Old carbon reservoirs were not important in the deglacial methane budget

• Published in: Science
• Main Authors: Dyonisius, M.N., Petrenko, V.V., Smith, A.M., Hua, Q., Yang, B., Schmitt, J., Beck, J., Seth, B., Bock, M., Hmiel, B., Vimont, I., Menking, J.A., Shackleton, S.A., Baggenstos, D., Bauska, T.K., Rhodes, R.H., Sperlich, P., Beaudette, R., Harth, C., Kalk, M., Brook, E.J., Fischer, H., Severinghaus, J.P., Weiss, R.F.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: American Association for the Advancement of Science 2020
• Subjects: Ice; ice core; permafrost
• Online Access: http://nora.nerc.ac.uk/id/eprint/527171/; https://science.sciencemag.org/content/367/6480/907

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.