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Background

Greenhouse gases in the Earth’s atmosphere trap warmth from the sun and make life as we know it possible. However, since the industrial revolution (about 1750) there has been a global increase in the atmospheric concentration of greenhouse gases such as carbon dioxide, methane and nitrous oxide1. This increase is attributed to human activities, particularly the burning of fossil fuels and land-use change.

In 2007, the Intergovernmental Panel on Climate Change (IPCC) concluded that most of the increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations1. The IPCC has projected that continued greenhouse gas emissions at, or above, current rates would cause further warming and induce many changes in the global climate system during the 21st century.

This overview presents a summary of the latest information on New Zealand’s greenhouse gas emissions and removals. The information is from the most recent national inventory report (the inventory) under the United Nations Framework Convention on Climate Change (New Zealand’s Greenhouse Gas Inventory 1990–2007). This latest inventory contains information from 1990 through to the current inventory year of 2007. Each inventory report is 15 months in arrears of the reported calendar year, allowing time for data to be collected and analysed.

Greenhouse gas estimates are based on international guidance established by the IPCC and follow an internationally agreed reporting format that groups emissions and removals into six sectors:

  • agriculture
  • energy (including transport)
  • industrial processes
  • solvent and other product use
  • waste
  • land use, land-use change and forestry.

The greenhouse gases estimated in the inventory include carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), sulphur hexafluoride (SF6), perfluorocarbons (PFCs) and hydrofluorocarbons (HFCs). To compare the warming effect of different gases, all emissions are converted to carbon dioxide equivalents (CO2-e). This is achieved by multiplying emissions by the appropriate global warming potential (Table 1).

Table 1: Units and global warming potentials

Units

Standard metric prefixes used in this overview are:

kilo (k) = 103 (one thousand)
mega (M) = 106 (one million)
giga (G)= 109 (one thousand million)

Emissions are expressed in megatonnes (Mt) in this overview. Numbers are generally rounded to one decimal place (this can lead to rounding errors in some figures).

1 megatonne (Mt) = 1,000,000 tonnes = 1,000 gigagrams (Gg)

Global warming potentials

A global warming potential is an index, representing the combined effect of the differing times greenhouse gases remain in the atmosphere and their relative effectiveness in absorbing thermal infrared radiation1. For instance, one tonne of methane has the same warming effect as 21 tonnes of carbon dioxide over a 100-year time period.

The internationally agreed global warming potentials for the direct gases in the inventory are:

CO2 = 1
CH4 = 21
N2O = 310
SF6 = 23,900

For further information on the global warming potentials used within this inventory refer to http://unfccc.int/ghg_emissions_data/items/3825.php

The United Nations Framework Convention on Climate Change

The United Nations Framework Convention on Climate Change (the Climate Change Convention) is an international agreement addressing climate change. All countries that ratify the Climate Change Convention are required to tackle climate change through national or regional programmes. The long-term objective of the Climate Change Convention is to “stabilise greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system”. Developed countries agreed to non-binding targets to reduce greenhouse gas emissions to 1990 levels by the year 2000.

Developed countries that are signatories to the Climate Change Convention, including New Zealand, are required to submit an annual greenhouse gas inventory. Inventory reporting covers all human-induced greenhouse gas emissions and removals.

The Kyoto Protocol

The international community recognised that the provisions of the Climate Change Convention alone were not enough to ensure greenhouse gases would be reduced to safe levels, and that more urgent action was required. In 1997, the Kyoto Protocol was adopted, committing Annex I Parties (developed countries) that ratified it to limit or reduce their greenhouse gas emissions to an agreed target and to take responsibility for emissions in excess of their target.

New Zealand ratified the Kyoto Protocol on 19 December 2002. New Zealand’s target is to ensure that average annual emissions over the first commitment period of the Kyoto Protocol (2008–2012) are less than, or equal to, emissions in 1990. Parties can use carbon sinks and the Kyoto Protocol flexibility mechanisms, for example carbon trading, to meet their target. The Kyoto Protocol came into force on 16 February 2005.

