Department of Earth Sciences, University of Bergen, Bergen, 5007, Norway.
Bjerknes Centre for Climate Research, Bergen, 5007, Norway.
Nat Commun. 2022 Sep 2;13(1):5158. doi: 10.1038/s41467-022-32712-3.
The tropical West Pacific hosts the warmest part of the surface ocean and has a considerable impact on the global climate system. Reconstructions of past temperature in this region can elucidate climate connections between the tropics and poles and the sensitivity of tropical temperature to greenhouse forcing. However, existing data are equivocal and reliable information from terrestrial archives is particularly sparse. Here we constrain the magnitude and timing of land temperature change in the tropical West Pacific across the last deglaciation using an exceptionally precise paleothermometer applied to a well-dated stalagmite from Northern Borneo. We show that the cave temperature increased by 4.4 ± 0.3 °C (2 SEM) from the Last Glacial Maximum to the Holocene, amounting to 3.6 ± 0.3 °C (2 SEM) when correcting for sea-level induced cave altitude change. The warming closely follows atmospheric CO and Southern Hemisphere warming. This contrasts with hydroclimate, as reflected by drip water δO, which responds to Northern Hemisphere cooling events in the form of prominent drying, while temperature was rising. Our results thus show a close response of tropical temperature to greenhouse forcing, independent of shifts in the tropical circulation patterns.
西太平洋热带地区拥有海洋表面最温暖的部分，对全球气候系统有相当大的影响。该地区过去温度的重建可以阐明热带和极地之间的气候联系，以及热带温度对温室强迫的敏感性。然而，现有数据存在争议，陆地档案中的可靠信息尤其稀少。在这里，我们利用一种非常精确的古温度计，对来自北婆罗洲的一个有良好年代记录的石笋进行了研究，从而限制了末次冰消期期间西太平洋热带地区陆地温度变化的幅度和时间。我们表明，洞穴温度从末次冰盛期到全新世增加了 4.4±0.3°C（2 个 SEM），当校正海平面引起的洞穴高度变化时，升温幅度为 3.6±0.3°C（2 个 SEM）。这种变暖与大气 CO 和南半球变暖密切相关。这与水滴 δO 反映的水文气候形成鲜明对比，水滴 δO 以显著干燥的形式对北半球冷却事件作出响应，而温度却在上升。因此，我们的结果表明，热带温度对温室强迫的响应非常密切，与热带环流模式的变化无关。
