Climate Change and Agriculture     in the United States:    Effects and Adaptation        USDA Technical Bulletin 1935
Climate Change and Agriculture in the United States: Effects and Adaptation                                               ...
Table of Contents                                                                                                         ...
Table of Contents                                                                                                         ...
Executive Summary                                                                            Climate Change and Agricultur...
Executive Summary                                                                       Climate Change and Agriculture in ...
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
Climate Change and Agriculture in the United States: Effects and Adaptation
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Climate Change and Agriculture in the United States: Effects and Adaptation

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This Agriculture Department report examines the likely effects of climate change on U.S. crops and livestock during the 21st century.

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Transcript of "Climate Change and Agriculture in the United States: Effects and Adaptation"

  1. 1. Climate Change and Agriculture in the United States: Effects and Adaptation USDA Technical Bulletin 1935
  2. 2. Climate Change and Agriculture in the United States: Effects and Adaptation Table of Contents Executive Summary........................................................................................................................................................................................ 1 Key Messages.................................................................................................................................................................................................... 1 Introduction....................................................................................................................................................................................................... 2 Crop Response to Changing Climate..................................................................................................................................................... 3 Livestock Response to Changing Climate........................................................................................................................................... 4 Effects of Climate Change on Soil and Water..................................................................................................................................... 4 Extreme Events................................................................................................................................................................................................. 5 Adaptation......................................................................................................................................................................................................... 6 Research Needs................................................................................................................................................................................................ 7Climate Change and Agriculture in the United States: Effects and Adaptation Understanding Exposure...................................................................................................................................................................... 7 Understanding Sensitivity.................................................................................................................................................................... 8This document may be cited as: Enhancing Adaptive Capacity............................................................................................................................................................. 8Walthall, C.L., J. Hatfield, P. Backlund, L. Lengnick, E. Marshall, M. Walsh, S. Adkins, M. Aillery, E.A. Ainsworth,C. Ammann, C.J. Anderson, I. Bartomeus, L.H. Baumgard, F. Booker, B. Bradley, D.M. Blumenthal, J. Bunce, K. Burkey,S.M. Dabney, J.A. Delgado, J. Dukes, A. Funk, K. Garrett, M. Glenn, D.A. Grantz, D. Goodrich, S. Hu, R.C. Izaurralde, Chapter 1: U.S. Agriculture and Climate.................................................................................................................................... 9R.A.C. Jones, S-H. Kim, A.D.B. Leaky, K. Lewers, T.L. Mader, A. McClung, J. Morgan, D.J. Muth, M. Nearing, D.M. Report Goals and Scope............................................................................................................................................................................... 9O­ osterhuis, D. Ort, C. Parmesan, W.T. Pettigrew, W. Polley, R. Rader, C. Rice, M. Rivington, E. Rosskopf, W.A. Salas, Document Organization............................................................................................................................................................................10L.E. Sollenberger, R. Srygley, C. Stöckle, E.S. Takle, D. Timlin, J.W. White, R. Winfree, L. Wright-Morton, L.H. Ziska.2012. Climate Change and Agriculture in the United States: Effects and Adaptation. USDA Technical Bulletin 1935. Authors...............................................................................................................................................................................................................10Washington, DC. 186 pages. Chapter 2: An Overview of U.S. Agriculture.........................................................................................................................11 Forces Affecting U.S. Agriculture...........................................................................................................................................................12 Economic Factors and U.S. Agriculture..........................................................................................................................................12 Effects of Technology on U.S. Agriculture.....................................................................................................................................17 Climate Effects on U.S. Agriculture..................................................................................................................................................17This document was produced as part of of a collaboration between the U.S. Department of Agriculture, the University Agriculture: A Complex Social-Ecological System (SES).............................................................................................................19Corporation