Rice Paddy Emissions Nearly Doubled Since 1960s, Study Finds

Greenhouse gas emissions from rice paddies have nearly doubled globally since the 1960s, according to research published in Nature Food. 1 billion tons of carbon dioxide-equivalent during the 2010s, an amount comparable to the yearly output of 239 million cars.

Just over half of the rise came from expansion of rice-growing areas, with the area in Africa roughly doubling since the 1960s. Intensified practices also contributed, including a 76 percent increase in synthetic nitrogen fertilizer use after 2000 and greater application of crop residues such as straw and manure.

Plowing rice stalks back into fields after harvest accounted for about 18 percent of the net emissions growth. Rising temperatures further accelerated microbial activity that produces methane in flooded soils.

The study examined three modeling approaches covering data from 1961 to 2020. Researchers concluded that combining reduced fertilizer and residue use, intermittent flooding, and lower tillage could cut global rice emissions by about 10 percent by midcentury without lowering yields.

No single practice proved optimal in every region. The authors stated that additional strategies beyond current methods will be required for larger reductions.