Sea-level trends across The Bahamas constrain peak last interglacial ice melt
Sea-level trends across The Bahamas constrain peak last interglacial ice melt
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DOI：
10.1073/pnas.2026839118
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发表时间：
2021-08-17
影响因子：
11.1
通讯作者：
Raymo, Maureen E.
中科院分区：
文献类型：
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作者：
Dyer, Blake;Austermann, Jacqueline;Raymo, Maureen E.
在末次间冰期（LIG）期间，全球平均海平面（GMSL）比现在高，这可能是由于高纬度日照增加。过去的海平面估算需要对海平面或接近海平面的海洋沉积物进行高程测量和年龄测定，这些高程必须进行冰川均衡调整（GIA）校正。然而，这GIA校正是受GIA模型输入的不确定性，即地球的流变学和过去的冰的历史，这降低了过去GMSL的估计精度和准确性。为了更好地约束GIA过程，我们比较了我们的数据和现有的LIG海平面数据在巴哈马群岛与一套576 GIA模型预测。我们根据模型与区域海平面数据空间趋势的拟合程度计算了每个GIA模型的权重，然后使用加权GIA校正来修订LIG期间GMSL的估计值。在LIG期间，我们发现95%的可能性，全球海平面峰值至少比今天高1.2米，并且不太可能（5%的可能性）超过5.3米。来自格陵兰冰盖（南极西部冰盖）的部分融化估计增加了30%（减少了20%）。总之，这项工作表明，LIG GMSL可能低于以前的假设。
During the last interglacial (LIG) period, global mean sea level (GMSL) was higher than at present, likely driven by greater high-latitude insolation. Past sea-level estimates require elevation measurements and age determination of marine sediments that formed at or near sea level, and those elevations must be corrected for glacial isostatic adjustment (GIA). However, this GIA correction is subject to uncertainties in the GIA model inputs, namely, Earth's rheology and past ice history, which reduces precision and accuracy in estimates of past GMSL. To better constrain the GIA process, we compare our data and existing LIG sea-level data across the Bahamian archipelago with a suite of 576 GIA model predictions. We calculated weights for each GIA model based on how well the model fits spatial trends in the regional sea-level data and then used the weighted GIA corrections to revise estimates of GMSL during the LIG. During the LIG, we find a 95% probability that global sea level peaked at least 1.2 m higher than today, and it is very unlikely (5% probability) to have exceeded 5.3 m. Estimates increase by up to 30% (decrease by up to 20%) for portions of melt that originate from the Greenland ice sheet (West Antarctic ice sheet). Altogether, this work suggests that LIG GMSL may be lower than previously assumed.