for Atmospheric Research, and the National Center for Atmospheric Research under USDA cooperative New Research for a Novel Challenge..............................................................................................................................................20agreement 58-0111-6-005. NCAR’s primary sponsor is the National Science Foundation. Chapter 3: An Overview of the Changing Climate..........................................................................................................23Images courtesy of USDA and UCAR. Evidence of Changing Climate Across the Globe...........................................................................................................................23This report is available on the Web at: http://www.usda.gov/oce/climate_change/effects.htm Projections of Future Global Climate..................................................................................................................................................24 Changing Climate Across the United States: The Last 100 Years...........................................................................................24Printed copies may be purchased from the National Technical Information Service. Call 1-800- 553-NTIS (6847) or Temperature............................................................................................................................................................................................26703-605-6000, or visit http://www.ntis.gov. Precipitation.............................................................................................................................................................................................27November 2012 Projections of Future U.S. Climate Change.......................................................................................................................................29 Temperature............................................................................................................................................................................................29 Precipitation.............................................................................................................................................................................................30The U.S. Department of Agriculture (USDA) prohibits discrimination in all of its programs and activities on the basis of race, color,national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, Extreme Conditions...............................................................................................................................................................................31political beliefs, genetic information, reprisal, or because all or part of an individual’s income is derived from any public assistance Changes in Tropospheric Ozone......................................................................................................................................................32program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communicationof program information (Braille, large print, audiotape, etc.) should contact USDA’s TARGET Center at (202) 720-2600 (voice and TDD). Conclusions......................................................................................................................................................................................................33To file a complaint of discrimination, write to USDA, Assistant Secretary for Civil Rights, Office of the Assistant Secretary for Civil Rights,1400 Independence Avenue, S.W., Stop 9410, Washington, DC 20250-9410, or call toll-free at (866) 632-9992 (English) or (800) 877-8339 (TDD) or (866) 377-8642 (English Federal-relay) or (800) 845-6136 (Spanish Federal-relay). USDA is an equal opportunity providerand employer. ii iii
  3. 3. Table of Contents Climate Change and Agriculture in the United States: Effects and Adaptation Climate Change and Agriculture in the United States: Effects and Adaptation Table of Contents Chapter 4: Climate Change Science and Agriculture...................................................................................................35 Chapter 6: Climate Change Effects on the Economics of U.S. Agriculture................................................99 Direct Climate Change Effects.................................................................................................................................................................35 Economic Impacts and Agricultural Adaptation......................................................................................................................... 100 Air Temperature......................................................................................................................................................................................35 Estimating Economic Impacts of Climate Change...................................................................................................................... 101 Water..........................................................................................................................................................................................................36 Sensitivity of Economic Impact Estimates to Climate and Yield Projections................................................................ 103 Atmospheric Carbon Dioxide............................................................................................................................................................36 Sensitivity of Economic Impact Estimates to Scope of Analysis......................................................................................... 104 Tropospheric Ozone..............................................................................................................................................................................38 Sensitivity of Economic Impact Estimates to Socioeconomic and Technology Projections and Indirect Climate Change Effects.............................................................................................................................................................39 Treatment of Adaptation Constraints.............................................................................................................................................. 106 Weeds and Invasive Plant Species...................................................................................................................................................39 The Changing Geography of Production................................................................................................................................... 