Old carbon reservoirs were not important in the deglacial methane budget

• Main Authors: Dyonisius, MN, Petrenko, VV, Smith, AM, Hua, Q, Yang, B, Schmitt, J, Beck, J, Seth, B, Bock, M, Hmiel, B, Vimont, I, Menking, JA, Shackleton, SA, Baggenstos, D, Bauska, TK, Rhodes, RH, Sperlich, P, Beaudette, R, Harth, C, Kalk, M, Brook, EJ, Fischer, H, Severinghaus, JP, Weiss, RF
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: eScholarship, University of California 2020
• Subjects: Earth Sciences; Geology; Climate Action; General Science & Technology; Ice; ice core; permafrost
• Online Access: https://escholarship.org/uc/item/79n946hz

Permafrost and methane hydrates are large, climate-sensitive old carbon reservoirs that have the potential to emit large quantities of methane, a potent greenhouse gas, as the Earth continues to warm. We present ice core isotopic measurements of methane (Δ14C, δ13C, and δD) from the last deglaciation, which is a partial analog for modern warming. Our results show that methane emissions from old carbon reservoirs in response to deglacial warming were small (<19 teragrams of methane per year, 95% confidence interval) and argue against similar methane emissions in response to future warming. Our results also indicate that methane emissions from biomass burning in the pre-Industrial Holocene were 22 to 56 teragrams of methane per year (95% confidence interval), which is comparable to today.