Independent rice paddy methane model validated for global applications: Study highlights emission mitigation potential

Rice paddies, responsible for approximately 10% of global anthropogenic methane (CH₄) emissions, are increasingly recognized as a key contributor to global warming. Reducing emissions from rice cultivation is essential to achieving international climate goals, especially in light of commitments to carbon neutrality and peak emissions targets.

A team led by Prof. LI Tingting from the Institute of Atmospheric Physics at the Chinese Academy of Sciences has validated an independently developed methane emission model, CH4MOD, at the global scale. This research highlights the advantages of process-based models over the commonly used emission factor method. While the emission factor method relies on generalized estimates that often overlook environmental and management complexities, CH4MOD provides a detailed simulation of methane production, oxidation, and emissions, considering factors such as climate, soil properties, organic matter, and water management practices.

The study, published in iScience, validated CH4MOD using 986 methane flux observations worldwide. The model showed strong agreement with observed data, achieving a correlation coefficient of 0.76 and a model efficiency of 0.78. These results confirm CH4MOD’s ability to more accurately simulate rice paddy methane emissions under diverse conditions and management practices.

“Our findings demonstrate how mechanistic models like CH4MOD can reduce uncertainties in methane emission inventories and enable more effective mitigation strategies,” said PLI.

The study found that methane emissions could range from 8 to 78 Tg CH₄ annually under different management scenarios. This variability underscores the significant opportunities for mitigation by adjusting practices such as water management and organic matter use.

HU Qiwen, a visiting Ph.D. student at Sun Yat-sen University, is the first author of the paper. The research also represents a collaborative effort among researchers including Prof. QIN Zhangcai (Sun Yat-sen University), Prof. HUANG Yao (Institute of Botany, CAS), Prof. Josep Canadell (Global Carbon Project), Prof. YUAN Wenping (Peking University), and Assoc. Prof. YANG Jinyang (Nanjing Agricultural University).