Integrated Assessment of Climatic Impacts on Agriculture and Water Resources: From MINK to the Conterminous USA

1. Integrated Assessment of Climatic Impacts on Agriculture and Water Resources: From MINK to the Conterminous USA R. César Izaurralde, Norman J. Rosenberg, and Allison M. Thomson Joint Global Change Research Institute (JGCRI) Center for Research on the Changing Earth System (CRCES) The CRCES Workshop on Societal Impacts of Decadal Climate Variability in the United States The Hilton Waikoloa Village, Waikoloa, Hawaii 26 - 28 April 2007

2. Objectives • To describe two integrated assessments of how climatic change could affect the United States • A Methodology for Assessing Regional Agricultural Consequences of Climate Change: Application to the Missouri-Iowa-Nebraska-Kansas (MINK) Region. 1992. Agric. For. Meteor. Vol. 59(1-2). • Climate Change Impacts for the Conterminous USA: An Integrated Assessment. 2005. Climatic Change. Vol. 69. • To examine how these assessment can guide the design of future studies of the impacts of decadal climate variability (DCV) 2

3. From the MINK Region… • Study region chosen for its • Physiographic homogeneity • Socio-economic and natural-resource vulnerability to climate change • Research approach used • Historical climate records as analog of climate change (1930s “Dust Bowl”) • Biophysical modeling with EPIC previously adapted to deal with CO2 effects on photosynthesis and evapotranspiration • A set of representative farms • Weather parameters • Soils • Farm management practices • The study also considered water resources, forestry and the energy economy and integrated the results through an economic input-output model The MINK region: Missouri, Iowa, Nebraska, and Kansas 3

4. Model Validation • EPIC simulations of crop productivity using the 1951 - 1980 climate were compared against • USDA County Yield Estimates for the period 1984 - 1987 • Expert estimates of yields for each representative farm • Results of agronomic experiments • Crop yield simulations fell within 20% of USDA yields and expert estimates • Simulated yields, evapotranspiration, and water use efficiency fell well within the range of experimental results 4

5. Simulating the crop response to climate change with and without technological adjustments • Simulations were performed under the control climate (1951 - 1980) and under the analog climate (1931 - 1940) • Without adjustments, crop yields reductions ranged from 7% for irrigated corn to 25% for dryland corn and soybean • Simulated yields of dryland wheat remained unchanged by the analog climate • Simulated “CO2 fertilization effect” alleviated yield losses • Simulated adaptations with current technology (e.g. early planting, longer-season cultivars, and furrow diking) partially offset yield losses • Advanced adaptations (e.g. cultivars with higher Light Use Efficiency) ameliorated and even increased yields 5

6. Summing up the MINK experience • The MINK study evaluated the following sectors: agriculture, forestry, water resources, and energy • Results of modeling the impacts of a return to the “dirty-thirties” climate were integrated through IMPLAN, a regional scale Dept. of Commerce economic input-output model • The modeled impacts suggest a negative effect on the regional economy, but… • Allowing for sectoral adjustments (new crop cultivars, selective tree harvesting, reduced navigation on the Missouri River, etc.) the overall decline in regional production and income would not be greater than 1-2% • The major impacts would be felt in the agricultural and water sectors. A large-scale national effort at afforestation to sequester CO2 would actually affect the region’s economy positively • A post MINK thought… • Growing trees in the southeastern portion of the MINK region and cellulosic biomass crops in other portions, particularly the northwest corner could also improve the regional economy 6

7. …and now to the conterminous USA • National study reported in a special issue of Climatic Change 69(1), March 2005 • Scenarios and Context (Smith et al. 2005) • Models and Validation (Thomson et al. 2005a) • Dryland Production of Grain and Forage Crops (Thomson et al. 2005b) • Water Resources (Thomson et al. 2005c) • Irrigated Agriculture and National Grain Crop Production (Thomson et al. 2005d) • Distribution and Productivity of Unmanaged Ecosystems (Izaurralde et al. 2005) • Economic Analysis of Field Crops and Land Use (Sands and Edmonds 2005) 7

8. Integrated Assessment of Energy, Economic and Environmental Systems • MiniCAM—a full integrated assessment model • Energy-economy-emissions module • Agriculture and land use (linked to energy and terrestrial carbon cycle) • Carbon cycle (MAGICC) • Atmospheric chemistry (MAGICC) • Climate change (MAGICC) • Regional climate change (SENGEN) • SGM—full general equilibrium model • EPIC (managed ecosystems, carbon cycle) • HUMUS (hydrology) • BIOME3 (unmanaged ecosystems) Integrated Assessment Framework and Modeling Tools Used at the Joint Global Change Research Institute (PNNL / UMD) 8

