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4 Projections Uncertainty

The projections will continue to change over the commitment period. The projection will always be based on the best information available at the date of the projection. Change will be caused by the use of the latest assumptions on variables such as economic growth or oil prices, use of the latest scientific research on emissions and removals, changes to government policy, and replacing projections with actual inventory data. For the first time, the April 2009 net position report uses provisional data for actual emissions from the agriculture and energy sectors for 2008.

The actual net position will remain uncertain until New Zealand’s national greenhouse gas inventories covering the first commitment period have been submitted, reviewed, and the review report noted by the Enforcement Branch of the Compliance Committee of the Kyoto Protocol. The internationally agreed timelines for these processes mean that New Zealand will submit its annual inventory for the 2008 calendar year (the first year of the commitment period) in 2010. New Zealand’s Kyoto Protocol compliance over the first commitment period will not be finalised until 2015.

To accommodate this uncertainty, upper and lower emissions projections are included for each sector (Figure 11). The projected net position is expected to continue to change each year as a result of new information being incorporated. The high and low estimates for each sector are reported in Table 2.

The total range of uncertainty summing across all sectors has decreased from 138.7 million tonnes reported in the 2008 net position report, to 117.7 million tonnes.

  • Agriculture: upper and lower emissions projections for the first commitment period are based on variations in animal numbers, animal performance and nitrogen fertiliser use. These variations are driven by the uncertainty in the economic factors (such as farm incomes and prices) and weather conditions (daily soil moisture deficit). These projections use current science and do not account for any future changes in science or methodology.

  • Stationary energy, transport and industrial processes: upper and lower emissions projections for the first commitment period are based on variations in the macroeconomic factors, levels of production and consumption, and policy measures. The projected energy emissions assume that a one-in-five year drought will reduce the hydro-electricity supply and increase the thermal electricity-generation emissions. Although there was a drought during 2008, for the remaining four years of the first commitment period (ie, 2009 to 2012) it is still assumed that a one-in-five year drought could occur.

  • Net removals from land use, land-use changeand forestry: upper and lower projections for the first commitment period are based on assumptions around the future deforestation and afforestation rates, the area of post-1989 forests, forest growth rates and soil carbon changes with afforestation.

  • Waste emissions: upper and lower emissions projections for the first commitment period are based on variations in the outcome of existing waste minimisation and management practices.

Land use, land-use change and forestry projections will continue to have the largest uncertainty bounds compared to all other sectors until the Land Use and Carbon Analysis System, being developed by the Ministry for the Environment, has been fully implemented. The Land Use and Carbon Analysis System will accurately map changes in the forest area since 1990. This is a requirement of reporting Article 3.3 sinks under the Kyoto Protocol. Presently the forest area estimates are based on a postal survey of forest owners known as the National Exotic Forest Description. Preliminary estimates from the mapping work are expected around mid-2009. Final forest areas will be available at the end of the commitment period.

Table 2: Projected net position over the first commitment period
(million emissions units)

Upper emissions scenarios Most likely scenarios Lower emissions scenarios
Projection of assigned amount units
Projected aggregate emissions 378.2
Stationary energy 99.6 93.0 87.7
Transport 73.6 71.9 70.4
Industrial processes 21.5 20.7 20.0
Total energy and industrial processes 194.7 185.6 178.1
Solvent and other product use 0.2
Agriculture 204.8 184.0 166.0
Waste 8.8 8.8 8.8
Projection of removal units
Removals by article 3.3 forests 70.2 92.3 115.4
Deforestation emissions –24.2 –7.3 –7.3
Net removals via forests 46.0 85.0 108.1

Note: One emissions unit is equivalent to one tonne of greenhouse gas emissions converted to carbon dioxide equivalents by its global warming potential.

Figure 11: Uncertainty range between high and low projection by sector

Figure 11: Uncertainty range between high and low projection by sector

Text description for figure 11