Emissions are the release of greenhouse gases from human activities. They can be estimated in different ways, including production-based and consumption-based approaches.
The production-based approach counts the emissions from the goods and services we produce within the country, whether we use them here or export them. This approach is used to calculate gross greenhouse gas emissions for the New Zealand Greenhouse Gas Inventory, the government’s official annual estimate of all human-generated emissions and removals in New Zealand.
The consumption-based approach counts the emissions from things we consume in Aotearoa from locally produced as well as imported goods and services. This approach is like calculating the country’s carbon footprint.
Together, both methods provide a fuller understanding of where our national emissions are coming from.
New Zealand has an unusual greenhouse gas emissions profile for a developed country. In 2018, almost half of our gross emissions were from agriculture – 48% compared to 12% on average for other developed countries. Although we export many of our agricultural, horticultural and forestry products, the export emissions are still counted in our inventory. Road transport also makes a large contribution to our gross emissions (19%).
New Zealand has a relatively small manufacturing sector, so we rely on imports for many of the products we use. As a result, we import more CO2 than we export – 44% of the carbon dioxide emissions embodied in the goods and services we use happen overseas. In 2015, Kiwis were responsible for 9.3 kg of carbon dioxide per person. This per-person consumption rate is similar to other developed countries. The highest emitters were the USA with 18.1 kg/per person and Australia with 17.9 kg/per person.
Methane and nitrous oxide made up more than half of the total production-based greenhouse gas emissions in New Zealand in 2018. Because of this, New Zealand is a net exporter of greenhouse gas emissions in a consumption-based approach that includes all greenhouse gases.
Road transport made up 43% of New Zealand’s carbon dioxide emissions in 2018 – emissions from this source increased by 22% between 2009 and 2018. Cars and other passenger vehicles emitted 27% of New Zealand’s carbon dioxide emissions in 2018. The manufacturing industries and construction sector were New Zealand’s next biggest source of gross carbon dioxide emissions after transport, at 18% of our total.
Most of the country’s methane and nitrous oxide emissions come from primary industries. Aotearoa has lots of sheep, cattle, deer and goats. These animals are ruminants – microbes in their digestive tract (rumen) break down the plant materials they eat. Methane is a byproduct of their digestion process and when the animals burp, they release the gas. Nitrous oxide is also a result of animals and bacteria. The bacteria live in the soil and convert nitrogen-rich cow urine into nitrous oxide gas.
The Ministry for the Environment is responsible for leading the development, co-ordination and implementation of whole-of-government climate change policy. Other government agencies like the Ministry of Transport and Ministry for Primary Industries fund research and provide policy advice to support the reduction of emissions from their sectors.
As individuals, there are actions we can take to reduce our emissions. Most actions require us to think about our consumption of electricity, petrol, the foods we eat and the products we buy.
Nature of science and technology
Scientific and technological developments are influenced by societal needs. Both sectors are working on ways to reduce greenhouse gas emissions. For example, scientists are working to cut methane emissions by breeding sheep that burp less. They are also working to improve battery capabilities for electric transportation alternatives.
Find out how scientists measure greenhouse gas emissions.
Electric transport is one way of cutting emissions. Learn more about the carbon footprint of electric compared to petrol-powered cars.
Electric cars have been around a lot longer than you may think. Have a look at the Electric car history timeline and a Participatory Science Platform (PSP) project in Taranaki called REV it UP, where students are building an electric vehicle.
Driving us into the future is an article on electric cars in Connected 2016, Level 4, which comes with additional teacher support material.
Find out how the primary sector is collaborating to reduce climate change.
This resource has been produced with the support of the Ministry for the Environment and Stats NZ. (c) Crown Copyright.