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How we track our city emissions

In order to reach our net zero climate action targets, we need to regularly and accurately measure a variety of emissions across the city.

Wellington has seen population growth of 24% over the last 20 years, yet our net emissions have reduced by 7%.

Although our emissions are slowly reducing, we need to reduce our carbon at a much faster rate to reach our commitment of being net carbon zero by 2050. To do this we need to make our biggest reductions over the next decade.

2020 City Emissions Inventory

Our 2020 target was a 10% reduction from 2001 levels. As a city, we achieved an 8% gross reduction, or a 7% net reduction due to increases in forestry emissions.

Wellington City Greenhouse Gas Inventory 2020 (1.7MB PDF)

Our city inventory is calculated every few years and was completed in 2014, 2016, and 2019.

As a city, 84% of emissions are related to transport and stationary energy, such as energy use in buildings. These are the areas where we can see the greatest reductions over the next 10 years by changing how we live and move around the city.

Pie chart showing the city emissions breakdown. Transport is the largest 48.3%, Stationery energy 35.8%, Waste 7.5%, Industry 7.1%, Agriculture 1.3%.

Emissions breakdown

In the 2020 reporting year, Wellington City emitted gross 1,049,016 metric tonnes of carbon dioxide equivalent (tCO2e).

  • Transportation is the biggest source of emissions accounting for 48.3% of total gross emissions.
  • Stationary energy is the second largest emitter, 35.8% of total gross emissions.
  • Waste (7.5% of total gross emissions), industry (7.1% of total gross emissions) and agriculture (1.3% of total gross emissions) are the smaller sources of emissions in Wellington City. 

What emissions are measured

The Wellington city greenhouse gas emissions inventory aligns with the Global Protocol for Community Scale Greenhouse Gas Emissions Inventories (GPC).

The report accounts for greenhouse gas emissions of sectors within the city boundaries. These sectors are:

  • Stationary energy – includes emissions from electricity and natural gas.
  • Transportation – includes emissions from on and off-road transportation (petrol and diesel), rail, air, bus electricity, LPG, and port activities.
  • Waste – including waste originating in Wellington City from both solid waste (open and closed landfills) and wastewater.
  • Industry (industrial processes and product use) – including emissions of synthetic gases used in activities such as refrigeration, air-conditioning, fire extinguishers, aerosols, and electrical equipment production.
  • Agriculture – from within the city boundaries.

The gross total is then subtracted to reflect emissions sequestered (removed) through forestry, which provides the net emissions.

Did you know? Carbon sequestration is the process of capturing and storing carbon dioxide from the atmosphere. This is often done by planting trees and forests.

What emissions aren't measured

This inventory does not include emissions from products created outside of Wellington's boundary. For example, concrete production is high in emissions but is made outside of Wellington before being trucked in to create a new building or footpath, so it wouldn't be included.

The emissions associated with goods purchased and consumed by Wellingtonians are not included in our inventory but do need to be considered. Future city inventories may include more data from the 'stuff' we buy that wasn't made in our city.

Find out more about our Te Atakura action areas and initiatives, and what you can do about climate change.

COVID-19 impact

The 2020 inventory also illustrated the impact of the COVID-19 pandemic and lockdown of Wellington City. The city's inventory showed that emissions for the 2019/2020 year were likely reduced between 1-6% due to COVID-19 response measures, mostly from reduced transport emissions.

Wellington City GHG Inventory - COVID-19 Impact Assessment (956KB PDF)