In 2020 emissions from managed fills, unmanaged fills and farm dumps contributed about a third each of total waste sector emissions. With a range of other sources including composting, open burning and incineration making smaller methane contributions.
The rise and fall in historical ‘managed landfill’ emissions was largely driven by the growing tonnages of organic waste being disposed at municipal landfills. This was followed by the implementation of gas capture requirements for larger municipal landfills in 2004.
Profile of emissions from New Zealand’s waste sector by source category from 1990 to 2020
Since 2004, improvements in waste management and landfill gas capture at municipal landfills have resulted in a significant reduction of waste sector emissions.
In 2020, waste sector emissions were 17.1 per cent below 1990 levels. This highlights the positive impact of regulation of a significant proportion of municipal landfills in New Zealand.
The reduction of emissions from the waste sector is attributed to a number of initiatives implemented to improve solid waste management practices in New Zealand.
These initiatives include:
- requiring municipal landfills to meet resource consent conditions under the Resource Management Act 1991
- requiring large municipal landfills to operate landfill gas capture systems (LFG) according to the National Environmental Standards for Air Quality (2004) under the Resource Management Act 1991
- providing direction and guidance to local governments and the waste sector through the New Zealand Waste Strategy and its revision in 2010
- developing the Solid Waste Analysis Protocol to set up a consistent waste classification system, sampling regimes and survey procedures for the estimation of solid waste composition
- implementing a waste levy of NZ$10 per tonne (2009-2021) for municipal solid waste and enabling regulations to establish product stewardship requirements under the Waste Minimisation Act 2008
In 2019, 94 per cent of waste emissions were biogenic methane – largely generated by the decomposition of organic waste (such as food, garden, wood and paper waste). While waste contributes a small percentage of our total emissions, biogenic methane has a greater warming effect than carbon dioxide while in the atmosphere.
Current measures will not be enough to meet the ambitious target recommended by the Climate Change Commission of a 40 per cent reduction in waste biogenic methane emissions by 2035. However, the New Zealand waste management sector is well placed to transition to a low emissions economy over the next decades.
Significant reductions in biogenic methane emissions generated from organic waste are entirely feasible with solutions that are well proven. Many other countries have established or are in the process of adopting for example processing technologies for food waste.
The following graph shows that the cumulative impact of the waste policies in the emissions reduction plan comes close to achieving the pathway necessary to meet the first waste sector sub-target (2022–2025). This scenario also indicates that greater emissions reductions will be required from 2026–2035 to meet subsequent emissions budgets.
Total projected methane emissions from waste — showing the impact of combined waste policies and measures
(High and low impact scenarios were modelled. This graphs shows the central impact scenario only)
While technically feasible, given the high level of ambition for waste emissions reductions and the relatively short timeframe, we must act quickly to achieve this target and meet emissions budgets set by the Government for 2022-2025.
The waste chapter of the Emissions reduction plan sets out the actions that will set us on the pathway to achieving the emissions reductions we need.