107 Invasive Weeds........................................................................................................................................................................................41 Sensitivity of Economic Impact Estimates to Estimation Methodology......................................................................... 107 Insect Pests...............................................................................................................................................................................................44 International Effects and Food Security Implications.............................................................................................................. 108 Pathogens.................................................................................................................................................................................................49 Climate Change Effects and the Environment............................................................................................................................. 110 Conclusions......................................................................................................................................................................................................52 Climate Change, Economic Resilience, and Extreme Weather Events.............................................................................. 110 Extreme Events............................................................................................................................................................................................ 111 Chapter 5: Climate Change Effects on U.S. Agricultural Production.............................................................53 Crop Insurance..................................................................................................................................................................................... 112 Aggregate Effects..........................................................................................................................................................................................53 Workable Field Days........................................................................................................................................................................... 115 Agricultural Soil Resources.................................................................................................................................................................53 Soil Erosion............................................................................................................................................................................................ 116 Soil Degradation and Soil Erosion...................................................................................................................................................53 Conclusions................................................................................................................................................................................................... 118 Rainfall.......................................................................................................................................................................................................54 Irrigation....................................................................................................................................................................................................54 Chapter 7: Adapting to Climate Change............................................................................................................................... 119 Snow and Winter Processes................................................................................................................................................................55 Understanding Agricultural Vulnerability..................................................................................................................................... 119 Wind............................................................................................................................................................................................................55 Adaptation Drivers.................................................................................................................................................................................... 120 Changing Agricultural Production and the Effects on Soil Erosion.....................................................................................55 A Typology of Adaptation...................................................................................................................................................................... 121 Enhanced Atmospheric Carbon Dioxide.......................................................................................................................................56 Enhancing the Adaptive Capacity of Agriculture....................................................................................................................... 123 Adaptation................................................................................................................................................................................................56 Climate Policy....................................................................................................................................................................................... 124 Agricultural Water Resources and Irrigation...................................................................................................................................56 National Climate Change Adaptation Strategies.................................................................................................................... 125 The U.S. Irrigated Sector Under a Changing Climate................................................................................................................57 Agricultural Adaptation Policy....................................................................................................................................................... 125 Agricultural Water Requirements.....................................................................................................................................................57 Mitigation and Adaptation: Complement or Tradeoff?......................................................................................................... 126 Water-Supply Availability....................................................................................................................................................................57 Integrated Assessment of Mitigation and Adaptation Responses.................................................................................... 