Collaborative Research: Arctic Sensitivity to Climate Perturbations and a Millenial Perspective on Current Warming Derived from Shrinking Ice Caps

该提案的目标是为目前的变暖提供千年背景，并更好地限制北极北大西洋地区过去5000年来气候突变的性质。这一目标将通过强大的数据集来实现，这些数据集来自于冰帽下保存了数百年至数千年的放射性碳定年植被，但现在每年都被加拿大东北部和西格陵兰岛的冰缘退缩所暴露。这些年表定义了最近夏季突然变冷的模式和时间，并将当前的变暖置于千年背景下。植被的14C测年将通过测量最近暴露的岩石表面的原位14C库存来补充，对整个全新世的冰盖和无冰条件的持续时间提供必要的时间限制。结合起来，这两个数据集将提供最安全的证据，通过明确地确定该地区最后一次像现在一样温暖的时间来证明当前夏季变暖的特征。比较我们的气候重建与正在进行的研究在西北欧将有助于分离的作用，非强迫变率从半球对称强迫的原因，气候突变。 将向土著人民提供该奖项下的研究活动，办法是将目标和最终结果翻译成因纽特语，张贴介绍研究的海报，并在努纳武特首府伊卡卢伊特和研究所长期存在的Qikiqtarjuaq举办公开讲座。该研究计划将培养一名博士和硕士生，并为本科生提供参与研究的机会，建立在前几年的成功传统基础上。

The goal of this proposal is to provide a millennial context for current warming and to better constrain the nature of abrupt climate changes over the past 5000 years in the North Atlantic sector of the Arctic. This goal will be addressed with the powerful datasets derived from radiocarbon-dated vegetation preserved beneath ice caps for centuries to millennia, but now being exposed annually by current ice-margin retreat across northeastern Canada and West Greenland. These chronologies define the pattern and timing of abrupt summer coolings in the recent past and place current warming in a millennial context. 14C dating of vegetation will be complemented by measuring in situ 14C inventories in recently exposed rock surfaces, providing essential temporal constraints on the duration of ice-covered and ice-free conditions throughout the Holocene. Combined, these two datasets will provide the most secure evidence for the character of current summer warming by explicitly dating when the region was last as warm as present. Comparing our climate reconstructions with on-going studies in NW Europe will help to separate the roles of unforced variability from hemispherically symmetric forcing as causes for abrupt climate change. Research activities under this award will be made accessible to indigenous peoples by translating the goals and eventual results into Inuktitut, through posters that describe the research, and by offering public lectures in Iqaluit, the capital of Nunavut, and at Qikiqtarjuaq, where INSTAAR has long had a presence. This research program will train a PhD and MSc student, and provides opportunities for undergraduate students to become involved with research, building on successful traditions from previous years.