ghg-inventory-1990-2013

Further details on the emission factor and activity data uncertainties for specific land uses
and non-carbon emissions are given within the relevant sections of this chapter. Further
detailed analysis of LULUCF uncertainties is presented in annex 3.2.1.
6.1.4 Recalculations in LULUCF
For the 2015 submission, New Zealand has recalculated its emission estimates for the
LULUCF sector from 1990 to 2012 to incorporate new activity data, New Zealandspecific
emission factors, improved methodology for the entire time series and to meet
the new requirement for reporting for the harvested wood products pool.
The recalculations have resulted in improvements to the accuracy and completeness of
the LULUCF estimates. An estimate of the impact of new activity data and emission
factors on the 1990 and 2012 figures has been made by excluding emissions from sources
for which reporting has changed, namely the harvested wood products pool, and
emissions from liming (this is now reported under Agriculture). Both sets of values have
also been estimated using the global warming potentials from the Contribution of
Working Group I to the Fourth Assessment Report of the IPCC (IPCC, 2007).
These estimates show emissions in 1990 have increased by approximately 23.8 per cent,
and emissions in 2012 have decreased by approximately 2.2 per cent (table 6.1.7).
Table 6.1.7 Recalculations to New Zealand’s total net LULUCF emissions for 1990 and 2012
Year
Reported net emissions
2014 submission
(kt CO 2 -e)
Change in estimate
2015 submission
(kt CO 2 -e) (kt CO 2 -e) (%)
1990 –37,615.0 –28,654.4 +8,960.5 –23.8
2012 –27,253.9 –27,848.8 –594.9 +2.2
The main differences between this submission and previous estimates of New Zealand’s
LULUCF emissions reported in the 2014 submission are the result of (in decreasing order
of magnitude):
revised estimates of carbon stock change in pre-1990 natural forest based on the first
complete set of re-measurement data for these forests. Carbon stock change estimates
in this report are based on results of the latest analysis, presented in Holdaway et al
(2014b). This has accounted for an increase in emissions of around 10,000 kt CO 2 -e
annually for every year of the inventory
a change to the pre-1990 planted forest age-class distribution to more accurately
reflect the latest available activity data on the forest class. Previously, an older ageclass
distribution was grown forward using harvesting data, but this method resulted
in a constructed pre-1990 planted forest age-class that departed from the latest
available data (Wakelin and Paul, 2012; Paul et al, 2014)
the post-1989 and pre-1990 planted forest yield tables being updated for the 2015
submission. The updates include reclassification of a small number of plots due to
mapping improvements, amendments to align with a revised estimate of net stocked
area in both forest classes and the inclusion of a sub-set of previously unused plots in
post-1989 planted forest
continued improvements to the 1990, 2008 and 2012 land-use maps. Mapping data
provided from the New Zealand Emissions Trading Scheme (NZ ETS) was
integrated into the three maps. This has improved the accuracy and consistency of the
mapping of pre-1990 planted forest and post-1989 forest
200 New Zealand’s Greenhouse Gas Inventory 1990–2013