Climate variability and human impact in South America during the last 2000 years: synthesis and perspectives from pollen records
Climate variability and human impact in South America during the last 2000 years: synthesis and perspectives from pollen records
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DOI：
10.5194/cp-12-483-2016
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发表时间：
2016-01-01
影响因子：
4.3
通讯作者：
Gonzalez-Arango, C.
中科院分区：
文献类型：
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作者：
Flantua, S. G. A.;Hooghiemstra, H.;Gonzalez-Arango, C.
提高对当今气候变率和变化的认识依赖于过去2000年的高质量数据集。建立区域气候模式的全球努力正处于对照过去植被变化记录进行验证并与之相结合的过程中。然而，对于南美洲，由于缺乏关于研究地点的时空覆盖的信息，植被记录在评价和改进气候模式方面的全部潜力迄今尚未得到充分认识。因此，这篇论文可以作为高质量花粉记录的指南，这些记录可以捕捉过去2000年的环境变化。我们确定了来自南美洲各地的60个植被（花粉）记录，这些记录满足气候模型的地质年代学要求，并讨论了它们对整个大陆气候模式空间特征的敏感性。植被对气候变化的响应模式多种多样，低地的变化模式较为相似，高原的响应强度和方向各不相同。花粉记录显示了局地尺度对气候模式的响应；因此，有必要了解在不同的环境下，植被-气候相互作用是如何分化的。我们提供了从花粉指标到气候变量的定性翻译。此外，花粉是人类影响的一个很好的指标。我们讨论了花粉记录中人类土地利用的证据，并提供了一个被认为对考古假设检验有用的概述，并且对区分自然和人为驱动的植被变化很重要。我们强调孢粉群落需要更加熟悉气候变率模式，以正确地归因于观测到的植被动态的潜在原因。这份手稿构成了更广泛的南美长期多代理气候重建和动力学- 2k计划的一部分，该计划为各种古气候分支学科和古科学的整合提供了理想的框架，从而启动和促进了百年和千年时间尺度上环境变化的多学科研究。
An improved understanding of present-day climate variability and change relies on high-quality data sets from the past 2 millennia. Global efforts to model regional climate modes are in the process of being validated against, and integrated with, records of past vegetation change. For South America, however, the full potential of vegetation records for evaluating and improving climate models has hitherto not been sufficiently acknowledged due to an absence of information on the spatial and temporal coverage of study sites. This paper therefore serves as a guide to high-quality pollen records that capture environmental variability during the last 2 millennia. We identify 60 vegetation (pollen) records from across South America which satisfy geochrono-logical requirements set out for climate modelling, and we discuss their sensitivity to the spatial signature of climate modes throughout the continent. Diverse patterns of vegetation response to climate change are observed, with more similar patterns of change in the lowlands and varying intensity and direction of responses in the highlands. Pollen records display local-scale responses to climate modes; thus, it is necessary to understand how vegetation-climate interactions might diverge under variable settings. We provide a qualitative translation from pollen metrics to climate variables. Additionally, pollen is an excellent indicator of human impact through time. We discuss evidence for human land use in pollen records and provide an overview considered useful for archaeological hypothesis testing and important in distinguishing natural from anthropogenically driven vegetation change. We stress the need for the palynological community to be more familiar with climate variability patterns to correctly attribute the potential causes of observed vegetation dynamics. This manuscript forms part of the wider LOng-Term multi-proxy climate REconstructions and Dynamics in South America - 2k initiative that provides the ideal framework for the integration of the various palaeoclimatic subdisciplines and palaeo-science, thereby jump-starting and fostering multidisciplinary research into environmental change on centennial and millennial timescales.