The environmental imperative

Choices about vehicle technology and fuels to meet rising demand for mobility in the coming decades will have far-reaching consequences for the environment. The use of conventional gasoline and diesel for road transport is already the leading cause of ambient (outdoor) air pollution in most major cities and the secondbiggest source of emissions of carbon-dioxide (CO2) worldwide after power generation. Public awareness about the environmental and health effects of road transport – and pressure on the authorities to act – is growing by the day.

Outdoor air pollution is the fourthlargest overall risk factor for human health worldwide after high blood pressure, dietary risks and smoking. It caused an estimated 4.2 million premature deaths worldwide per year in 2016 due to cardiovascular and respiratory disease, and cancers.1 Data for 2017 show that 97% of cities with more than 100 000 inhabitants do not meet the Air Quality Guidelines of the World Health Organization (WHO) in low and middle income countries, and 49% in high-income countries.2 In some emerging economies, notably China and India, urban air pollution has reached catastrophic proportions. Emissions of nitrogen oxides (NOx), volatile organic compounds (VOC), carbon monoxide (CO) and particulate matter (PM) from cars and trucks are the main sources of this pollution in most cases. The head of the WHO recently called air pollution the “new tobacco”.3

Concerns about the health impact of emissions of fine PM from diesel vehicles in particular have been growing in recent years, as more evidence of their impact on health emerges. A 2012 assessment by the WHO’s International Agency for Research on Cancer (IARC) concluded that ambient air pollution is carcinogenic to humans, with PM2.5 (particles with a diameter of less than 2.5 microns) most closely associated with increased incidence of cancer, especially lung cancer.4 These worries, heightened by revelations about fraudulent emissions testing of diesel cars by the German carmaker, Volkswagen, have prompted some local and national authorities to restrict the movement of diesel vehicles and seek to discourage use of the fuel. For example, four German cities – Berlin, Frankfurt, Hamburg and Stuttgart – have introduced exclusion zones for diesel cars. In many countries, taxes on diesel have been raised. And more than a dozen countries, including France, India and the United Kingdom, have already announced long-term goals of banning the sale of both diesel and gasoline cars, while other countries are posed to follow suit.

There is also an urgent need to step up efforts to curb emissions of greenhouse gases from road transport. The sector accounts for almost a fifth of total energyrelated emissions of CO2, a share that has been rising constantly in recent years. According to the latest report from the Inter-governmental Panel on Climate Change (IPCC), global net emissions of greenhouse gases including CO2 would need to fall by 45% between 2010 and 2030 and to zero by around 2050 to be on track to meet the long-term goal of limiting the temperature increase to 1.5 degrees under the 2015 Paris Agreement (IPCC, 2018).

This will require far more radical policy action around the world than is currently planned. Under current policies, including nationally determined contributions under the Paris Agreement, global energy-related CO2 emissions – the main greenhouse gas – are projected to carry on rising, levelling off at around 40 gigatonnes by 2060 – 16% higher than in 2014, implying a temperature increase of over 3 degrees (IEA, 2017a). It is clear that keeping the increase even to less than 2 degrees will require big reductions in emissions in all end-use sectors, including road transport. For example, the European Parliament has called for a goal of achieving a zero-emission car fleet by 2050; biofuels are expected to play a major role in meeting this goal (EAFO, 2017).

“Keeping the global temperature increase to under 2 degrees will require big reductions in emissions in all end-use sectors, including road transport; this will not happen without far more radical policy action around the world than is currently planned. ”