Modeling the economic and environmental impacts of land scarcity under
deep uncertainty
Abstract
Land scarcity is increasing over time, driven by complex multi-sector
dynamics. The impacts of land scarcity on the economy and environment
are multi-faceted and regional, so any action to convert land will
contain inherent tradeoffs. These impacts are complicated by the deeply
uncertain evolution of the various sectors influencing land scarcity. A
need therefore exists to provide multi-metric and multi-sector
assessments that are robust to myriad uncertainties. Land conservation
effectively limits the supply of productive land, while biofuel
consumption increases the demand and competition for that land, and how
these dynamics individually and jointly propagate to economic and
environmental impacts is an important open question. To address this, we
adopt the Global Change Analysis Model (GCAM) that has representations
of various important sectors including the climate, land-use economy,
energy systems, agriculture, and water resources. Scenarios of increased
land demand (from biofuels) and decreased land supply (from
conservation) under various socioeconomic pathways drawn from the SSPs
were simulated using GCAM. We find that while biofuel consumption and
land conservation reduce carbon emissions, this comes at the cost of
higher food prices, reduced crop production, and increased water
withdrawals. Additionally, some regions experience these tradeoffs more
severely than others and are more heavily impacted from the same biofuel
mandate or by an additional percent of protected land. These and other
findings highlight the importance of multi-sector modeling frameworks
that capture many cross-sector linkages, and acknowledge the important
uncertainties confronting the human-Earth system when making any
analysis of the land scarcity impacts.