How will Christchurch Ōtautahi meet its carbon goals?

Christchurch City Council has set a target of net zero greenhouse emissions (excluding methane) for the city by 2045. (here)

This follows on from our international responsibilities (e.g. Paris agreement) and national policies (e.g. zero carbon act), while also being based on what locals want.

In 2019 Council surveyed 2,724 locals about climate change. 77% said it was an “extremely important” issue, 84% thought it was going to have a big impact on them, 77% felt that New Zealand businesses were not doing enough to address climate change, 68% felt that Central Government was not doing enough, and 61% felt that Christchurch City Council were not doing enough.

Transport is the city’s biggest emitter, pumping out 2.5 million tonnes of carbon every year – equivalent to 53% of the city’s total emissions.

We clearly need to do something about this, but there are a lot of different views on what exactly this is.

There has been a flurry of articles lately about how to reduce carbon emissions from transport in cities. Auckland Transport did some modelling that suggested the things which will make the biggest dent in our emissions is electric cars, higher taxes on petrol/diesel, and the introduction of road pricing. It suggested that the things that have relatively little impact are low emission buses, improved walking and cycling facilities, and a more compact city. Greater Auckland wrote an article on it here, arguing some of the smaller bubbles would actually be much larger if modelled slightly differently, and that many important bubbles are not included in the modelling (e.g. road reallocation).

MRCagney did some different modelling here, which the NZ Herald reported on. This suggested that a range of interventions are needed. Each one on its own has a limited impact, but when implemented together they do have the potential to reduce our emissions to the levels required.

There is some consistency here with AT’s modelling. Again, the things that have relatively little impact are public transport initiatives and cycling increase. The things with a bigger impact are the things that remove petrol and diesel cars from our cities – reduction in trips and replacement with electric/cleaner cars.

To date, New Zealand cities have tended to focus on the interventions that have the smallest impact, at least according to this modelling. We’ve done a lot of work making the alternatives to driving far more attractive. Christchurch has been busy building a citywide network of safe cycleways. They’ve done this very successfully, and it has indeed resulted in big increases in the number of people riding bikes. Auckland has invested in its public transport, again very successfully, with big increases in the number of people training and bussing. Christchurch has recently agreed to a plan to significantly boost investment in public transport in Christchurch, with associated growth in patronage forecast. But the diagrams above show all these measures are likely to have a relatively small impact on carbon emissions.

To reduce transport emissions you have to reduce the number of people driving fossil fuel vehicles. Making public transport and biking more attractive does result in people switching, but the trouble is that the road space that gets freed up just gets filled up again with other people driving.

The only way to really make a big dent in our emissions is to have fewer people driving fossil-fuel vehicles, and the only way you’ll get this is by making it harder and/or more expensive. There are lots of ways to do this – increase parking costs, introducing road pricing, increasing fuel taxes, reducing capacity on our roads, or just outright banning fossil fuel vehicles (as many other countries are doing). But we’ve tended to avoid them because they involve difficult conversations.

One thing that makes these very hard politically to implement is when people don’t have viable alternatives. Auckland is looking more and more seriously at introducing road pricing, but the primary thing holding this back is that people don’t feel they have any choice in their transport mode – there is no decent public transport or safe cycleways. Nick Lovett writes here that:

With London, Stockholm and Singapore proving the concept in the twenty-first century, transport pricing is beginning to look more like an inevitability.

Nick Lovett

It hasn’t really come through in this modelling above but one important point from other unpublished modelling I’ve seen is that interventions for reducing carbon emissions tend to amplify eachother, so the combined impact is greater than the sum of the individual impacts. For example, if you increase parking costs and improve public transport together, the reduction will be greater than the sum of doing each of these on their own. And if you combine these two with building cycleways as well the reduction will be greater again.

So what does Christchurch need to do to reduce it’s transport emissions? I don’t think we’re especially different to most other cities on earth, and we can learn from what others are doing and planning. From what I’ve seen so far, I suspect the way forward is a holistic programme of works that would include:

1. Reducing attractiveness of driving petrol/diesel cars:
   • Increase cost – the fairest way is through a combination of road pricing and increased fuel excise. Increased parking charges might be an easier interim option.
   • Reduced level of service – reallocate roadspace from traffic/parking lanes to footpaths, cycleways, grass and trees, public realm etc.
   • Allow higher density development throughout our urban areas.
2. Increased attractiveness of alternatives:
   • Improve walking – allow higher density development, reduce traffic through residential neighbourhoods, lower speed limits
   • Improve cycling – Complete cycleways programme, then expand to fill in the gaps.
   • Improve public transport – implement bus improvements, electrify fleet, reduce fares for targetted groups investigate and implement MRT,
   • Potentially subsidise electric cars. I don’t really like this but it’s such an easy one politically that it is probably inevitable.

Every one of these things has been looked at in some capacity, but from what I’ve seen, they tend to be looked at as separate projects. This means the analysis doesn’t fully appreciate what would happen if you did them all together as an integrated programme.

I’d really like to see a piece of work done looking at different combinations of these to see what the combined impact would be on emissions.

I suspect if this was done, we’d see that some combination of these would get us a long way towards our goal.

What do you think about how to reduce carbon emissions from transport?