BE/CNH: An Integrated Analysis of Regional Land-Climate Interactions

当代人类对地球陆地表面改变的强度和空间范围是前所未有的。土地利用和土地覆盖变化（LULCC）是这些人类影响中最重要的。许多研究表明，LULCC对局部和区域气候的影响，当这些影响叠加在一起时，可能会显著改变全球气候。同时，由于温度和降水模式的改变，与大气温室气体浓度增加有关的气候变化预计将对人类和生态系统产生重大影响。虽然重要的研究集中在全球气候模拟和影响土地利用变化的社会经济因素上，但需要在区域尺度上对耦合的人类-气候系统进行综合评估，以解决区域和地方尺度上土地利用与气候变化之间相互作用的幅度和性质是什么？通过这个研究项目，一个由社会、生态、大气和统计科学家组成的国际多学科团队将通过探索全球变化研究的两个焦点——LULCC和气候变化之间的联系来解决这个问题。全球变化科学的一个主要目标是获得对未来气候条件的更可靠的估计。这一目标越来越需要高分辨率的区域尺度气候模型，其中包括陆地和大气之间的反馈。本项目旨在完成土地利用/气候/土地利用影响评估的循环。它的贡献在于分析各组成部分之间的复杂联系，特别强调土地利用变化如何影响气候以及气候变化将如何影响土地利用等问题。这些联系将通过对农业系统、土地利用变化、土地覆盖的物理特性和区域气候动态的分析和建模来加以审查。这项研究将把重点放在东非，那里有广泛的生态系统、热带气候条件、土地利用快速变化的地区以及易受气候变化影响的人口。该项目将整合(1)从全球气候模式降尺度推导出的未来局地气候情景；(2) LULCC详细的长期案例研究和长期观测气候记录分析所得的信息；(3)从局地尺度到区域尺度的LULCC预估模式；(4)利用时间序列卫星影像分析LULCC对地表特征的影响；(5)净初级生产力模拟；(6)利用局地地表参数参数化的区域气候模式的气候信息。该项目的高潮将是一系列气候-土地系统反馈实验，以确定区域尺度上土地和气候动态之间相互作用的幅度和性质。研究人员将根据反馈的决定形式、联系的强度、时空尺度问题以及“临界点”对气候-陆地相互作用的影响来描述这些相互作用。这个项目将对科学和政策作出重大贡献。其科学重要性在于通过综合最先进的方法和多学科方法来解决气候变化与土地利用变化之间复杂的相互作用和反馈。它将明确地解决生物复杂性理论和复杂系统建模的重要问题，包括反馈、阈值、不确定性和非线性。这些是将从各种模式和案例研究中获得的信息联系起来的固有问题，以便了解与将LULCC与气候变化联系起来相关的多尺度动力学。预期的科学发现和新方法将推动未来在区域和全球尺度上的气候变化研究。在应用方面，该项目将提供未来气候变化及其对东非主要生计系统的影响的可信情景。该小组将与决策者和其他利益攸关方（包括农民和牧民）合作，评估这些情景对该地区未来农业研究和政策、保护和土地利用规划的影响。这些发现将与世界上许多其他地区的科学家和决策者有关，他们关注土地利用与气候之间复杂的相互作用对社会和环境的影响。除了解决许多基本的气候、生态和社会经济问题外，研究还将与从小学到研究生的学生教育紧密结合。它将为年轻的和处于职业生涯中期的美国和非洲科学家提供能力建设机会，并与从地方到国际社会的各种利益相关者进行接触。该项目获得了2003年度环境生物复杂性特别竞赛奖项的支持，该竞赛侧重于自然和人类系统耦合动力学。

The intensity and spatial reach of contemporary human alterations of the Earth's land surface are unprecedented. Land-use and land-cover change (LULCC) are among the most significant of these human influences. Many studies demonstrate the influence of LULCC on local and regional climate, which, when aggregated, may significantly alter the global climate. Meanwhile, climate change related to increased atmospheric concentrations of greenhouse gases is expected to considerably affect people and ecosystems due to altered temperature and precipitation patterns. While significant research has focused on global climate modeling and socioeconomic factors influencing land-use change, an integrated assessment at the regional scale of coupled human-climatic systems is required to address the question, What is the magnitude and nature of the interaction between land use and climate change at regional and local scales? Through this research project, an international multidisciplinary team including social, ecological, atmospheric, and statistical scientists will address this question by exploring the linkages between two foci of global change research, LULCC and climate change. A major goal of global change science is to obtain a more reliable estimation of future climatic conditions. This goal increasingly requires high-resolution regional scale climate modeling that includes feedbacks between the land and atmosphere. This project aims to complete the loop of land-use/climate/land-use impacts assessment. Its contribution is in analysis of the complex linkages among components, with special emphasis on the questions, how does land-use change affect climate and how will climate change affect land use? These linkages will be examined through analysis and modeling of agricultural systems, land-use change, the physical properties of land cover, and regional climate dynamics. The study will focus on East Africa, which has broad ranges of ecosystems, tropical climatic conditions, and areas of rapid land use change as well as a population vulnerable to climatic variability. The project will integrate (1) future local-level climate scenarios derived from downscaling of global climate models; (2) information derived from detailed long-term case studies of LULCC and analyses of long records of observed climate; (3) models to project LULCC from local to regional scales; (4) analyses of time-series satellite imagery to translate the effects of LULCC on land surface characteristics; (5) net primary productivity simulations; and (6) climate information from a regional climate model parameterized using local land surface parameters. The culmination of the project will be a series of climate-land system feedback experiments identifying the magnitude and nature of interactions between land and climate dynamics at regional scales. The investigators will characterize these interactions in terms of the determining form of feedbacks, the strength of linkages, issues of spatial and temporal scales, and the effect of "tipping points" on climate-land interactions.The project will make a significant contribution both to science and to policy. Its scientific importance lies in addressing the complex interactions and feedback between climate change and land-use change by integrating state-of-the-art methodologies and multidisciplinary approaches. It will explicitly address issues important to biocomplexity theory and complex system modeling, including feedback, thresholds, uncertainty, and non-linearity. These are inherent issues in linking information derived from a variety of models and case studies in order to understand the multi-scale dynamics associated with linking LULCC and climate change over time. The anticipated scientific findings and new methodologies will advance future climate change research at regional and global scales. With respect to application, the project will provide plausible scenarios of future climate change and its impacts upon the dominant livelihood systems of East Africa. The team will work with policy-makers and other stakeholders, including farmers and herders, to assess the implications of these scenarios for future agricultural research and policy, conservation, and land-use planning in the region. The findings will be relevant to scientists and policy-makers in many other parts of the world who are concerned with the implications for society and environment of complex interactions between land use and climate. In addition to addressing many fundamental climatic, ecological and socioeconomic questions, the research will be tightly integrated with the education of students from elementary school to graduate school. It will provide capacity-building opportunities for young and mid-career American and African scientists as well as outreach to various stakeholders from local to international communities. This project is supported by an award resulting from the FY 2003 special competition in Biocomplexity in the Environment focusing on the Dynamics of Coupled Natural and Human Systems.