Climatic Variability in the Southwest Pacific during the Last Termination

The degree to which palaeoclimatic changes in the Southern Hemisphere co-varied with events in the high latitude Northern Hemisphere during the Last Termination is a contentious issue, with conflicting evidence for the degree of `teleconnection' between different regions of the Southern Hemisphere. The available hypotheses are difficult to test robustly, however, because there are few detailed palaeoclimatic records in the Southern Hemisphere. Here we present climatic reconstructions from the southwestern Pacific, a key region in the Southern Hemisphere because of the potentially important role it plays in global climate change. The reconstructions for the period 20-10 kyr BP were obtained from five sites along a transect from southern New Zealand, through Australia to Indonesia, supported by 125 calibrated 14C ages. Two periods of significant climatic change can be identified across the region at around 17 and 14.2 cal kyr BP, most probably associated with the onset of warming in the West Pacific Warm Pool and the collapse of Antarctic ice during Meltwater Pulse-1A, respectively. The severe geochronological constraints that inherently afflict age models based on radiocarbon dating and the lack of quantified climatic parameters make more detailed interpretations problematic, however. There is an urgent need to address the geochronological limitations, and to develop more precise and quantified estimates of the pronounced climate variations that clearly affected this region during the Last Termination.

末次冰消期期间南半球古气候变化与高纬度北半球事件的协同变化程度是一个有争议的问题，关于南半球不同区域之间‘遥相关（teleconnection）’的程度存在相互矛盾的证据。然而，由于南半球缺乏详细的古气候记录，现有的假说难以得到可靠验证。本文呈现了西南太平洋的气候重建结果，该区域是南半球的关键区域，因其在全球气候变化中可能发挥重要作用。20-10千年距今（kyr BP）期间的重建结果来自沿新西兰南部经澳大利亚至印度尼西亚的一条断面的五个站点，由125个校正的14C年龄支持。在该区域可识别出两个显著的气候变化期，分别约在17和14.2校正千年距今（cal kyr BP），很可能分别与西太平洋暖池的变暖开始和融水脉冲1A事件期间南极冰盖的崩塌相关。然而，基于放射性碳定年的年龄模型固有的严重年代学限制，以及缺乏量化的气候参数，使得更详细的解释存在困难。迫切需要解决年代学限制，并对末次冰消期明显影响该区域的显著气候变化进行更精确和量化的估算。