Lower-than-expected CH4 emissions from rice paddies with rising CO2 concentrations

Haoyu Qian, Shan Huang, Jin Chen, Ling Wang, Bruce A. Hungate, Chris van Kessel, Jun Zhang, Aixing Deng, Yu Jiang, Kees Jan van Groenigen, Weijian Zhang

Research output: Contribution to journalArticlepeer-review

41 Scopus citations


Elevated atmospheric CO2 (eCO2) generally increases carbon input in rice paddy soils and stimulates the growth of methane-producing microorganisms. Therefore, eCO2 is widely expected to increase methane (CH4) emissions from rice agriculture, a major source of anthropogenic CH4. Agricultural practices strongly affect CH4 emissions from rice paddies as well, but whether these practices modulate effects of eCO2 is unclear. Here we show, by combining a series of experiments and meta-analyses, that whereas eCO2 strongly increased CH4 emissions from paddies without straw incorporation, it tended to reduce CH4 emissions from paddy soils with straw incorporation. Our experiments also identified the microbial processes underlying these results: eCO2 increased methane-consuming microorganisms more strongly in soils with straw incorporation than in soils without straw, with the opposite pattern for methane-producing microorganisms. Accounting for the interaction between CO2 and straw management, we estimate that eCO2 increases global CH4 emissions from rice paddies by 3.7%, an order of magnitude lower than previous estimates. Our results suggest that the effect of eCO2 on CH4 emissions from rice paddies is smaller than previously thought and underline the need for judicious agricultural management to curb future CH4 emissions.

Original languageEnglish (US)
Pages (from-to)2368-2376
Number of pages9
JournalGlobal change biology
Issue number4
StatePublished - Apr 1 2020


  • climate change
  • greenhouse gases
  • meta-analysis
  • rice agriculture
  • straw management

ASJC Scopus subject areas

  • Global and Planetary Change
  • Environmental Chemistry
  • Ecology
  • General Environmental Science


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