Under Article 7.1 of the Kyoto Protocol, New Zealand is required to include supplementary information with the inventory. The supplementary information becomes mandatory for the 1990–2008 inventory to be submitted in 2010. However, in order to fully participate in Kyoto mechanisms, for example carbon trading, a Party must submit a complete inventory containing some of the supplementary information under the Kyoto Protocol from 2007 and continue to do so for all years of the commitment period.

In the 2009 inventory submission, New Zealand has reported supplementary information under the Kyoto Protocol in Annex 8 of the inventory. This includes information on transactions of transferred and/or acquired units under Kyoto mechanisms during the 2008 calendar year.

New Zealand’s national greenhouse gas inventory

In New Zealand, the inventory is managed and produced by the Ministry for the Environment. Emission and removal estimates are compiled using data from a number of government agencies, particularly the Ministry of Economic Development, the Ministry of Agriculture and Forestry and Statistics New Zealand. The inventory forms part of the Ministry for the Environment’s wider ‘state of the environment’ reporting.

The guiding documents in preparing the inventory are the Revised 1996 IPCC Guidelines for National Greenhouse Gas Inventories, the Good Practice Guidance and Uncertainty Management in National Greenhouse Gas Inventories, Good Practice Guidance for Land Use, Land-Use Change and Forestry2 and the Climate Change Convention guidelines on reporting and review3. These guiding documents contain methods to estimate emissions at different levels, starting from a Tier 1 or general approach. Higher tier or more complex methods are used for the sources and sinks with the largest emissions.

A brief overview of the methods used to estimate emissions and removals in each sector is provided below. The full inventory report contains a thorough description of the methods used in each sector.

Energy sector

The Ministry of Economic Development compiles the greenhouse gas emission estimates from the energy sector. The data used to calculate the emissions is supplied directly from industry or from Statistics New Zealand. New Zealand-specific emission factors are used for calculating carbon dioxide emissions. Applicable IPCC default factors are used for calculating non-carbon dioxide emissions where New Zealand emission factors are not available.

Industrial processes sector and the solvent and other product use sector

The Ministry for the Environment compiles the greenhouse gas emission estimates from the industrial processes sector and the solvent and other product use sector. Activity data and the associated carbon dioxide emissions are supplied directly to the Ministry for the Environment and/or the Ministry of Economic Development by industry sources. New Zealand-specific emission factors are used for calculating carbon dioxide emissions. Data for the non-carbon dioxide gases are collected via an industry survey.

Agriculture sector

The Ministry of Agriculture and Forestry compiles the greenhouse gas emission estimates from the agriculture sector. Livestock population data are obtained from Statistics New Zealand through the agricultural production census and surveys. A model with New Zealand-specific emission factors is used to estimate methane emissions from dairy cattle, non-dairy cattle, sheep and deer. This model uses New Zealand animal productivity data to estimate dry matter intake and methane production. The same dry matter intake data and different New Zealand-specific emission factors are used to calculate nitrous oxide emissions from animal excreta. IPCC default emission factors are used to calculate methane and nitrous oxide emissions for other livestock species.

Land use, land-use change and forestry (LULUCF) sector

The Ministry for the Environment and the Ministry of Agriculture and Forestry compile the emissions and removals reported in the LULUCF sector. Changes in planted forest stocks are assessed from national forest survey data and modelling of the planted forest estate. The IPCC default approach is used for the cropland, grassland, wetland, settlements and other land categories. Results from New Zealand’s Land Use and Carbon Analysis System (LUCAS) will improve the reporting for the LULUCF sector and provide consistency with reporting under the Kyoto Protocol. This information will be included in the next inventory submission in 2010.

