Collaborative Research: Understanding the Full Range of Amazon Drought and Impacts

技术描述该资助将提供在面对自然气候变率和变化时管理亚马逊地区所需的改进的古气候和古干旱视角。该项目以巴西、厄瓜多尔和秘鲁的三个亚马孙西部湖泊群为目标，建立一个区域性网络，该网络至少包含四个分十年确定的1500至3000年的亚马孙西部古气候、植被和火史综合记录。该团队将使用气候和地球系统建模策略来解决许多问题，包括：*每个湖泊记录中假设的干旱事件在多大程度上是真正的干旱，即在附近（有限干旱）和1000公里以外（更广泛的干旱）的其他湖泊记录中重现？*对亚马逊地区干旱和突变风险的最佳“古信息”估计是什么？亚马逊的植被和火灾动态如何响应过去干旱严重程度的光谱，这些生物物理反馈如何影响未来森林的可持续性和临界点的风险？*亚马逊动力系统在接近关键转变时是否存在早期预警行为？*最先进的模型模拟观测到的干旱和突变记录的效果如何？*亚马逊地区年代际到世纪尺度的干旱变异性和水文气候突变的主要控制因素是什么？2005年，亚马逊流域遭受了仪器观测以来前所未有的干旱。科学家们很快意识到，这次干旱是一个新的威胁，它使亚马逊地区的生物多样性、碳汇能力和生态系统服务（如水文和经济）处于危险之中。2010年，发生了第二次更严重的干旱。有人认为，亚马逊可能无法在加速的气候变化中幸存下来，甚至可能达到一个临界点，超过这个临界点，大片森林将不可逆转地转变为稀树草原。亚利桑那大学和佛罗里达理工学院的研究小组收集的数据显示，在亚马逊地区，一年一次的严重干旱并不罕见，更长的多年干旱（长达15年）和气候突变也曾发生过。将这1500年的记录与最先进的气候模型模拟进行比较也表明，模型可能低估了未来亚马逊地区长期干旱的风险。由于碳反馈是现代全耦合气候模型的重要组成部分，因此将森林恢复力估算纳入古气候评估对于了解干旱在这一景观中的过去和未来的作用至关重要。该项目将通过科学出版物以及以土著语言向亚马逊政策制定者和管理者提交的报告，提供在面对气候变率和变化时管理亚马逊生态系统服务的有用信息。该团队正在美国建立机构间联系，并在亚马逊地区建立新的合作伙伴关系。该团队还将创建两种新的机制，向公众（包括学生和非英语人士）解释亚马逊的气候挑战和关键的古生物观点：(1)在美国最大的热带雨林现场展览中举办新的展览，(2)举办一场关于科学及其含义的最佳多语种短片制作比赛。我们还将在这个高度相关的跨学科背景下培养两名古环境博士科学家，以及几名本科生，包括来自亚利桑那大学大型西班牙裔和美洲原住民学生社区的学生。

TECHNICAL DESCRIPTIONThis grant will provide improved paleoclimatic and paleo-drought perspectives needed to manage Amazonia in the face of natural climate variability and change. The project targets three clusters of western Amazonian lakes in Brazil, Ecuador and Peru to establish a regional network of at least four sub-decadally resolved 1500- to 3000-year long integrated records of paleoclimate, vegetation, and fire-history for western Amazonia. The team will use a climate and Earth system modeling strategy to address many questions, including:*To what extent are the hypothesized drought events in each lake record really droughts, i.e., reproduced in other lake records nearby (restricted drought) and over 1,000 km away (broader drought)?*What are the best "paleo-informed" estimates of drought and abrupt change risk for Amazonia?*How did Amazonian vegetation and fire dynamics respond to the spectrum of past drought severity, and how might these biophysical feedbacks affect future forest sustainability and the risk of a tipping point?*Is there early warning behavior in the Amazonian dynamical system approaching critical transitions?*How well do state-of-the-art models simulate the observed record of drought and abrupt change?*What are the dominant controls on decadal to century-scale drought variability and abrupt hydro climatic change in Amazonia?NON-TECHNICAL DESCRIPTIONIn 2005, the Amazon basin was hit with a drought unprecedented in the period of instrumental observation. Scientists quickly realized this drought was a new threat that put Amazonia's biodiversity, ability to act as a carbon sink, and ecosystem services (e.g., hydrologic and economic) at risk. In 2010, a second, more severe drought occurred. It has been posited that Amazonia might not survive accelerating climate change, perhaps even reaching a tipping point beyond which substantial areas of the forest would convert irreversibly to savanna.The University of Arizona and Florida Institute of Technology team has collected data showing that single-year periods of severe drought were not uncommon in Amazonia, and that longer multi-year (up to ~15 yr) droughts and abrupt climate changes have also occurred. Comparisons between this 1500-year record and state-of-the-art climate model simulations also indicated that models might underestimate the risk of future prolonged Amazonian drought. As carbon feedbacks are important components of modern fully-coupled climate models, integrating estimates of forest resilience into the paleoclimatic assessment is critically important to understanding the past and future role of drought in this landscape.This project will provide information useful in managing Amazonian ecosystem services in the face of climate variability and change, via scientific publications as well as reports to Amazonian policy-makers and managers in their native languages. The team is building on inter-institutional ties within the US and also forming new partnerships in Amazonia. The team will also create two new mechanisms for explaining the Amazon's climate challenge and key paleo-perspectives to the public, including students and non-English speakers: (1) a new exhibit at the largest live rainforest exhibit in the US, and (2) a contest to produce the best short multi-lingual video on the science and its implications. We will also train two paleoenvironmental Ph.D. scientists in this highly relevant interdisciplinary context, as well as several undergraduate students, including those from the large Hispanic and Native American student communities at the University of Arizona.