9. SCENARIOS SIMULATIONS ASSESSMENT Greenhouse Gas Emissions Agriculture Land Allocation EPIC Water Demand HadCM NCARPCM Irrigated Agriculture AgLU Water Supply Economic Welfare Climate Change Projections HUMUS Hydrology Biomass BIOME3 Ecosystems Integrated Assessment of Climate Change Impacts on Agriculture, Water Resources, and Unmanaged Ecosystems 9

10. Climate Change Scenarios • Extracted from the SCENGEN system • Two General Circulation Models: BMRC (Bureau of Meteorology Research Centre) and UIUC (University of Illinois Urbana-Champagne) • Two levels of global mean temperature change (GMT): +1°C and +2.5°C • Presence (560 ppmv) or absence (365 ppmv) of CO2 fertilization effect • Sulfate aerosols in the UIUC model 10

11. Temp. Prec. Climate Change Projections Smith et al. (2005) 11

12. Changes in Dryland Winter Wheat Yield (Mg ha-1) Thomson et al. (2005a) 12

13. Regional Variability in Winter Wheat Production GMT = 1 GMT = 2.5 GMT = 1 GMT = 2.5 CO2 = 365 CO2 = 560 CO2 = 365 CO2 = 560 CO2 = 365 CO2 = 560 CO2 = 365 CO2 = 560 Thomson et al. (2005a) 13

14. Land Use – Areas of agricultural production Thomson et al. (2005a) 14

15. Changes in Annual Water Yield (mm) Thomson et al. (2005b) 15

16. Regional Impact on Water Yield (WY, mm), Runoff (Q, mm) and Evapotranspiration (ET, mm) Thomson et al. (2005b) 16

17. Seasonal Impact: Middle Columbia RiverDeviations from long-term mean water yield Thomson et al. (2005b) 17

18. Ratio: Water supply to irrigation demand for winter wheat BMRC UIUC Thomson et al. (2005c) 18

19. The IA also modeled the distribution and productivity of unmanaged ecosystems under current and future climates Izaurralde et al. (2005) 19

20. Significant changes were predicted in the distribution of unmanaged ecosystems and agricultural production areas under climate change Izaurralde et al. (2005) 20

21. Economic Analysis • The IA work also included an economic analysis of field crops and land use under climate change • The analysis used the Agriculture and Land Use (AgLU) model to simulate food consumption, food production, and land use in 14 regions of the world in 15-year time steps starting in 1990 • The presence or absence of a CO2 fertilization effect was a main determinant for yield change and economic welfare • Choice of climate change model and international trade introduced uncertainty in the analysis • A single distribution of land quality in the U.S. may affect the distribution of land use change Land allocation in the AgLU model Baseline global land use scenario Sands and Edmonds et al. (2005) 21

22. In summary… • The methodology discussed allowed for an integrated assessment of impacts and consequences of climatic change on crop production, irrigation demand, water supply, change in productivity and geography of unmanaged ecosystems, and economic impacts • The analysis demonstrated • Global implications of national scale production • Importance of GCM selection • Importance of CO2 fertilization effect on crop yields, irrigation demand and water supply 22

23. Concluding remarks in relation to the DCV Workshop • Impacts of climatic change are not simple; they ramify through the economy • Same maybe true for impacts of DCV events although these are not as unidirectional and, hence, more complicated in some ways • Integrated assessment methodologies, properly adapted, may be useful in DCV impacts research 23

24. Norman J. Rosenberg • A Biomass Future for the North American Great Plains • Toward Sustainable Land Use and Mitigation of Greenhouse Warming • The Great Plains' ecological fragility and economic weakness are attributed by many to removal of its original grass cover. Abandonment of agricultural cropping and restoration of the grass cover is one proposed solution to the region’s problems. Simulation models suggest that the agriculture and water resources of the Plains may be stressed even further as its climate changes because of global warming. This book explores the possibility that the ecology and economy of the Plains region (and similar regions) would benefit from the introduction of perennial biomass crops. Biomass production and processing (possibly aided by genetic engineering) would partially restore a perennial vegetative cover and create new employment opportunities. Biomass also offers a means of reducing fossil fuel use, providing fuel to local power plants and a feedstock for production of cellulosic ethanol, a gasoline substitute. Interest in biofuels is growing rapidly in public, political and business circles with rising fossil fuel prices and because of a growing recognition of the need for energy independence in petroleum importing countries. • From the contents: Acknowledgements.- Preface.- 1. Introduction.- 2. The Physical Environment.- 3. People and the Economy.- 4. Agriculture and Sustainability.- 5. The Wildcard of Climate Change.- 6. A Role for the Plains in Combating Climate Change.- 7. Outlook.- Section containing coloured figures. • 2007VIII, 192 p.Hardcover • Advances in Global Change Research, Volume 27 • ►€ 99.95 | £ 77.00 | $139.00 • ISBN : 978-1-4020-5600-0Published: February 2007 24