Drivers and trade-offs of multiple environmental stressors from global rice

Rice is a staple food supplying a large share of calories in so many countries and requiring a large amount of land and water. Rice is also a substantial source of methane (CH4) emissions. In this paper, water and land use, and CH4 emissions from rice in 167 countries during the period2000-2016 are estimated.A Physical Trade Analysis based on a Material Flow Analysis is developed to estimate the virtual water, land and emissions linked to international rice trade and to final consumption. Globally, while water and land use, and CH4 emissions from rice slightly grew from 2000 to 2016 (7-8%), a substantial improvement of the production efficiency resulted in saving of 187 Gm(3) of green water, 82 Gm(3) of blue water, 40 Mha of land and 31 ktonnes of CH4 emissions (2000-2016). It implies that the main driver is the volume of rice produced. Domestic consumption covered the largest share (94%) whereas international trade had low significance (6%). However, for some Asiatic and African countries the trade contribution was relevant.The multiple assessment developed in this study allows the parallel evaluation of three environmental stressors revealing potential drivers and trade-offs among them. In particular, we find that when improving the yield by 0.5 tonnes/ha, a global reduction of about 10% for each stressor is recorded. The approach used in this paper constitutes a more advanced information for policymakersand an innovative tool upon which environmental policies may be based. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Automated summary

Rice production worldwide saw slight growth in water and land use as well as CH4 emissions from 2000 to 2016, but significant improvements in production efficiency led to substantial savings in water resources, land, and emissions. Domestic consumption covered the majority share (94%) while international trade played a less significant role (6%), although it was relevant for some Asian and African countries. Increasing yield by 0.5 tonnes/ha resulted in a global reduction of about 10% for each environmental stressor, suggesting potential trade-offs among them.