- May 27, 2026
- By Cazzy Medley
Global greenhouse gas emissions from rice production have doubled in the last 60 years, despite worldwide initiatives to lower the crop’s climate impact, according to a new study from University of Maryland researchers.
Published Thursday in the journal Nature Food, it is the most comprehensive global assessment of rice-related greenhouse gas emissions to date, analyzing methane, nitrous oxide and soil carbon changes from 1961 to 2020.
Rice is a daily staple food for over half of the world’s population, and 90% of the supply comes from Asia, where the grain is cultivated in fields known as rice paddies. Rice paddies are flooded continuously, creating low-oxygen conditions that choke out weeds and allow rice to flourish. However, low-oxygen soil is also the perfect environment for bacteria that produce methane, a potent greenhouse gas driving near-term climate warming.
To meet global demand, Southern Africa, particularly Angola and Zambia, has doubled its rice paddies since 1960. Consequently, this expansion also caused the region’s methane emissions to double. In East Asia, excessive incorporation of straw in rice paddies as part of a farming method called crop residue return also drove methane increases.
The research team, including atmospheric and oceanic sciences Professor Xin-Zhong Liang, who holds a joint appointment in the Earth System Science Interdisciplinary Center (ESSIC), and postdoctoral associate Jingting Zhang, combined machine learning training on more than 21,000 field observations, a process-based ecosystem model and a global meta-analysis.
“Our findings illustrate the importance of farm management practices, but also the danger of a one-size-fits-all approach,” Liang said. “Practices that are beneficial in one area may hurt rather than help in others. We need to rethink which management solutions are actually optimal for resilience in different areas, which requires evaluating system-level interactions at local and regional scales. Beyond that, we need to make sure that this information is available to policymakers and farmers at those same scales.”