CAREER: South Greenland's Holocene Climate History Reconstructed Using Three Paleolimnological Approaches

职业：使用三种古湖泊学方法重建格陵兰岛南部的全新世气候历史

• 批准号: 1454734
• 负责人: Yarrow Axford
• 金额: $ 59.8万
• 依托单位: Northwestern University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-01 至 2021-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1454734&HistoricalAwards=false
• 关键词: CAREER; South; Greenland; Holocene; Climate

This NSF CAREER award to Yarrow Axford at Northwestern University would support a multi-pronged effort at deciphering and understanding the climate history of southern Greenland over the last eleven thousand years, and an educational effort focused on public communication of science and K-12 science literacy. Paleoclimate data provide our only empirical observations of how the arctic system responds to major sustained climate change. It is especially urgent to understand how past climate change unfolded on Greenland, because mass loss from the Greenland Ice Sheet will drive a large fraction of future sea level rise. Existing data from south Greenland hint that climate trends there may differ from trends observed elsewhere in the Northern Hemisphere on a range of timescales, with potential consequences for future temperature change and thus for ice sheet mass balance. The proposed research will assess the apparent divergence through the Holocene (the last 11,000 years), by developing a suite of climate reconstructions from lakes in southernmost Greenland. Climate records to be generated include quantitative temperature reconstructions based on insect (chironomid) assemblages and reconstructions of precipitation isotopes (reflecting changes in atmospheric circulation) using an emerging method based on chironomid oxygen-18. A third approach -- reconstructions of alpine glacier fluctuations using sediments from glacial threshold lakes -- will constrain local ice mass balance and help to further characterize local atmospheric climate through the Holocene, especially its influence on the ice sheet. This work would double the number of continuous, quantitative Holocene terrestrial temperature reconstructions available from Greenland beyond the ice sheet, thus contributing to community-wide efforts to understand how the arctic system responds to sustained climate change. Data will be incorporated into paleodata syntheses, in keeping with the PI's track record of participation in such efforts, and will allow for better tests of climate and ice sheet models. Independent reconstructions of Holocene precipitation isotopes will be used to assess whether changes in atmospheric circulation accompanied past climate change, and thus might accompany future climate change. By constraining summer temperatures and local glacier mass balance, and comparing results with glacial geologic studies, this work will help clarify the role of atmospheric climate at the ice sheet margin in driving ice sheet changes. This work will also advance two methods: It will validate and apply an emerging isotopic proxy with potential for widespread application, and the PI will lead international collaborative development of a new calibration dataset for the chironomid paleothermometer. This grant will train at least two Ph.D. students and at least five undergraduates in international polar research, and will advance the professional development of a pre-tenure geoscientist who has a demonstrated commitment to the broader impacts of her research. Multiple collaborations, including with glacial geologists and paleoecologists at five foreign institutions, will be advanced. A new seminar will train graduate students in sustainability-relevant STEM fields in skills for communicating science beyond academia, contributing to broad training of the future STEM workforce. This project will provide sustained professional development for K-12 teachers, who in turn will bring climate and energy science to Chicago-area classrooms, promoting innovative STEM education for students in one of the largest U.S. urban school districts (Chicago's District 299).

授予西北大学亚罗·阿克斯福德 (Yarrow Axford) 的 NSF 职业奖将支持破译和理解格陵兰岛南部过去一万一千年的气候历史的多管齐下的努力，以及侧重于公众科学传播和 K-12 科学素养的教育工作。古气候数据提供了我们对北极系统如何应对重大持续气候变化的唯一经验观察。了解格陵兰岛过去的气候变化是如何发生的尤为紧迫，因为格陵兰冰盖的质量损失将导致未来海平面上升的很大一部分。来自格陵兰岛南部的现有数据表明，那里的气候趋势可能与北半球其他地方在一系列时间尺度上观察到的趋势不同，这对未来的温度变化以及冰盖质量平衡具有潜在的影响。拟议的研究将通过对格陵兰岛最南端的湖泊进行一系列气候重建来评估整个全新世（过去11,000年）的明显差异。将生成的气候记录包括基于昆虫（摇蚊）组合的定量温度重建和使用基于摇蚊氧18的新兴方法重建降水同位素（反映大气环流的变化）。第三种方法——利用冰川阈值湖的沉积物重建高山冰川波动——将限制当地的冰质量平衡，并有助于进一步描述全新世期间当地的大气气候，特别是其对冰盖的影响。这项工作将使格陵兰岛冰盖以外的连续、定量全新世陆地温度重建的数量增加一倍，从而有助于全社区努力了解北极系统如何应对持续的气候变化。数据将被纳入古数据综合中，以与 PI 参与此类工作的记录保持一致，并将允许更好地测试气候和冰盖模型。全新世降水同位素的独立重建将用于评估大气环流的变化是否伴随着过去的气候变化，从而可能伴随着未来的气候变化。通过限制夏季气温和当地冰川质量平衡，并将结果与​​冰川地质研究进行比较，这项工作将有助于阐明冰盖边缘大气气候在驱动冰盖变化中的作用。这项工作还将推进两种方法：它将验证和应用具有广泛应用潜力的新兴同位素代理，而首席研究员将领导摇蚊古温度计新校准数据集的国际合作开发。这笔赠款将培养至少两名博士。学生和至少五名从事国际极地研究的本科生，并将促进一名准终身地球科学家的专业发展，她已明确致力于其研究的更广泛影响。将推进多项合作，包括与五个外国机构的冰川地质学家和古生态学家的合作。一个新的研讨会将培训可持续发展相关 STEM 领域的研究生在学术界之外传播科学的技能，从而为未来 STEM 劳动力的广泛培训做出贡献。该项目将为 K-12 教师提供持续的专业发展，进而将气候和能源科学带入芝加哥地区的课堂，促进美国最大城市学区之一（芝加哥 299 学区）学生的创新 STEM 教育。

项目成果

Direct evidence for thinning and retreat of the southernmost Greenland ice sheet during the Younger Dryas

• DOI: 10.1016/j.quascirev.2021.107105
• 发表时间: 2021-09
• 期刊: Quaternary Science Reviews
• 影响因子: 4
• 作者: A. Carlson;A. Reyes;Emily Gusterson;Y. Axford;K. Wilcken;D. Rood