Examining the glacial cycle phase space through data-integrated glacial systems modelling

过去是我们通向未来的模糊窗口。透过这个窗口，诱人的差异指向了我们对冰、地球和气候系统耦合的理解的裂缝。过去13万年的冰和气候变化历史提供了气候系统状态的重大变化，以及突变临界点行为的例子。该系统可变性的动力来源仍然知之甚少。在解释推断出的末次冰期极大期全球平均海平面（“缺冰”问题）以及推断出的约12.5万年前末次间冰期（Eemian间冰期）海平面高出6-10米的来源方面，也存在令人困惑的不足。对潜在气候变化的科学评估严重依赖气候模式。尽管对模型来说，复制当前气候是一项具有挑战性的测试，但这只是一项有限的测试，因为这些模型已经经过了调整，以适应当前的情况。为了回答与气候系统中潜在的巨大变化（特别是所谓的临界点）有关的问题，模型最好是用过去来检验。对这些测试至关重要的是对过去地形、冰盖和相关的融水排入海洋的变化作出可靠的推断。这项研究将通过先进的计算模型和大量不同的古数据集在统计上的强大整合，显著地完善这些推论。这将解决或进一步澄清缺失冰的问题。该研究项目还将运用这些精细化的冰年表，直接考察冰川冰和气候系统的变化，包括气候、冰盖和地球成分的模型。通过在这个框架内部署越来越复杂的模型，我们将测试当前的模型和理解在多大程度上可以复制和解释过去的冰盖演变和不稳定事件。这些试验反过来又将有助于估计未来冰盖演变和冰盖与气候系统相互作用的不确定性，从而弥补目前气候变化评估中的一个重大空白。

The past is our fuzzy window to the future. Through this window, tantalizing discrepancies point to cracksin our understanding of the coupled ice, earth, and climate system. The last 130,000 year history of ice andclimate change offers major changes in the state of the climate system as well as examples of abrupt tippingpoint behaviour.The dynamical source of the variability of this system is still poorly understood. There are also perplexingshortfalls in explaining inferred global mean sea level at Last Glacial Maximum (the problem of “missingice”) as well the source of an inferred 6-10 m higher sea level during the last (Eemian) interglacial, about125,000 years ago.Scientific assessments of potential climate change rely heavily on climate models. Though replication ofpresent-day climate is a challenging test for models, it is only a limited test since these models are alreadytuned to fit the present. To answer questions related to potentially large changes in the climate system(especially so-called tipping points), models are best tested against the past.Critical to these tests is a confident inference of the past change in topography, ice cover, and associatedmeltwater drainage into the ocean. The proposed research will significantly refine these inferences throughstatistically robust integration of advanced computed models and large diverse sets of paleo data. Thiswill either resolve or further clarify the missing ice issue. The research program will also apply theserefined ice chronologies to direct examination of variability in the glacial ice and climate system with modelsencompassing the climate, ice sheet, and earth components.By deploying increasingly sophisticated models within this framework, we will test the extent to whichcurrent models and understanding can replicate and explain past ice sheet evolution and instability events.These tests will in turn facilitate the estimation of uncertainties concerning both future ice sheet evolutionand associated ice sheet interactions with the climate system, addressing a major gap in current climatechange assessments.