127 Returns to Crop Production...............................................................................................................................................................58 Adaptation Costs and Benefits....................................................................................................................................................... 128 Adaptation................................................................................................................................................................................................59 Limits to Adaptation................................................................................................................................................................................. 128 Ecosystem Services.......................................................................................................................................................................................59 Ecological Limits to Adaptation..................................................................................................................................................... 128 Pollinators.................................................................................................................................................................................................60 Social Barriers to Adaptation.......................................................................................................................................................... 129 Adaptation................................................................................................................................................................................................61 Assessing Options, Taking Action...................................................................................................................................................... 130 U.S. Agricultural Production....................................................................................................................................................................61 Vulnerability Assessment................................................................................................................................................................. 130 Corn and Soybean.................................................................................................................................................................................61 Assessing Adaptive Capacity.......................................................................................................................................................... 132 Rice..............................................................................................................................................................................................................63 Incremental Adaptation: Extending Existing Production Practices.................................................................................. 134 Wheat.........................................................................................................................................................................................................67 Managing Climate Risk: New Strategies for Novel Uncertainty......................................................................................... 136 Cotton........................................................................................................................................................................................................69 Conclusions................................................................................................................................................................................................... 137 Annual Specialty Crops........................................................................................................................................................................75 Risk Assessment and Climate Change: An overview.............................................................................................................. 137 Perennial Specialty Crops...................................................................................................................................................................78 Grazing Lands and Domestic Livestock.........................................................................................................................................88 Conclusions......................................................................................................................................................................................................97 iv v
  4. 4. Table of Contents Climate Change and Agriculture in the United States: Effects and Adaptation Chapter 8: Conclusions and Research Needs.................................................................................................................... 139 Climate Change and Agriculture in the United States: Exposure to Changing Climate Conditions.................................................................................................................................... 140 Effects and Adaptation Sensitivity to Changing Climate Conditions................................................................................................................................. 140 Capacity of the Agricultural System to Adapt to Changing Climate Conditions......................................................... 142 Executive Summary Research Needs........................................................................................................................................................................................... 143 Understanding Exposure................................................................................................................................................................. 144 Understanding Sensitivity............................................................................................................................................................... 144 Enhancing Adaptive Capacity........................................................................................................................................................ 145 Key Messages Understanding Basic Processes..................................................................................................................................................... 145 Climate Change and Sustainable Agriculture.............................................................................................................................. 