Oxford study shows UK offshoring emissions via used cars

New research led by Oxford University has found that exported used vehicles generate more emissions per mile than those that are scrapped or on the road in Great Britain.


The researchers used MOT tests of all 65 million used vehicles on British roads between 2005 and 2021 to compare the pollution and emissions intensity of vehicles exported compared to those scrapped, destroyed, or driven in Britain.

Results showed that exported used vehicles generate at least 13–53 per cent more emissions per mile than those that are scrapped or on the road, as well as finding substantially higher rates of carbon dioxide and pollution generation in these exported vehicles.

According to the study, amongst the seven million vehicles legally exported from GB, at least 13 per cent generated more CO2 per km than scrapped cars, and 17 per cent more than used vehicles on British roads. Exported vehicles were also 3.3 miles per gallon worse on fuel efficiency than those sent to the scrapyard.

In a statement, lead author and research associate at the Leverhulme Centre for Demographic Science and Demographic Science Unit at Oxford Population Health, Dr Saul Newman, said: “Our study reveals that the UK, a leading global exporter of used vehicles with high vehicle emissions standards inside its own borders, offshores vehicle emissions to lower-income countries who are already suffering the most from climate change.”

The study found that over half of all vehicle exports to low and middle-income countries originate from the EU and UK, with virtually all remaining trade coming from Japan and the United States.

Researchers said that whilst these countries maintain high emission standards domestically, almost all countries that receive their vehicle exports have no emission standards of their own.

Additionally, significantly higher nitrogen oxide rates – an air pollutant that causes millions of deaths each year and can be effectively avoided when emission standards are enforced – were emitted per km from exported than scrapped cars.

The researchers said that it was ‘striking’ that almost all exported diesel cars (98 per cent) failed the EU’s EURO-6 diesel emissions standards for nitrogen oxide and carbon monoxide, and most (83 per cent) were predicted to fail the carbon dioxide standards.

The study also highlights the issues surrounding the manipulation of emissions testing data which adds to the challenges of measuring emissions.

“This study shows that we have been exporting dirtier cars than those we send to the scrapyard,” said Dr Newman. “This presents an enormous opportunity to clean up emissions in lower-income countries, simply by applying our own domestic emission standards to vehicles sent offshore.”

The study calls for the UK’s world-leading vehicle emissions standards to be applied to all exported vehicles which would see cleaner instead of dirtier vehicles sent to lower-income countries. Such measures would reduce economic burdens of vehicle ownership as cleaner vehicles require lower ongoing maintenance and fuel costs, and align with increasing cleaner air and climate action calls. 

This forms one of many upcoming studies by the Leverhulme Centre for Demographic Science and Demographic Science Unit, Oxford University, focusing on geospatial and environmental demography, and issues and solutions to growing global vehicle emissions.

The research, published in Nature Climate Change yesterday (February 20, 2024) can be read in full here.