Aviation emissions would have to be cut in half and overall marine emissions would need to be reduced by 40%, provisional modelling showed.
There might also need to be greater emissions reduction from cruise ships.
The percentages are relative to a 2018-19 baseline year and indicate an appreciable cultural shift, technological advancement and substantial government spending would be needed for the city to achieve climate-change goals.
The Dunedin City Council declared a climate emergency in 2019 and announced an ambitious goal to make the city carbon neutral by 2030.
A plan in the final stage of development — covering a range of subjects including energy efficiency, reducing waste and changing transport infrastructure to "make it easier for people to travel in different ways" — is expected to come before the council next month.
References to the plan were included in the council’s draft submission to the government about the future of tourism, to be discussed by councillors today.
"Managing down emissions from the transport sector is important for achieving Ōtepoti Dunedin’s 2030 targets because transport is a high-emitting sector," the draft said.
International and domestic tourism affected the city’s emissions, contributing to roading accounting for 56% of transport emissions and aviation 4%.
Cruise vessels were not yet included in the profile "due to a lack of data", but they were a "significant source of emissions".
The council’s draft submission included suggestions for the government to invest to "improve the emissions intensity of aviation fuels" and support tourism businesses to decarbonise.
It indicated support for "use of electricity for domestic flights".
It mentioned inter-regional passenger rail, which Otago lacks, and potential for the government to help fill gaps in cycleway networks.
Regarding cruise ships, the draft submission encouraged "government support for feasibility studies and investigations into the provision of shore power to marine vessels", which might enable ships to save on fuel.
"We note the substantial upfront costs associated with any such infrastructure is currently a barrier to establishment."
Broad aspirations of the city council’s zero-carbon plan are outlined in material aimed at engaging young people.
"In a Zero Carbon Ōtepoti, catching the bus, cycling and walking will be much easier, safer and more enjoyable," a section of the council’s website said.
"Our homes will be warmer. People will be able to breathe cleaner air in the city. We will produce less waste and our community will have ready access to experiences in nature.
"By reducing our emissions here in Dunedin, we’re joining with communities all over the world working towards a positive climate future, while also improving the wellbeing of our communities."