146 Increases of atmospheric carbon dioxide (CO2), rising temperatures, and altered precipitation Appendix A: References Cited (by Chapter)...................................................................................................................... 147 patterns will affect agricultural productivity. Increases in temperature coupled with more variable Chapter 1 References......................................................................................................................................................................... 147 precipitation will reduce productivity of crops, and Chapter 2 References......................................................................................................................................................................... 147 these effects will outweigh the benefits of increasing Chapter 3 References......................................................................................................................................................................... 148 carbon dioxide. Effects will vary among annual and Chapter 4 References......................................................................................................................................................................... 149 perennial crops, and regions of the United States; however, all production systems will be affected to Chapter 5 References......................................................................................................................................................................... 155 some degree by climate change. Agricultural systems Chapter 6 References......................................................................................................................................................................... 172 depend upon reliable water sources, and the pattern Chapter 7 References......................................................................................................................................................................... 174 and potential magnitude of precipitation changes is Chapter 8 References......................................................................................................................................................................... 179 not well understood, thus adding considerable uncer- Fig. 1. Storm gathers over farmland. Image courtesy UCAR. tainty to assessment efforts. Appendix B: Glossary of Commonly Used Terms.......................................................................................................... 181 Livestock production systems are vulnerable to physiological and genetic responses may help guide temperature stresses. An animal’s ability to adjust future enhancements to weed management. Appendix C: Report Authors and Affiliations................................................................................................................... 184 its metabolic rate to cope with temperature extremes can lead to reduced productivity and in extreme cases Agriculture is dependent on a wide range of eco- death. Prolonged exposure to extreme temperatures system processes that support productivity includ- will also further increase production costs and pro- ing maintenance of soil quality and regulation ductivity losses associated with all animal products, of water quality and quantity. Multiple stressors, e.g., meat, eggs, and milk. including climate change, increasingly compromise the ability of ecosystems to provide these services. Projections for crops and livestock production Key near-term climate change effects on agricultural systems reveal that climate change effects over the soil and water resources include the potential for next 25 years will be mixed. The continued degree increased soil erosion through extreme precipitation of change in the climate by midcentury and beyond is events, as well as regional and seasonal changes in expected to have overall detrimental effects on most the availability of water resources for both rain-fed crops and livestock. and irrigated agriculture. Climate change will exacerbate current biotic The predicted higher incidence of extreme stresses on agricultural plants and animals. weather events will have an increasing influence Changing pressures associated with weeds, diseases, on agricultural productivity. Extremes matter and insect pests, together with potential changes in because agricultural productivity is driven largely by timing and coincidence of pollinator lifecycles, will environmental conditions during critical threshold affect growth and yields. The potential magnitude of periods of crop and livestock development. Improved these effects is not yet well understood. For example, assessment of climate change effects on agricultural while some pest insects will thrive under increas- productivity requires greater integration of extreme ing air temperatures, warming temperatures may events into crop and economic models. force others out of their current geographical ranges. S ­ everal weeds have shown a greater response to The vulnerability of agriculture to climatic change carbon dioxide relative to crops; understanding these is strongly dependent on the responses taken by vi 1
  5. 5. Executive Summary Climate Change and Agriculture in the United States: Effects and Adaptation Climate Change and Agriculture in the United States: Effects and Adaptation Executive Summary humans to moderate the effects of climate change. Introduction incorporate production constraints caused by changes While many agricultural enterprises have the option Adaptive actions within agricultural sectors are driven of pest pressures, ecosystem services and conditions to respond to climate changes by shifting crop by perceptions of risk, direct productivity effects of Agriculture in the United States produces that limit adaptation that can significantly increase selection, development of new cultivars in perennial climate change, and by complex changes in domes- approximately $300 billion a year in commodities production costs and yield losses. specialty crops commonly requires 15 to 30 or more tic and international markets, policies, and other with livestock accounting for roughly half the value. years, greatly limiting that sector’s opportunity to institutions as they respond to those effects within Production of these commodities is vulnerable to adapt by shifting cultivars unless cultivars can be the United States and worldwide. Opportunities for climate change through the direct (i.e., abiotic) Crop Response to Changing Climate introduced from other areas. adaptation are shaped by the operating context within effects of changing climate