Covering Climate Now: What's driving up NZ's transport emissions?

As part of the global Covering Climate Now initiative, the Herald is dedicating a week of coverage to the issues surrounding the climate crisis. In the second of a series of in-depth interviews with leading experts on key policy areas, Herald science reporter Jamie Morton speaks with Professor Simon Kingham, a Canterbury University sustainable transport expert and the Ministry of Transport's chief science adviser, about how we tackle New Zealand's soaring road emissions.

Transport makes up just over a third of New Zealand's long-lived greenhouse gases. Since 1990, emissions from road transport, particularly, have shot up by 100 per cent. What's driven the increase?

It's pretty simple; there are more of us, we travel further, and we use fossil fuel single occupancy vehicles more than we used to.

All of these factors have led to a dramatic increase in transport emissions.

The Government recently announced a series of policy moves in the space: namely, passing a clean car import standard this year, only buying zero-emissions public transport buses from 2025, and mandating a lower-emitting biofuel blend across the sector. How far will these moves get us down the road?

All these will help, but none will enable us meet our GHG emissions targets in time. We need to do more than reduce the emissions from conventionally fuelled vehicles.

But what have been some of the biggest failures or missed opportunities to decarbonise?

We have either not understood, or ignored the fact, that if you build more roads and/or increase road capacity you induce demand.

Transport makes up just over a third of New Zealand's long-lived greenhouse gases. Photo / Brett Phibbs

In other words, if new road capacity makes it easier and/or faster to travel somewhere, more people will drive.

Even in very recent years we have continued to increase road capacity which has unsurprisingly increased vehicle kilometres travelled and hence increased greenhouse gases.

The closure of many tram routes in the 1940s and 1950s, was, with hindsight, a lost opportunity.

The Climate Change Commission has recommended that, to meet the proposed emissions budgets it set out in its draft advice, and to be on track for 2050, at least 50 per cent of all light vehicle and motorbike imports should be electric - either battery EV and plug-in hybrid - by 2027. Going by the current trajectory of EV uptake, is it fair to say this is unrealistic?

If we carry on as we are, yes, this is unrealistic.

But hopefully we will make changes. There are a number of current or proposed policies that should mean our trajectory will go up.

Given roughly 98 per cent of our light vehicles run on fossil fuels - and that our fleet is one of the oldest in the OECD - does New Zealand have a steeper path to climb than other countries do?

Definitely. Our vehicle fleet is older than many other countries, as we keep our vehicles longer.

This means more inefficient, polluting vehicles are on our roads.

Part of the problem is that cars are incredibly inefficiently used.

They spend 95 per cent of the time parked or garaged.

In other countries, shared vehicle schemes are increasingly popular. People "share" rather than own vehicles, which means the vehicles are used more.

With more trips per vehicle, the vehicles lifetime is actually shorter.

There is therefore a higher turnover of vehicles keeping the fleet up to date.

The other benefit is that as people don't have to buy a car and pay only when they use a vehicle they make a separate decision for each journey.

Research shows that as a result people sometimes choose to travel by bus, bike or not make a trip, and thus total motor vehicle trips decline.

New vehicle technologies - along with cleaner fuels and fuel pricing - are all big drivers for decarbonisation. The Government, nationally and locally, is investing in walking, cycling and public transport. What role can they have in reducing our greenhouse gas emissions?

One non-technological way – or not just electrifying our fleet - of reducing our emissions is to encourage more walking, cycling and public transport.

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These forms of transport produce far less, or no, greenhouse gases.

They can and should, be a very important part of any attempts to reduce emissions.

One recent European study suggested that cycling can be "10 times more important than electric cars for reaching net-zero cities".

How much does better networks and infrastructure matter? Are our urban centres still lacking in providing what's needed for people to train, bus, cycle or walk?

Evidence from all around the world is really clear.

If you provide good transport infrastructure people will choose to use it, whatever the mode of transport.

In New Zealand, for the past 50 years, we have mainly provided good road infrastructure and so unsurprisingly people have chosen to drive.

We're now seeing that when good public transport is available - especially rail, such as in parts of Auckland and Wellington - people choose to use it.

In Christchurch, the investment in quality cycle infrastructure is seeing more people travel by bicycle, and in places where there are pleasant car-free environments, such as the Wellington waterfront, people choose to walk.

The mantra "build it and they will come" is true for transport.

What would be the gains and benefits to society of having a greener transport sector?

There are multiple co-benefits of greener transport.

For example, evidence shows us in places where more people walk and cycle, the health of the population improves.

Some New Zealand research shows the potential for significant health and greenhouse gas emission savings through switching car trips to walking and cycling.

Other New Zealand research found communities with reduced traffic have better social and wellbeing outcomes.

There are also emerging links between transport and mental wellbeing, with a recent New Zealand report finding that noise pollution, neighbourhood severance, declining levels of active transport use from increased private car use all affect mental wellbeing.

People who walk and cycle - including e-bike users - also tend to be happier.

Reducing our emissions will lead to other health benefits.

For example, traffic-related air pollution is currently killing around 400 people per year, and noise pollution is also a problem.