A novel integrated assessment framework to inform Australia's net zero transition

Adam Castonguay, Yingying Lu, Martin Nolan, Javier Navarro, Michiel van Dijk, Raymundo Marcos-Martinez, Duy Nong, George Verikios, Stefan Frank, Enayat Moallemi, Petr Havlik, Stuart Whitten

Australia has set an ambitious goal of achieving net-zero greenhouse gas emissions by 2050. Attaining this target will require important transformations across multiple sectors of the economy. Integrated assessment models can provide valuable insights into the interactions across sectors of the economy, including land, agriculture and energy, to guide these complex transformations. However, many existing global integrated assessment models either do not include Australia as a distinct region or lack alignment with national statistics, particularly with regards to agriculture and land use change. To address these limitations, we develop an updated version of the Global Biosphere Management model (GLOBIOM), specifically validated for Australia. The model is then integrated with the Global Trade and Environment Model (GTEM), a computable general equilibrium model, enabling the projection of emissions across all economic sectors, while also providing detailed assessment of implications for the agriculture and land use sectors. The resulting emissions pathway indicates that net zero emissions would be achieved by 2040 for Australia’s agriculture and land-use change sectors, and by 2050 for the whole economy with net emissions from agriculture and land use sectors of -178 Mt CO2eq per year. This would be realised through 1.5 million hectares of additional reforested area through environmental plantings and 23.7 million hectares of regenerated native vegetation. Future improvements in the framework are expected to include the simulation of bioenergy demand and supply, and the uptake of agricultural technologies to mitigate emissions to provide comprehensive climate and agricultural policy recommendations for Australia.