conditions on crop and which decision‑making occurs, access to effective livestock development and yield (e.g., changes in Plant response to climate change is dictated by a An increase in winter temperatures also affects adaptation options, and the capacity of individuals temperature or precipitation), as well as through the complex set of interactions to CO2, temperature, perennial cropping systems through interactions and institutions to take adaptive action as climate con- indirect (i.e., biotic) effects arising from changes solar radiation, and precipitation. Each crop species with plant chilling requirements. All perennial ditions change. Effective adaptive action across the in the severity of pest pressures, availability has a given set of temperature thresholds that define specialty crops have a winter chilling requirement multiple dimensions of the U.S. agricultural system of pollination services, and performance of the upper and lower boundaries for growth and (typically expressed as hours below 10°C and above offers potential to capitalize on emerging opportuni- other ecosystem services that affect agricultural reproduction, along with optimum temperatures 0°C) ranging from 200 to 2,000 cumulative hours. ties and minimize the costs associated with climate productivity. Thus, U.S. agriculture exists as a for each developmental phase. Plants are currently Yields will decline if the chilling requirement is change. A climate-ready U.S. agriculture will depend complex web of interactions between agricultural grown in areas in which they are exposed to not completely satisfied because flower emergence on the development of geographically specific, agri- productivity, ecosystem services, and climate change. temperatures that match their threshold values. and viability will be low. Projected air temperature culturally relevant, climate projections for the near As temperatures increase over the next century, increases for California, for example, may prevent and medium term; effective adaptation planning and Climate change poses unprecedented challenges shifts may occur in crop production areas because the chilling requirements for fruit and nut trees by assessment strategies; and soil, crop and livestock to U.S. agriculture because of the sensitivity of temperatures will no longer occur within the range, the middle to the end of the 21st century. In the management practices that enhance agricultural pro- agricultural productivity and costs to changing or during the critical time period for optimal growth Northeast United States, perennial crops with a duction system resilience to climatic variability and climate conditions. Adaptive action offers the and yield of grain or fruit. lower 400-hour chilling requirement will continue extremes. Anticipated adaptation to climate change potential to manage the effects of climate change by to be met for most of the Northeast during this in production agriculture includes adjustments to altering patterns of agricultural activity to capitalize For example, one critical period of exposure to century, but crops with prolonged cold requirements production system inputs, tillage, crop species, crop on emerging opportunities while minimizing the temperatures is the pollination stage, when pollen is (1,000 or more hours) could demonstrate reducedClimate change rotations, and harvest strategies. New research and costs associated with negative effects. The aggregate released to fertilize the plant and trigger development yields, particularly in southern sections of theposes unprecedented development in new crop varieties that are more resis- effects of climate change will ultimately depend on a of reproductive organs, for fruit, grain, or fiber. Such Northeast. Climate change affects winter temperaturechallenges to U.S. tant to drought, disease, and heat stress will increase complex web of adaptive responses to local climate thresholds are typically cooler for each crop than variability, as well; mid-winter warming can leadagriculture because of the the resilience of agronomic systems to climate change stressors. These adaptive responses may range the thresholds and optima for growth. Pollination to early bud-burst or bloom of some perennialsensitivity of agricultural and will enable exploitation of opportunities that may from farmers adjusting planting patterns and soil is one of the most sensitive stages to temperatures, plants, resulting in frost damage when cold winterproductivity and costs arise. management practices in response to more variable and exposure to high temperatures during this period temperatures return.to changing climate weather patterns, to seed producers investing in can greatly reduce crop yields and increase theconditions. Over the last 150 years, U.S. agriculture has the development of drought-tolerant varieties, to risk of total crop failure. Plants exposed to warm Increasing carbon dioxide (CO2) in the atmosphere exhibited a remarkable capacity to adapt to a wide increased demand for Federal risk management nighttime temperatures during grain, fiber, or fruit is a positive for plant growth, and controlled diversity of growing conditions amid dynamic programs, to adjustments in international trade as production also experience lower productivity and experiments have documented that elevated CO2 social and economic changes. These adaptations nations respond to food security concerns. Potential reduced quality. Increasing temperatures cause concentrations can increase plant growth while were made during a period of relative climatic stabil- adaptive behavior can occur at multiple levels in plants to mature and complete their stages of decreasing soil water-use rates. The effects of ity and abundant technical, financial and natural a highly diverse international agricultural system development faster, which may alter the feasibility elevated CO2 on grain and fruit yield and quality, resources. Future agricultural adaptation will be including production, consumption, education, and profitability of regional crop rotations and field however, are mixed; reduced nitrogen and protein undertaken in a decision environment characterized research, services, and governance. Understanding management options, including double-cropping and content observed in some nitrogen-fixing plants by high complexity and uncertainty driven by the the complexity of such interactions is critical for use of cover crops. Faster growth may create smaller causes a reduction in grain and forage quality. This sensitivity of agricultural system response to climatic developing effective adaptive strategies. plants, because soil may not be able to supply water effect reduces the ability of pasture and rangeland variability, the complexity of interactions between or nutrients at required