Climate interconnections of the Pliocene greenhouse

由于持续的温室气体排放，全球变暖已经比工业化前的水平高出1摄氏度。极地地区的冰量正在减少，海洋正在变暖，减少了海洋的混合和深层沃茨的通风，限制了海洋生态系统的氧气供应。这些相互关联的变化是全球性的，但最尖锐和迫切的研究区域因素使系统缺氧。一个关键的目标是将古气候记录追溯到足够远的时间，以吸取上一个由二氧化碳引起的全球变暖和南极冰盖退缩的大间隔的教训：上新世（约300万至500万年前）。我们将研究阿拉伯海，它是全球海洋中最厚的氧气最小区，因为（i）它位于印度洋北方的尽头，意味着寒冷的富氧水团只能从南方供应（舌源）和（ii）强大的西南印度夏季季风驱动一个非常富有成效的上升流喂养的生态系统，随着有机物通过水柱和深度氧气消耗的强烈降雨。我们将研究全球变暖，南极冰量，季风环流强度和海洋氧化（通风）之间的关系。

Global warming has already reached 1C above the pre-industrial level because of ongoing greenhouse gas emissions. The polar regions are losing ice mass and the ocean is warming, reducing oceanic mixing and ventilation of deep waters, limiting oxygen supply to marine ecosystems. These interconnecting changes are relevant globally but most acute and urgent to study where regional factors predispose the system towards anoxia. A key objective is to extend palaeoclimate records back in time far enough to learn the lessons of the last great interval of sustained CO2-induced global warmth and Antarctic ice sheet retreat: the Pliocene (~3 to 5 million years ago). We will study the Arabian Sea which features the thickest oxygen minimum zone in the global ocean because (i) its cul-de-sac location in the northern Indian Ocean means that cold oxygen-rich water masses can only be supplied from the south (Antarctic-sourced) and (ii) strong southwest Indian summer monsoon winds drive an extremely productive upwelling-fed ecosystem, with intense rain out of organic matter through the water column and oxygen consumption at depth. We will investigate the relationships between past changes in global warmth, Antarctic ice volume, monsoon circulation strength and oxygenation (ventilation) of the ocean.