National Outcome 3: Greenhouse Gases
Improved measurement and mitigation of greenhouse gases from the terrestrial biosphere
Background
For New Zealand to meet its international greenhouse gas reporting obligations, it is necessary to have a robust inventory of net emissions and carbon storage at a national scale. As the global community, including New Zealand, considers how best to agree and set a new suite of national emissions reduction targets later this year, it will be important for New Zealand to be able to model the environmental and economic impacts of proposed emissions reduction targets, and have access to effective mitigation options for reducing net emissions.
The science challenges are substantial, as are the policy and land management challenges. Collaborative partnerships between research groups, government agencies and the primary industries sector are the key to meeting these challenges and delivering the National Outcome.
Impact 3.1: The status of terrestrial greenhouse gas emissions and removals are known, and changes in relation to management strategies, land-use policies and global change are forecast
Core Funding Investment
Key Performance Indicator 3.1: MPI and MfE are using verified estimates of greenhouse gas emissions and carbon storage to reduce uncertainty in national inventories
Core-funded progress for 2015/16 is reported in the achievements table, particularly under:
Highlights
Supporting decisions on New Zealand commitments in Paris: We summarised available information on soil carbon stock changes in New Zealand for MPI. This included an analysis of consequent implications for New Zealand’s national greenhouse gas reporting obligations, as well as in terms of meeting any future national greenhouse gas reduction target. Our work was used to inform both governmental consideration of potential risks and opportunities in the lead up to the Paris Climate Conference in December, and New Zealand’s negotiating position in respect to emission reduction targets likely to be set at the Conference.
Refining New Zealand’s national inventory: Emission factors are key to models that predict greenhouse gas emissions nationally, and so underpin global inventories (e.g. Intergovernmental Panel on Climate Change). We demonstrated large variation in nitrous oxide emissions from fertiliser urea and farm dairy effluent. Urease and nitrification inhibitors produced no consistent reduction in emissions, showing that the effects of nitrification inhibitors on nitrous oxide emission can vary with the type of nitrogen input, management history, and other site specific factors.
Carbon in old trees vulnerable to climate change: We calculated national-scale carbon stocks and stock changes in New Zealand’s natural forests and showed that disturbance is the primary driver of net carbon change, rather than climate or soil fertility. Climate change is forecast to increase both the frequency and intensity of disturbance, presenting a concern for maintaining carbon stocks in natural forests (for example, as part of any new international climate change regime that required national-scale accounting of carbon stocks, similar to the Kyoto Protocol). Our research suggests that old growth forests, where much of the carbon is held in just a few large trees, will be most vulnerable to significant carbon losses under a future of more frequent and intense disturbances.
Impact 3.2: Land-use options, asset management, and other methods that increase carbon storage and mitigate greenhouse gas emissions are understood and balanced for environmental, economic and social benefits
Core Funding Investment
Key Performance Indicator 3.2: Validated methodologies and land use practices to mitigate greenhouse gas emissions and increase carbon storage and adapt to likely climate change effects
Core-funded progress for 2015/16 is reported in the achievements table, particularly under:
Highlights
Environmental regulation of soil carbon turnover: Using analyses of soil samples from the National Soils Archive collected at different times, we linked multiple environmental factors to the composition of soil organic matter to improve understanding of the make-up and persistence of soil organic carbon in the environment. This work will contribute to recommendations to landowners and industry for greater land-based carbon sequestration.
Better quantifying council emissions: We provided a strategy to the Kapiti Coast District Council for measuring methane and nitrous oxide emissions from composting sewage sludge. This work will help the Council better reduce its greenhouse gas emissions from this source, and also improve reporting as part of its inventory reporting on emissions from waste.
Refining dairy effluent emission factors: We worked with AgResearch to review the most significant variables influencing the greenhouse gas emission factor for farm dairy effluent (FDE) for MPI. We assessed the efficacy of expressing the emission factor for FDE as a percentage of inorganic nitrogen applied and refined New Zealand’s country-specific emission factors for urea fertiliser and FDE. This highlighted the need for adequate consideration of soils, climate, and farming systems in country-specific emission factors.