Methane emissions from rice paddies in the Yangtze River Delta region of China: synthesis of new estimates

Agriculture (e.g., rice paddies) emissions have been considered one of the main sources contributing to the revived atmospheric methane (CH₄) increase since 2007 while it remains debated. In this study, we synthesized available paddy field CH₄ emissions from publications in a representative region of China. The results showed that CH₄ emissions exhibited strong variation among the 416 samples. Compared to the period 2000–2009, CH₄ emissions significantly (p < 0.01) increased during 2010–2018 and the average (252.17 kg ha^-1) was 1.52 times higher than that in 2000–2009 (146.02 kg ha^-1), which was consistent with the trend of atmospheric CH₄ concentrations. CH₄ emissions were significantly affected by both air temperature and water saving practices, however, this was not likely the reason for the increase after 2009. This study provides a quantitative estimate of regional CH₄ emissions based on available data, although the connection with the revived atmospheric CH₄ increase since 2007 remains uncertain.