CNH: Climate Change, Hydrology, and Landscapes of America's Heartland: A Multi-Scale Natural-Human System

农业景观是自然与社会的关键，它能很好地适应社会经济力量和气候，但两者都在不断变化。这个跨学科的研究项目将调查预期的气候变化对美国中部农业中心地带的影响，以及对气候变化的适应将如何产生新的景观模式。作为一个具有气候、农业技术、市场和政策反馈的自然-人类耦合系统，未来的景观将在水量、水质和农业生产方面不同于当前的模式。研究人员将把注意力集中在三个核心研究问题上：(1)21世纪的气候变化，以及不断变化的市场和政策环境，将如何影响从整个美国中部到宏观尺度地区（如“玉米带”）到中尺度流域到单个农场和田地的不同尺度的土地利用模式？这将如何改变农业生产的地理格局？(2)在什么样的政策和价格下，气候变化引起的景观变化通过农业景观碳储量、蒸散发和反照率的变化产生正反馈或负反馈？(3)气候变化是扩大还是减少具有农业代表性的中尺度流域的农业生产和生态系统服务生成能力？这些问题将通过相关的方法得到解答，首先是根据IPCC 2020-2025年、2030-2035年、2060-2065年和2095-2100年的第五次评估报告缩减温室气体排放情景，这将推动基于主体的农民行为模型。从这些情景中，利用NASS/USDA耕地数据层的土地利用变化模型将生成美国农业中心地带最有可能的景观。SWAT流域模型随后将用于估算河流流量、沉积物和养分负荷，并将其与EPIC的碳储量估算结合使用，在遗传算法中推导出每种气候情景下每个时间段每个代表性流域的生态经济生产可能性边界。研究人员假设，气候变化将减少某些地区的农业和生态潜力，例如通过减少水资源供应，而气候变化将在其他地区扩大，例如通过延长生长季节，但是这些影响将受到市场和政策发展的极大影响，例如生物燃料生产和碳信用额。本项目将加强对气候变化在各种政策和激励机制下影响农业用地和水资源方式的基本认识。项目成果将促进早期适应，并及时为农业、环境和贸易政策的成功整合做出贡献。地图将显示哪些地区的种植模式和相关的农业收入、水量和水质最有可能发生变化，这些地图将分发给广大科学界和美国农业部及其他相关政府机构的相关决策者。初中和高中教师将直接参与教学模块的开发，这些模块将通过CD/ROM分发，并与现有的教育政策和实践相一致，将系统中的积木概念和自然-社会互动的建模方法引入6-12年级的科学和9-12年级的社会研究教育。本项目由美国国家科学基金会自然与人类系统耦合动力学（CNH）项目资助。

A lynchpin between nature and society, agricultural landscapes are finely adapted to socioeconomic forces and climate, yet both are now in flux. This interdisciplinary research project will investigate the effects of anticipated climatic change on the agricultural heartland of the central United States and how adaptations to climate change will generate new landscape patterns. As a coupled natural-human system with climatic, agrotechnology, market, and policy feedbacks, future landscapes will differ from current patterns in terms of water quantity, water quality, and agricultural production. The investigators will focus their attention on three central sets of research questions: (1) How will 21st-century climate change, together with changing market and policy environments, affect land-use patterns at various scales ranging from the central U.S. as a whole to macroscale regions like the "Corn Belt" to mesoscale watersheds to individual farms and fields? How will this change the geography of agricultural production? (2) Under what policies and prices does landscape change induced by climate change generate a positive or a negative feedback through changes in carbon storage, evapotranspiration, and albedo in agricultural landscapes? (3) Will climate change expand or diminish the agricultural production and ecosystem service generation capacities of mesoscale watersheds representative of agricultural regions? These questions will be answered using linked methodologies, starting with downscaling of greenhouse gas emissions scenarios based on the 5th Assessment Report of the IPCC for 2020-2025, 2030-2035, 2060-2065, and 2095-2100 that will drive agent-based models of farmer behavior. From these scenarios, land-use change models utilizing the NASS/USDA Cropland Data Layer will generate most-likely landscapes for the American agricultural heartland. The SWAT watershed model then will be used to derive estimates of stream flow, sediment, and nutrient loads, which will be used in conjunction with carbon storage estimates from EPIC in a genetic algorithm to derive ecological-economic production possibility frontiers for each representative watershed for each time period for each climatic scenario. The investigators hypothesize that climatic change will diminish agricultural and ecologic potentials in some regions, such as through reduced water availability, while it will expand in other areas, such as through lengthening of the growing season, but these effects will be greatly influenced through market and policy developments, such as biofuel production and carbon credits. This project will enhance basic understanding about the ways that climate change will affect agricultural land use and water resources under various policies and incentive structures. Project results will facilitate early adaptation and make a timely contribution to the successful integration of agricultural, environmental, and trade policy. Maps that will show where cropping patterns and associated agricultural revenues, water quantity, and water quality are most likely to change will be disseminated to the broad scientific community and relevant policy makers in USDA and other relevant governmental bodies. Middle and high school teachers will be directly involved in developing teaching modules, distributable by CD/ROM and consistent with existing educational policies and practices, to bring building block concepts in systems and modeling approaches to nature-society interaction to Grade 6-12 science and Grade 9-12 social studies education. This project is supported by the NSF Dynamics of Coupled Natural and Human Systems (CNH) Program.