P2C2: Collaborative Research: Timing of the Glacial Termination in Southernmost South America

气候变化是我们这个时代最紧迫的社会问题之一，对人类健康和福利、经济和国家安全都有影响。对未来气候的更好预测取决于对驱动地球气候系统的机制的更详细了解，这通常可以从过去气候的地质记录的角度得到阐明。这项由该奖项资助的研究将研究最近地质历史上最大的全球变暖事件：从上一个冰河时代到现在的间冰期世界的过渡。首先，将通过记录上一次冰河时代结束时迅速消退的冰川留下的地貌的年龄和位置来制作气候记录。然后，这些记录将与计算机模型一起被用来测试关于气候系统不同组成部分的假设，这些组成部分被认为在地球迅速变暖中发挥着重要作用。这些信息将提高对地球气候系统如何运行的理解，并为用于气候预测的模型提供信息。这种对地球气候系统的详细了解可能有助于政策制定者阐明将提供多种社会效益的气候政策。研究人员还将在STEM领域教育年轻科学家，从而增加STEM劳动力，这符合国家利益。该奖项还将支持一名科学新闻系学生的教育，他们将接受向公众传达科学成果的培训，提供公众对全球变化科学的认识和理解的长期好处。尽管取得了重大进展，但冰河时代终止的根源仍未解决。这个问题的核心是冰河时代结束的准确的半球间和半球内的时间，因为这种信息提供了关于冰河时代结束的机制的线索。研究小组将测试这样一个假设，即南纬地区最后一次终止的气温上升比之前认识到的更早、更快，速度如此之快，可能需要对现有的假设进行重大改革。该研究项目将使用详细的冰川地貌放射性碳和暴露年代测定，以及冰川学模型，来记录南美洲最南端的科迪勒拉达尔文冰原终止的时间和规模。这些数据将与GFDL地球系统模型2M在较低纬度的现有古气候记录相结合，以评估终止的各种强迫因素的可行性，例如海洋两极拉锯、南半球西风带的移动和大气二氧化碳浓度。这项工作将加强美国和智利机构之间的合作，并为学生提供指导和教育机会。研究团队将在现场派对中安插一名科学新闻学研究生，他将以各种媒体格式撰写文章。这一奖项反映了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。

Climate change is one of the most pressing societal issues of our time, with implications for human health and welfare, the economy, and national security. Improved projections of future climate rely on more detailed understanding of the mechanisms driving Earth’s climate system, which can often be illuminated from the perspective of geological records of past climates. The research funded by this award will examine the largest global warming event in the recent geological past: the transition from the last ice age to the present interglacial world. First, a climate record will be produced by documenting the age and location of landforms left by rapidly retreating glaciers at the end of the last ice age. These records will then be used, along with computer models, to test hypotheses about different components of the climate system that are thought to play important roles in rapid warming of Earth. Such information will improve understanding of how Earth’s climate system operates and inform models used for climate prediction. This detailed understanding of Earth's climate system may help policy makers to articulate climate policies that will provide multiple societal benefits. The researchers will also educate young scientists in STEM fields, thereby increasing the STEM workforce, which is in the national interest. This award will also will support the education of a science journalism student, who will be trained to communicate the science results to the public, providing long-term benefits of public awareness and understanding of global change science.Despite significant progress, the origin of ice-age terminations remains unresolved. At the core of this issue is the precise inter- and intra-hemispheric timing of the end of the ice age, because such information yields clues as to the mechanisms that underlie the termination. The research team will test the hypothesis that the temperature rise of the last termination in southern latitudes was earlier and faster than previously recognized, so fast that it may require a major overhaul of existing hypotheses. The research project will use detailed radiocarbon and exposure dating of glacial landforms, along with glaciological modeling, to document the timing and magnitude of the termination of the Cordillera Darwin icefield, in southernmost South America. These data will be integrated with existing paleoclimate records at lower latitudes with the GFDL Earth System Model 2M to assess the feasibility of various forcing factors for the termination, such as an ocean bipolar seesaw, shifting of the southern hemisphere westerlies, and atmospheric carbon dioxide concentrations. This work will strengthen collaborations between US and Chilean institutions and afford mentoring and education opportunities for students. The research team will embed a science journalism graduate student in the field party, who will produce articles in a variety of media formats.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.