Future spatially explicit patterns of land transitions in the United States with multiple stressors

Key Points
● Coupling socio-economic and land-use downscaling models advances capabilities in
representing natural and human systems interactions.
● With global pressures on food systems the U.S. shifts from cropland to pastures due to
comparative advantage in livestock.
● Spatial specificities drive heterogeneous land use changes responses across the sub-basins of
the Mississippi.

Abstract
Climate change, income and population growth, and changing diets are major drivers of the global
food system with implications for land use change. Land use in the U.S. will be affected directly by
local and regional forces and indirectly through international trade. In order to investigate the effects
of several potential forces on land use changes in the U.S., we advanced capabilities in representing
the interactions between natural and human systems by linking a multisectoral and multiregional
socio-economic model of the world economy to a model that downscales land use to a 0.5°grid scale. This enables us to translate regional projections of future land use into higher-resolution
representations of time-evolving land cover (effectively spatially explicit land use transitions). 

We applied the framework over the U.S., with a particular interest in the Mississippi River Basin and its four sub-basins, to consider how a range of global drivers affect land use and cover in the target
regions. Our results show that under scenarios of high pressure on the world food system, a
comparative advantage in livestock production amplifies the recent trend toward less cropland and
more pastures in the U.S. Under low pressures on the world food system, agricultural land is used less intensively. However, there can be key differences among the various land-use transitions at the sub-basin scale. 

Overall, these results highlighted the need for high resolution details to explicitly understand the implications of land use change on environmental impacts such as carbon storage, soil erosion, chemical use, hydrology, and water quality.

Plain Language Summary
Several domestic and international forces and drivers impact how land is allocated among different
uses in the U.S. We developed scientific models and tools to investigate at a fine spatial resolution the potential effects of such drivers on land allocated to crops, pastures and forests. In particular, we
assess the effects in four sub-basins of the Mississippi River from a range of global pressures and
drivers, such as population growth, economic development, change in diets and climate change
impacts on crop yields. We show that the U.S. tends to increase pastureland area in the long run at
expenses of cropland under higher population growth and other economic pressures, since livestock
production in the U.S. is relatively more advantageous than in other parts of the world. However,
patterns of land use changes are different across regions and sub-basins inside the U.S. Our results
highlight the value of high resolution representation of land use allocation which can be used to
understand environmental impacts, such as carbon storage, soil erosion, chemical use, hydrology, and water quality.