Waste sector

The Ministry for the Environment compiles the greenhouse gas emission estimates from the waste sector. Emissions from the waste sector are estimated using waste survey data combined with population data from Statistics New Zealand. Calculation of emissions from solid waste disposal uses New Zealand-specific emission factors. Methane and nitrous oxide emissions from domestic and industrial wastewater handling are calculated using a refinement of the IPCC method and IPCC default emission factors. Waste incineration emissions are calculated using IPCC default emission factors.

International review of New Zealand’s greenhouse gas inventory

To ensure the quality of reporting meets the standards required of the Climate Change Convention, the inventory is subject to an annual international review. The results of the reviews are available on the Climate Change Convention website4.

New Zealand has consistently met the reporting requirements of the Climate Change Convention and the Kyoto Protocol. The inventory has been submitted annually within the allocated six weeks of 15 April, as required under decision 15/CMP.15.

To become eligible to participate in the Kyoto Protocol mechanisms such as carbon trading, the national system for the inventory, the national registry, and the 1990 (base year) inventory were reviewed by an expert review team in February 2007. The expert review report6 concluded that:

  • “New Zealand’s greenhouse gas inventory is consistent with the Revised 1996 IPCC Guidelines and the IPCC good practice guidance, and adheres to the reporting guidelines under Article 7 of the Kyoto Protocol
  • New Zealand’s national system is prepared in accordance with the guidelines for national systems under Article 5, paragraph 1, of the Kyoto Protocol and reported in accordance with the guidelines for the preparation of the information required under Article 7 of the Kyoto Protocol
  • New Zealand’s national registry is fully compliant with the registry requirements as defined by decisions 13/CMP.15 and 5/CMP.17.”

This progress allowed New Zealand to be one of the first four Annex 1 Parties to be eligible to participate in the Kyoto Protocol mechanisms. New Zealand’s registry for recording and holding national carbon trading units was operational on 1 January 2008.

Improvements in the 2009 inventory submission

The New Zealand inventory is under continuous improvement. The full inventory report contains a thorough description of the improvements in each sector.

During the 2008 calendar year, improvements focussed on building capacity within the national inventory system and documenting inventory procedures.

Emissions and removals for the whole time series were recalculated due to the following:

  • year-specific calorific values for all fuel types were applied to the energy sector
  • updated emission factors and assumptions, and the inclusion of new activity data within various categories of the industrial processes sector
  • activity data within the agriculture sector was updated with the latest data from Statistics New Zealand
  • updated solid waste compositional values, adjustments to wastewater activity data and corrections made to modelling errors for incinerated waste
  • revised planted forest modelling and an updated emission factor for cropland.

The overall effect of all of the recalculations is a 0.2 per cent (0.1 Mt CO2-e) decrease in emissions in 1990 and a 0.3 per cent (0.3 Mt CO2-e) decrease in emissions for the 2006 year.

 

1  IPCC 2007. Solomon S, Qin D, Manning M, Chen Z, Marquis M, Averyt K, Tignor MB, and Miller HL (Eds). Climate Change 2007: The physical science basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press: UK.

2  IPCC. United Nations Framework Convention on Climate Change. Methodology reports (see: http://www.ipcc.ch/ipccreports/methodology-reports.htm).

3  United Nations Framework Convention on Climate Change. FCCC/SBSTA/2006/9 (see: http://unfccc.int/resource/docs/2006/sbsta/eng/09.pdf).

4  United Nations Framework Convention on Climate Change. Inventory review reports (see: http://unfccc.int/national_reports/annex_i_ghg_inventories/inventory_review_reports/items/3723.php).

5  United Nations Framework Convention on Climate Change. 15/CMP.1 and 13/CMP.1 (see: http://unfccc.int/resource/docs/2005/cmp1/eng/08a02.pdf).

6  United Nations Framework Convention on Climate Change. FCCC/IRR/2007/NZL (see: http://unfccc.int/resource/docs/2007/irr/nzl.pdf).

7  United Nations Framework Convention on Climate Change. 5/CMP.1 (see: http://unfccc.int/resource/docs/2005/cmp1/eng/08a01.pdf).