Vulnerability of U.S. Agriculture and Energy Sectors to Changes in Climate and Socioeconomics

Tuesday, 16 December 2014: 5:48 PM
Mohamad Issa Hejazi1, Nathalie Voisin2, Lu Liu3, Lisa Bramer4, Daniel Fortin4, Maoyi Huang5, John Hathaway4, Page Kyle4, L. Ruby Leung5, Hong-Yi Li6, Ying Liu7, Pralit Patel1, Trenton Pulsipher8, Jennie Rice4, Teklu K Tesfa4, Chris R Vernon8 and Yuyu Zhou9, (1)Joint Global Change Research Institute at the University of Maryland, Pacific Northwest National Laboratory, College Park, MD, United States, (2)PNNL, Seattle, WA, United States, (3)Pacific Northwest National Lab, College Park, MD, United States, (4)Pacific Northwest National Laboratory, Richland, WA, United States, (5)Pacific NW Nat'l Lab-Atmos Sci, Richland, WA, United States, (6)Pac NW National Lab, Richland, WA, United States, (7)PNNL / Climate Physics, Richland, WA, United States, (8)Pacific Northwest National Lab, Richland, WA, United States, (9)Pacific Northwest National Laboratory, College Park, MD, United States
A prominent integrated assessment model (IAM), the Global Change Assessment Model (GCAM), has been coupled with the Community Land Model (CLM) of the Community Earth system model (CESM) to assess the vulnerability of the US agriculture and energy sectors to future water shortages under changing climate and socioeconomics. This study utilizes the regionalized version of GCAM for the U.S. with 50-state. GCAM-USA includes a detailed representation of water demands and tracks them at multiple spatial scales and annual scale. A spatial and temporal disaggregation approach is developed to project the annual regional water demand simulations into a daily time step and 1/8o spatial resolution for input to CLM, which has been coupled to a river routing model and generic water management model applicable globally at 1/2o resolution and regionally at 1/8o resolution. The coupled modeling framework demonstrated reasonable ability to simulate the historical flow regulation and water supply over the continental U.S.

The coupled modeling framework has been used to investigate: 1) Which water use sector (agriculture or energy) and subbasins in the conterminous U.S. will experience water deficits in future decades; 2) What are the drivers for the deficit (i.e., water availability, water demands, or both); 3) Will climate mitigation policies alleviate or exacerbate the situation; and lastly 4) How will the frequency , severity, and spatial extent of water deficits (hot spots) evolve under a non-mitigation scenario (RCP8.5) in which conventional fossil-fueled technologies prevail versus a mitigation scenario (RCP4.5) in which the carbon price causes a shift toward renewables and expansion of bioenergy productions. Results show that irrigation will face greater water deficit overall except in the northeastern U.S. Water deficit is greatest in the western U.S. except the Pacific Northwest. Human footprints on the regulated flows are most pronounced over the Rio Grande, Colorado, Great Lake, Great, and Missouri basins. Overall, total water deficit in term of both total volume and land area are projected to increase in the future under both RCPs.