October 16, 2025
This study assesses the natural- and human-caused sources and sinks of methane (CH4) and nitrous oxide (N2O) in Australia and New Zealand, together referred to as the Australasian CH4 and N2O budgets, for 2010 to 2019. We estimate that Australasia emitted 14.1 Tg of CH4 over the past decade, with Australia contributing 84% and New Zealand 16% of the total emissions. However, an independent analysis using satellite and ground-based observations suggests these CH4 emissions may be 25% lower. For the N2O budget, Australasia emitted 0.8 Tg of N2O per year, with 91% of these emissions originating in Australia. In contrast to the CH4 budget, an independent assessment based on ground-based observations, indicates that actual N2O emissions may be around 62% higher. Reducing the large uncertainties in CH4 (e.g., emissions from natural wetlands) and N2O (e.g., emissions from natural soils) fluxes is essential to understand better the scale of these natural sources and their potential for future impacts on climate change.
Key points:
Anthropogenic activities drive 55% of Australasia’s CH4 budget, natural sources 45%, with wetlands contributing 42%, though uncertain
Natural sources dominate 82% of Australasia’s N2O budget, anthropogenic 18%, with Australia contributing 92% of total N2O emissions
Australia’s CH4 and N2O top-down and bottom-up budgets align within uncertainties, while New Zealand shows major discrepancies
Read more > Yohanna Villalobos, Josep G. Canadell, Elizabeth D. Keller, Peter R. Briggs, Phillip Ford, Ian N. Harman, Timothy W. Hilton, Allison Hogikyan, Ronny Lauerwald, Damien T. Maher, Adrien Martinez, Naiqing Pan, Benjamin Poulter, Laure Resplandy, Judith A. Rosentreter, Marielle Saunois, Hanqin Tian, Jacob Yeo, Zhen Zhang, https://doi.org/10.1029/2024GB008484
