Cars in one country emit much more CO2 than elsewhere: ScienceAlert

Australian passenger vehicles emit 50% more carbon dioxide (CO₂) than the average of the world’s major markets. And the situation in the real world is even worse than official figures show.

That’s the conclusion of a new study comparing the CO₂ emissions performance of cars, SUVs and light commercial vehicles in Australia and abroad.

The comparison shows that Australia is likely to fall far short of its economy-wide target of net-zero road transport emissions by 2050. To achieve this target, policies to reduce vehicle emissions must be intensified and supported by a range of other policies.

This month, the Australian government announced options for a New Vehicle Efficiency Standard (NVES) – not to be confused with the National Electric Vehicle Strategy (NEVS). Each option would set a national limit on the number of grams of CO₂ that can be emitted per kilometer driven, averaged across all new cars sold.

Mandatory CO₂ emissions or fuel efficiency standards are internationally recognized as a fundamental building block for reducing transport emissions.

To provide further context and input into the development of an Australian standard, Australia-based Transport Energy/Emission Research (TER) and the International Council on Clean Transportation (ICCT) have collaborated on a newly published briefing paper.

The independent analysis shows that Australia urgently needs to implement a stringent, well-designed and mandatory fuel efficiency standard. These standard and additional policies are essential to keep pace with the technological advances and decarbonization of other developed countries.

How did we get so far behind?

Both fuel efficiency and emissions standards share roughly the same goal: reducing fuel consumption and greenhouse gas emissions. By doing this, they also reduce fuel costs for consumers and improve energy security.

About 85% of the global light vehicle market adopted these standards over time, in some cases decades ago. The United States, European Union, Canada, United Kingdom, Japan, China, South Korea, Brazil, Mexico, New Zealand, Chile and India all have them. Australia and Russia are the two exceptions in the developed world.

Australia has a long history of discussion about mandating such standards for passenger cars and light commercial vehicles. The federal government has released six public consultation documents since 2008, without reaching mandatory standards. This is going to change.

Australia has had voluntary standards since 1978. These objectives have not always been achieved due to a lack of enforcement. They have been criticized for lacking both ambition and effectiveness in reducing real-world emissions.

It appears that the government’s current proposal will be more ambitious. It may aim to converge with US targets by 2027, but lag behind what is being done in Europe. The effectiveness of the Australian standard in achieving real emissions reductions and net zero emissions by 2050 will need to be explored once the design and details are clearer.

How is Australia performing based on official figures?

The new study compared the officially reported CO₂ emissions performance of passenger and light commercial vehicles in Australia, China, the EU, Japan and the US. We found that Australian passenger car CO₂ emissions in 2021 were 53% higher than the average for these major markets.

Officially reported average fleet emissions performance for new passenger cars, comparing Australia with four major markets. (TER and ICCT, 2024)

Importantly, without effective action, this performance gap is expected to widen in the coming years. That’s because these other markets are aggressively adopting standards that encourage the transition to a low- or zero-emission fleet.

How does Australia actually compare?

The official Australian figures are based on a testing protocol called the New European Drive Cycle (NEDC). It was developed in the early 1970s.

The biggest problem is that the difference between NEDC test results and actual on-road emissions has steadily increased. Actual road emissions were estimated to be around 10% higher in 2007, growing to over 45% in 2021.

After all, the EU no longer uses the outdated NEDC protocol. It has adopted a more realistic test procedure, the Worldwide Harmonized Light-Vehicles Test Procedure (WLTP).

The briefing paper used previous research into Australian and international real-world emissions performance to provide a more accurate comparison. While the official figures suggest that newly sold Australian passenger cars have relatively high emissions, these at least appear to have improved every year. The picture is very different when we look at emissions on the road.

Estimated average real-world fleet emissions for new passenger cars, comparing Australia with four major markets. (TER and ICCT 2024)

Our estimates suggest that emissions from newly sold Australian passenger cars have actually increased since 2015. This trend is due to increasing vehicle size and weight, a shift toward more SUVs and large four-wheel drive cars, and a lack of mandatory standards or targets.

Australia’s real-world emissions performance is also much worse than the four major markets. Before 2016, the average difference was about 20% higher on average. In 2021, Australian emissions were almost 50% higher for passenger vehicles.

What does this mean for policy?

Our analysis shows that both officially reported and actual on-road CO₂ emissions from new Australian light vehicles are much higher than in other developed countries. The available evidence suggests that this poor performance will become worse if strict, mandatory standards are not introduced.

The good news is that the government is acting based on the lack of an effective standard. Mandatory standards are likely to be adopted this year. The New Vehicle Efficiency Standard should come into effect in 2025.

However, the standard must be carefully designed to achieve real emissions reductions for new vehicles.

For example, the Official Australian Test Protocol (NEDC) is outdated and increasingly underestimates on-road emissions. It produces an unrealistic and distorted picture that undermines effective emission reduction. The government says it plans to use a more realistic testing protocol.

The standards should also include on-board fuel consumption monitoring – as the EU now does. It is crucial to measure the fuel consumption and emissions of new vehicles in practice and make this information public to ensure that the standards achieve their objectives. But the latest government report made no mention of it.

A mandatory fuel efficiency standard in Australia is long overdue. It can help close the achievement gap between Australia and the rest of the world. So we better make sure it works.The conversation

Robin Smit, Adjunct Professor, School of Civil and Environmental Engineering, Sydney University of Technology

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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