Department of Anthropology, University of Maine, Orono, ME 04469;
Climate Change Institute, University of Maine, Orono, ME 04469.
Proc Natl Acad Sci U S A. 2020 Apr 14;117(15):8271-8279. doi: 10.1073/pnas.1912242117.
Archaeological evidence plays a key role in longitudinal studies of humans and climate. Climate proxy data from Peruvian archaeological sites provide a case study through insight into the history of the "flavors" or varieties of El Niño (EN) events after ∼11 ka: eastern Pacific EN, La Niña, coastal EN (COA), and central Pacific or Modoki EN (CP). Archaeological proxies are important to the coastal Peruvian case because more commonly used paleoclimate proxies are unavailable or equivocal. Previously, multiproxy evidence from the Peruvian coast and elsewhere suggested that EN frequency varied over the Holocene: 1) present in the Early Holocene; 2) absent or very low frequency during the Middle Holocene (∼9 to 6 ka); 3) low after ∼6 ka; and 4) rapidly increasing frequency after 3 ka. Despite skepticism about the reliability of archaeological proxies, nonarchaeological proxies seemed to confirm this archaeological EN reconstruction. Although there is consensus that EN frequency varied over this period, some nonarchaeological and archaeological proxies call parts of this reconstruction into question. Here we review Holocene EN frequency reconstructions for the Peruvian coast, point to complexities introduced by apparent contradictions in a range of proxy records, consider the impact of CP and COA phenomena, and assess the merits of archaeological proxies in EN reconstructions. Reconciling Peruvian coastal paleoclimate data is critical for testing models of future EN behavior under climate variability.
考古证据在人类和气候的纵向研究中起着关键作用。来自秘鲁考古遗址的气候代理数据提供了一个案例研究，深入了解了约 11 千年来厄尔尼诺（EN）事件“风味”或品种的历史：东太平洋 EN、拉尼娜、沿海 EN（COA）和中太平洋或模态 EN（CP）。考古代理对于秘鲁沿海地区很重要，因为更常用的古气候代理不可用或不确定。以前，来自秘鲁海岸和其他地区的多代理证据表明，EN 频率在全新世期间发生了变化：1）在全新世早期存在；2）在中全新世（约 9 至 6 千年前）期间不存在或频率非常低；3）在约 6 千年后频率较低；4）在 3 千年前后频率迅速增加。尽管对考古代理的可靠性存在怀疑，但非考古代理似乎证实了这种考古 EN 重建。尽管人们一致认为在此期间 EN 频率发生了变化，但一些非考古和考古代理对这一重建提出了质疑。在这里，我们回顾了秘鲁海岸全新世 EN 频率重建，指出了一系列代理记录中的明显矛盾所带来的复杂性，考虑了 CP 和 COA 现象的影响，并评估了考古代理在 EN 重建中的优点。协调秘鲁沿海古气候数据对于测试未来气候变异性下 EN 行为的模型至关重要。
