Global climate disruption and regional climate shelters after the Toba supereruption
Global climate disruption and regional climate shelters after the Toba supereruption
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DOI：
10.1073/pnas.2013046118
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发表时间：
2021-07-20
影响因子：
11.1
通讯作者：
Bardeen, Charles G.
中科院分区：
文献类型：
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作者：
Black, Benjamin A.;Lamarque, Jean-Francois;Bardeen, Charles G.
与 74,000 年前类似的多巴火山喷发是更新世开始以来最大规模的火山喷发，是了解大型火山喷发对气候和生态系统影响的重要测试案例。然而，火山喷发引起的气候变化的严重程度和影响引起了激烈的争论。来自非洲的高分辨率古气候和考古记录几乎没有发现火山喷发后气候或人类活动受到破坏的证据，相反，与人类进化瓶颈和气候模型模拟预测多巴规模喷发后长达十年内火山强烈冷却的有争议的联系相反。在这里，我们使用大量高分辨率社区地球系统模型 (CESM1.3) 模拟来协调气候模型预测与古气候记录，从而解释了高排放情景和低排放情景下多巴硫排放量的不确定性。我们发现，非洲大部分地区年平均地表温度异常超过 4 摄氏度的概率接近于零，而在高硫排放情况下，亚洲和北美出现如此严重的降温的概率接近 100%。非洲大部分地区降水量大幅减少的可能性很低。因此，即使多巴硫排放量处于合理估计的上限，仍然与古气候指标所表明的非洲的温和反应一致。我们的研究结果提供了人类进化的关键时期火山气候破坏的不均匀模式的概率观点，对于理解过去和未来超级喷发对环境的影响范围具有重要意义。
The Toba eruption similar to 74,000 y ago was the largest volcanic eruption since the start of the Pleistocene and represents an important test case for understanding the effects of large explosive eruptions on climate and ecosystems. However, the magnitude and repercussions of climatic changes driven by the eruption are strongly debated. High-resolution paleoclimate and archaeological records from Africa find little evidence for the disruption of climate or human activity in the wake of the eruption in contrast with a controversial link with a bottleneck in human evolution and climate model simulations predicting strong volcanic cooling for up to a decade after a Toba-scale eruption. Here, we use a large ensemble of high-resolution Community Earth System Model (CESM1.3) simulations to reconcile climate model predictions with paleoclimate records, accounting for uncertainties in the magnitude of Toba sulfur emissions with high and low emission scenarios. We find a near-zero probability of annual mean surface temperature anomalies exceeding 4 degrees C in most of Africa in contrast with near 100% probabilities of cooling this severe in Asia and North America for the high sulfur emission case. The likelihood of strong decreases in precipitation is low in most of Africa. Therefore, even Toba sulfur release at the upper range of plausible estimates remains consistent with the muted response in Africa indicated by paleoclimate proxies. Our results provide a probabilistic view of the uneven patterns of volcanic climate disruption during a crucial interval in human evolution, with implications for understanding the range of environmental impacts from past and future supereruptions.