Marine Isotope Stage 19: analogue for the present interglacial

海洋同位素第 19 阶段：当前间冰期的类似物

• 批准号: NE/I025115/1
• 负责人: Polychronis Tzedakis
• 金额: $ 27.51万
• 依托单位: University College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2012
• 资助国家: 英国
• 起止时间: 2012 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FI025115%2F1
• 关键词: Marine; Isotope; Stage; 19; analogue

Past interglacials characterized by an orbital geometry similar to the current interglacial (Holocene) provide a basis for assessing the natural evolution of different components of the climate system and the extent of anthropogenic interference during recent millennia. While human modification of vegetation and landscapes has been underway throughout the Holocene, arguably the most significant interference with global environments has been the onset of anthropogenic emissions of greenhouse gases (GHG) over the past two centuries. However, in his 'early anthropogenic hypothesis', Ruddiman (2003) proposed that humans began modifying greenhouse gas concentrations thousands of years before the industrial era, with forest clearance and intensification of rice agriculture leading to increases in atmospheric CO2 and CH4 levels, respectively. More specifically, the concentrations of these gases show early Holocene peaks followed by declines, but the downward trend was reversed after 8 and 5 thousand years ago for CO2 and CH4, respectively. By drawing analogies with natural trends in the previous four interglacials, Ruddiman suggested that the Holocene evolution of GHG concentrations was anomalous, but differences in orbital configurations and uncertainties over their precise synchronization have underlined the limitations of such comparisons. More recently, the period around 780 thousand years ago, known as Marine Isotope Stage (MIS) 19 has been identified as the closest analogue to the current interglacial on the basis of the phasing of orbital parameters and overall climate evolution. As such, it provides a more appropriate testbed for evaluating the Holocene evolution of GHG and vegetation succession. However, despite this potential, MIS 19 remains substantially understudied. The proposed project aims to address this imbalance by generating the most detailed record (~200-yr resolution) of vegetation and hydrological changes during MIS 19 from ODP Site 977 in the Alboran Sea, S Iberian margin and combine it with ongoing analyses of palaeoceanographic proxies from the same samples, currently underway by the Spanish Consortium GRACCIE. In recent years, the western and southern parts of the Iberian margin have emerged as critical areas for linking marine and terrestrial records directly through joint pollen and palaeoceanographic proxy analyses in the same marine archive recovered adjacent to the continent. This allows a direct comparison between ocean and terrestrial changes, bypassing timescale and correlation uncertainties. The results will establish:(1) the duration of the MIS 19 interglacial in sea surface conditions and the precise phasing with vegetation changes;(2) Vegetation trends during MIS 19 vis-à-vis those already observed in the region during the Holocene;(3) the nature of vegetation and hydrological changes during the peak in atmospheric methane concentrations at the end of MIS 19c;(4) the response of vegetation and impact on erosion to short-term climate variability during the intervals before and after the interglacial as well as within it.If the MIS 19 - MIS 1 analogy is correct, these results will have implications for assessing: (i) the natural length of the current interglacial, in the absence of anthropogenic forcing; (ii) the extent to which human impact over the past millennia has overprinted natural vegetation trends in the region; (iii) the underlying causes for the Holocene evolution of methane.

