Using Iclus V2 to Characterize Global Change Impacts, Vulnerabilities, and Adaptation Opportunities (Presentation)
We found that VMTs increase in all states by 2050 under all scenarios, despite overall densification of human settlement, as a result of national-level population growth, with some differences resulting from the relative proportion of growth in urban vs. exurban and rural areas. Despite this across-the-board increase in VMTs, however, passenger vehicle emissions decrease, substantially in some states, as a result of assumed tightening of emissions standards that offsets the increase in VMTs. In addition, while densification should in principle lead to reductions in per-person VMT, as a result of altered driving habits, some states (e.g., CA) showed slight increases in VMTs with increased density, as a result of shifts toward more sprawling development patterns of some of the higher-density land-use classes. In other states (e.g., VA), density-driven changes in driving habits helped contribute to the overall reduction in emissions.
The research also finds that after accounting for urban growth, temperature and precipitation changes, and land use shifts between agriculture and forestry, the extent of U.S. cropland increases through 2100 under four equally plausible scenarios. The increase was observed both in absolute terms, as well as relative to a baseline FASOM projection that uses older urban growth projections, and does not include changes in temperature and precipitation. The primary driver of this growth was a national reduction in crop yields, although some crop-region-scenario combinations ran counter to this trend. In all four scenarios, cropland area increased significantly in the Northern Great Plains, as did nitrogen fertilizer applications.
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