Food security in a changing world

To examine how food security might change around the world, the IIASA Ecosystem Services and Management Program used its Environmental Policy Integrated Model to examine how agricultural intensification will affect the productivity of the world’s main crops as well as its environmental effects, such as changes to the levels of nutrients, water, and organic carbon stored in the soil. In turn, this research was used to inform another of the program’s integrated models, the Global Biosphere Management Model, which is used to analyze the competition for land use between agriculture, forestry, and bioenergy.

In further work, carried our as part of the Agricultural Model Intercomparison and Improvement Project, the team showed that incorporating accurate data on soil type in such models is vital. The study was the first global assessment of the importance of soils in global crop models and showed that the effects of soil type can often outweigh the effects of weather variability—such as year to year changes in rainfall and temperature [1].

This is because soils have the capacity to amplify or buffer climate impacts, for example through the provision of water during the early stages of a drought. In extreme cases, climate change impacts on yield were either negative or positive depending on the soil type chosen for the simulation, the researchers found. In particular, for yield projections in regions that use little fertilizer or irrigation—often poorer regions with many small farms—crop yield variability related to soil type can be larger than yield variability due to weather. In places where farmers use a large amount of fertilizer, the impact of soil type was smaller.

In addition, global crop models often do not include soil management for climate resilience, nutrient management, or erosion control, all factors that can affect yield. Better soil data could therefore substantially improve projections of future crop yields, the researchers conclude.