Diesel engines may be doing nothing to slow global warming despite being the backbone of Europe’s policy to reduce car emissions, a new report claims.
Tailpipe emissions of sooty ‘black carbon’ could be as much as 25-50% higher than the EU estimates for cars made before 2005, says the paper by Professor Erckard Helmers of Triers University.
On this analysis, some 20m cars in use since the 1990s may each have produced 40-80g of CO2 equivalent per kilometre more than previously thought.
However, the finding was questioned by the car industry and other experts.
Diesel engines made after 2005 have all had particulate filters installed, but Helmers’ study cites French research which found that 75% of the devices tested were not working properly.
“Diesel cars are intensifying rather than mitigating global warming,” Helmers told the Guardian. “EU policy has produced the opposite result to what it intended, and has exposed its population to more pollutants than was necessary.”
Brussels has used tax perks to favour diesel over petrol since the 1990s, even though they are a leading emitter of the air pollutant nitrogen dioxide (NO2), which is responsible for an estimated 70,000 premature European deaths each year.