过去的间冰期具有与当前间冰期（全新世）相似的轨道几何学特征，为评估近千年来气候系统不同组成部分的自然演变和人为干扰的程度提供了基础。虽然人类对植被和景观的改造在整个全新世都在进行，但可以说对全球环境最重要的干扰是过去两个世纪以来人类温室气体排放的开始。然而，在他的“早期人为假设”中，Ruddiman（2003）提出，人类在工业时代之前数千年就开始改变温室气体浓度，森林砍伐和水稻农业的集约化分别导致大气中CO2和CH 4水平的增加。更具体地说，这些气体的浓度显示出全新世早期的峰值，然后下降，但下降的趋势分别在8000年和5000年前的CO2和CH 4后被逆转。通过与前四次间冰期的自然趋势进行类比，Ruddiman认为，全新世温室气体浓度的演变是异常的，但轨道配置的差异和精确同步的不确定性突出了这种比较的局限性。最近，在78万年前的海洋同位素阶段（MIS）19被确定为最接近于当前间冰期的时期，这是基于轨道参数和整体气候演变的阶段。因此，它提供了一个更合适的测试平台，评估全新世的温室气体和植被演替的演变。然而，尽管有这种潜力，MIS 19仍然没有得到充分的研究。拟议的项目旨在解决这一不平衡问题，通过生成最详细的记录（~200年分辨率）的植被和水文变化在MIS 19从ODP站点977在阿尔沃兰海，伊比利亚半岛南部的边缘和联合收割机它与正在进行的分析古海洋学代理从相同的样品，目前正在进行的西班牙财团GRACCIE。近年来，伊比利亚边缘的西部和南部地区已成为通过在邻近该大陆的同一海洋档案中进行联合花粉和古海洋学代用品分析，将海洋和陆地记录直接联系起来的关键地区。这使得海洋和陆地变化之间的直接比较，绕过时间尺度和相关性的不确定性。结果将确定：（1）MIS 19间冰期海面条件的持续时间和植被变化的精确阶段;（2）MIS 19期间的植被趋势维斯全新世期间在该地区已经观察到的植被趋势;（3）MIS 19 c结束时大气甲烷浓度峰值期间植被和水文变化的性质;（4）间冰期前后和期间植被对短期气候变化的响应及其对侵蚀的影响。如果MIS 19 - MIS 1类比是正确的，这些结果将对评估以下方面产生影响：（一）在没有人为强迫的情况下，当前间冰期的自然长度;（二）过去几千年来人类影响在多大程度上覆盖了该地区的自然植被趋势;（三）全新世甲烷演变的根本原因。

项目成果

Determining the natural length of the current interglacial

• DOI: 10.1038/ngeo1358
• 发表时间: 2012-02-01
• 期刊: NATURE GEOSCIENCE
• 影响因子: 18.3
• 作者: Tzedakis, P. C.;Channell, J. E. T.;Skinner, L. C.
• 通讯作者: Skinner, L. C.

Frequency and dynamics of millennial-scale variability during Marine Isotope Stage 19: Insights from the Sulmona Basin (central Italy)

• DOI: 10.1016/j.quascirev.2019.04.024
• 发表时间: 2019-06
• 期刊: Quaternary Science Reviews
• 影响因子: 4
• 作者: E. Regattieri;B. Giaccio;G. Mannella;G. Zanchetta;S. Nomade;A. Tognarelli;N. Perchiazzi;H. Vogel;C. Boschi;R. Drysdale;B. Wagner;M. Gemelli;Polichronis Tzedakis

Duration and dynamics of the best orbital analogue to the present interglacial

• DOI: 10.1130/g36677.1
• 发表时间: 2015-07-01
• 期刊: GEOLOGY
• 影响因子: 5.8
• 作者: Giaccio, Biagio;Regattieri, Eleonora;Bassinot, Franck
• 通讯作者: Bassinot, Franck

Glacial Inception in Marine Isotope Stage 19: An Orbital Analog for a Natural Holocene Climate.

• DOI: 10.1038/s41598-018-28419-5
• 发表时间: 2018-07-05
• 期刊: Scientific reports
• 影响因子: 4.6
• 作者: Vavrus SJ;He F;Kutzbach JE;Ruddiman WF;Tzedakis PC
• 通讯作者: Tzedakis PC

Late Holocene climate: Natural or anthropogenic?

• DOI: 10.1002/2015rg000503
• 发表时间: 2016-03
• 期刊: Reviews of Geophysics
• 影响因子: 25.2
• 作者: W. Ruddiman;D. Fuller;J. Kutzbach;P. Tzedakis;J. Kaplan;Erle C. Ellis;S. Vavrus;C. Roberts