Land Use Change in the Continental United States under a Multisystem Dynamics Approach: Are There Tipping Points?
Land use in US is driven by multiple forces operating at the global level, as income and population growth, yield and productivity improvement, trade policy, climate change, and changing diets. Future land use changes have implications for biodiversity, run-off, carbon storage, ecosystem values, agriculture, and the broader economy. We investigate those forces in the US and their implications from a multisector, multisystem dynamics (MSD) perspective focused on understanding dynamics and resilience in complex interdependent systems. Our modeling approach explicitly represents socio-economic behavior and natural resources, as also as interactions and feedbacks among them. Recent historical trends on land use in US show slightly increased grassland and natural forest areas and decreases in cropland. Considering multiple future scenarios of diverging strength of forces affecting land use, we project these trends are intensified under higher pressures for agriculture land or reduced under lower pressures, with no evidence of tipping points toward larger agricultural land abandonment or deforestation. However, US sectoral output and trade, fertilizer use, N2O and CH4 emissions from agriculture activities and CO2 emissions from land use changes are substantially impacted under several land use forcing scenarios. Economic growth is the major force driving future land use scenarios. Faster global economic growth can increase CH4 emissions from agriculture sector in US by 50%, land use emissions by 40%, N2O emissions and chemical use in agriculture by 20%, intensifying future environmental challenges.