rates, thereby reducing to support grazing livestock. The magnitude of the agricultural systems, non-climate stressors and The U.S. agricultural system is expected to be grain, forage, fruit, or fiber production. Increasing the growth stimulation effect of elevated CO2 the global climate system, and the increasing pace fairly resilient to climate change in the short term temperatures also increase the rate of water use concentrations under field conditions, in conjunction and intensity of climatic change. New approaches due to the system’s flexibility to engage in adaptive by plants, causing more water stress in areas with with changing water and nutrient constraints, is to managing the uncertainty associated with climate behaviors such as expansion of irrigated acreage, variable precipitation. Estimated reductions in solar uncertain. Because elevated CO2 concentrations change, such as integrated assessment of climate regional shifts in acreage for specific crops, crop radiation in agricultural areas over the last 60 years disproportionately stimulate growth of weed species, change effects and adaptation options, the use of rotations, changes to management decisions such as are projected to continue due to increased cloud they are likely to contribute to increased risk of crop adaptive management and robust decision-support choice and timing of inputs and cultivation practices, cover and radiative scattering caused by atmospheric loss from weed pressure. strategies, the integration of climate knowledge into and altered trade patterns compensating for yield aerosols. Such reductions may partially offset the decisionmaking by producers, technical advisors, changes caused by changing climate patterns. By temperature-induced acceleration of plant growth. The effects of elevated CO2 on water-use efficiency and agricultural research and development planning midcentury, when temperature increases are expected For vegetables, exposure to temperatures in the may be an advantage for areas with limited efforts, and the development of resilient agricultural to exceed 1°C to 3°C and precipitation extremes range of 1°C to 4°C above optimal for biomass precipitation. Other changing climate conditions may production systems will help to sustain agricultural intensify, yields of major U.S. crops and farm returns growth moderately reduces yield, and exposure to either offset or complement such effects. Warming production during the 21st century. are projected to decline. However, the simulation temperatures more than 5°C to 7°C above optimal temperatures, for instance, will act to increase crop studies underlying such projections often fail to often leads to severe, if not total, production losses. water demand, increasing the rate of water use by 2 3
  6. 6. Executive Summary Climate Change and Agriculture in the United States: Effects and Adaptation Climate Change and Agriculture in the United States: Effects and Adaptation Executive Summary crops. Crops grown on soils with a limiting soil Livestock production systems that provide partial acidification, salinization, toxification, and net loss of Climate change effects on snowpack have important water-holding capacity are likely to experience an or total shelter to mitigate thermal environmental organic matter. implications for surface-water availability and stored increased risk of drought and potential crop failure challenges can reduce the risk and vulnerability water reserves, particularly in the West, where much as a result of temperature-induced increases in associated with adverse weather events. Livestock Several of these processes are sensitive to changing of the surface-water runoff comes from mountain crop water demand, even with improved water-use such as poultry and swine are generally managed climate conditions. Changes to the rate of soil snowmelt. Higher temperatures will continue to efficiencies. Conversely, declining trends of near- in housed systems where airflow can be controlled organic matter accumulation will be affected restrict the snow storage season, resulting in reduced surface winds over the last several decades and and housing temperature modified to minimize or by climate through soil temperature, soil water snow accumulations and earlier spring snowmelt. projections for future declines of winds may decrease buffer against adverse environmental conditions. availability, and the amount of organic matter Stored water reserves are projected to decline in evapotranspiration of cropping regions. However, management and energy costs associated input from plants. Erosion is of particular concern. many river basins, especially during critical summerClimate affects with increased temperature regulation will increase Changing climate will contribute to the erosivity growing season months when crop-water demandsmicrobial populations Crops and forage plants will continue to be subjected for confined production enterprises. Protection of from rainfall, snowmelt, and wind. Rainfall’s erosive are greatest. As a result, agriculture may becomeand distribution, the to increasing temperatures, increasing CO2, and animals against exposure to high temperatures will power will increase if increases in rainfall amount increasingly water constrained across the centraldistribution of vector- more variable water availability caused by changing require modification of shelter and perhaps even are accompanied by increases of intensity. Shifts and southern portions of the Mountain and Pacificborne diseases, host precipitation patterns. These factors interact in methods of increasing cooling. of rainfall intensity have begun to occur in the Southwest regions, while projected precipitationresistance to infections, their effect on plant growth and yield. A balanced United States with more extreme events expected increases in the Northern Rockies and Pacific Changes in productionfood and water shortages, understanding of the consequences of management Warmer, more humid conditions will also have for the future. Although there is a general lack of Northwest could improve surface-water supplies for practices can also haveand food-borne diseases. actions and genetic responses to these factors will indirect effects on animal health and productivity knowledge about the rates of soil erosion associated those areas. effects on soil erosion form the basis for more resilient production systems through promotion of insect growth and spread with snowmelt or rain-on-thawing-soil erosion, if that may be greater than to climate change. Due to the complexities of these of diseases. Such effects may be substantial; decreased days of snowfall translate to increased The effect of precipitation changes on surface-water other effects of climate relationships, integrated research and development