Global rice methane emissions tripled over six decades amid declining emission intensity

Le résumé fourni par la source

Abstract Rice paddies are among the largest anthropogenic sources of methane (CH4), yet substantial uncertainties persist in the long-term magnitude and spatiotemporal dynamics of the emissions. Here we show a spatially explicit global estimate of rice CH4 emissions from 1961 to 2020, leveraging a new high-resolution dataset and two Tier 3 modeling approaches (process-based and machine-learning-based). We find that global emissions have more than tripled over the past six decades, reaching a record high of 38.8 Tg CH4 yr−1 in 2020 based on the mean of the two Tier 3 estimates, both the rate and magnitude are substantially higher than conventional emission-factor-based inventories. Traditional rice-producing regions (e.g. Asia) dominated the increase due to expanded cultivation and intensified organic inputs, while Africa emerged as a rapidly growing source. Beyond trends in absolute emissions, the CH4 emission intensity (per unit of rice yield) declined across 70% of the global paddy area, mainly reflecting yield-driven efficiency gains. Notably, 44% of global rice production in the 2010 s occurs in countries with below-average emission intensity, with China being the largest contributor. By resolving long-term spatial heterogeneity with new data and models, this study provides a robust reassessment of the global rice methane budget and highlights pathways to reconcile food production with climate mitigation.

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