Review of emissions data and modelling systems (Phase 1) Report

The purpose of this report is to review greenhouse gas (GHG) emissions and climate change mitigation data and models. Building an evidence base to monitor and assess the impacts of initiatives is explicitly mentioned in Aotearoa New Zealand’s First Emissions Reduction Plan (05/2022). Economic-Environmental modelling plays an important role in decision making to achieve emission reduction targets. Data is hosted by a range of organisations and collected using different frameworks and methodologies. There is less awareness of data available through Stats NZ which may have led to it being underused. Main collated data sources are the GHG emissions account and the GHG emissions inventory. Sector specific data are available through relevant agencies. A detailed stock-take of New Zealand’s modelling capacity identified 84 climate change or climate change mitigation models: 13 multi-sector models, 23 land use and agricultural models, 25 energy models, and 23 transport models. The stock-take identified at least one model for each sector of the ERP, except for Building and Construction. Modelling capacity varies between sectors with those that are more developed, demonstrating greater interdependency between models. Almost all modelling takes a production-based approach. Capacity for a consumption-based approach was much more limited. Two examples of formal collaboration are identified through the review. No formal international collaboration (outside of international reporting requirements) was identified. A preference was expressed for modelling in-house to facilitate alignment with policy development. However, this may have contributed to lack of collaboration on progress towards common targets. Connections with groups outside of government are also limited.