(REPOST: Green Car Reports)

Diesel-powered cars have enjoyed a comfortable market share in Europe for decades, but their decline in popularity continues following numerous diesel-emission cheating scandals and regulatory crackdowns.

As if diesel cars hadn’t already had enough negative press, a new study says “fuel-efficient” diesel vehicles actually produce more lifetime carbon dioxide than do equivalent average gasoline-powered cars.

The study also notes that lower fuel taxes in many European countries deliberately created an uneven playing field for gasoline versus diesel.

Moreover, relaxed test measures and loose oversight have only amplified Europe’s addiction to diesel fuel.

Looking at the average diesel- and gasoline-powered car, the diesel car produces significantly more CO2 over its entire lifetime than a gasoline car.

Diesel cars make 1.6 tonnes more wells-to-wheels carbon emissions than do gasoline cars running E95, a blend of 95 percent gasoline and 5 percent ethanol, according to a Transport & Environment study.

Even using a B7 blend of diesel—95 percent diesel and 5 percent biodiesel—the study shows that producing the heavier engines of the diesel cars produce 0.25 more tonnes of CO2.

That adds to the 1.8 tonnes more CO2 it produces during its miles on the road versus a gasoline-powered car fueled with E95, in part because diesel fuel has more energy per volume, which skews its fuel-efficiency ratings against gasoline.

Therefore, in its lifetime, a diesel car will make 42.65 tonnes of CO2 versus 39 tonnes from a gasoline car.

The comparison is based on 182,000 kilometers (113,000 miles) driven in a diesel car and 175,000 km (108,000 miles) driven in a gasoline vehicle.

However, the analysis doesn’t take into account the full number of extra miles diesel cars drive on average.

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