A Southern Hemispheric Perspective on Holocene Climate Variability Based on Mountain Glacial Chronologies

山地冰川对地球大气的变化反应灵敏，因此它们的历史记录可以作为过去气候的有用代用品。因此，冰川范围的全面记录可以与其他类型的气候档案相结合，以提供过去对目前气候系统控制的视角。这个项目将建立在研究人员最近的观察基础上，他们发现南美洲南端的冰川气候历史显示出不同于北美和欧洲观察到的模式。在这些观测的基础上，这项研究将审查南半球沿中高纬度梯度的冰川和气候最近的变化，这可用于检验关于在气候仪器记录之前控制冰川活动的因素的假说。因此，冰川对过去气候变化的敏感性这一观点将有助于提高我们对现在和预计的气候变化的理解。研究人员将与智利和阿根廷的科学家合作，汇集国际专业知识来实现研究目标，这可能会为地区和全球对水利和水电资源的社会影响以及当地文化意义提供信息。该团队将包括本科生和研究生，包括与梅迪尔新闻学院的一名研究生合作，这名研究生将加入实地研究，制作一份将引起广泛公众兴趣的媒体包。研究人员还将通过地球课堂计划让K-12科学教师和他们的学生参与进来。这项研究将测试假说，这些假说将阐明古气候信号的时空变异性，以及极地和非极地控制对区域和全球气候的相互作用。该项目将确定过去冰川和气候的变化如何随南半球的纬度变化。具体地说，该项目将：1)绘制冰川特征图，并从南美洲至少三个地点收集样本；2)对早于历史记录的地形进行14-C和最先进的10-BE测年(以测试可靠性)，3)与气候冰川建模专家合作重建平衡线高度，并消除温度和降水的原因变化；4)与全球气候模型师合作，深入了解可能的区域和半球强迫作用；5)将研究结果纳入更大的跨学科工作。这种多方面的方法将提高对冰川的时空变异性、敏感性和对过去气候变化的反应的了解。这种对冰川对气候变化响应历史的理解将为我们理解当前的变化提供视角，并为全球气候模型提供测试数据集。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Mountain glaciers respond sensitively to changes in Earth's atmosphere such that records of their history serve as a useful proxy for past climates. Thus, comprehensive records of glacier extents can be combined with other types of climate archives to provide a perspective from the past on the present controls on the climate system. This project will build on recent observations by the researchers, who found that glacier-climate histories at the southern tip of South America showed different patterns from those observed in North America and Europe. Based on these observations, this research will examine recent variability in glaciers and climates along middle to high latitudinal gradients in the Southern Hemisphere, which can be used to test hypotheses regarding factors that controlled glacier activities prior to instrumental records of climate. Thus, this perspective of glacier sensitivity to past climate changes will help improve our understanding of present and projected climate changes. The researchers will collaborate with scientists from Chile and Argentina, bringing together international expertise to accomplish the research goals, which may inform regional and global societal implications for water and hydroelectric resources and local cultural significance. The team will include both undergraduate and graduate students, including collaboration with a graduate student from the Medill School of Journalism who will join the field research to produce a media package that will be of broad public interest. The researchers will also engage K-12 science teachers and their students through the Earth2Class program.This research will test hypotheses that will illuminate the spatial and temporal variability of paleoclimate signals and the interaction of polar and non-polar controls on regional and global climates. The project will determine how past variability in glaciers and climate varied along latitude in the Southern Hemisphere. Specifically, the project will: 1) map glacial features and collect samples from at least three sites in South America; 2) employ 14-C and state-of-the-art 10-Be dating on landforms as young as the historical record (to test reliability), 3) collaborate with climate-glacier modeling experts to reconstruct equilibrium line altitudes and back out the causal temperature and precipitation changes; 4) collaborate with a global climate modeler to provide insight into possible regional and hemispherical forcings, and 5) integrate findings into larger interdisciplinary efforts. This multi-faceted approach will improve understanding of temporal and spatial variability, sensitivity and response of glaciers to past climate changes. This understanding of the history of glacier responses to climate change will provide perspective on our understanding of present changes, and provide test data sets for global climate models.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.