor Manufacturers and Traders calculates that Britain’s average new-car CO₂ emissions fell from 181 g/km in 2000 to 120.1 g/km in 2016 before rising to 121.0 g/km last year.

SMMT’s New Car CO2 Report 2018 says the gain was the result of slumping diesel sales and an increase in demand for less fuel-efficient SUVs. Diesels typically emit 15%-20% less CO₂ than comparable gasoline vehicles.

The average new model in Britain last year released 13% less CO₂ than the car it replaced. But those gains were more than offset by an unfavorable shift in the sales mix.

Last year, diesel’s share of the U.K.’s new-car market fell to 42% from nearly 48% in 2016. SMMT figures many diesel owners either opted not to buy any new vehicle or switched from diesel to gasoline. Either choice would hurt the country’s attempt to achieve the pan-European target of 95 g/km by 2021.

At the same time, consumer preferences have swung from efficient minicars to larger SUV/crossovers. Between 2000 and 2017, registrations of new minicars in Britain plunged 30%, while sales of crossovers—which emit 27% more CO₂—more than tripled, according to SMMT.