Collaborative Research: Toward placing contemporary Arctic summer warming in a millennial perspective with a pan-Arctic record of Neoglacial crysophere expansion

合作研究：通过新冰川期冰冻圈扩张的泛北极记录，从千禧年的角度看待当代北极夏季变暖

• 批准号: 2100381
• 负责人: Gifford Miller
• 金额: $ 6.27万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-15 至 2024-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2100381&HistoricalAwards=false
• 关键词: Collaborative; Research; Toward; placing; contemporary

Miller/Kaufman: Toward placing contemporary Arctic summer warming in a millennial perspective with a pan- Arctic record of Neoglacial crysophere expansionNon-technical summary. Glacier dimensions in the Arctic are set by summer temperature, but changes in the dimensions of Alaskan glaciers since the end of the ice age are poorly constrained. In response to recent Arctic warming, glaciers in the Brooks Range, Alaska are receding rapidly, and in special settings, on gentle slopes where the ice is thin, glaciers act as preservation agents, rather than erosive agents, preserving intact tiny tundra plants living before the ice expanded over that site in the distant past. The goal of this project is to visit the most likely sites in the Brooks Range where glaciers preserved, rather than eroded the landscape, where we expect tundra plants are being re-exposed as ice recedes. The radiocarbon ages of these plants document when past summers grew colder, allowing ice to expand across these sites, and provide the most reliableevidence of when in the past Arctic summers cooled enough to allow glaciers to grow.Broader Impacts. Comparing the ages of ice-entombed Alaska plants to ages of plants exposed in other Arctic regions will allow us to better understand large-scale climate change on a hemispheric scale. These results serve as tests for climate models that are used to predict future climate. The same models used for future projections can be run in reverse to predict climate evolution in the past. If the models predict similar patterns of past climate change as documented by the ages of ice-entombed plants across the Arctic, our confidence in the ability of climate models to reliably predict future climate is increased. If the models fail to predict patterns similar to the plant ages, then it is likely the models have underestimated certain aspects of the climate system.Technical summary. Changes in the dimensions of Brooks Range glaciers through the Holocene, a primary proxy for changes in summer temperature, are poorly constrained. Where glaciers are cold-based and on gently sloping terrain, they often do not erode, but act as exceptional preservation agents, preserving tiny tundra plants killed by expanding ice. Rapid ice recession across the Brooks Range is now exposing landscapes likely to preserve in situ tundra plants killed by late Holocene ice expansion, with their radiocarbon ages defining episodes of consistently cold summers. This project will visit the most promising sites to look for iceentombed plants emerging as the ice margins recede, and take advantage of the new NSF-supported accelerator mass spectrometer at Northern Arizona University for dating. We expect the resultant composite probability density functions of dated plants to produce age clusters reflecting episodes of ice expansion/cold summers, which can be compared with results from the North Atlantic Arctic, and collectively serve as targets for Common Era climate modeling now underway with CMIP-6.Broader Impacts. Communicating climate change with the wider public is more important than ever as climate change accelerates and climate literacy lags. Although it's widely understood that glaciers in Alaska (and elsewhere) are rapidly receding, there is less understanding of how unusual this recession really is. This study will place glacier recession in a millennial perspective, likely illustrating that current warming is unprecedented over thousands of years, a concept easily grasped by the general public. To advance public outreach, we will support an experienced graphic designer to translate our science to a form that is accessible to the citizens of Alaska and the broader US community.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.

Miller/Kaufman：旨在将当代北极夏季变暖以千禧一代的视角，并在北极记录Neogalasial Crossophere扩展Non-Technical摘要。北极的冰川尺寸是由夏季温度设定的，但是自冰河时代结束以来，阿拉斯加冰川的尺寸的变化受到限制。为了响应最近的北极变暖，布鲁克斯山脉的冰川正在迅速退缩，在特殊的环境中，在冰薄的柔和斜坡上，冰川充当保护剂，而不是侵蚀剂，而不是保存完整的小苔原植物。该项目的目的是参观冰川保存而不是侵蚀景观的布鲁克斯范围内最有可能的地点，我们期望随着冰的消退，我们期望苔原植物会重新暴露。这些植物的放射性碳年龄在过去的夏季变得越来越冷时记录，使冰遍布这些地点，并提供了过去北极夏季何时冷却足够冷却以使冰川生长的最可靠的证据。将冰炸弹植物的年龄与其他北极地区暴露的植物年龄进行比较，将使我们能够更好地理解半球尺度上的大规模气候变化。这些结果是用于预测未来气候的气候模型的测试。用于未来预测的相同模型可以反向运行，以预测过去的气候演变。如果这些模型预测了过去气候变化的类似模式，如北极冰叶植物的年龄所记录的，我们对气候模型可靠预测未来气候的能力的信心会增加。如果模型无法预测与植物年龄相似的模式，那么模型很可能已经低估了气候系统的某些方面。技术摘要。 Brooks范围冰川范围通过全新世的变化，这是夏季温度变化的主要代理。在冰川以冷且轻轻倾斜的地形上，它们通常不会侵蚀，而是充当特殊的保存剂，可以保存微小的苔原植物，因为田间膨胀而造成的冰块杀死。整个布鲁克斯范围的快速冰衰退现在正在暴露可能保存的景观，这些景观可能会保留被晚期冰冰造成的原位苔原植物，其放射性碳年龄定义为始终如一的夏季发作。该项目将访问最有前途的网站，寻找随着冰块的退缩而出现的冰炸植物，并利用亚利桑那州北部亚利桑那大学约会的新的NSF支持的加速器质谱仪。我们预计，日期植物的合成概率密度功能将产生反映冰膨胀/寒冷夏季发作的年龄簇，这可以与北大西洋北极的结果进行比较，并集体用作CMIP-6.BROAD.BROAD.BROAD.BROAD.BROAD.BROAD.BROAD.BROAD.BROAD.BROAD.BROAD.BROAD.BROAD.BROAD.BROAD.BROAD.BROAD.BROAD.BROAD.BROACH。随着气候变化的加速和气候素养滞后，与更广泛的公众交流气候变化比以往任何时候都更为重要。尽管人们广泛理解的是，阿拉斯加（和其他地方）的冰川正在迅速退缩，但对这次衰退的不寻常性的了解较少。这项研究将使冰川经济衰退以千禧一代的观点，这可能说明了数千年来当前的变暖是前所未有的，这一概念很容易被公众掌握。为了推进公众的宣传，我们将支持一位经验丰富的图形设计师，将我们的科学翻译成一种形式，即阿拉斯加公民和更广泛的美国社区可以使用的形式。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的智力优点和更广泛的影响审查标准通过评估来进行评估的。