About New Zealand's Greenhouse Gas Inventory

New Zealand's Greenhouse Gas Inventory is produced each year as part of New Zealand’s obligations under the United Nations Framework Convention on Climate Change (UNFCCC).

The inventory is the key source of evidence on New Zealand’s greenhouse gas emissions trends. New Zealand’s inventory data are used for both international and domestic reporting. The inventory informs New Zealand’s policy recommendations on climate change and enables us to monitor progress towards our emissions reductions targets.

The inventory is a Tier 1 statistic under the New Zealand Official Statistics System. This means it is one of the most important publicly available statistics for understanding how well New Zealand is performing. Tier 1 statistics are also subject to certain principles and protocols.

Tier 1 statistics [Stats NZ website]

The Ministry for the Environment produces and submits the inventory under the UNFCCC every year by 15 April.

We work closely with the Ministry of Business, Innovation and Employment, the Ministry for Primary Industries and the Environmental Protection Authority to compile the data. Many of the values used in the inventory are derived from data collated by Stats NZ. The Ministry of Foreign Affairs and Trade provides supplementary information under Article 7.1 of the Kyoto Protocol.

The inventory reports greenhouse gas emissions and removals from five sectors:

• Agriculture
• Energy
• Industrial Processes and Product Use (IPPU)
• Land Use, Land-Use Change and Forestry (LULUCF)
• Waste

Tokelau’s emissions are also reported separately by sector as ‘Other’.

Gross emissions are New Zealand's total emissions from Agriculture, Energy, IPPU and Waste sectors as well as gross emissions from Tokelau.

Net emissions are made up of gross emissions combined with emissions and removals from the LULUCF sector.

The LULUCF sector keeps track of greenhouse gases from land use (eg, for forests, crops and pasture). This is separate from the livestock emissions reported in the agriculture sector. It covers our use of soil, trees, plants, biomass and timber and is the only sector where carbon dioxide is removed from the atmosphere.

The most recent inventory report published in April 2023 covers greenhouse gases which have direct warming effects:

• carbon dioxide (CO₂)
• methane (CH₄)
• nitrous oxide (N₂O)
• hydrofluorocarbons (HFCs)
• perfluorocarbons (PFCs)
• sulphur hexafluoride (SF₆)
• nitrogen trifluoride (NF₃).

Only emissions and removals of these direct greenhouse gases are included in the national greenhouse gas total.

The inventory also reports indirect greenhouse gases but they are not included in New Zealand’s greenhouse gas total. These gases do not have a direct warming effect, but react with other gases in the atmosphere and increase the concentration of direct greenhouse gases.

The indirect gases are:

• oxides of nitrogen (NOx)
• sulphur dioxide (SO₂)
• carbon monoxide (CO)
• non-methane volatile organic compounds (NMVOCs).

International reporting guidelines govern what the inventory covers and when it is submitted. The inventory year is 15 months behind the current calendar year to give countries time to collect and process the inventory data and prepare the submission. The latest inventory, published in April 2023 contains data from 1990 to 2021 inclusively. All Annex I countries report using the same international guidelines.

For List of Annex 1 countries [UNFCCC website].

The New Zealand inventory is compiled using internationally agreed guidelines produced by the Intergovernmental Panel on Climate Change (IPCC).

2006 IPCC Guidelines for National Greenhouse Gas Inventories [IPCC website]

The New Zealand inventory is reviewed annually by a team of international experts certified by the UNFCCC. Review reports are published up to 15 months after submission of the inventory.

See the latest review report on New Zealand’s inventory [UNFCCC website].

When the methodology or underlying data change, the whole inventory time series from the base year to the latest year is recalculated. This means that the emissions estimates are only up to date in the latest inventory, and previous inventories are not useful for comparisons. Changes made to the inventory are often related to improvements in activity data collection, emission factors, and methodology, or the identification of additional emission sources.