Delaying action on car emissions will make Australia more vulnerable

France has set its car manufacturers the goal of halting sales of diesel and petrol cars by 2040. The announcement last week came a day after the Swedish manufacturer Volvo declared it will build only hybrid and electric cars from 2019.

Moving away from highly polluting cars is an urgent global priority. Worldwide, transport accounts for 26% of humanity’s carbon dioxide emissions and, of these emissions, 81% comes from road transport.

Our latest research, published in the International Journal of Sustainable Transportation, shows that car ownership and the total distance travelled by cars are both likely to keep growing, globally and in Australia.

But just because there will be more cars, covering more ground, that doesn’t necessarily mean CO₂ emissions will continue to rise. It depends on a complex mix of population trends, income growth and the impacts of new policies and technologies.

It might therefore seem sensible to delay policy decisions until we can see what type of future emerges. However, our research found that a “wait and see” approach will dramatically increase our economic, social and environmental vulnerability.

Lower-income Australians are particularly at risk. This is because transport accounts for a greater proportion of their household income and they tend to live on the urban fringe where daily travel distances are necessarily higher.

Future-proofing our transport policy means we must engage with uncertainty, not ignore it. That means choosing policies that allow us to adapt to a range of technological or social developments.

We modelled different policy options in Western Australia, looking for options that reduced CO₂ emissions without creating social vulnerabilities. The most effective approach requires simultaneously improving fuel standards, making cars more efficient, and increasing city density to reduce both car ownership and the total distance we need to travel in cars.

However, CO₂ emissions alone don’t provide the full picture. Our model found that encouraging biofuels, for example, could mean increasing our agricultural footprint to grow feedstock.

Similarly, electric and hydrogen-fuelled vehicles require energy supplied by the electricity sector. As this sector itself decarbonises, technologies such as solar, hydro and wind will require greater areas of land than coal and gas technologies.

However, managing carbon dioxide emissions and demand on land is not necessarily mutually exclusive. Wind turbines can co-exist with grazing, and decentralised solar panels are already common on existing buildings. Offshore wind farms and solar installed on otherwise unproductive land can lessen impact. Targeted investment in technological efficiency can further reduce this impact.

Using land for both agriculture and energy production could actually give farmers greater economic resilience. Alternative fuels that use waste products or are low-impact (such as biofuel made from algae) are also promising avenues.

Although the implementation of stringent transport policy will be costly – it requires massive changes in capital infrastructure and behaviour – it will open up other benefits and saving.

Vehicle emissions are recognised as the source of more air pollution than any other single human activity. These emissions cause hundreds of preventable deaths in Australia every year. (As well as saving lives, we’d also save billions of dollars in related costs.)

Well-designed, more compact urban spaces encourage more biking and walking. This, in turn, reduces chronic diseases that also cost Australians billions every year.