Quaternary QUEST: Regulation of atmospheric carbon dioxide on glacial-interglacial timescales and its coupling to climate change

过去一百万年的气候特征是在寒冷的冰期和温暖的间冰期之间有规律的振荡，这被认为是由地球绕太阳轨道的变化所决定的。古代气候数据的来源，如海洋和湖泊沉积物以及极地冰芯中的空气，揭示了一种显著的行为；气候就像一个由相互联系的部分组成的系统，以一种复杂而有序的方式变化，以一种反复出现的顺序变化，就像交响乐中的主题一样。构成这一组成的各个部分受到大气和海洋物理循环、植被覆盖、冰盖和海冰、海洋生物群、二氧化碳、甲烷、尘埃和全球降水浓度变化的影响。这种行为表明，该系统是可预测的，但它敏感地依赖于条件和历史。如果我们想要了解这个复杂的系统，我们就必须把我们从数据来源获得的知识与对地球系统如何运作的理解结合起来。因此，一个由英国科学家组成的联盟将从冰芯和沉积物中合成古代记录，改善这些记录彼此之间的同步，并利用这些信息来改进和测试地球系统模型（主要是“GENIE”模型，旨在模拟100万年时间尺度上气候系统的不同组成部分）。特别是，我们将重点关注仍未解决的问题，即为什么大气中的二氧化碳会随着气候周期而如此有规律地变化。我们还将研究这种变化如何与地球系统的其他组成部分相互作用。在我们对过去有这样的了解之前，我们不太可能对我们对未来地球气候将如何变化的预测有很大的信心，因为我们受到了由于二氧化碳和其他温室气体增加而引起的人类引起的变化的实质性攻击。

The climate of the last million years is characterized by regular oscillations between cold glacial and warm interglacial states, thought to be paced by variations in the Earth's orbit around the sun. Sources of ancient climate data, such as marine and lake sediments and air trapped in polar ice cores reveal a remarkable behaviour; the climate behaves as a system of interlinked parts, changing in a complex but ordered way, in a sequence which recurs, with variations, like the themes in a symphony. The individual parts making up this composition are affected by changes in the physical circulation of the atmosphere and ocean, the coverage of vegetation, ice sheets and sea ice, the marine biota, concentrations of carbon dioxide, methane, dust, and precipitation around the world. This behaviour suggests that the system is predictable, but that it is sensitively dependent on conditions and history. If we are ever to understand this complex system we must synthesise our knowledge from the data sources with understanding of how the Earth system works. Accordingly, a consortium of UK scientists will compile syntheses of ancient records from ice cores and sediments, improve the synchronization of these records one with another, and use that information to improve and test Earth System models (principally the 'GENIE' model, designed to simulate the diverse components of the climate system over time scales up to a million years). In particular, we will focus on the still unresolved problem of why atmospheric carbon dioxide changed so regularly with the climate cycles. We will also study how this change interacts with the other components of the Earth system. Until we have such understanding of the past, we are unlikely to have great confidence in our predictions of how Earth's climate will change in the future as we subject it the substantial assaults of human-induced change due to increasing carbon dioxide and other greenhouse gases.