Old carbon reservoirs were not important in the deglacial methane budget

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. Copyright © 2020 The Authors
Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. This is an article distributed under the terms of the Science Journals Default License.
Methane, Carbon, Gas hydrates, Permafrost, Greenhouse gases, Earth atmosphere, Ice, Drill cores, Quaternary period
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. M., Kalk, M., Brook, E. J., Fischer, H., Severinghaus, J. P. & Weiss, R. F. (2020). Old carbon reservoirs were not important in the deglacial methane budget. Science, 367(6480), 907-910. doi:10.1126/science.aax0504