LONDON – The U.K. consumers’ flight from “dirty” diesel-powered cars has raised carbon-dioxide emissions recorded by new vehicles for the first time in 14 years.

Department for Transport figures cited by online car retailer show the average new car sold in 2017 produces more CO2 than one sold in 2016, reversing a continuous decline in emissions of the greenhouse gas since the government first published the figures in 2003.

Industry experts attribute the rise to the slump in sales of diesel cars, which can emit much less CO2 than an equivalent gasoline model. After recent tax increases, the threat of widespread inner-city charges for older diesel cars and new findings about the harmful effects of fumes, diesel sales have declined 16% so far this year.

This rise threatens to derail the government’s ambitious climate-change targets, and ministers previously have warned they will “intervene firmly” if emissions reductions continue to stall.

Official government statistics for the first 10 months of 2017 show the average new car produces 121.1 g/km of CO2. The full annual figure is on course to exceed the 120.3 g/km recorded last year, ending a trend of falling CO2 emissions, which have declined by 4.02 g/km annually since 2003.

“Many customers now tell us that they’re avoiding diesel even if it means spending more on fuel,” says Austin Collins, managing director “Although switching to gasoline makes good financial sense for some, especially with plenty of economical gasoline, hybrid or electric cars available, diesel’s fuel economy still makes it a good option for long-distance drivers or SUV buyers at the moment.”

The retailer also claims the recent backlash against diesel has shattered automakers’ efforts to meet a European Union target of cutting average car CO2 emissions across the industry to 95 g/km.

Although sales of new electric and hybrid cars have increased 35% this year, this only represents an extra 28,611 cars compared with 2016. The number of new diesel cars sold has fallen by more than 190,000.

Tamzen Isacsson, director of the auto industry’s Society of Motor Manufacturers and Traders, says: “If industry is to meet challenging CO2 targets, getting more of the latest low-emission diesels onto our roads is crucial, as they can emit 20% less CO2 than the equivalent gasoline models.”

Isacsson also blames the drop in diesel sales on “confusion around government air-quality plans and taxation.”

However, advanced gasoline engines, as well as electric and hybrid technology, could cut CO2 emissions without the need for diesel, according to the International Council on Clean Transportation, a research group that has led the campaign against harmful diesel emissions.

“Quite a lot of gasoline vehicles do not use the latest technologies available and still have higher CO2 emissions than comparable diesel cars,” says Peter Mock, managing director of ICCT Europe. “However, the unfortunately often repeated statement that diesel cars are necessary to decrease CO2 emissions is simply wrong. Instead, hybridizing gasoline vehicles and transitioning to electric vehicles today makes more sense for vehicle manufacturers.”

Mock also says the increasing popularity of heavy SUVs, which generally are less fuel-efficient than hatchbacks, has made significantly contributed to the rise in average CO2 emissions.