urbanization, climate change, and rice crop sustainability



As the world experiences climate change and the global population continues to multiply, food security is becoming a foremost concern. Though crop yields have increased significantly due to ‘Green Revolution’ technologies, there is evidence this is leveling off. Thus, the same amount of food that currently feeds the world’s 7 billion people will need to feed 9 billion by 2050. Further, rapid rates of urbanization are taking vast amounts of agricultural land out of production, resulting in less area on which more food needs to be produced to feed growing populations. Many studies on the impacts of urbanization and climate change have been focused on China in recent years, while comparatively fewer studies have been conducted in also-booming South Asian countries. Vietnam is one of the world’s leading exporters of rice, and there is concern that the combination of urban expansion and climate change could lead to a substantial decrease in rice yields. Most of Vietnam’s rice crop is grown near Ho Chi Minh City, which is expanding toward the country’s main rice-producing region, the Mekong River Delta. The primary goal of the proposed research is to determine the sustainability of rice systems in Vietnam in the coming decades by integrating findings on agricultural land lost to urbanization, future land cover and climate scenarios, and simulations from a crop systems model that reveal how these projections could impact rice yields and productivity. To do this, this multi-disciplinary research project has the following objectives:

(1) Measure rates and patterns of urban expansion, agricultural land loss and other land cover changes in the predominantly agricultural Mekong River Delta region of Vietnam using NASA satellite data (Landsat), and discriminate changes in single- vs. multi-cropping rice systems using vegetation index trajectories;

(2) Using map outputs from Objective 1, elevation and road data within a dynamic simulation model (Land Transformation Model), develop potential land cover scenarios on urban development and agricultural transitions; and

(3) Estimate crop yields under current and future land use and climate conditions using maps and projections from Objectives 1 and 2, and a spatially-explicit crop systems model, the Decision Support System for Agrotechnology Transfer (DSSAT), which is capable of simulating the productivity of rice-cropping systems.

The primary outcome of this research – funded by NASA’s Earth and Space Science Fellowship – will be new insights into how current and future rice production will be impacted by urban expansion and climate change in Vietnam. Specifically, a series of experiments will be generated for the study region that provide detailed information on the agricultural impacts of different environmental conditions and urbanization scenarios. If simulations reveal that current cropping systems are not sustainable, this work could illuminate what is having the greatest influence on rice cropping, so that steps might be taken to mitigate the effects of urbanization and/or climate change. In addition, this project will use NASA’s rich archive of satellite imagery to generate new maps and projections for a region that is currently only mapped at a coarse scale. These datasets will be useful to a wide variety of planners, land managers, officials and researchers in the region.

Recent publications

Kontgis, C., Schneider, A., Ozdogan, M. (2015) Mapping rice paddy extent and intensification in the Vietnamese Mekong River Delta with dense time stacks of Landsat data. Remote Sensing of Environment, vol. 169, p. 255-269.

Kontgis, C., Schneider, A., Fox, J., Saksena, S., Spencer, J., Castrence, M. (2014) Monitoring peri-urbanization in the greater Ho Chi Minh City metropolitan area. Applied Geography, vol. 53, p. 377-388.

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Research questions

How are rice systems changing in the Vietnamese Mekong River Delta? How does the nexus of climate change, urbanization and crop management affect rice crop productivity?

Research team

Caitlin Kontgis, Annemarie Schneider, Mutlu Ozdogan, Jefferson Fox (East-West Center)

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