当今世界，外部冲击对全球粮食安全的影响频繁发生，全球气候变暖加剧且影响持续发酵，多次诱发全球粮食安全危机，给全球粮食系统和世界安全带来严峻挑战。在全球气候变化的背景下，粮食安全已成为全球可持续发展目标的核心议题，直接影响世界各国制定安全政策、促进农业可持续发展和构建人类命运共同体的战略全局。粮食安全是一个综合性概念，如何评价粮食安全是一个复杂的科学问题，涉及多个维度、多项指标和多种因素。已有相关研究较少利用跨学科方法深入探讨多尺度、多维度、多因素的粮食安全变化问题。如何在气候变化经济学分析框架下，构建一套能系统评估粮食安全的指标体系和方法，准确监测全球粮食安全的时空演变，厘清影响粮食安全变化的驱动因素及其作用机制，成为亟待解决的重要科学问题。
       本论文在已有研究的基础上，从经济学、气候变化科学、粮食安全等学科交叉的角度思考问题，基于全球面板数据，参阅大量权威资料，首先从数量、经济和资源安全三个维度构建了粮食安全评价指标体系，评估了2001-2020年（20年）全球和区域尺度粮食安全综合指数的时空演变规律。其次，甄别了影响粮食安全的关键驱动因素（土地资源、社会经济和气候变化层面），并进一步探讨了历史时期这些驱动因素对全球和区域尺度粮食安全的影响。最后，预估了未来10-30年内不同气候变化情景下气候变化对全球各区域粮食安全的影响程度。以下是本文的主要研究内容和结论：
     （1）自主设计了一套多维度集成的粮食安全评价指标体系，构建了一个可用于现实评估的粮食安全综合指数。从数量、经济和资源安全三个关键维度入手，构建了一套量化粮食安全综合水平的指标体系，将粮食安全的各个要素有机地融合在一起。采用多指标综合评价方法，构建了一个稳健可靠的粮食安全综合指数（GSCI），以此反映粮食安全的整体状况。这种综合性设计力争做到全面地反映粮食安全的多个维度和多个要素之间的相互作用，使评价更加准确和有针对性。通过在全球和区域尺度上的应用，进一步验证了GSCI在不同地域的实用性和适应性，体现了该指数的创新性和实用价值。
     （2）计算了全球及区域尺度的粮食安全综合指数，量化了全球各区域粮食安全的时空动态变化。以粮食安全综合指数为评估指标，利用2001-2020年全球粮食安全指标面板数据集，刻画了过去20年全球各区域粮食安全水平的时空演变。同时利用粮食安全综合比较优势指数（GCAI）指标，揭示了各区域粮食安全水平相对于全球平均水平的优劣程度。结果发现：近20年来，全球粮食安全水平持续上升，其中亚洲、欧洲、拉丁美洲及加勒比地区尤为明显，而撒哈拉以南非洲则呈现下降态势。在空间分布中，粮食安全高水平区域集中于欧洲（GSCI为0.639），而低水平区域分布在撒哈拉以南非洲（GSCI为0.307）。值得注意的是，与全球粮食安全平均水平相比，欧洲凸显极强的优势（GCAI为1.322），而撒哈拉以南非洲呈现极强的劣势（GCAI为0.54），亚洲和拉丁美洲及加勒比地区则相对较弱。
     （3）甄别了对粮食安全产生关键影响的驱动因素，并评估了历史时期内不同驱动因素对全球各区域粮食安全的影响。利用2001-2020年全球粮食安全驱动因素面板数据集，识别了影响粮食安全综合指数变化的主要驱动因素；首次将气候变化因素引入面板数据模型，评估了过去20年间全球各区域粮食安全对不同驱动因素变化的响应程度。结果表明：耕地面积、农业劳动力、政治稳定度、政府支出的农业导向指数、铁路密度是促进粮食安全水平显著提升的主要驱动因素，而粮食价格通货膨胀程度、年平均气温和降水量距平百分率是导致粮食安全水平显著降低的主要驱动因素。尤其，过去20年的年平均气温和降水量距平百分率变化均显著地导致全球尺度的粮食安全水平降低，其影响系数分别为-1.113和-0.029。其中，年平均气温每增加10%，导致亚洲、欧洲、拉丁美洲及加勒比地区粮食安全水平分别降低10.02%、6.85%和33.16%；降水量距平百分率每增加10%，则导致亚洲和撒哈拉以南非洲粮食安全水平分别下降0.9%和0.37%。
     （4）预测了未来10-30年内不同气候变化情景下全球各区域粮食安全对气温和降水变化的响应。首次结合面板数据模型与气候变化影响量模型，引入不同气候变化情景下的CMIP6全球气候模式数据，多模式集合平均预测了未来全球气温和降水变化，并预估了未来10-30年内不同气候变化情景下各区域粮食安全对长期气候变化的响应。结果表明：未来气温和降水变化对全球粮食安全的影响呈现显著的空间差异和尺度效应。未来10-30年内，气温和降水变化的共同驱动作用对全球尺度粮食安全的整体影响将从负面转变为正面效应，其影响程度从SSP1-2.6情景下的-37.34%~43.74%减小到SSP5-8.5情景下的-46.99%~35.08%。在区域尺度上，亚洲气温和降水变化对粮食安全的负面影响在三种气候情景预估下均呈现逐渐减弱的趋势，而欧洲和拉丁美洲及加勒比地区的影响将逐渐从负面转变为正面效应，并且影响程度随时间的推移和排放浓度的增加而增大。
       本论文通过上述一系列工作，旨在为气候变化背景下的全球和区域尺度粮食安全及其影响因素研究提供新的视角和方向，为制定实现可持续发展目标的粮食安全政策提供科学依据，以及为建立更具韧性和可持续性的全球粮食系统提供坚实的科学支撑。

       In today's world, external shocks frequently disrupt global grain security, exacerbated by ongoing climate change and disruptions, leading to crises and challenges for the global food system and world security. Against the backdrop of climate change, grain security has become a core concern for global sustainable development, influencing national security policies, sustainable agriculture promotion, and the vision of a shared human destiny. Evaluating grain security is a complex scientific task, involving multiple dimensions, indicators, and factors. There has been limited exploration of the multi-scalar, multidimensional, and multifactorial changes in grain security using interdisciplinary approaches. How to develop a comprehensive set of indicators and methods for systematically assessing grain security, accurately monitoring the spatiotemporal dynamics of global grain security, and elucidating the driving factors and mechanisms affecting grain security within the framework of climate change economics has emerged as an urgent and significant scientific issue.
