Model limits on the role of volcanic carbon emissions in regulating glacial-interglacial CO₂ variations

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• 作者：Raphael Roth ; ^{roth@climate.unibe.ch} ; Fortunat Joos
• 关键词：volcanism ; deglaciation ; CO2 ; carbon cycle ; carbon isotopes ; ocean chemistry
• 刊名：Earth and Planetary Science Letters
• 出版年：2012
• 期刊代码：18_0012821x
• 类别：ph
• 出版时间：1 May, 2012
• 卷：329-330
• 期：Complete
• 页码：141-149
• 文件大小：1415 K

摘要

Huybers and Langmuir (2009) proposed that an increase in volcanic activity provoked by ice sheet melting contributed substantially to the deglacial CO₂ increase. Here, their hypothesis is evaluated by prescribing their central, high, and low volcanic CO₂ emission scenarios in the Bern3D carbon cycle-climate model as a perturbation. Reconstructed emissions increase mainly between 15 and 11 ka BP, remain high in the early Holocene and drop after 7 ka BP in all scenarios with total emissions between 181 and 2011 GtC. Simulated increase of atmospheric CO₂ peaks around 6 ka BP at 46 ppm for the central scenario and with a range between 13 and 142 ppm. Modeled carbonate ion concentration in the deep ocean decreases and the calcite saturation horizon shoals on global average by 440 m (150 to 1500 m). Simulated changes in 未¹³C and 螖¹⁴C isotopic signatures are small compared to reconstructed, proxy-based changes over the deglacial period. The comparison of our model results and available proxy evidence suggests a small role for volcanic carbon emissions in regulating glacial-interglacial CO₂ variations, but uncertainties prevent a firm conclusion. A problem with the volcanic emission hypothesis is in the timing of emissions which peak in the early Holocene, a period of decreasing atmospheric CO₂.