Climate Economics Seminar: Estimating Climate Change Impacts in the Energy Demand, Water, and Agriculture Sectors in the Global Change Assessment Model
Date(s): June 4, 2013, 2 - 3:30 PM
Location: Room 4128, EPA West Building, 1301 Constitution Ave., NW, Washington, DC
Contact: Carl Pasurka, 202-566-2275
Presenter: Kate Calvin (Joint Global Change Research Institute)
Description: The Global Change Assessment Model (GCAM) is an integrated model of economic, energy, agriculture and land use, and climate systems, with 14 geopolitical regions that are further disaggregated into up to 18 agro-ecological zones. GCAM has been widely used to examine the costs and technological feasibility of greenhouse gas emissions mitigation policies. More recent model development has included expanding the model’s capabilities to estimate the impacts and economic damages associated with climate change. The study of climate change impacts in GCAM has been focused on three principal sectors and their interactions and feedbacks: energy, agriculture and land use change, and water. Recent energy-impacts work has focused on the changing energy demands on cooling and heating energy use in the building sector, including a global analysis and detailed analyses of the U.S. (50 states) and China (four climate zones). This work goes beyond the impact on total energy consumption and also examines the spatial distribution of the shift in energy sources—increased electricity consumption and decreased use of fossil fuels—due to changes in relative demand for building heating and cooling and estimates impacts on consumer expenditures. Water-related impacts work began with the development of a globally gridded hydrologic model to reproduce historical streamflow observations and simulate the future availability of freshwater under both a changing climate and an evolving landscape. A technologically oriented representation of water demand in the agriculture (irrigation and livestock), energy (electricity generation and primary energy production and processing), industry (manufacturing and mining), and municipal sectors is also developed. The combination enables the development of a water-scarcity index and the disaggregation of the relative effects of climate emission mitigation policies and socioeconomic drivers on water scarcity conditions over the 21st century both globally and regionally. Under a reference scenario with no climate change mitigation policy, almost half of the world population is living under extreme water scarcity by the end of the 21st century. Under scenarios with more stringent climate mitigation targets, water scarcity can either decline or increase, depending on whether a policy targets only fossil fuel and industrial emissions or also includes emissions from land-use change. The incorporation of climate change impacts on the agricultural sector has begun with incorporation of irrigation as a technology input. Several options for the impact on agricultural yields due to changes in temperature, precipitation, and CO2 concentrations are being explored, including econometrically-derived estimates and use of a biophysical model such as EPIC.