      This dissertation, building upon existing research, takes an interdisciplinary approach encompassing economics, climate change science, and grain security. Utilizing global panel data and referencing authoritative sources, a grain security assessment indicator system from the dimensions of quantity, economy, and resource security is established. It assesses the spatiotemporal dynamics of global and regional grain security from 2001 to 2020 (20 years). Furthermore, it identifies key driving factors affecting food security, including land resource, socio-economic aspects, and climate change, and explores the historical impact of these factors on grain security. Finally, it projects climate change's impact on global grain security under different climate change scenarios over the next 10-30 years. The following summarizes the main research content and conclusions:
      (1) A multidimensional grain security evaluation indicator system was passively designed, and a composite grain security index (GSCI) for real-world evaluation was developed. A multidimensional grain security evaluation indicator system was autonomously designed, focusing on quantity, economic, and resource security dimensions. This system integrated various grain security elements and utilized a multi-indicator comprehensive evaluation approach to construct a robust grain security composite index (GSCI), capturing the overall status of grain security. This comprehensive design strived to achieve a comprehensive reflection of multiple dimensions of grain security and the interactions among these elements, aiming to make the assessment more accurate and targeted. The GSCI's innovation and practical value were verified through its application at both global and regional scales.
       (2) The composite grain security index (GSCI) was simulated at both global and regional scales, quantifying the spatiotemporal dynamics of grain security across areas. Utilizing the GSCI as the evaluation indicator and the global grain security indicator panel dataset from 2001 to 2020, we depicted the spatiotemporal changes in global grain security level over the past two decades while revealing regional variations in grain security levels relative to the global average using a grain security composite advantage index (GCAI). A continuous global increase in grain security over the past 20 years, with particularly significant improvements in Asia, Europe, Latin America and the Caribbean, while sub-Saharan Africa has experienced a decline. Geographically, high GSCI values are concentrated in Europe (with a GSCI of 0.639), contrasting with lower values in sub-Saharan Africa (with a GSCI of 0.307). Notably, Europe exhibits a pronounced advantage in grain security (with a GCAI of 1.322) compared to the global average, whereas sub-Saharan Africa faces significant grain security challenges (with a GCAI of 0.54). Asia and Latin America and the Caribbean show relatively weaker grain security levels. These results highlight the dynamic shifts in grain security across different areas, providing valuable insights into the current status and trends in global grain security.
       (3) The key driving factors influencing grain security were identified, and the impacts of various driving factors on grain security across different regions were evaluated during historical periods. Utilizing a dataset spanning from 2001 to 2020, we identified key driving factors influencing changes in the GSCI and introduced climate change factors into the model to assess global grain security responses over the past two decades. The results indicated that arable land area, agricultural labor force, political stability, government expenditure with an agricultural focus, and railway density were the primary driving factors significantly enhancing grain security levels. Conversely, food price inflation, annual average temperature, and deviation in precipitation from the norm were the major driving factors leading to a significant decrease in grain security levels. In particular, variations in annual mean temperature and precipitation anomalies over the past 20 years significantly reduced grain security at the global scale, with impact coefficients of -1.113 and -0.029, respectively. Among them, for every 10% increase in the annual average temperature, grain security levels in Asia, Europe, Latin America and the Caribbean decreased by 10.02%, 6.85%, and 33.16%, respectively. Similarly, a 10% increase in the deviation of precipitation from the norm led to a 0.9% and 0.37% reduction in grain security levels in Asia and Sub-Saharan Africa, respectively.
      (4) The responses of global and regional grain security to the variations of temperature and precipitation under different climate change senarios in the next 10-30 years were forecasted. The integration of a panel data model with a climate change impact model enabled the multi-model ensemble prediction of future global temperature and precipitation changes. This was employed to estimate how different regional grain security would respond to long-term climate changes in different climate change scenarios over the next 10-30 years. Future climate change will exhibit significant spatial disparities and scale effects on global grain security. Over the next 10-30 years, the overall impact of the combined drivers of temperature and precipitation on global grain security will transition from negative to positive. The impact will decrease from -37.34% to 43.74% under low emission scenario (SSP1-2.6) to -46.99% to 35.08% under high emission scenario (SSP5-8.5). At the regional level, different regions may experience varying grain security conditions due to climate change in the coming decades. In the next 10-30 years, the adverse effects of temperature and precipitation on grain security in Asia are expected to gradually weaken under three climate scenarios. Meanwhile, in Europe and Latin America and the Caribbean, the impact of climate change on grain security will shift from negative to positive over time, with the magnitude increasing with time and increasing emission concentrations.
      Through the series of work presented in this dissertation, our aim is to offer new perspectives and directions for research on global and regional grain security and its influencing factors under the context of climate change. This work provides a scientific foundation for the development of grain security policies aligned with the achievement of sustainable development goals and contributes to the establishment of a more resilient and sustainable global food system.