however, exact relationships between climate days of rainfall, erosion by storm runoff is likely to flows may be offset or compounded by temperature- change. Tillage intensity, of management practices, plant genetics, change and vectors of animal health are not well increase. induced shifts of potential evapotranspiration. crop selection, as well hydrometeorology, socio-economics, and agronomy understood. Climate affects microbial populations Higher temperatures are projected to increase both as planting and harvest is necessary to enable successful agricultural and distribution, the distribution of vector-borne Changes in production practices can also have effects evaporative losses from land and water surfaces, dates can significantly adaptation to climate change. diseases, host resistance to infections, food and on soil erosion that may be greater than other effects and transpiration losses from non-crop land cover, affect runoff and soil loss. water shortages, and food-borne diseases. Earlier of climate change. Tillage intensity, crop selection, potentially reducing annual runoff and streamflow. springs and warmer winters may enable greater as well as planting and harvest dates can significantly The resulting shifts of water stress, crop yields, and Livestock Response to Changing proliferation and survivability of pathogens and affect runoff and soil loss. Though the magnitude of crop competitiveness, in turn, will drive changes of Climate parasites. Regional warming and changes of rainfall these effects is still highly uncertain, studies have cropland allocations and production systems within distribution may lead to changes in the spatial shown potential for significant increases of erosion and across regions. Animal agriculture is a major component of the U.S. or temporal distributions of diseases sensitive to loss, in part due to a reduction of projected crop agricultural system. Changing climatic conditions temperature and moisture, such as anthrax, blackleg, biomass, which results in less overwintering residue Groundwater is a primary water source for irrigation affect animal agriculture in four primary ways: (1) hemorrhagic septicemia, as well as increased available to protect the soil. As soil erosion changes in the Plains States and an important irrigation water feed-grain production, availability and price; (2) incidence of ketosis, mastitis and lameness in dairy under climate change, so does the potential for supply for the Eastern United States, as well as areas pastures and forage crop production and quality; cows. associated, off-site, non-point-source pollution. Soil of the Mountain and Pacific West regions. While (3) animal health, growth and reproduction; and conservation practices will therefore be an important groundwater aquifers are generally less influenced in (4) disease and pest distributions. The optimal element of agricultural adaptation to climate change. the short term by weather patterns, changing climate environmental conditions for livestock production Effects of Climate Change on Soil and effects on precipitation, streamflow, and soil water include a range of temperatures and other Water Changing climate conditions over the coming evaporation can affect groundwater systems over environmental conditions for which the animal decades will also significantly affect water resources, time through changes in groundwater recharge. does not need to significantly alter behavior or Climate change effects on agriculture also include the with broad implications for the U.S. crop sector. physiological functions to maintain a relatively effects of changing climate conditions on resources Climate change will affect surface-water resources, constant core body temperature. Optimum animal of key importance to agricultural production, such which account for 58% of water withdrawals for Extreme Events core body temperature is often maintained within a as soil and water. Seasonal precipitation affects irrigated production nationally. Rising temperatures 2°C to 3°C range. For many species, deviations of the potential amount of water available for crop and shifting precipitation patterns will alter crop- Climate change projections into the future suggest core body temperature in excess of 2°C to 3°C cause production, but the actual amount of water available water requirements, crop-water availability, crop an increased variability of temperature and disruptions of performance, production, and fertility to plants also depends upon soil type, soil water- productivity, and costs of water access across the precipitation. Extreme climate conditions, such that limit an animal’s ability to produce meat, milk, holding capacity, and infiltration rate. Healthy soils agricultural landscape. Temperature and precipitation as dry spells, sustained drought, and heat waves or eggs. Deviations of 5°C to 7°C often result have characteristics that include appropriate levels shifts are expected to alter the volume and timing of can have large effects on crops and livestock. in death. For cattle that breed during spring and of nutrients necessary for the production of healthy storm and snowmelt runoff to surface water bodies. Although climate models are limited in their ability summer, exposure to high temperatures decreases plants, moderately high levels of organic matter, a Annual streamflow may increase in the northern and to accurately project the occurrence and timing conception rates. Livestock and dairy production soil structure with good aggregation of the primary eastern United States, where annual precipitation of individual extreme events, emerging patterns may be more affected by changes in the number of soil particles and macro-porosity, moderate pH is projected to increase. Precipitation declines for project increased incidence of areas experiencing days of extreme heat than by adjustments of average levels, thickness sufficient to store adequate water for regions such as the Southwest and Southern Plains droughts and periods of more intense precipitation. temperature. The combined effect of temperature and plants, a healthy microbial community, and absence will result in reduced streamflow and a shift of The occurrence of very hot nights and the duration humidity affect animal response and are quantified of elements or compounds in concentrations toxic for seasonal flow volumes to the wetter winter months in of very low (agriculturally insignificant) rainfall through the thermal-humidity index. plant, animal, and microbial life. Several processes areas already dominated by irrigation. events are projected to increase by the end of the act to degrade soils including, erosion, compaction, 21st century. The timing of extreme events relative to 4 5

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