Drivers and spatiotemporal patterns of greenhouse gas emissions from rice paddies: a global meta-analysis and future projections

Abstract Rice cultivation is a significant anthropogenic source of greenhouse gas (GHG) emissions. Reducing methane (CH4) and nitrous oxide (N2O) emissions from rice paddies is crucial for ensuring global food security and mitigating climate change. Based on a synthesis of the mechanisms underlying these emissions, this study compiled 4073 in situ methane and nitrous oxide emission observations from 23 rice-growing countries spanning 1986 to 2024, establishing a “Climate Factors/Agricultural Management Practices–GHG Flux” dataset. Using this database, a meta-analysis reveals climate change impacts: warming and elevated atmospheric carbon dioxide (eCO2) both promoted CH4 emissions, while exhibiting antagonistic effects on the overall net greenhouse gas balance (NGHGB). Concurrently, agricultural management also alters emission patterns: organic fertilizer application increased both NGHGB and greenhouse gas intensity (GHGI). Conversely, non-continuous flooding, crop rotation, and direct seeding of rice significantly mitigated NGHGB. Additionally, these driving factors exhibit complex interactions. We then estimated rice paddy GHG emissions from 1961 to 2020 using comprehensive bottom-up datasets, revealing strong spatiotemporal heterogeneity in global rice paddy GHG emissions. Finally, future emission projections based on the Shared Socioeconomic Pathways (SSPs) framework and effect sizes from meta-analyses indicate that the NGHGB from rice paddies could increase by 9% to 328% by the end of this century. In summary, the climate-adaptive paddy management strategies proposed in this study offer a scientific basis and practical reference for policymakers and agricultural producers.