Global temperature response to century-scale degassing from the Siberian Traps Large igneous province
Global temperature response to century-scale degassing from the Siberian Traps Large igneous province
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DOI：
10.1016/j.palaeo.2017.01.045
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发表时间：
2017-04
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影响因子：
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通讯作者：
F. Stordal;H. Svensen;I. Aarnes;Marco Roscher
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文献类型：
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作者：
F. Stordal;H. Svensen;I. Aarnes;Marco Roscher
大火成岩省是二叠纪末灭绝和气候变化的关键因素，这是由于熔岩和加热的沉积岩脱气造成的。尽管该省的具体脱气方案存在争议，但这意味着在熔岩流和次火山侵入冷却的时间尺度上（即数十年至数百年）的气体释放必须足以影响大气化学。在这里，我们测试这一假设，使用简单的盒子模型计算，以限制百年规模的脱气CO2和CH 4从高端量的个人熔岩流和岩床从西伯利亚圈闭。该模式包括CH 4和CO2的气体通量，它们的大气寿命和辐射强迫，以及全球平均气候系统的气候敏感性校准到二叠纪末的时间。流量估计的基础上熔岩脱气和接触晕体积和脱挥发分在第一个100年后的侵位。我们测试了极端排放的敏感性，高达25 GtC/年，CH 4分数从0到100%，广泛的气候敏感性（1.5-6.0 °C的CO2加倍），事件前的浓度和大气寿命。我们发现，全球年平均温度扰动是7.0 °C，在我们的基线情况下，使用10 GtC/年的排放量和60%的CH 4分数，假设4.5 °C的气候敏感性。即使对于低排放情景（0.7-1.2 GtC/年），温度响应也约为1.5 °C。我们的结论是，在大火成岩省零星的个别大规模火山事件有可能在很短的时间尺度上造成强烈的全球变暖。除排放强度外，CH 4组分和气候敏感性对百年尺度温度扰动的影响最大。
The Siberian Traps Large igneous province was a key player in the end-Permian extinction and climatic change due to degassing from lavas and heated sedimentary rocks. Although the specific degassing scenarios from the province are debated, this implies that gas release on a timescale tuned to the cooling of lava flows and subvolcanic intrusions (i.e. decades to centuries) must have been sufficient to affect the atmospheric chemistry. Here we test this assumption by using simple box model calculations to constrain century-scale degassing of CO2and CH4from high-end volumes of individual lava flows and sills from the Siberian Traps. The model includes gas fluxes of CH4and CO2, their atmospheric lifetimes and radiative forcing, as well as the climate sensitivity in a global average climate system calibrated to end-Permian time. The fluxes are estimated based on lava degassing and contact aureole volumes and devolatilization during the first 100 years following emplacement. We test the sensitivity to extreme emissions of up to 25 GtC/yr, CH4fractions from 0 to 100%, wide ranges of climate sensitivities (1.5–6.0 °C for CO2doubling), pre-event concentrations, and atmospheric lifetimes. We find that the global annual mean temperature perturbation is 7.0 °C in our baseline case using a 10 GtC/yr emission and a 60% CH4fraction, assuming 4.5 °C as the climate sensitivity. Even for low emission scenarios (0.7–1.2 GtC/yr), the temperature response is ~ 1.5 °C. We conclude that sporadic individual large-scale volcanic events in Large igneous provinces have the potential to cause a strong global warming on very short timescales. In addition to the emission strength, the CH4fraction and the climate sensitivity have the strongest impact on the century-scale temperature perturbation.