Environmental impact of scrapping old cars

Many countries introduced scrapping programs in the 90s, partly legitimated by environmental impact reductions. However, reducing the age of the current car fleet may result in an increase of life-cycle CO2 emissions. This will probably also be true for cars to be produced in future unless fuel efficiency of new cars improves much faster than the historical trend indicates. Reducing the age of petrol-fuelled cars without a catalytic converter will reduce both life-cycle NOx and VOC emissions but is less cost-effective than fitting catalytic converters on these cars. In any case, the influence of a car's lifetime on life-cycle NOx and VOC emissions will be reduced in the near future.