See chapter 1, ‘Environmental reporting’, for more information on the core national environmental indicators and how they are used.
There are two national environmental indicators for atmosphere.
The first is a climate change-related indicator that provides information on emissions and removals of greenhouse gases. The second is an ozone-related indicator that provides information on concentrations of stratospheric ozone.
Further detail follows on the two national environmental indicators for atmosphere.
Greenhouse gas emissions and removals
This indicator is used to measure New Zealand’s contribution to global climate change.
The quantity of greenhouse gases emitted in to the atmosphere as a result of human activity in New Zealand is estimated as part of a national inventory. Gases included in this inventory are: carbon dioxide, methane, nitrous oxide, sulphur hexafluoride, hydrofluorocarbons, and perfluorocarbons. The amount of greenhouse gases removed from the atmosphere as a result of absorption by forestry is also estimated. (Greenhouse gases are removed from the atmosphere by forests, because the trees absorb carbon dioxide as they grow – these are termed ‘forest sinks’ or ‘carbon sinks’. )
Methodologies and reporting formats for use in compiling national inventories have been agreed by the parties to the United Nations Framework Convention on Climate Change (UNFCCC). These methodologies have been used in reporting the New Zealand greenhouse gas inventory.
Additional information on the atmospheric concentrations of greenhouse gases in New Zealand is also reported.
This indicator measures concentrations of stratospheric ozone over New Zealand. It is used to provide information on the condition of the ozone layer over mid-latitudes in the southern hemisphere.
To report on this indicator, the National Institute of Water and Atmospheric Research measures stratospheric ozone levels over Lauder in Central Ōtago. At this site, ozone is measured as ‘total column ozone’: the total amount of ozone in a column of air from the earth’s surface to the top of the atmosphere. Data is used to illustrate the degree of ozone depletion, or how fast the ozone layer may be recovering at mid-latitudes in the southern hemisphere.
The following additional information is also discussed:
levels of ozone-depleting substances in the atmosphere
levels of UV radiation.
Limitations of the indicators
The indicators for atmosphere measure only stratospheric ozone and the greenhouse gases covered by the UNFCCC and Kyoto Protocol (see box ‘International initiatives on climate change’). Several other gases can cause concern about the atmosphere, but these are not discussed in this report.
United Nations Framework Convention on Climate Change
The United Nations Framework Convention on Climate Change (UNFCCC) took effect in 1994. Its main objective is to stabilise greenhouse gas concentrations to prevent dangerous human-caused interference with the climate system. Developed countries that have ratified the UNFCCC have a commitment to limit greenhouse gas emissions and to protect and enhance greenhouse gas sinks. The UNFCCC requires parties to submit a national greenhouse gas inventory of emissions by source and removals by sinks for an annual technical review process. (In New Zealand, forests are the primary carbon sink.)
The Kyoto Protocol under the UNFCCC was agreed in 1997 and came into force in 2005. The protocol sets targets for the greenhouse gas emissions of developed countries for the period 2008 to 2012 (the first commitment period). For that period it aims to reduce the total greenhouse gas emissions of developed countries to 5 per cent below the level they were in 1990.
Different countries have different targets to achieve. New Zealand's target is to reduce its greenhouse gas emissions to the level they were in 1990, or take responsibility for excess emissions. Negotiations are now under way on further commitments for developed countries under the Kyoto Protocol.
Intergovernmental Panel on Climate Change
The Intergovernmental Panel on Climate Change (IPCC) was established by governments in 1988 to improve understanding of and response to climate change. The role of the IPCC is to assess scientific, technical, and socio-economic information relevant to:
the risk of human-induced climate change
global vulnerability to climate change
negative and positive consequences of climate change
options for adapting to climate change.
The IPCC also assesses options for how to limit greenhouse gas emissions and how to otherwise mitigate climate change. The IPCC assesses and develops methods and practices for the development of national greenhouse gas inventories and disseminates information about inventory methods and practices. These methodologies have been agreed by the UNFCCC for use in compiling national inventories.