Many Governments are encouraging their citizens to replace their old cars with new on the environmental grounds of reducing emissions of the greenhouse gas carbon dioxide (CO2). Bert van Wee of the National Institute of Public Health and the Environment at Utrecht University (Holland) checked ouit the facts.

New cars for instance, tend to be heavier than old cars (and thus consume more fuel), and both scrapping old cars and building new ones cause CO2 emissions. When his team readjusted the Dutch emission figures, they found that reducing average car age would increase overall CO2 emissions by 4%.

Their advice was that, environmentally, it was better overall if individuals kept their old cars, possibly fitting them with catalytic converters to reduce emissions of nitrogen oxide and volatile organic compounds, until manufacturers increased fuel-burning efficiency.