Rice is the seed of a grass species. The cereal grain is the most widely consumed staple food for a large part of the world's human population.
Asian farmers still account for 87% of the world's total rice production. Asia is one of the most polluted continents. Deep water rice cultivation is thought to be responsible for 11% of the anthropogenic methane emissions. On the contrary, small parcels cultivated on terraces decrease surface runoff.
Long term flooding of rice fields cuts the soil off from atmospheric oxygen and causes anaerobic fermentation of organic matter in the soil. Methane production from rice cultivation contributes approximately 1,5 % to anthropogenic greenhouse gases. Methane is twenty times more potent a greenhouse gas than carbon dioxide.